Immune cells may heal bleeding brain after strokes

While immune cells called neutrophils are known to act as infantry in the body’s war on germs, a National Institutes of Health-funded study suggests they can act as medics as well. By studying rodents, researchers showed that instead of attacking germs, some neutrophils may help heal the brain after an intracerebral hemorrhage, a form of stroke caused by ruptured blood vessels. The study suggests that two neutrophil-related proteins may play critical roles in protecting the brain from stroke-induced damage and could be used as treatments for intracerebral hemorrhage.

“Intracerebral hemorrhage is a damaging and often fatal form of stroke for which there are no effective medicines,” said Jaroslaw Aronowski, M.D., Ph.D., professor, department of neurology, at the University of Texas Health Science Center at Houston, and senior author of the study published in Nature Communications. “Our results are a hopeful first step towards developing a treatment for this devastating form of stroke.”

Accounting for 10 to 15 percent of all strokes, intracerebral hemorrhages happen when blood vessels rupture and leak blood into the brain, often leading to death or long-term disability. Chronic high blood pressure is the leading risk factor for these types of strokes. The initial phase of damage appears to be caused by the pressure of blood leaking into the brain. Over time, further damage may be caused by the accumulation of toxic levels of blood products, infiltrating immune cells, and swelling.

Decades of research suggest that neutrophils are some of the earliest immune cells to respond to a hemorrhage, and that they may both harm and heal the brain. In this study, the researchers found that interleukin-27 (IL-27), a protein that controls the activity of immune cells, may shift the role of neutrophils from harming the brain to helping with recovery.

Injections of IL-27 after a hemorrhage helped mice recover. Days after the strokes, the treated mice had better mobility, including walking, limb stretching and navigating holes in a floor. In contrast, injections of an antibody that blocked natural IL-27 activity slowed recovery. The brains of the mice treated with IL-27 also showed less damage. They had less swelling around the hemorrhages and lower levels of iron and the blood protein hemoglobin, both of which are toxic at high levels.

“This study shines a spotlight on the critical role the immune system may play in helping the brain heal after a hemorrhage or stroke and opens new avenues for stroke treatment strategies,” said Jim Koenig, Ph.D., program director at the NIH’s National Institute of Neurological Disorders and Stroke.

Neutrophils are born in bone marrow and carry chemicals in hundreds of densely filled packets called granules, which look like dark spots under a microscope. Typically, when the body senses bacteria or an injury, neutrophils rush to the invasion site and release germ killing chemicals from the granules. This appears to happen minutes after a hemorrhagic stroke.

In this study, the researchers suggested that after a hemorrhagic stroke the brain secretes high levels of IL-27, which leads to a second wave of neutrophils arriving with granules filled with higher amounts of healing molecules. IL-27 levels were elevated in the brain and blood of the mice an hour after hemorrhages and stayed high for three days, peaking at 24 hours later. Further experiments suggested that brain cells called microglia produced the IL-27 in response to the presence of red blood cells.

Once released, IL-27 molecules appeared to travel to the bones of the mice, infiltrated the marrow, and changed the role newborn neutrophils played in response to a stroke. When the researchers extracted newborn neutrophils from the bones of mice and treated them with IL-27, the chemical raised the activity of genes associated with healing, especially lactoferrin, while reducing the activity of genes associated with killing cells. Conversely, treating mice with an IL-27 neutralizing antibody after a hemorrhage lowered lactoferrin gene activity.

“Our results suggested that IL-27 links the brain to the bones,” said Dr. Aronowski. “We can use these results as a source for ideas for developing potential treatments for hemorrhagic stroke.”

Finally, the researchers showed the iron binding protein lactoferrin may protect the brain from intracerebral hemorrhagic strokes. Mice and rats injected with lactoferrin 30 minutes after hemorrhages recovered faster and had reduced brain damage as compared to animals given placebos. In one set of experiments, the researchers found that giving mice lactoferrin 24 hours after a stroke was also effective.

“Lactoferrin appears to have a long treatment window,” said Dr. Aronowski. “This means lactoferrin might one day be used to help patients recover from intracerebral hemorrhage.”

Dr. Aronowski’s team is taking the next steps towards testing lactoferrin treatment in patients.

Immunotherapy treatment option for selected breast cancer patients, genetic study suggests

Immunotherapy drugs could help some breast cancer patients based on the genetic changes in their tumours, researchers at the Wellcome Trust Sanger Institute and their collaborators find. Published today (13 September) in Cancer Research, scientists identify particular genetic changes in a DNA repair mechanism in breast cancer.

The results open up the possibility to another therapy option for around 1,000 breast cancer patients in the UK, who could benefit from existing drugs.

Breast cancer is the most common cancer in the UK, affecting nearly 55,000 women a year. Globally it accounts for nearly 1.7 million cancer cases.

In the study, scientists found that a particular group of breast cancer patients have genetic changes, or mutations, that occur because of an abnormality of a DNA repair mechanism known as mismatch repair*. These mutations are found in other cancers, such as colorectal cancer, but are rarely looked for in breast cancer.

Colorectal cancers with deficient mismatch repair have recently been treated with immunotherapies called checkpoint inhibitors in the US**, including the drug pembrolizumab. Immunotherapies exploit the fact that, under the influence of check point inhibitors, highly mutated tumour cells can be recognised as ‘foreign’ by the patient’s immune system.

The results of this new study suggest that these immunotherapies could also be effective for some breast cancer patients based on the same mutation patterns seen in their tumours. Therefore clinical trials are required to determine if immunotherapies could help selected breast cancer patients.

In the study, the team analysed the whole genome sequences of 640 breast cancer tumours. They looked for patterns in the mutations, known as mutational signatures, which indicated abnormalities in the mismatch repair mechanism. From the mutational signatures, the team identified 11 tumours that had the mismatch repair defects causing the breast cancer.

Dr Serena Nik-Zainal, lead author from the Wellcome Trust Sanger Institute, said: “We’ve unequivocally found mismatch repair deficient breast cancers. As these tumours have the same mutational signatures as those of other cancers, like colorectal cancer, they should in theory respond to the same immunotherapy drugs. Our results suggest expanding the cohort of cancer patients that could possibly be treated with checkpoint inhibitors to include these mismatch repair deficient breast cancer patients.”

Dr Helen Davies, first author from the Wellcome Trust Sanger Institute, said: “Using whole genome sequencing we can start to stratify breast cancer patients into different categories based on their mutational signatures. Current clinical criteria means these tumours would not have been detected as being deficient in the mismatch repair pathway. We have shown that there is in fact another category of breast cancers – those with defective mismatch repair.”

Professor Karen Vousden, Cancer Research UK’s chief scientist, said: “Immunotherapies have shown promise for some cancer patients, but the challenge for doctors has been predicting which patients they are likely to help. This study, using a technique called whole genome sequencing, reveals more about the genetic patterns that could show which women with breast cancer are more likely to respond to immunotherapy treatments. The next step will be to test this approach in clinical trials to find out if identifying these patterns and using them to tailor breast cancer treatments helps to improve survival.”

Modulating T-Cell Metabolism Uncovers New Technology for Enhancing Immunotherapy

T lymphocytes found in tumors and implicated in killing tumor cells cope with the shortage of oxygen and nutrients in the tumor microenvironment by using fat as the main source of energy. Promoting a switch from glucose to fatty acid to generate energy enhances T cell antitumor activity. These findings from a study conducted at The Wistar Institute were published in the journal Cancer Cell.

The presence of tumor infiltrating T lymphocytes (TILs) in solid tumors is often associated with better clinical outcomes and better patient responses to some immunotherapeutic treatments. These cells can be isolated from a cancer patient, manipulated ex vivo, and infused into the same patient to treat her/his own cancer. However, the effectiveness of TILs antitumor responses is limited by their progressive loss of functions. Metabolic stress plays a central role in the exhaustion of T cells as they compete with tumor cells for oxygen and nutrients in the tumor microenvironment. In these unfavorable conditions, the function of TILs is impaired, reducing their potency against the tumor and the efficacy of T cell-based immunotherapy.

“The mechanisms behind TILs exhaustion are poorly understood,” said lead author of the study Hildegund C.J. Ertl, M.D., Caspar Wistar Professor in Vaccine Research and member of Wistar’s Vaccine & Immunotherapy Center. “Considering the central importance of TILs for cancer immunotherapy, we believe that our findings may have critical implications to boost the efficacy of T cell-based therapies.”

This study by Ertl and colleagues shows that low oxygen levels combined with low glucose availability cause TILs to adapt their metabolism and change their source for energy production from glucose to fatty acids, the building blocks of fat. Further inducing this metabolic shift instructs the T cells to increase their use of fatty acids for energy production, thus improving TILs’ effector functions and their ability to delay tumor progression.

The Ertl lab studied the effectiveness of metabolic manipulations to improve TIL functions in two melanoma mouse models and in the context of two different immunotherapy approaches. Ertl and colleagues confirmed the clinical relevance of these observations by showing that T cells isolated from metastases of melanoma patients have increased fatty acid metabolism compared with circulating lymphocytes from healthy donors. Furthermore, using fibrates, a class of FDA approved drugs used to lower cholesterol levels, they promoted the breakdown of fatty acids and observed that this enforced metabolic switch is associated with improved T cell functions within tumors. Importantly, these drugs can also synergize with immune checkpoint blockade therapy, improving the efficacy of this melanoma immunotherapy.

