A rare opportunity

I presented the Alliance's poster at AACR.

By Suzie Siegel
Someday all cancers will be rare.

So says Rick Pazdur, MD, director of the FDA's Oncology Center of Excellence. As physicians and scientists learn more about genetics, they are breaking down cancers into smaller and smaller categories that may respond to specific drugs.

Dr. Pazdur spoke this spring to a group of advocates who won scholarships to attend the annual meeting of the American Association for Cancer Research (AACR) in Washington, D.C. I was the only sarcoma advocate in the Scientist↔Survivor Program, but that’s not surprising, considering sarcoma represents only 1 percent of adult cancer cases.

Carcinomas – what most people call cancer – are named for where they occur in the body, such as breast cancer or colon cancer. Sarcomas are named for the cells in which they are thought to come from. But sarcoma subtypes are now being divided still further.

“Histological classifications are now supplemented by molecular subclassifications, which strongly influence prognosis and guide treatment decisions. More than ever, sarcomas are regarded as a complex and fragmented collection of uncommon entities, altogether rare and often extremely rare,” Jean-Yves Blay, MD, PhD, director of the Centre Léon Bérard in Lyon, France, wrote in Future Medicine. An example is liposarcoma, which arises in fat cells. It has been separated into well-differentiated, dedifferentiated, myxoid and pleomorphic liposarcoma.

Results of the largest study of sarcoma genetics were published last year, with more data coming from the Garvan Institute in Sydney, Australia. It leads the International Sarcoma Kindred Study, which is looking at the genetics of more than 1,000 people.

We also await more results from The Cancer Genome Atlas, a project of the National Cancer Institute in Bethesda, Md. Anna Barker, PhD, chair of the AACR survivor program, helped conceive and develop TCGA when she was deputy director of the NCI.  She is now co-director of Complex Adaptive Systems and director of the National Biomarker Development Alliance at Arizona State University in Tempe.

At the recent American Society of Clinical Oncology (ASCO) meeting in Chicago, a study was presented on an experimental drug named larotrectinib that targets TRK gene fusions. Some sarcoma patients should benefit.
 
The clinical trial was done basket-style, enrolling patients with different types of cancer. Getting enough sarcoma patients for meaningful research takes time; I think we benefit from basket studies that include people with other cancers. In a sense, many clinical trials in sarcoma have been basket studies because they enrolled people with different sarcoma subtypes.

Dr. Rick Pazdur

Companies need clinical trials to get their drugs approved. But Dr. Pazdur believes: “Clinical trials are here to serve the patient. Patients are not here to serve clinical trials.”

The FDA used to require companies prove that their drugs would help patients live longer. This can be hard to measure, in part because some patients have very advanced cancer by the time they go on a clinical trial. The FDA now approves some drugs if patients can go longer without their cancer progressing than they could on a standard drug. This change allowed trabectedin (Yondelis) to be approved for liposarcoma and leiomyosarcoma, for example.

I hope the FDA will use similar criteria to approve aldoxorubicin, which I wrote about in 2014.

Dr. Pazdur wants to expand access to clinical trials for patients who might not qualify because of how advanced their cancer is. He has suggested other innovations here and here. But he said he can do only so much because drug companies pay for almost all clinical trials. They control eligibility requirements, except where safety and a few other issues are concerned.

His desire to expand access stops at the “Right to Try” laws, which allow people with terminal illnesses to take unapproved drugs outside of trials. He said these laws directly contradict the Food, Drug and Cosmetic Act, which requires the FDA to oversee drug safety.

Trials are much more likely to be done in North America, Europe and Asia than in South America or Africa. That needs to be rectified, Dr. Pazdur said, to see if different populations respond differently to new drugs.

The AACR meeting drew 22,850 people from 60 countries, said CEO Margaret Foti, MD, PhD. She has spent 35 years with the organization and sees a much greater emphasis on cancer prevention.

