Earlier this week, The White House released the Cancer Moonshot report, which calls upon the public and private sectors to transform cancer research and care. Children’s National’s Javad Nazarian, Ph.D., M.S.C., joined peers from prestigious children’s hospitals from around the world at the news conference. Dr. Nazarian is a key player in the initiative, as his lab is part of the Children’s Brain Tumor Tissue Consortium (CBTTC) and is answering the call to action. The CBTTC and the Pacific Pediatric Neuro-Oncology Consortium, in partnership with Seven Bridges, announced the launch of CAVATICA, a data analysis platform that will help researchers to collaboratively access and share data about pediatric cancers, congenital disorders and rare diseases such as epilepsy and autism. More data will be connected than ever before—CAVATICA will interoperate with the Genomic Data Commons and other NIH data repositories. “It’s an exciting time for research,” says Dr. Nazarian.
Children diagnosed with cancer face fear and uncertainty, a series of medical appointments, and multiple diagnostic tests and treatments. On top of these challenges, says Children’s National Health System urologist Michael Hsieh, M.D., Ph.D., many patients contend with additional issues: Treatment side effects, discomforts, and dangers that nearly eclipse that of the cancer itself. One of the most common side effects is hemorrhagic cystitis (HC), a problem marked by extreme inflammation in the bladder that can lead to tremendous pain and bleeding.
HC often results from administering two common chemotherapy drugs, cyclophosphamide and ifosfamide, used to treat a wide variety of pediatric cancers, including leukemias and cancers of the eye and nerves. In the United States alone, nearly 400,000 patients of all ages receive these drugs annually. Of these, up to 40 percent develop some form of HC, from symptomatic disease characterized by pain and bloody urine to cellular changes to the bladder detected by microscopic analysis.
“Having to deal with therapy complications makes the cancer ordeal so much worse for our patients,” says Dr. Hsieh, Director of the Clinic for Adolescent and Adult Pediatric Onset Urology at Children’s National. “Being able to eliminate this extremely detrimental side effect once and for all could have an enormous impact on patients at our hospital and around the world.”
Preventing complications with mesna
The severity of side effects from cyclophosphamide and ifosfamide can vary from mild and fleeting to bladder bleeding so extensive that patients require multiple transfusions and surgery to remove blood clots that can obstruct urinary release, says Dr. Hsieh, who frequently treats patients with this condition. But HC isn’t inevitable, he adds. A drug called mesna has the potential to prevent this complication when prescribed before a patient receives chemotherapy.
The problem is for a fraction of patients, mesna simply doesn’t work. For others, mesna can cause its own serious side effects, such as life-threatening malfunctions of the heart’s electrical system or allergic reactions.
“These kids are often already very sick from their cancers and treatments, and then you compound it with these complications,” says Dr. Hsieh. “There’s a desperate need for alternatives to mesna.”
Looking at alternative treatments
In a new review of the scientific literature, published August 24 by Urology, senior author Dr. Hsieh and a colleague detail all the substitutes for this drug that researchers have examined over several years.
One of these is hyperhydration, or delivering extra fluid intravenously to help flush the bladder and keep dangerous chemotherapy drug metabolites from accumulating and causing damage. Hyperhydration, however, isn’t an option for some patients with kidney, lung, or liver problems, who can’t tolerate excess fluid.
Researchers also have invested heavily in antioxidants as alternative treatments. Because much of the damage caused by these chemotherapy agents is thought to result from a cascade of oxidizing free radicals that cyclophosphamide and ifosfamide launch in the bladder, antioxidants might prevent injury by halting the free radical attack. Antioxidants that researchers have explored for this purpose include cytokines, or immune-signaling molecules, known as interleukin-1 and tumor necrosis factor, and a compound called reduced glutathione. Other studies have tested plant-based antioxidants, including a component of red wine known as resveratrol; a compound called diallyl disulfide isolated from garlic oil; and extracts from Uncaria tomentosa, a woody vine commonly known as “cat’s claw” that grows in the jungles of Central and South America.
Researchers also have tested options that focus on reducing the intense inflammation that cyclophosphamide and ifosfamide cause in the bladder, including the corticoid steroid drug dexamethasone as well as another cytokine known as interleukin-4.
However, Dr. Hsieh says, studies have shown that each of these treatments is inferior to mesna. To truly combat HC, researchers not only need to find new drugs and methods that outperform mesna but also new ways to reverse HC after other measures fail—problems he’s working to solve in his own lab.
For more than four decades, clinicians around the nation have been giving the parents of pediatric patients diagnosed with diffuse intrinsic pontine glioma (DIPG) the same grim prognosis. In the past five years, there has been an explosion of innovative research at Children’s National Health System and elsewhere that promises to change that narrative. That’s because the black box that is DIPG is beginning to divulge its genetic secrets. The new-found research knowledge comes as a direct result of parents donating specimens, judicious shepherding of these scarce resources by researchers, development of pre-clinical models, and financing from small foundations.