“Pharmacological interventions aimed at promoting the metabolic adaptation of TILs towards fatty acid metabolism may have a broad implication for T cell-based immunotherapy for different cancer types,” added Ertl.

Cell Surface Protein May Offer Big Target in Treating High-Risk Childhood Cancers

Oncology researchers studying high-risk children’s cancers have identified a protein that offers a likely target for immunotherapy–harnessing the immune system in medical treatments. In cell cultures and animal models, a potent drug attached to an antibody selectively zeroes in on cancer cells without harming healthy cells.

“We have built a strong foundation for developing a completely new and hopefully much less toxic treatment for neuroblastoma, the most common cancer in infants,” said study supervisor John M. Maris, MD, a pediatric oncologist at Children’s Hospital of Philadelphia (CHOP). “Furthermore, our findings may also lend support to the development of other immune-based therapies, such as CAR T-cells, in children with multiple aggressive cancers in addition to neuroblastoma.”

Maris, along with study leader and first author Kristopher R. Bosse, MD, and colleagues published their study today in Cancer Cell, which featured their findings as the cover story.

Neuroblastoma is a cancer of the developing peripheral nervous system that usually occurs as a solid tumor in a child’s chest or abdomen, and is the most common cancer in infants. It accounts for a disproportionate share of cancer deaths in children. Over decades, CHOP clinicians and researchers have built one of the world’s leading programs in neuroblastoma.

The study team used sophisticated sequencing tools to first discover molecules that are much more commonly found on the surface of neuroblastoma cells than on normal cells. “Our rationale was to identify a cell-surface molecule that an immune-based therapy could target without damaging healthy tissues,” said Bosse. “Using this approach, we identified a protein called glypican-2, or GPC2.” GPC2 is one of a family of glypicans—cell-surface proteins that interact with growth factors and cell surface receptors, influencing many intracellular signaling pathways important in development and cancer.

In addition to GPC2’s presence on neuroblastoma cells, the study team also found that GPC2 is necessary for a neuroblastoma tumor to proliferate. Both of those facts implied that a compound that acted against GPC2 might kill cancer cells, spare healthy cells, and limit the possibility of these tumors developing “immune escape” mechanisms, in which cancer cells resist an immunotherapy by shedding the target. “Given GPC2’s critical role in the growth of neuroblastomas, we hope that tumors will not be able to simply downregulate this protein in order to escape recognition by our immunotherapies that target GPC2,” said Bosse.

After pinpointing GPC2 as a very promising target for therapy, the researchers next worked with their colleagues at the National Cancer Institute to search for a weapon. They developed an antibody-drug conjugate (ADC) called D3-GPC2-PBD, which combined a very specific antibody that recognizes GPC2 with a potent chemotherapy drug that is internalized specifically by cancer cells. The drug payload damages DNA in tumors, while sparing healthy tissues from its toxic effects.

In cell cultures and mouse models of neuroblastoma, the ADC robustly killed neuroblastoma cells with no discernible toxicity to normal cells. “These findings establish that this type of immunotherapy could be potentially safe and effective against neuroblastoma,” said Maris. “Our next steps will be to further evaluate this ADC and also develop other immune-based therapies directed against GPC2. Because other glypicans in addition to GPC2 are overexpressed in other childhood cancers, it may also be possible to apply this approach across various types of high-risk pediatric cancers.”

KEYNOTE-040 evaluates pembrolizumab in head and neck cancer

Immunotherapy with the checkpoint inhibitor pembrolizumab may be a better option than standard treatments for patients whose head and neck cancer has spread, or recurred after an initial round of chemotherapy, according to results of the Keynote-040 trial presented at the ESMO 2017 Congress in Madrid. (1)

Although the 19% improvement in overall survival among patients treated with pembrolizumab did not meet the prespecified difference for statistical significance, it was nevertheless a clinically meaningful difference for this population who only lived seven to eight months, on average, after initiating treatment, said lead investigator Dr. Ezra Cohen, from the University of California, San Diego Moores Cancer Center, in La Jolla, California.

“Even though the study did not meet its primary endpoint, I still think it is a positive trial,” he said. “It reinforces that pembrolizumab should continue to be offered as an important option for all patients with this devastating disease.”

The KEYNOTE-040 trial was a global, open-label, phase 3 study which included patients with recurrent or metastatic head and neck squamous cell carcinoma (R/M HNSCC) after a platinum-based chemotherapy.

Patients were randomised to receive either pembrolizumab (n=247) or standard of care (SOC) treatment (n=248), which was the investigator’s choice of either methotrexate, docetaxel, or cetuximab.

Median overall survival (OS) was only marginally higher in the pembrolizumab compared to standard treatment arm (8.4 versus 7.1 months, hazard ratio [HR] 0.81 95% CI 0.66-0.99, P= .0204), however for a subset of patients who had PD-L1-expressing tumours, pembrolizumab was associated with dramatic and significantly improved outcomes.

Specifically, among patients with combined tumour and immune cell PD-L1-expression (CPS) of at least 1%, median OS was 8.7 months with pembrolizumab versus 7.1 months with standard treatments (HR 0.75; 95% CI 0.59-0.95, P=.0078), and among patients with PD-L1-expression in more than 50% of their cancer cells, median OS was 11.6 versus 7.9 months respectively (HR 0.54; 95% CI 0.35-0.82, P=.0017).

Compared to the other treatments, pembrolizumab measured up well in terms of side-effects.

“In almost every category it had a better side-effect profile, meaning a lower incidence of toxicity, versus standard treatments,” said Cohen. “The exception is hypothrodism, which occurred in 13% of those treated with pembro versus only 1% of those given other treatments.”

Overall, Cohen said the KEYNOTE-040 trial reinforces what is already known about anti-PD therapy in head and neck cancer. “From a clinician’s perspective I would feel the same in any country. This is a meaningful therapy that improves survival.”

Asked to comment for ESMO, Dr. Amanda Psyrri, from the University of Athens Medical School, and Attikon University Hospital in Athens said: “Keynote-040 did not reach its primary endpoint of overall survival; however, pembrolizumab was superior to investigator’s choice in terms of toxicity, an important consideration in treatment decisions for these poor-prognosis patients with recurrent/metastatic platinum-refractory HNSCC. As the authors point out, subsequent immunotherapy in the SOC arm may have confounded OS analysis. The magnitude of treatment effect was greater in patients with PD-L1 combined positive score (CPS) ? 1%, especially those with CPS ?50%,suggesting that pembrolizumab may represent the preferable treatment option for this subset of patients.”

Cancer Immunotherapy May Get a Boost by Disabling Specific T Cells

Cancer immunotherapy drugs only work for a minority of patients, but a generic drug now used to increase blood flow may be able to improve those odds, a study by Columbia University Medical Center (CUMC) researchers suggests.

In mice with melanoma, the researchers found that the drug – called pentoxifylline – boosts the effectiveness of immune-checkpoint inhibitors, a type of immunotherapy now commonly used in the treatment of melanoma and other cancers.

The study was published today in the online edition of Cell.

Checkpoint-blockade immunotherapy drugs – the first drugs were approved in 2011 – target proteins on tumor cells or cells of the immune system that prevent “killer” T cells from attacking cancer. These drugs have revolutionized cancer care, but do not work for all patients. “In advanced melanoma, for example, the cure rate is only about 20 percent. That’s a remarkable improvement over previous therapies,” says study leader Sankar Ghosh, PhD, Chair and Silverstein and Hutt Family Professor of Microbiology & Immunology. “But why doesn’t it work for the other 80 percent? There must be another mechanism that contributes to the suppression of the immune response.”

Dr. Ghosh and other cancer biologists suspected that a different type of T cell, known as regulatory T cells, or Tregs, may also suppress the immune system’s attack on cancer. Large numbers of these cells are found within several types of tumors. “One possible therapy would be to get rid of Tregs,” he said. “But Tregs are also needed to keep the immune system in check, and shutting down Tregs completely would unleash an attack against the body’s healthy cells and organs.”

This point is underscored by a related study, published today in Immunity, in which Dr. Ghosh and colleagues found that removing NF-kB from Tregs caused widespread and lethal autoimmunity in mice. However, a partial inhibition of NF-kB, achieved by removing only one, specific, NF-kB protein, called c-Rel, changed Treg function without causing widespread autoimmunity.  In the Cell study Ghosh and colleagues showed that these c-Rel deficient Tregs were specifically crippled in their ability to protect cancer cells. As a result, when c-Rel is blocked, killer T cells mounted a more robust attack on cancer cells without causing autoimmunity.

Pentoxifylline is a drug that is used in patients to increase blood flow in the hands and feet of people with poor circulation, but it’s also known to inhibit the c-Rel protein. In the Cell study, the researchers demonstrated that pentoxifylline blocked Treg function and boosted the effectiveness of standard checkpoint-blockade immunotherapies.  As a result, mice treated with both drugs showed significantly reduced melanoma tumor burden, compared to animals that received the standard therapy alone.

“The next step is to test this drug combination in human clinical trials,” Dr. Ghosh says. “If trials are successful, the use of c-Rel inhibitors could become a standard addition to immune checkpoint therapy for many types of cancer.”

Study Unlocks How Changes in Gene Activity Early During Therapy Can Establish the Roots of Drug-Resistant Melanoma

FINDINGS
A UCLA-led study of changes in gene activity in BRAF-mutated melanoma suggests these epigenomic alterations are not random but can explain how tumors are already developing resistance as they shrink in response to treatment with a powerful class of drugs called MAP kinase (MAPK)-targeted inhibitors. The discovery marks a potential milestone in the understanding of treatment-resistant melanoma and provides scientists with powerful targets for drug development and new clinical studies.