Sarcoma researchers have been active in the AACR since its founding 110 years ago. The founders included Dr. William Coley, considered the father of immunotherapy, and Dr. James Ewing,  AACR’s first president. Dr. Ewing discovered the bone sarcoma that bears his name.  

George Demetri, MD, director of the Center for Sarcoma and Bone Oncology at Dana-Farber Cancer Institute in Boston, is on AACR’s current board. He decries cuts in federal funding for cancer research. “I do not believe for one second this is what the public wants.” 

Dr. Drew Pardoll

Recent gains in immunotherapy show the importance of investing in science even when the payoff isn’t immediate, said Drew Pardoll, MD, PhD, director of the Bloomberg-Kimmel Institute for Cancer Immunotherapy at Johns Hopkins University in Baltimore. He has been working in the field more than 30 years.

“Cancer genetics has married immunotherapy,” said Dr. Pardoll, discussing how pembrolizumab (Keytruda) works in people with DNA mismatch-repair deficiency (MMR), which causes microsatellite instability (MSI).

After approving Keytruda last month for this genetic defect, the FDA noted: “This is the first time the agency has approved a cancer treatment based on a common biomarker.”

Stefanie Joho

The evidence for supporting immunotherapy stood by Dr. Pardoll’s side: Stefanie Joho of Philadelphia, whose colon cancer disappeared after she joined a clinical trial for Keytruda. She recalled when she was inoperable: “The doctors say there’s nothing they can do. There’s no more hope. I’m ready to give up. I basically feel dead.”

Then her sister found the study at Hopkins. “The public has a misconception of clinical trials. I did, too. I was under the impression they were the last resort. I’d just be a guinea pig. But right now, you could be getting the most precise treatment for your specific kind of cancer.

“How do you go through an experience like this and not want to advocate, not just for other patients, but for cancer research?”

Suzie Siegel, a 15-year survivor of leiomyosarcoma, is a former board member of the Sarcoma Alliance. 

'Basic Science of Sarcomas' fascinates

By Suzie Siegel

As a patient who last took biology 40 years ago, much of what was presented at the American Association for Cancer Research’s “Basic Science of Sarcomas” conference flew over my head. But even if you and I don’t know what a TLR4 agonist GLA-SE is, I hope you can get a sense of the ways doctors and scientists are working on better treatments for sarcoma.

Michael Dyer, PhD

At the first AACR conference on sarcoma this fall, the first presentation was by Michael Dyer, PhD, of St. Jude Children’s Research Hospital in Memphis. In 2013, he helped launch the Childhood Solid Tumor Network, which “offers the world's largest and most comprehensive collection of scientific resources for researchers studying pediatric solid tumors and related biology,” according to its website. It shares resources with other researchers without asking for credit, and shares its data with drug companies.

Dr. Dyer used mice with a piece of human Ewing sarcoma grafted onto them (“xenografts”). He gave them a PARP inhibitor with the drugs irinotecan and temozolamide. Increasing the dose of irinotecan made the combination much more effective.

“Irinotecan has been around for a million years,” Kurt Weiss, MD, of the University of Pittsburgh Medical Center, said later. “Combination therapy is going to be huge. If we had not one more drug developed, we’d be fine. We need to use drugs smarter.”

Testing drug combinations takes time, money and the cooperation of the companies that own the different drugs. As researchers learn more about the biology of different cancers, they are making better guesses of what combinations will work.

Karen Cichowski, PhD

Karen Cichowski, PhD, of Brigham and Women’s Hospital in Boston, discussed a phase 2 trial that found selumetinib alone was not effective against soft-tissue sarcoma, but did show activity against leiomyosarcoma when combined with temsirolimus. The dosage of temsirolimus was reduced to lessen the side effects.

She taught us that researchers may not grasp how harsh drugs will be on humans, just by trying them in mice first.

Dr. Cichowski is also working on adding an mTOR inhibitor to either HDAC or HSP90 inhibitors for malignant peripheral nerve sheath tumors.  