From just 12 samples six years ago, Children’s National has amassed one of the nation’s largest tumor bio banks – 3,000 specimens donated by more than 900 patients with all types of pediatric brain tumors, including DIPG.
Such donated specimens have led to the identification of H3K27M mutations, a groundbreaking finding that has been described as the single-most important discovery in DIPG. Mutations in histone-encoding genes are associated with the vast majority of pediatric DIPG cases.
Histone mutations (also referred to as oncohistones) are sustained in the tumor throughout its molecular evolution, found a research team led by Javad Nazarian, Ph.D. Not only were H3K27M mutations nearly ubiquitous in all samples studied, the driver mutation maintained partnerships with other secondary mutations as DIPG tumor cells spread throughout the developing brain. Children’s National researchers have identified tumor driver mutations and obligate partner mutations in DIPG. They are examining what happens downstream from the histone mutation – changes in the genome that indicate locations they can target in their path toward personalized medicine. The value of that genomic knowledge is akin to emergency responders being told the specific house where their help is needed, rather than a ZIP code or city name, Dr. Nazarian says. While there is currently no effective treatment for DIPG, new research has identified a growing number of genomic targets for future therapeutics.“That changed the dynamic,” says Dr. Nazarian. “In DIPG clinical research, nothing had changed for 45 years. Now we know some of the genomic mutations, how the tumor was evolving – gaining new mutations, losing mutations. With precision medicine, we can target those mutations.”
Another study led by neuro-oncologist Eugene Hwang, M.D., reported the most comprehensive phenotypic analyses comparing multiple sites in a young girl’s primary and metastatic tumors. This study showed that despite being uniform, small molecules (mRNA) could be used to distinguish an evolved tumor from its primary original tumor mass.Key to this multidisciplinary work is collaboration across divisions and departments. Within the research lab, knowledge about DIPG is expanding.
Each member of the DIPG team – neurosurgery, neuro-oncology, immunology, genomics, proteomics – feeds insight back to the rest of the team, accelerating the pace of research discoveries being translated into clinical care. Among the challenges that the team will address in the coming months is outmaneuvering tumors that outsmart T-cells (immune cells).
“What is happening in the checkpoint inhibitor field is exciting,” says Catherine M. Bollard, MBChB, MD, Chief of Allergy and Immunology and Director of the Program for Cell Enhancement of Technologies for Immunotherapy. “The inhibitors work by reversing the ‘off’ switch – releasing the brake that has been placed on the T-cells so they can again attack multiple tumor proteins. The next exciting step, and novel to Children’s National, will be to combine this approach with T-cell therapies specifically designed to attack the DIPG tumors. Unlike the use of combination chemotherapy, which has had a limited impact, we hope that the novel combination of immunotherapeutic approaches will offer the hope of a potential cure.”
Dr. Hwang, another member of the multidisciplinary team, adds: “When you’re looking at the landscape – for me, at least – it starts and ends with how my patients are doing. There are kids for whom we have had great successes in improving survival rates in some cancers, like leukemia, and some where the needle has moved nowhere, like DIPG. We’re still trying to figure out the whole picture of who responds. The immune system is present in all kids. Its ability to attack is present in all kids.”
Children’s National is one of the few hospitals in the nation that conducts brainstem biopsies for DIPG and does so with very little chance of complications. The pons is like a superhighway through which nerves pass, making it instrumental in smooth operation of such vital functions as breathing, heart rate, sleeping, and consciousness. The ability of neurosurgeon Suresh Magge, MD, to perform such sensitive biopsies upends conventional wisdom that these procedures were inherently too dangerous. Within two weeks of diagnosis, genomics analyses are run to better understand the biology of that specific tumor. Within the following weeks, the tumor board occurs, and patients with DIPG are placed on therapy that best targets their tumor’s mutations.
Despite an increasing number of experimental therapies tested via clinical trials, more than 95 percent of children with DIPG die within two years of diagnoses. Biomarkers that point to DIPG – like the copies of DNA that tumors shed and leave behind in the bloodstream – could enable creation of liquid biopsies, compared with today’s surgical approach.
Children’s also is making a concerted effort to create preclinical models of DIPG. Preclinical models will be used to winnow the field of potential therapeutics to the candidates most likely to help children survive DIPG. The preclinical tumor cells will be labeled with luciferase – enzymes that, like photoproteins, produce bioluminescence – permitting the researcher to visually see the formation, progression, and response of DIPG tumors to treatment in preclinical settings.