BACKGROUND
Approximately 50 percent of advanced melanoma tumors are driven to grow by the presence of BRAF mutations. The use of BRAF inhibitors, both alone and in combination with another MAPK pathway inhibitor called MEK, have shown unprecedented responses as a treatment for these types of tumors, rapidly shrinking them. However, BRAF-mutated tumors frequently show early resistance to treatment and respond only partially to BRAF inhibitors, leaving behind cancer cells that may evolve to cause eventual tumor regrowth.

The findings build upon research by Dr. Roger Lo, professor of medicine (dermatology) and molecular and medical pharmacology at the David Geffen School of Medicine, and lead author of the new study. Previously, he discovered that epigenomic alterations (via a regulatory mechanism called CpG methylation) accounted for a wide range of altered gene activities and behaviors in BRAF-mutant therapy-resistant melanoma tumor cells. The loss of tumor-fighting immune or T-cells in drug-resistant tumors may lead to resistance to subsequent salvage immunotherapy, Lo said, and drug resistance can grow at the same time that anti-tumor immune cells diminish and weaken.

This means that in some patients the melanoma might develop resistance to both MAP kinase-targeted therapy and anti-PD-L1 antibodies, which capitalize on the abundance of immune cells inside the tumor to unleash their anti-cancer activities. Lo concluded that non-genomic, epigenomic, and immunologic evolution of melanoma explain why patients relapse on MAPK-targeted therapies.

Along with co-first authors, Drs. Chunying Song, Marco Piva and Lu Sun, Lo hypothesized that epigenomic and immunologic resistance evident during clinical relapse may be developing already during the first few weeks of therapy as the tumors shrink and clinical responses are viewed as successes. If this proves to be true, then scientists could potentially identify combination treatments that suppress the earliest resistance-promoting activities.

METHOD
Lo’s team utilized state-of-the-art technologies to comprehensively profile recurrent patterns of gene activity changes. They analyzed 46 samples of patients’ melanoma tumors, both before and early during MAPK therapy. They also replicated the process outside of the human body, modeling both non-genomic drug resistance by growing melanoma cell lines from patients’ tumors and immunologic resistance in mouse melanoma. Patient-derived cell lines and mouse melanoma tumors were treated with drugs that block the MAP kinase pathway and sampled at various times over the course of the study to track gene activity changes.

The researchers found that MAPK therapies fostered CpG methylation and gene activity reprogramming of tumors. This reduced the tumor cells’ dependence on the mutated BRAF protein, and switched their growth and survival strategies to rely on proteins called receptor-tyrosine kinases and PD-L2. In addition, PD-L2 gene activity was found to be turned on in immune cells surrounding the tumor cells. They also demonstrated that blocking PD-L2 with an antibody could prevent the loss of T-cells in the tumor’s immune microenvironment and suppressing therapy resistance.

Lo’s team continues to identify other adaptations during this early phase of therapy that could be targets of future combination treatment regiments.

IMPACT
More than 87,000 new cases of melanoma will be diagnosed this year in the United States alone, and more than 9,500 people are expected to die of the disease.

The findings can prompt drug development and new clinical studies based on epigenetic or gene expression and immune targets in combination with mutation-targeted therapies. As scientists learn what these mechanisms of tumor resistance are, they can combine inhibitor drugs that block multiple resistance routes and eventually make the tumors shrink for much longer or go away completely, Lo said.

JOURNAL
The research is published online in Cancer Discovery, the peer-reviewed journal of the American Association of Cancer Research.

AUTHORS
UCLA’s Dr. Roger Lo is senior author. The co-first authors are Drs. Chunying Song, Marco Piva and Lu Sun at the David Geffen School of Medicine at UCLA. Other authors are Drs. Aayoung Hong, Gatien Moriceau, Xiangju Kong, Hong Zhang, Shirley Lomeli, Jin Qian, Clarissa Yu, Robert Damoiseaux, Philip Scumpia, Antoni Ribas and Willy Hugo at UCLA; and Mark Kelley, Kimberly Dahlman, Jeffrey Sosman, Douglas Johnson at Vanderbilt University. Lo, Damoiseaux, Scumpia and Ribas are members of UCLA’s Jonsson Comprehensive Cancer Center.

FUNDING
The research was supported by the National Institutes of Health, the American Cancer Society, the Melanoma Research Alliance, the American Skin Association, the American Association for Cancer Research, the National Cancer Center, the Burroughs Wellcome Fund, the Ressler Family Foundation, the Ian Copeland Melanoma Fund, the SWOG/Hope Foundation, the Steven C. Gordon Family Foundation, the Department of Defense Horizon Award, the Dermatology Foundation, and the ASCO Conquer Cancer Career Development Award.

Liver Cancer Patients Can Start with Lower Dose of Chemotherapy and Live Just as Long

Penn study shows patients can benefit from fewer side effects and lower treatment costs

Patients with the most common type of liver cancer who are taking the chemotherapy drug sorafenib can begin their treatment with a lower dose than is currently considered standard, and it will not affect how long they live when compared to patients who start on the full dose. That finding comes from a new study from the Abramson Cancer Center of the University of Pennsylvania, published this week in the Journal of Clinical Oncology, and it opens the door for patients with hepatocellular carcinoma to begin with a reduced dose of sorafenib, which helps to minimize the drug’s side effects while also saving money for patients, providers, and insurers.

Hepatocellular carcinoma (HCC) is the most common form of liver cancer among adults and is the second leading cause of cancer-related deaths worldwide. Currently, sorafenib is the only first-line treatment approved for HCC by the U.S. Food and Drug Administration, but its side effects can be particularly difficult on patients. A recent study found 85 percent of HCC patients taking the drug experienced adverse events. In 31 percent of patients on that study, the effects were severe enough to stop treatment. The standard dose sorafenib is 400mg, twice per day.

“Previous studies have started patients with half that dose, escalating only after the patients show they can handle it, but those studies have all been on a smaller scale,” said the study’s lead author Kim A. Reiss, MD, an assistant professor of Hematology Oncology in the Perelman School of Medicine at the University of Pennsylvania. “We wanted to see if we could reproduce those results using a much larger cohort of patients.”

Reiss and her team used a Veterans Health Administration database and identified almost 5,000 HCC patients who were treated with sorafenib between 2006 and 2015, but they couldn’t do a side-by-side analysis of those who received a reduced dose versus those who received the full amount.

“One of the challenges that we faced was that the sickest patients tended to get the reduced dose because of concerns over how much they could tolerate, so any attempt to evaluate these groups based on how long they lived was skewed,” Reiss said.

To solve that problem, researchers looked at patient information to match people from each group based on disease stage, overall health, and other factors. That left them with two groups, each with 1,675 patients.

“Essentially, we used a computer model to simulate putting these patients into a randomized, controlled clinical trial,” said senior author David E. Kaplan, MD, MSc, an assistant professor of Gastroenterology and an associate professor of Medicine at the Corporal Michael J. Crescenz VA Medical Center in Philadelphia.

The controlled data showed the reduced dose had no effect on overall survival. Patients starting at a lower dose had a median survival of 198 days, compared to 195 days for patients starting at the full dose.

In addition, about 40 percent of patients receiving the reduced dose escalated the drug amount within the first two months, while almost 12 percent of standard dose patients had to reduce their level within the same time period.

“It’s important to remember that the reduced dose patients will ramp up as they show they can handle it, while the full dose patients may have to ramp down because of these toxicities, so the dosage levels will converge in the middle,” Reiss said. “All of the patients get the treatment they need, but the reduced dose approach helps keep cost and toxicities down.”

The cost saving was significant. The study found the reduced dose patients took an average of about 100 fewer pills over the course of their treatment. That translated to an average savings of about $3,000 per patient. Reiss noted those numbers are based on VA prices, which tend to be lower than other centers, meaning the real savings for many patients could be even larger.

The researchers note that some doctors are already making use of this practice, which is why they were able to identify so many reduced dose patients for this study, but the majority of physicians are still starting with the full dose.

“Our data suggest starting at a reduced dose is a safe strategy that can be used more commonly,” Reiss said.

This study was supported by research funds from Bayer Healthcare Pharmaceuticals and the VA HIV, Hepatitis, and Related Conditions Programs in the Office of Specialty Care Services.

Exploring Immunotherapy for Carcinoid and Pancreatic Neuroendocrine Tumors

A clinical trial testing the immunotherapy drug pembrolizumab shows the drug to be well tolerated among patients who have carcinoid or pancreatic neuroendocrine tumors.  Janice M. Mehnert, MD, director of the Phase 1 and Developmental Therapeutics Program at Rutgers Cancer Institute of New Jersey, is the lead author of research that is part of an oral presentation at the European Society for Medical Oncology 2017 Congress taking place this week in Madrid, Spain. Dr. Mehnert, who is also a medical oncologist in the Melanoma and Soft Tissue Oncology Program at Rutgers Cancer Institute, shares more about the work, conducted by a collective of international investigators.

Q: Why explore immunotherapy in these particular patient populations?

A: Immunotherapy drugs put the body’s natural defenses back to work by targeting the PD-L1 protein and PD-1 receptor and blocking their ability to prevent T cells from destroying cancer cells. Pembrolizumab has shown anti-tumor activity in advanced malignancies including melanoma and non-small cell lung cancer. With treatment options being limited for patients with carcinoid and pancreatic neuroendocrine tumors, it is imperative to explore new therapy options for these populations.