Elaine Mardis, PhD

For genomic testing, doctors cannot just collect DNA from a tumor, said Elaine Mardis, PhD, co-director of the Genome Institute at Washington University in St. Louis. They also need RNA as well as a sample of normal tissue for comparison. But such a comprehensive study cannot guarantee a doctor will find a way to treat the person’s cancer, she noted. A drug may not be available or sufficient by itself. Dr. Mardis, who is on the AACR board, works on The Cancer Genome Atlas (TCGA) sarcoma project. All the results are made public for others to use.

Cancer gobbles up more glucose than does normal tissue. The trick is to starve the tumor, but not other cells. “The brain needs glucose, too,” said Matthew Vander Heiden, MD, PhD, of the Massachusetts Institute of Technology in Cambridge. His lab looks at the metabolism of cancer cells, with the realization that the tumor environment and tumor cell of origin make a difference. The metabolism of leiomyosarcoma of the kidney, for example, will differ from a bone sarcoma, he said.

Brian Van Tine, MD, PhD

Synovial sarcoma cells are "unusually addicted to glucose" and die quickly when deprived of it, said Brian Van Tine, MD, PhD, of Washington University in St. Louis. He bought the anabolic steroid DHEA to alter glucose biology and tried it on xenografted mice. He hopes to open a clinical trial with pharmaceutical-grade DHEA.

Rama Khokha, PhD, of the Prince Margaret Cancer Centre in Toronto, said a study of RANKL signaling in osteosarcoma led to a phase 2 clinical trial for denosumab. She helped develop Lentihop, a technology that uses lentiviruses to inject normal cells with elements to turn them into cancer. The process can help identify cancer genes and pathways.  She is offering the tech to others.

Cigall Kadoch, PhD

Cigall Kadoch, PhD, of Dana-Farber Cancer Institute in Boston, discussed her work to develop treatment for cancers, such as synovial sarcoma, that are driven by BAF complex alteration.

Research on an LSD1 inhibitor for Ewing sarcoma led to the drug SP-2577, said Stephen Lessnick, MD, PhD, of Nationwide Children’s Hospital in Columbus, Ohio. “This is a very, very encouraging molecule in pre-clinical development.”  

Pancras Hogendoorn, MD, PhD, of Leiden University in the Netherlands, also studies Ewing. By using zebrafish, he can see a 3-D image of a tumor in a living animal.

The number of possible combinations of immune therapy drugs outnumber sarcoma patients, and collaboration will be needed to figure out what works, said Robert Maki, MD, PhD, of Mount Sinai Medical Center in New York. With 70+ subtypes of sarcoma, he wondered whether researchers will focus on the biology first or look at patients who have exceptional responses.

A promising sign is the recent announcement by some of the companies with immunotherapy drugs that they are working with one another on combinations. 

Karolina Palucka, MD, PhD

We might not need to determine all the mutations of a cancer if we could turn on the dendritic cells in and around it, said Karolina Palucka, MD, PhD, of the Jackson Laboratory for Genomic Medicine in Farmington, Conn. But, she warned, doctors need to be careful in injecting a vaccine into a tumor because it could affect cells throughout the body.

Seth Pollack, MD

Macrophage and checkpoint inhibitors combined may be important for leiomyosarcoma, said Seth Pollack, MD, of the Fred Hutchinson Cancer Research Institute in Seattle. His research also includes a phase 1 trial for TLR4 agonist GLA-SE and radiation therapy for metastatic sarcoma.

David Langenau, PhD, of Harvard, described how NOTCH/SNAI1 inhibition may help children whose embryonal rhabdomyosarcoma has returned.

The Pax3:Foxo1 fusion gene can cause chemotherapy to fail in some children with alveolar rhabdomyosarcoma, said Charles Keller, MD, of the Children’s Cancer Therapy Development Institute of Beaverton, Ore. His team is researching whether the addition of the HDAC inhibitor entinostat to chemo will make it more effective.  

Questions? Ask them in the comment section; I’ll answer them the best that I can.