These preclinical models could be used to test multiple drug combinations in conjunction with radiation therapy. Molecular signatures and response to treatment could then be assessed to learn how the tumor resists therapy. Due to the obligate partnerships between driver mutations and secondary mutations, the research team already knows that effective DIPG medicines will need more than one target. If there were a single mutation, that would be like having a single master key to open many locks. Multiple mutations imply that more than one key will be needed. Thus, the search for cures for DIPG will necessitate taking a multi-pronged approach.
Combined drug regimens, including those created with proprietary technology, with or without radiation, will be keys to targeting myriad mutations in order to kill tumors where they are. Those drug combinations that demonstrate they can do their jobs – slowing tumor growth, increasing chances of survival, taming toxicity – will be selected for clinical application.
Immunotherapy leverages T-cells, the immune system’s most able fighters, to help in the overall goal of extending patients’ survival. One of the most challenging aspects of pediatric brain tumors is the body does a very good job of shielding the brain from potential pathogens. Precise drug delivery means finding innovative ways for therapeutics to cross the blood-brain barrier in order to reach the tumor. The team has identified one such potential target, the protein NG2, which may represent a good target for immune therapy. The protein is expressed in primitive cells that have not become specialized – meaning there may be an opportunity to intervene before it is driven to become a tumor cell.
Research at a Glance: Clinicopathology of diffuse intrinsic pontine glioma and its redefined genomic and epigenomic landscape
Research at a Glance: The role of NG2 proteoglycan in glioma
Research at a Glance: Spatial and temporal homogeneity of driver mutations in diffuse intrinsic pontine glioma
Research at a Glance: Histological and molecular analysis of a progressive diffuse intrinsic pontine glioma: a case report
June 6, 2016 –Targeting tumors more precisely, with fewer lasting side effects for kids
Pediatric patients with cancer are often treated with a cocktail of therapies to attack the disease through a variety of mechanisms. While this approach has been instrumental in saving children’s lives, the life-saving therapies can be accompanied by acute side effects, and the treatments may have lingering impacts as cancer survivors enter adulthood. Magnetic resonance-guided high-intensity focused ultrasound (MR-HIFU) holds the promise of surgically removing large tumors without exacting the same array of harsh side effects. Ultrasound relies on high-frequency sound waves to make diagnostic images, and those same sound waves can be used therapeutically to destroy tumors. Layering on MR imaging gives clinicians the ability to precisely guide the ultrasound therapy in real time. A study led by Children’s National Health System researchers and clinicians is using MR-HIFU for the first time in children to examine its safety and feasibility.
May 11, 2016 – Quantitative MRI criteria for optic pathway enlargement in neurofibromatosis type 1
Symptoms of neurofibromatosis type 1 (NF1) vary widely, but the condition is characterized by changes in skin pigmentation and growth of tumors along nerves. The research team sought to determine quantitative size thresholds for enlargement of the optic nerve, chiasm, and tract in children aged 0.5 to 18.6 years with NF1. The study, published in Neurology, found that quantitative reference values for anterior visual pathway enlargement will enhance development of objective diagnostic criteria for optic pathway gliomas secondary to NF1.
Source: P.J. Hanley, J. J. Melenhors, S. Nikiforow, P. Scheinberg, J.W. Blaney, G. Demmler-Harrison, C.R. Cruz, S. Lam, R.A. Krance, K.S. Leung, C.A. Martinez, H. Liu, D.C. Douek, H.E. Heslop, C. M. Rooney, E.J. Shpall, A.J. Barrett, J.R. Rodgers, and C.M. Bollard. “CMV-Specific T-Cells Generated From Naïve T-Cells Recognize Atypical Epitopes and May Be Protective In Vivo.” Published by Science Translational Medicine on April 29, 2015
Patients with leukemia, lymphoma, other cancers, and genetic disorders who receive stem cell or cord blood transplants face the post-transplant risk of developing a life-threatening infection with adenovirus, cytomegalovirus (CMV), or Epstein-Barr virus (EBV).
The study reports the results of a head-to-head comparison of two powerful immunotherapeutic strategies to thwart such viral infections. Both therapeutic approaches leverage the power of multivirus-specific, donor-derived T-cells (mCTL), which are highly skilled at recognizing foreign invaders and, in the case of the peripheral blood cells, have long memories of past battles.
The award-winning paper, “Multivirus-Specific T Cells From Both Cord Blood and Bone Marrow Transplant Donors” was presented during the International Society for Cellular Therapy (ISCT) 2016 Annual Meeting, held from May 25 through May 28, in Singapore. The abstract’s lead author, Patrick J. Hanley, PhD, Laboratory Facility Director of Children’s Cellular Therapy and Stem Cell Processing facility, was recognized by ISCT with a Young Investigator award during the meeting.
Nine research scientists and clinicians affiliated with Children’s National Health System are co-authors of a paper, including Michael D. Keller, MD, the lead clinical investigator of the peripheral blood T-cell study, and Catherine M. Bollard, MBChB, MD, the study’s sponsor and Director of Children’s National Program for Cell Enhancement and Technologies for Immunotherapy.