Q:  How was the study structured?

A: At the time our abstract was submitted, 25 participants who presented with advanced carcinoid tumors and 16 patients with pancreatic neuroendocrine tumors were accrued from multiple international sites.  Participants received 10 mg of pembrolizumab for up to 24 months or until confirmed progression or intolerable toxicity.  Safety, tolerability and response were assessed every eight weeks for the first six months and every 12 weeks thereafter.

Q:  What did you find?

A: At the time our results were reported we discovered findings similar to other trials of immunotherapy agents, with the majority of patients actually not responding to therapy. 12 percent of patients with carcinoid tumors and six percent of patients with pancreatic neuroendocrine tumors experienced a response to therapy. However, patients who achieved response were likely to have durable control of their disease, with all responses greater than or equal to six months in duration. Therapy was overall well tolerated and safe, with some side effects related to autoimmune processes caused by the medication.

Q: What is the implication of these findings?

A: These findings are interesting but need further validation in larger studies of patients with carcinoid and pancreatic neuroendocrine tumors. As well, investigative work focusing on identifying valuable biomarkers that could help predict which patients would respond to treatment with these agents is critical. Discoveries in this realm would improve the selection of patients for this particular therapeutic approach.

Research opens possibility of reducing risk of gut bacterial infections with next-generation probiotic

A team of researchers is exploring the possibility that next-generation probiotics – live bacteria that are good for your health – would reduce the risk of infection with the bacterium Clostridium difficile. In laboratory-grown bacterial communities, the researchers determined that, when supplied with glycerol, the probiotic Lactobacillus reuteri produced reuterin, an antibacterial compound that selectively killed C. difficile. The study appears in Infection and Immunity.

C. difficile causes thousands of deaths and billions of dollars in healthcare expenses in the U.S. each year. Although most patients respond to antibiotic treatment, up to 35 percent will relapse and require extended antibiotic treatments,” said first and corresponding author Dr. Jennifer K. Spinler, instructor of pathology & immunology at Baylor College of Medicine, who oversees microbial genetics and genomics efforts at the Texas Children’s Microbiome Center at Texas Children’s Hospital.

C. difficile infections are the most common cause of diarrhea associated with the use of antibiotics. If these bacteria attempt to invade the human gut, the ‘good bacteria,’ which outnumber C. difficile, usually prevent them from growing. However, when a person takes antibiotics, for example to treat pneumonia, the antibiotic also can kill the good bacteria in the gut, opening an opportunity for C. difficile to thrive into a potentially life-threatening infection.

“When repeated antibiotic treatments fail to eliminate C. difficile infections, some patients are resorting to fecal microbiome transplant – the transfer of fecal matter from a healthy donor – which treats the disease but also could have negative side effects,” Spinler said. “We wanted to find an alternative treatment, a prophylactic strategy based on probiotics that could help prevent C. difficile from thriving in the first place.”

“Probiotics are commonly used to treat a range of human diseases, yet clinical studies are generally fraught by variable clinical outcomes and protective mechanisms are poorly understood in patients. This study provides important clues on why clinical efficacy may be seen in some patients treated with one probiotic bacterium but not with others,” said senior author Dr. Tor Savidge, associate professor of pathology & immunology and of pediatrics at Baylor and the Texas Children’s Microbiome Center.

Working in the Texas Children’s Microbiome Center, Spinler and her colleagues tested the possibility that probiotic L. reuteri, which is known to produce antibacterial compounds, could help prevent C. difficile from establishing a microbial community in lab cultures.

An unexpected result with major implications for a preventative strategy

Spinler and Savidge established a collaboration with co-author Dr. Robert A. Britton, professor of molecular virology and microbiology at Baylor and member of the Dan L Duncan Comprehensive Cancer Center.

The Britton lab uses mini-bioreactor arrays – multiple small culture chambers – that provide a platform in which researchers could recreate the invasion of an antibiotic-treated human intestinal community by C. difficile.

“Using the mini-bioreactors model we showed that L. reuteri reduced the burden of C. difficile infection in a complex gut community,” Britton said. “To achieve its beneficial effect, L. reuteri requires glycerol and converts it into the antimicrobial reuterin.”

The literature reports reuterin as a broad-spectrum antibiotic; it affects the growth of a wide variety of bacteria when they are tested individually in the lab. What was intriguing in this study is that reuterin didn’t have a broad-spectrum effect in the mini-bioreactor bacterial community setting.

“I expected reuterin to have an antibacterial effect on several different types of bacteria in the community, but it only affected C. difficile and not the good bacteria, which was exciting because it has major implications for a preventative strategy,” Spinler said.

“Although these results are too preliminary to be translated directly into human therapy, they provide a foundation upon which to further develop treatments based on co-administration of L. reuteri and glycerol to prevent C. difficile infection,” said co-author Dr. Jennifer Auchtung, director of the Cultivation Core at Baylor’s Alkek Center for Metagenomics and Microbiome Research and assistant professor of molecular virology and microbiology at Baylor.

In the future, this potential treatment could be administered prophylactically to patients before they take antibiotics known to disrupt normal gut microbes. The L. reuteri/glycerol formulation would help maintain the healthy gut microbial community and also help prevent the growth of C. difficile, which would result in decreased hospital stay and costs and reduced long-term health consequences of C. difficile recurrent infections.

Immune cells may be key to better allergy, infection therapies

By learning how a recently discovered immune cell works in the body, researchers hope to one day harness the cells to better treat allergies and infections, according to new Cornell University research.

Type 1 regulatory (Tr1) cells are a type of regulatory immune cell that help suppress immune responses, including inflammation and tissue damage, but very few details were known about their development and function.

A new study with mice and humans, published in the journal Nature Communications, describes how an enzyme called ITK plays a crucial role in the development of Tr1 cells during an immune response. The enzyme offers an entry point for researchers to manipulate the development of Tr1 cells to enhance them to treat allergies, for instance, or block their development to treat viral and bacterial infections.

“The more we understand about how these cells develop, the signals and pathways they use, the more likely we’ll be able to devise approaches to manipulate them,” said Avery August, professor of microbiology and immunology in Cornell’s College of Veterinary Medicine and the paper’s senior author. Weishan Huang, assistant research professor of microbiology and immunology, is lead author.

Doctors employ antigen immunotherapy to treat allergies by administering a regimen that exposes a patient to increasing doses of an allergen over a period of months. Since allergies are caused by an overactive immune response to an allergen, the treatment works because Tr1 cells help suppress the immune system and lower inflammation. In the future, clinicians may want to enhance the pathway to produce more Tr1 cells, August said.

But when treating viral infections such as the flu, bacterial infections and tumors, clinicians may want to selectively block the pathway to lower the number of Tr1 cells. In experiments with mice, August and colleagues found that Tr1 cells increase when a mouse is infected with viruses or bacteria or when fighting tumors. By tempering the development of Tr1 cells, and carefully reducing their activity to suppress the immune response, patients may recover faster from certain diseases.

“This is a balance because these cells are there for a purpose, and we think their purpose is to make sure the immune system doesn’t destroy and cause pathology in an immune response,” August said.

The danger with flu, for example, is that at a certain point other types of immune system T cells, whose purpose is to kill infected cells, start to destroy tissue. In such cases, an overactive immune response can lead to death.

“We’d have to do experiments to find out whether we can tune the function of Tr1 cells,” August said, “so we balance the beneficial aspects of the immune response with the damaging aspects of the immune response.”

In the study, August, Huang and their colleagues bred genetically altered mice so they carried a gene that makes Tr1 cells glow green when they develop, which allows for easy tracking. They then bred another type of mouse that had fluorescent Tr1 cells and also allowed the researchers to specifically block the enzymatic activity of ITK. Using the same protocol, they created a third type of mouse that lacked ITK.

In both the mice where ITK was inhibited and the mice that lacked ITK, Tr1 cells failed to develop. Using blood cells from anonymous human volunteers, they got the same results.

In a second experiment, the researchers identified a second critical enzyme in the pathway that leads to the development of Tr1 cells. This other enzyme, called IRF4, is a transcription factor that regulates the expression of a number of genes and proved key for controlling whether Tr1 cells developed. The team also confirmed that the same pathway exists in people.

Experimental HIV vaccine regimen is well-tolerated, elicits immune responses

Results from an early-stage clinical trial called APPROACH show that an investigational HIV vaccine regimen was well-tolerated and generated immune responses against HIV in healthy adults. The APPROACH findings, as well as results expected in late 2017 from another early-stage clinical trial called TRAVERSE, will form the basis of the decision whether to move forward with a larger trial in southern Africa to evaluate vaccine safety and efficacy among women at risk of acquiring HIV.

The APPROACH results will be presented July 24 at the 9th International AIDS Society Conference on HIV Science in Paris.

The experimental vaccine regimens evaluated in APPROACH are based on “mosaic” vaccines designed to induce immunological responses against a wide variety of HIV subtypes responsible for HIV infections globally. Different HIV subtypes, or clades, predominate in various geographic regions around the world. The National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health, funded pre-clinical development of these vaccines. Together with other partners, NIAID supported the APPROACH trial, which is sponsored by Janssen Vaccines & Prevention B.V., part of the Janssen Pharmaceutical Companies of Johnson & Johnson. The manufacture and clinical development of the mosaic vaccines are led by Janssen.

“A safe and effective HIV vaccine would be a powerful tool to reduce new HIV infections worldwide and help bring about a durable end to the HIV/AIDS pandemic,” said NIAID Director Anthony S. Fauci, M.D. “By exploring multiple promising avenues of vaccine development research, we expand our opportunities to achieve these goals.”

APPROACH involved nearly 400 volunteers in the United States, Rwanda, Uganda, South Africa and Thailand who were randomly assigned to receive one of seven experimental vaccine regimens or a placebo. APPROACH found that different mosaic vaccine regimens were well-tolerated and capable of generating anti-HIV immune responses in healthy, HIV-negative adults. Notably, the vaccine regimen that was most protective in pre-clinical studies in animals elicited among the greatest immune responses in the study participants. However, further research will be needed because the ability to elicit anti-HIV immune responses does not necessarily indicate that a candidate vaccine regimen can prevent HIV acquisition.

According to the researchers, the findings from APPROACH, as well as from animal studies, support further evaluation of a lead candidate regimen in a clinical trial to assess its safety and efficacy. Plans for such a clinical trial to be conducted in southern Africa are in development, with projected enrollment of 2,600 healthy, HIV-negative women. Should the larger trial move forward, it is expected to begin enrollment in late 2017 or early 2018.

In APPROACH, study participants received four vaccinations over 48 weeks: two doses of an initial, or “prime,” vaccine, followed by two doses of a booster vaccine. The experimental regimens all incorporated the same vaccine components in the prime vaccination, known as Ad26.Mos.HIV. The vaccine uses a strain of common-cold virus (adenovirus serotype 26, or Ad26), engineered so that it does not cause illness, as a vector to deliver three mosaic antigens created from genes from many HIV variants. The booster vaccination included various combinations of the Ad26.Mos.HIV components or a different mosaic component, called MVA-Mosaic, and/or two different doses of clade C HIV gp140 envelope protein containing an aluminum adjuvant to boost immune responses.

The Ad26-based mosaic vaccines were initially developed by the laboratory of NIAID grantee Dan H. Barouch, M.D., Ph.D., and Janssen. In pre-clinical studies, regimens incorporating these mosaic vaccines protected monkeys against infection with an HIV-like virus called simian human immunodeficiency virus (SHIV). The most effective prime-boost regimen reduced the risk of infection per exposure to SHIV by 94 percent and resulted in 66 percent complete protection after six exposures. Researchers identified and characterized the vaccine-induced immune responses that correlated with this protection.

“The promising, early-stage results from the APPROACH study support further evaluation of these candidate vaccines to assess their ability to protect those at risk of acquiring HIV,” said Dr. Barouch, a principal investigator for APPROACH. He also is director of the Center for Virology and Vaccine Research at Beth Israel Deaconess Medical Center in Boston and professor of medicine at Harvard Medical School.

Following the third vaccination, most APPROACH participants had developed antibody and cellular immune responses against HIV. The different boost vaccines altered the magnitude and character of these immune responses, with the regimen that showed greatest protection in monkey studies also eliciting among the greatest immune responses in humans. The anti-HIV immune responses increased after the fourth vaccination.

The researchers conclude that further evaluation of this approach would use a regimen comprising two Ad26 mosaic primes and two boosts with Ad26 mosaic and clade C gp140. The ongoing TRAVERSE trial is comparing Ad26-based regimens containing three mosaic antigens (trivalent) with Ad26-based regimens containing four mosaic antigens (tetravalent). Results from TRAVERSE are expected in late 2017.

Immune-cell numbers predict response to combination immunotherapy in melanoma

Whether a melanoma patient will better respond to a single immunotherapy drug or two in combination depends on the abundance of certain white blood cells within their tumors, according to a new study conducted by UC San Francisco researchers joined by physicians from UCSF Health. The findings provide a novel predictive biomarker to identify patients who are most likely to respond well to a combination of immunotherapy drugs known as checkpoint inhibitors — and to protect those who won’t respond from potentially adverse side effects of combination treatment.

“Combination immunotherapy is super-expensive and very toxic,” said Adil Daud, MD, director of Melanoma Clinical Research at the UCSF Helen Diller Family Comprehensive Cancer Center and senior author of the new study. “You’re putting patients at a lot of extra risk if they don’t need it, and you can adjust for that risk by knowing in advance who can benefit.”

The study, published online July 20, 2017 in Journal of Clinical Investigation Insight, describes an assay that measures the abundance of immune cells that infiltrate melanoma tumors. The findings revealed that patients who had lower levels of immune cells called T cells within their tumors benefitted most from two immunotherapy drugs in tandem. The measurements could provide clinicians with a means to predict patients who would most benefit from combination immunotherapy, the authors said.

“This is clinical research at its best,” said UCSF’s Katy Tsai, MD, a medical oncologist and lead author of the new report. “We have identified something as a predictive biomarker in melanoma, and we’re hoping to validate it in other tumor types as well.”

T cells are immune cells that patrol our body for signs of infection or other diseases, recognizing culprit cells via telltale proteins on their membranes. Our body’s normal cells carry certain proteins on their coats that act as “checkpoints,” making them invisible to T cells. But it turns out many cancer cells adopt the same trick — they cloak themselves with one of those same proteins, called PD-L1, causing T cells, which carry a complementary protein called PD-1, to mistake them as harmless. PD-L1 thus acts like a fake identification card, allowing cancer cells to live and multiply without being detected by the immune system.

Immunotherapy drugs called checkpoint inhibitors work to uncloak cancer cells by throwing a wrench in their disappearing act: these drugs block PD-L1 or PD-1, allowing T cells to recognize cancer cells as detrimental and kill them.

There are four FDA-approved checkpoint inhibitors: ipilimumab, nivolumab, pembrolizumab and atezolizumab. These drugs have been very successful in some cases, but they help only about 20 to 40 percent of patients. One of the ways doctors have improved their efficacy is by using multiple drugs at the same time. But the toxic side effects of these drugs can add up, and clinicians need to be able to correctly predict those who are most likely to respond to single drugs or combinations.

In a previous study, Daud and colleagues homed in on what makes some individuals respond well to checkpoint inhibitors that block PD-1, finding that patients whose tumors harbored high populations of T cells known as partially exhausted CD8+ cells responded well to treatment with nivolumab, an anti-PD-1 drug. Intriguingly, these cells had high levels of both PD-1 and CTLA-4, another well-known immune checkpoint protein, which is targeted by immunotherapy drugs such as ipilimumab.

In the new report, the researchers studied tumor samples from 102 melanoma patients, extracted T cells from the samples, and used cell sorting equipment to estimate the relative proportion of immune cells in the samples. The patients then underwent treatment either with only nivolumab, or with both nivolumab and ipilimumab. Finally, the researchers ran statistical tests to discover correlations among patient demographics, immune cell populations, and drug responses.

The team found that patients with high levels of exhausted T cells benefitted significantly from treatment with only a single drug. On the other hand, women and those who had liver metastases had lower number of immune cells patrolling their tumors, and responded well to the combination treatment.

“You’re pushing on two different gas pedals – PD-1 and CTLA-4,” said Daud, a member of UCSF’s Parker Institute for Cancer Immunotherapy center. “If you’re one of those patients with a low number of exhausted T cells, you have a better likelihood of benefitting from both drugs.”

The team will next explore why women have fewer T cells — and in turn, a diminished response to single immunotherapy drugs — and whether these factors could be related to age, estrogen levels, or are related to pregnancy.

The cell-counting assay developed by the researchers is time- and resource-intensive, especially because it requires fresh tumor samples and elaborate cell-sorting machines, and it is only available at UCSF. To get around these limitations, the team is now working on a more broadly applicable test that would measure the levels of PD-1 and CTLA-4 proteins — both present on T cells — in tumors and use that as a surrogate marker for immune cell count.

“In six months to a year, we should have an assay that works using fairly common, less expensive techniques,” said Daud. “And it could work on fresh, frozen or paraffin-embedded tumor blocks.” With this easier test, the researchers hope to expand their study of immune cell infiltration to other cancer types and to bigger groups of patients, both from different areas of the U.S. and internationally

Genetically enhanced, cord-blood derived immune cells strike B-cell cancers

Immune cells with a general knack for recognizing and killing many types of infected or abnormal cells also can be engineered to hunt down cells with specific targets on them to treat cancer, researchers at The University of Texas MD Anderson Cancer Center report in the journal Leukemia.

The team’s preclinical research shows that natural killer cells derived from donated umbilical cords can be modified to seek and destroy some types of leukemia and lymphoma. Genetic engineering also boosts their persistence and embeds a suicide gene that allows the modified cells to be shut down if they cause a severe inflammatory response.

A first-in-human phase I/II clinical trial of these cord-blood-derived, chimeric antigen receptor-equipped natural killer cells opened at MD Anderson in June for patients with relapsed or resistant chronic lymphocytic leukemia (CLL), acute lymphocytic leukemia (ALL), or non-Hodgkin lymphoma. All are cancers of the B cells, another white blood cell involved in immune response.

“Natural killer cells are the immune system’s most potent killers, but they are short-lived and cancers manage to evade a patient’s own NK cells to progress,” said Katy Rezvani, M.D., Ph.D., professor of Stem Cell Transplantation and Cellular Therapy.

“Our cord-blood derived NK cells, genetically equipped with a receptor that focuses them on B-cell malignancies and with interleukin-15 to help them persist longer — potentially for months instead of two or three weeks — are designed to address these challenges,” Rezvani said.