After certain treatments, some cancer patients’ bodies are stripped of their natural ability to fight infection. The stem cell or the cord blood transplant restores the body’s ability to produce a full complement of blood cells, including infection-fighting white blood cells. As a further boost to these patients, the T-cells are trained to spot and neutralize all three potentially lethal viruses (CMV, EBV, and adenovirus) simultaneously. The personalized cell therapy can be accomplished in a single infusion and administered in the outpatient setting.
In the phase I perspective study, the personalized T-cells were grown from peripheral blood (PB) of adult donors who were seropositive for CMV, a relative of the virus that causes chickenpox, and were also coaxed to grow from naïve cord blood (CB). These naïve cells need additional training since they have never been to battle.
Since the mid-1990s, PB has been shown to be effective for such use. Hanley says that fewer than one dozen facilities in the United States perform PB antiviral T-cell infusions. Of that selective group, Children’s National is the only U.S. location that also grows the specialized T-cells from naïve CB, a procedure that takes a bit longer to accomplish but can help patients whose blood type is in short supply.
Thirteen patients were infused with PB mCTL, and 12 patients were infused with the T-cells derived from cord blood. Patients received their transfusions from 35 to 384 days after their stem cell or cord blood transplant. Within four weeks, the research team saw up to a 160-fold increase in virus-specific T-cells, a development that coincided with patients’ response to therapy. “The overall … response rate in both groups was 81 percent,” writes Hanley and colleagues.
Eight patients had a complete response. Five had a partial response. Nine remain free of infection/reactivation. What’s more, the patients’ restored immunity was durable with at least one patient remaining free of infection two years after treatment – without the need for pharmaceuticals administered in a hospital setting, which exacts a higher overall cost to the healthcare system.
“This study demonstrates that mCTL derived from the PB of seropositive donors, as well as the CB of virus naïve donors, expand in vivo and are active against multiple viruses. Furthermore, by restoring immunity to multiple viruses simultaneously, the need for continued prophylaxis with pharmacotherapy is eliminated, thus, improving the efficiency and cost-effectiveness of protecting SCT and CBT recipients from these potentially lethal viruses,” Hanley and co-authors conclude.
Related Resources: Research at a Glance
Questions for Future Research
Source: “Histological and Molecular Analysis of a Progressive Diffuse Intrinsic Pontine Glioma and Synchronous Metastatic Lesions: A Case Report.” J. Nazarian, G.E. Mason, C.Y. Ho, E. Panditharatna, M. Kambhampati, L.G. Vezina, R.J. Packer, and E.I. Hwang. Published by Oncotarget on June 14, 2016.
Questions for Future Research
Source: “A Phase 1 Perspective: Multivirus-Specific T Cells From Both Cord Blood and Bone Marrow Transplant Donors.” Hanley, P., M. D. Keller, M. Martin Manso, C. Martinez, K. Leung, C.R. Cruz, C. Barese, S. McCormack, M. Luo, R.A. Krance, D. Jacobsohn, C. Rooney, H. Heslop, E.J. Shpall, and C. Bollard. Presented during the International Society for Cellular Therapy 2016 Annual Meeting, Singapore. May 26, 2016.
Questions for Future Research
Source: “Spatial and Temporal Homogeneity of Driver Mutations in Diffuse Intrinsic Pontine Glioma.” H. Nikbakht, E. Panditharatna, L.G. Mikael, R. Li, T. Gayden, M. Osmond, C.Y. Ho, M. Kambhampati, E.I. Hwang, D. Faury, A. Siu, S. Papillon-Cavanagh, D. Bechet, K.L. Ligon, B. Ellezam, W.J. Ingram, C. Stinson, A.S. Moore, K.E. Warren, J. Karamchandani, R.J. Packer, N. Jabado, J. Majewski, and J. Nazarian. Published by Nature Communications on April 6, 2016.
Questions for Future Research
Q: Because healthy oligodendrocyte progenitor cells are important for the child’s developing brain, how could further characterization of NG2 isoforms help prevent drugs from damaging those beneficial cells?
Q: Could NG2-binding peptides cross the blood-brain barrier to deliver anti-cancer therapies precisely to tumor sites?
Source: “The Role of NG2 Proteoglycan in Glioma.” S. Yadavilli, E.I. Hwang, R. J. Packer, and J. Nazarian. Published by Translational Oncology on February 2016.
What’s New: Frequently found genetic alterations prevalent in DIPGs
Source: “Clinicopathology of Diffuse Intrinsic Pontine Glioma and Its Redefined Genomic and Epigenomic Landscape.” E. Panditharatna, K. Yaeger, L.B. Kilburn, R.J. Packer, and J. Nazarian. Published by Cancer Genetics on May 1, 2015.