Moon Shots Program funds project

The clinical trial is funded by MD Anderson’s Moon Shots Program™, designed to more rapidly develop life-saving advances based on scientific discoveries.

The chimeric antigen receptor (CAR), so-called because it’s added to the cells, targets CD19, a surface protein found on B cells.

In cell lines and mouse models of lymphoma and CLL, CD19-targeted NK cells killed cancer cells and extended survival of animals compared to simply giving NK cells alone. Addition of IL-15 to the CD19 receptor was crucial for the longer persistence and enhanced activity of the NK cells against tumor cells.

NK cells are a different breed of killer from their more famous immune system cousins, the T cells. Both are white blood cells, but T cells are highly specialized hunters that look for invaders or abnormal cells that bear a specific antigen target, kill them and then remember the antigen target forever.

Natural killers have an array of inhibitory and activating receptors that work together to allow them to detect a wider variety of infected, stressed or abnormal cells.

“By adding the CD19 CAR, we’re also turning them into guided missiles,” said Elizabeth Shpall, M.D., professor of Stem Cell Transplantation and Cell Therapy.

Using a viral vector, the researchers transduce NK cells taken from cord blood with the CD19 CAR, the IL-15 gene, and an inducible caspase-9-based suicide gene.

Cell line tests found the engineered NK cells to be more efficient killers of lymphoma and CLL cells, compared to unmodified NK cells, indicating the engineered cells’ killing was not related to non-specific natural killer cell cytotoxicity.

Another experiment showed the engineered cord blood NK cells killed CLL cells much more efficiently than NK cells taken from CLL patients and engineered, highlighting the need to transplant CAR-engineered NK cells from healthy cord blood rather than use a patient’s own cells.

Suicide gene to counter cytokine release syndrome

Mouse model lymphoma experiments using a single infusion of low dose NK cells resulted in prolongation of survival. At a higher, double dose, none of the mice treated with the CD19/IL-15 NK cells died of lymphoma, with half surviving for 100 days and beyond. All mice treated with other types of NK cells died by day 41.

A proportion of mice treated with the higher dose of engineered NK cells died of cytokine release syndrome, a severe inflammatory response that also occurs in people treated with CAR T cells.

To counteract this toxicity, the researchers incorporated a suicide gene (iC9) that can be activated to kill the NK cells by treatment with a small-molecule dimerizer. This combination worked to swiftly reduce the engineered NK cells in the mouse model.

Subsequent safety experiments were conducted in preparation for the clinical trial. Rezvani, the principal investigator of the clinical trial, says the protocol calls for vigilance for signs of cytokine release syndrome, treatment with steroids and tocilizumab for low-grade CRS with AP1903 added to activate the suicide gene for grade 3 or 4 CRS.

NK CARs available off the shelf

T cells modified with chimeric antigen receptors against CD19 have shown efficacy in clinical trials. In these therapies, a patient’s own T cells are modified, expanded, and given back to the patient, a process that takes weeks. Finding a matched donor for T cells would be a challenge, but would be necessary because unmatched T cells could attack the recipient’s normal tissue – graft vs. host disease.

Rezvani and Shpall have given patients cord-blood derived NK cells in a variety of clinical trials and found that they do not cause graft vs. host disease, therefore don’t have to be matched. NK cells can be an off-the-shelf product, prepared in advance with the necessary receptor and given promptly to patients.

“CAR NK cells are scalable in a way that CAR T cells are not,” Rezvani noted.

A strength of T cells is the development of memory cells that persist and repeatedly attack cells bearing the specific antigen that return. NK cells do not seem to have a memory function, but Rezvani says the experience of the longer-lived mice, which are now more than a year old, raises the possibility that a prolonged NK cell attack will suffice.

Shpall, Rezvani and colleagues are developing cord blood NK CARs for other targets in a variety of blood cancers and solid tumors.

MD Anderson and the researchers have intellectual property related to the engineered NK cells, which is being managed in accordance with the institution’s conflict-of-interest rules.

Shpall founded and directs MD Anderson’s Cord Blood Bank, originally established to provide umbilical cord blood stem cells for patients who need them but cannot get a precise donor match. Donated by mothers who deliver babies at seven Houston hospitals and two others from California and Michigan, the bank now has 26,000 cords stored. MD Anderson researchers pioneered the extraction and expansion of NK cells from umbilical cords.

Targeting ‘broken’ metabolism in immune cells reduces inflammatory disease

The team, led by researchers at Imperial College London, Queen Mary University of London and Ergon Pharmaceuticals, believes the approach could offer new hope in the treatment of inflammatory conditions like arthritis, autoimmune diseases and sepsis.

In a study published this week in the journal Nature Communications, they explain how blocking a single enzyme enabled them to reprogram macrophages – the immune cells which are activated in inflammatory conditions – to calm their activity and reduce inflammation in rats and mice with human-like disease.

At the heart of the research is the Krebs cycle, a complex loop of reactions which cells use to feed on sugar and generate molecules of ATP, the universal energy currency for cells.

In recent years, research has shown that the usual pathway is interrupted in immune cells such as macrophages, leading to a broken Krebs cycle.

“In immune cells that have to fight invaders, the metabolism is diverted from its usual cycle to make compounds that fight microbes,” explained Dr Jacques Behmoaras, from the Department of Medicine at Imperial, who led the research.

Dr Behmoaras added: “What we have found is that there’s an enzyme involved in this diversion of the usual cycle, which make immune cells produce these bacteria-killing compounds. If you block that enzyme, you block that specific branch of their metabolism, and make the cells cause less damage during inflammation.”

Using human macrophages, the researchers found that an enzyme called BCAT1 was pivotal in reprogramming macrophages. When the cells were activated – by exposing them to molecules found on the surface of bacteria – BCAT1 interfered with their usual metabolic pathways, and regulated another enzyme, responsible for producing bacteria-killing chemicals.

They used an experimental compound called ERG240, developed by Ergon Pharmaceuticals, a small biotech company based in the US. ERG240 resembles the amino acid leucine, one of the building blocks of proteins, which is linked together by BCAT1. By flooding the cells with ERG240 they were able to jam up BCAT1 and block its action, so stopping the metabolism being diverted and ‘fixing’ the broken Krebs cycle. What’s more, the compound was shown to work in animal models of inflammation, without toxic side effects.

The team found that when ERG240 was given to mice with symptoms of rheumatoid arthritis, it reduced the inflammation in their joints by more than half while protecting the integrity of their joints. Similarly, in a rat model of severe kidney inflammation, they found that ERG240 improved kidney function by reducing the number of macrophages flooding into the affected tissue to cause inflammation.

Dr Behmoaras states that although the research is still at an early stage, there is potential for treating inflammatory conditions in patients by targeting the metabolic activity in immune cells. The team believes that BCAT1 works together with other key enzymes of the Krebs cycle, which could themselves provide targets for therapy.

However, one of the key challenges in developing a therapy would be in finding the balancing point: calming the immune cells enough such that they reduce inflammation, but enabling them to react to microbial invaders.

“I think this ability to regulate metabolism in cells could have an effect on many human diseases,” said Dr Behmoaras. “Manipulating cell activity in inflammatory diseases where macrophages have a role, could have important therapeutic benefits.

“Our next step is to understand how other enzymes in the cycle are involved, to see if there is any possibility to block them and have similar effects. Understanding the complex metabolic circuits of these immune cells is a huge task. We will need to tackle this before we can manipulate cell activity and influence disease.

“This is a growing field of research with exciting discoveries ahead.”

Personal neoantigen vaccine prompts strong anti-tumor response in patients, study shows

A personal cancer treatment vaccine that targets distinctive “neoantigens” on tumor cells has been shown to stimulate a potent, safe, and highly specific immune anti-tumor response in melanoma patients, report scientists from Dana-Farber Cancer Institute and the Broad Institute of MIT and Harvard.

The study, published online by Nature “provides proof-of-principle that a personal vaccine tailored to a patient’s tumor can be produced and generates highly specific responses to that patient’s tumor after vaccination,” said the researchers, led by Catherine J. Wu, MD, senior author of the report. She is a researcher at Dana-Farber, the Broad Institute, and Harvard Medical School.

The scientists said that while most therapies are based on the on-size-fits-all model of medicine, “we’ve long recognized in cancer that every patient’s tumor is different. With recent advances in technology, it’s now becoming possible to create a therapy that’s suited to target an individual’s tumor.”

The researchers say the results warrant further development of neoantigen vaccines, both alone and in combination with other immunotherapy weapons such as checkpoint inhibitors. The vaccine, known as NeoVax, prompted strong activity by the patients’ immune systems while causing negligible side effects.

First authors of the report are Patrick A. Ott, MD, PhD, and Zhuting Hu, PhD, of Dana-Farber. Other senior authors include Nir Hacohen, PhD, of the Broad Institute and Massachusetts General Hospital, Edward Fritsch, PhD, formerly of Dana-Farber and now at Neon Therapeutics in Cambridge, Mass, and Eric Lander, PhD, of the Broad Institute.

Antigens are molecules that are displayed on the surface of cells and stimulate the immune system. Neoantigens are molecules on cell’s surfaces that are produced by DNA mutations that are present in cancer cells but not in normal cells, making neoantigens ideal targets for immune therapy against cancer, say the scientists. The vaccines used in the phase I trial contained up to 20 neoantigens, derived from an individual patient’s tumor. The vaccines were administered to patients to train their immune system to recognize these neoantigens, with the goal of stimulating the immune system to destroy the cancer cells that display them.

While other immunotherapies, such as checkpoint inhibitor drugs, also trigger immune responses against cancer neoantigens, they are not designed to be specific. They can also induce responses against normal tissue antigens, leading the immune system to attack normal tissues and cause toxicity in a subset of patients. The researchers found that the personal vaccine induced a focused T cell response against several tumor neoantigens, beyond what is normally seen in response to existing immunotherapies.

The vaccine was administered to six patients with melanoma whose tumors had been removed by surgery and who were considered at high risk for recurrence. The vaccinations were started at a median of 18 weeks after surgery. At a median of 25 months after vaccination, four of the six patients showed no evidence of cancer recurrence. In the other two patients, whose cancer had spread to their lungs, the disease recurred after vaccination. At that point, they began treatment with the drug pembrolizumab, which inhibits the PD-1 immune checkpoint. Both patients had complete resolution of their tumors and remain free of disease according to imaging scans.

The study results suggest, that a personalized neoantigen vaccine can potentially overcome two major hurdles in cancer therapy.

One is the heterogeneity of tumors – the fact that they are made up of cells with a variety of different traits, which often allows cancers to evade drugs targeted to malignant cells having a single genetic abnormality. The vaccine, because it contains many different neoantigens from the tumor, targets multiple genetic types of tumor cells. Wu added that in this respect, the response generated by a neoantigen vaccine is similar to the new wave of combination therapies, which are showing more promise in treating cancers that typically develop resistance to single drugs. “We are leveraging the immune system’s natural ability to detect and attack many target antigens, as it does every time we get an infection,” she said.

A second hurdle in cancer is to generate an immune response sharply focused on cancer cells while avoiding normal cells and tissues. This aim was achieved by the vaccine, which appeared to have few “off-target” effects, causing only flu-like symptoms, fatigue, rashes, and irritation at the site of the vaccine injection, according to the report.

Despite decades of attempts to develop effective cancer treatment vaccines, they have mostly failed at producing potent antitumor immune responses. The study authors say that is because these vaccines have generally been made with tumor antigens that are too similar to antigens on normal cells: as a result, the body generates a weaker immune response to avoid harming normal cells, a process called immune tolerance. By contrast, the neoantigen vaccine is custom-made for each patient using antigens produced by mutations unique to the patient’s cancer and only present on cancer cells, thus bypassing the nature immune tolerance process.

To create the vaccine, samples of a patient’s tumor and normal DNA from the patient’s blood underwent whole-exome sequencing to reveal mutations present only in the tumor’s genetic program. Because some mutations are present in the DNA but the gene is not made into RNA and protein, the researchers used RNA sequencing to identify mutations that caused the production of a mutated RNA, which is then normally translated into a protein.

Since T cells can only recognize neoantigens that are “presented” to them by HLA molecules of the immune system, a key step in making the vaccine is using computer algorithms to predict which neoantigen peptides will bind strongly to the HLA molecules for recognition by T cells. Algorithms, such as NetMHC, have been developed in recent years, making it feasible to select HLA-binding neoantigen peptides for the vaccine. Applying this tool to the six patients’ tumor samples yielded dozens of unique neoantigens for each patient’s personal vaccine.

Finally, the selected neoantigen peptides were synthesized and mixed with an adjuvant – a biochemical substance that helps to jump-start the immune response. The vaccine was then injected under the skin of the patient, with five priming doses followed by two booster doses of the vaccine.

The vaccine was aimed at generating responses to the neoantigens from T cells of two kinds – CD8+ killer cells and CD4+ helper cells. When the team monitored the vaccine’s effects on the immune system in each patient, they found that both T cell types had indeed been activated by the vaccine and could recognize the neoantigens bound to HLA molecules. Most importantly, many of the T cells were able to recognize the tumor cells directly, demonstrating that the vaccine had triggered a tumor-specific immune response that could target the patient’s tumor.

“Future neoantigen vaccine trials will recruit more patients with advanced disease to test the efficacy of the vaccine, take advantage of improved methods for predicting antigen presentation to boost the number of effective neoantigens and test for synergy with checkpoint blockade and other immunotherapeutics,” the scientists said. “If successful in subsequent trials, a personal vaccine has the potential to be applied to any cancer that harbors a sufficient numbers of neoantigens for vaccination.”

FDA Halts Three Multiple Myeloma Studies Evaluating Merck’s KEYTRUDA®

Merck known as MSD outside the United States and Canada, today announced that the U.S. Food and Drug Administration (FDA) has placed a clinical hold on KEYNOTE-183, KEYNOTE-185 and KEYNOTE-023, three combination studies of KEYTRUDA® (pembrolizumab), the company’s anti-PD-1 therapy, in the blood cancer multiple myeloma.

This decision follows a review of data by the Data Monitoring Committee in which more deaths were observed in the KEYTRUDA arms of KEYNOTE-183 and KEYNOTE-185 and which led to the pause in new patient enrollment, as announced on June 12, 2017. The FDA has determined that the data available at the present time indicate that the risks of KEYTRUDA plus pomalidomide or lenalidomide outweigh any potential benefit for patients with multiple myeloma. All patients enrolled in KEYNOTE-183 and KEYNOTE-185 and those in the KEYTRUDA/lenalidomide/dexamethasone cohort in KEYNOTE-023 will discontinue investigational treatment with KEYTRUDA.

This clinical hold does not apply to other studies with KEYTRUDA.

The following studies have been placed on full clinical hold:

  • KEYNOTE-183: “A Phase III study of Pomalidomide and low-dose Dexamethasone with or without Pembrolizumab (MK3475) in refractory or relapsed and refractory Multiple Myeloma (KEYNOTE-183).”
  • KEYNOTE-185: “A Phase III study of Lenalidomide and low-dose Dexamethasone with or without Pembrolizumab (MK3475) in newly diagnosed and treatment naïve Multiple Myeloma (KEYNOTE-185).”

The following study has been placed on partial clinical hold:

  • KEYNOTE-023 Cohort 1: “A Phase I Multi-Cohort Trial of Pembrolizumab (MK-3475) in Combination with Backbone Treatments for Subjects with Multiple Myeloma (KEYNOTE 023).” Cohort 1 of KEYNOTE-023 evaluated KEYTRUDA (pembrolizumab) in combination with lenalidomide and dexamethasone in patients who received prior anti-multiple myeloma treatment with an immunomodulatory (IMiD) treatment (lenalidomide, pomalidomide or thalidomide).

“Patient safety is Merck’s primary concern, and we are grateful to the study investigators and patients involved in these studies for their commitment to this important research,” said Dr. Roger M. Perlmutter, president, Merck Research Laboratories. “Merck’s development program for KEYTRUDA, spanning more than 30 different tumor types, has one priority: helping patients suffering from cancer.”

For more information about Merck’s oncology clinical trials, visit www.merck.com/clinicaltrials.

Combo immunotherapy may herald new standard of care for kidney cancer

Combination therapy with two immunotherapy drugs produces an unprecedented doubling of response rates from 20 percent to 40 percent, a new study shows.

The multicenter trial involving 100 patients showed that the addition of ipilimumab to nivolumab, which is currently FDA-approved for treatment of kidney cancer, leads to responses that can last beyond two years. Half of the patients in the study, which appears in the Journal of Clinical Oncology, had metastases that had grown while they were on previous therapy.

“For this group of patients, these are very significant results,” said lead author Dr. Hans Hammers, Associate Professor of Internal Medicine and co-leader of the Kidney Cancer Program at the Harold C. Simmons Comprehensive Cancer Center of UT Southwestern Medical Center.

The results set the stage for a pivotal Phase III trial, which has completed enrollment of patients. Should the results of this study be repeated in the larger Phase III trial, it would lead to a new standard of care for kidney cancer patients, said Dr. Hammers, formerly of Johns Hopkins medical system, who holds the Eugene P. Frenkel, M.D. Scholar in Clinical Medicine at UT Southwestern.

While significant advances in the treatment for kidney cancer over the last decade have led to the approval of a dozen drugs, these drugs are mostly palliative, lacking the potential for cure. “By contrast, durable responses lasting many years can be achieved with immunotherapy,” said Dr. Hammers.

Activation of the immune system, however, can lead to serious complications, requiring potent anti-inflammatory drugs. “While side effects of immunotherapy can be significant, they are typically reversible, and unlike current therapies, don’t significantly dampen patients’ daily quality of life,” said Dr. Hammers.

“Given the potential severity of the adverse effects, patients benefit from expert management available at centers of excellence,” said Dr. James Brugarolas, Associate Professor of Internal Medicine and Leader of the Kidney Cancer Program at UT Southwestern.

Ongoing efforts in the Kidney Cancer Program focus on leveraging Nobel Prize-winning discoveries from UT Southwestern’s Dr. Bruce Beutler leading to a new family of proteins that activate the immune system, the toll-like receptors. “Another avenue we are exploring, is the combination of immunotherapy and radiation,” said Dr. Brugarolas.

Nobel Laureate Dr. Beutler, Regental Professor and Director of the Center for the Genetics of Host Disease, discovered an important family of receptors that allow mammals to sense infections when they occur, triggering a powerful inflammatory response. For this work, he received the 2011 Nobel Prize in Physiology or Medicine. Dr. Beutler, also Professor of Immunology, holds the Raymond and Ellen Willie Distinguished Chair in Cancer Research, in Honor of Laverne and Raymond Willie, Sr.

Kidney cancer is the sixth most common cancer type affecting both men and women. Classic chemotherapy has never worked well for kidney cancer. Targeted therapies have prolonged life expectancy, but are associated with daily side effects. Single-agent immunotherapies improve patients’ survival, but only benefit a subset of patients. Combination immunotherapy with nivolumab and ipilimumab as tested in the kidney cancer study described here is already FDA-approved for treatment of melanoma, and is being tested for other cancers.

The Kidney Cancer Program at UTSW is one of two programs in the U.S. recognized with a Specialized Program of Research Excellence award by the National Cancer Institute. Discoveries at the Kidney Cancer Program have led to a new understanding of how kidney cancer develops and are leading to new treatments.

The Harold C. Simmons Comprehensive Cancer Center is the only NCI-designated Comprehensive Cancer Center in North Texas and one of just 48 NCI-designated Comprehensive Cancer Centers in the nation. Simmons Comprehensive Cancer Center includes 13 major cancer care programs. In addition, the Center’s education and training programs support and develop the next generation of cancer researchers and clinicians. Simmons Comprehensive Cancer Center is among only 30 U.S. cancer research centers to be designated by the NCI as a National Clinical Trials Network Lead Academic Participating Site.

Tumor immune fitness determines survival of lung cancer patients

In recent years, immunotherapy, a new form of cancer therapy that rouses the immune system to attack tumor cells, has captivated the public’s imagination. When it works, the results are breathtaking. But more often than not it doesn’t, and scientists still don’t know why.

Publishing in the June 19, 2017, issue of Nature Immunology, researchers at La Jolla Institute for Allergy and Immunology, identify a subpopulation of T cells in tumors known as tissue-resident memory T cells (TRM) as an important distinguishing factor between cancer patients whose immune system mounts an effective anti-tumor response and those who are unable to do so. Their finding emerged from the first large-scale effort to profile the gene expression patterns of cytotoxic T cells isolated directly from patients’ tumors.

“Systematically studying cancer patients’ immune cells reveals a lot of information,” says LJI Associate Professor and William K. Bowes Jr. Distinguished Professor Pandurangan Vijayanand, M.D., Ph.D., who co-directed the study with Professor Christian Ottensmeier at the University of Southampton, England. “It could be a baseline test to predict whether a patient will respond to immunotherapy and guide the choice of immunotherapy that is most likely to be effective. It is almost like judging tumor immune fitness,” adds Vijayanand. The systematic profiling of tumor-infiltrating T cells will also provide new insight into their basic biology revealing new potential immunotherapy drug targets.

Scientists initially found that when T cells were swarming a patient’s tumor that patient lived longer. Over time, however, they found that T-cells lose their fervor and cancer cells gain the upper hand. In the last decade they discovered why: Inhibitory molecular signals emitted from a tumor or its environment undercut the immune response, making tumor cells invisible to the immune system. One class of cancer immunotherapy drugs, known as checkpoint blockade inhibitors, disables either PD-1 or CTLA-4, two known molecules that allow cancer cells to live and multiply undetected by the immune system.

“The challenge with immunotherapy based on PD-1 and CTLA-4 is that if they work, they work miraculously, but they only work in about 30 percent of patients,” says the study’s first author, Anusha-Preethi Ganesan, M.D., Ph.D., a physician in the Division of Pediatric Hematology and Oncology at Rady’s Children’s Hospital, UC San Diego. “If we are doing all these immunotherapies based on activating T cells to kill tumor cells it is really important to know what the transcriptional profiles of these T cells are, what molecules do they make?”

To uncover the underlying reasons why some patients see little or no benefit and to identify those patients most likely to respond, Ganesan utilized advanced genomics tools to define the molecular features of a robust anti-tumor immune response using freshly resected tumors from patients with cancer. Comparing gene expression profiles of cytotoxic T cells (CTLs) isolated from 41 head and neck tumors and 36 untreated, early stage lung tumors with CTLs isolated from adjacent normal lung tissue, Ganesan identified a shared molecular fingerprint between different tumor types suggesting extensive reprogramming of CTLs infiltrating tumor tissue.

Beyond their shared molecular signature, tumor-infiltrating CTLs differed widely in their expression of molecules associated with T cell activation and known immune checkpoints. “There is a huge deal of heterogeneity, which has a lot of implications for immunotherapy,” says Ganesan. “We see the traditional immunotherapy targets but they are not expressed in every single patient, which means not every patient is a candidate for currently available immunotherapies targeted at PD-1 or CTL4-1. That’s why having the full transcriptional profile is so important to understand the entire complexity of the immune network and to identify novel targets.”

Interestingly, gene expression patterns that signal the presence of tissue resident memory T cells (TRM) corresponded with better anti-tumor activity. The only recently identified tissue resident memory T cells act as local first responders that provide rapid onsite immune protection. A large scale analysis in an independent cohort of 689 lung cancer patients confirmed that patients with a high density of TRM cells in tumor tissue survived significantly longer, demonstrating that these cells serve a critical role in protecting against tumor recurrence.

“Any time you remove a tumor, the patient is a ticking time bomb after that. In some people it will come back and it others it won’t,” says Vijayanand. “Our study suggests that the presence of these tissue resident memory cells is an important factor in determining whether somebody is having an effective immune response against cancer and whether they will live longer.”

Nanoparticles Reprogram Immune Cells to Fight Cancer

Researchers at Fred Hutchinson Cancer Research Center have developed biodegradable nanoparticles that can be used to genetically program immune cells to recognize and destroy cancer cells — while the immune cells are still inside the body.

In a proof-of-principle study to be published April 17 in Nature Nanotechnology, the team showed that nanoparticle-programmed immune cells, known as T cells, can rapidly clear or slow the progression of leukemia in a mouse model.

“Our technology is the first that we know of to quickly program tumor-recognizing capabilities into T cells without extracting them for laboratory manipulation,” said Fred Hutch’s Dr. Matthias Stephan, the study’s senior author. “The reprogrammed cells begin to work within 24 to 48 hours and continue to produce these receptors for weeks. This suggests that our technology has the potential to allow the immune system to quickly mount a strong enough response to destroy cancerous cells before the disease becomes fatal.”

Cellular immunotherapies have shown promise in clinical trials, but challenges remain to making them more widely available and to being able to deploy them quickly. At present, it typically takes a couple of weeks to prepare these treatments: the T cells must be removed from the patient and  genetically engineered and grown in special cell processing facilities before they are infused back into the patient. These new nanoparticles could eliminate the need for such expensive and time consuming steps.

Although his T-cell programming method is still several steps away from the clinic, Stephan imagines a future in which nanoparticles transform cell-based immunotherapies — whether for cancer or infectious disease — into an easily administered, off-the-shelf treatment that’s available anywhere.

“I’ve never had cancer, but if I did get a cancer diagnosis I would want to start treatment right away,” Stephan said. “I want to make cellular immunotherapy a treatment option the day of diagnosis and have it able to be done in an outpatient setting near where people live.”

The body as a genetic engineering lab

Stephan created his T-cell homing nanoparticles as a way to bring the power of cellular cancer immunotherapy to more people.

In his method, the laborious, time-consuming T-cell programming steps all take place within the body, creating a potential army of “serial killers” within days.

As reported in the new study, Stephan and his team developed biodegradable nanoparticles that turned T cells into CAR T cells, a particular type of cellular immunotherapy that has delivered promising results against leukemia in clinical trials.

The researchers designed the nanoparticles to carry genes that encode for chimeric antigen receptors, or CARs, that target and eliminate cancer. They also tagged the nanoparticles with molecules that make them stick like burrs to T cells, which engulf the nanoparticles. The cell’s internal traffic system then directs the nanoparticle to the nucleus, and it dissolves.

The study provides proof-of-principle that the nanoparticles can educate the immune system to target cancer cells. Stephan and his team designed the new CAR genes to integrate into chromosomes housed in the nucleus, making it possible for T cells to begin decoding the new genes and producing CARs within just one or two days.

Once the team determined that their CAR-carrying nanoparticles reprogrammed a noticeable percent of T cells, they tested their efficacy. Using a preclinical mouse model of leukemia, Stephan and his colleagues compared their nanoparticle-programming strategy against chemotherapy followed by an infusion of T cells programmed in the lab to express CARs, which mimics current CAR-T-cell therapy.

The nanoparticle-programmed CAR-T cells held their own against the infused CAR-T cells. Treatment with nanoparticles or infused CAR-T cells improved survival 58 days on average, up from a median survival of about two weeks.

The study was funded by Fred Hutch’s Immunotherapy Initiative, the Leukemia & Lymphoma Society, the Phi Beta Psi Sorority, the National Science Foundation and the National Cancer Institute.

Next steps and other applications

Stephan’s nanoparticles still have to clear several hurdles before they get close to human trials. He’s pursuing new strategies to make the gene-delivery-and-expression system safe in people and working with companies that have the capacity to produce clinical-grade nanoparticles. Additionally, Stephan has turned his sights to treating solid tumors and is collaborating to this end with several research groups at Fred Hutch.

And, he said, immunotherapy may be just the beginning. In theory, nanoparticles could be modified to serve the needs of patients whose immune systems need a boost, but who cannot wait for several months for a conventional vaccine to kick in.

“We hope that this can be used for infectious diseases like hepatitis or HIV,” Stephan said.  This method may be a way to “provide patients with receptors they don’t have in their own body,” he explained.  “You just need a tiny number of programmed T cells to protect against a virus.”