ATLANTA, May 28, 2020 – Recurrent or refractory malignant brain tumors are stubborn, unmanageable and resistant to treatment. For kids with these tumors, currently known and recognized standard treatments have failed, and investigational trials remain a limited option. With support from the Peach Bowl LegACy Fund, a $20 million commitment to launch new pediatric oncology clinical trials through Peach Bowl, Inc., and CURE Childhood Cancer, Tobey MacDonald, MD, Director of the Neuro-oncology Program at the Aflac Cancer and Blood Disorders Center of Children’s Healthcare of Atlanta, is now recruiting patients for one such trial testing a new therapy with a powerful molecular target and immunotherapy combination.
The treatment known as WP1066 inhibits STAT3, a cancer stem cell protein that regulates gene activity while simultaneously activating the immune response. Dr. MacDonald and Co-Principal Investigator Kavita Dhodapkar, MD, Director of Pediatric Immuno-Oncology at the Aflac Cancer and Blood Disorders Center, hope this dual-acting treatment will slow tumor growth, eventually enabling a path to recovery.
“If we hit the stem cells and stimulate the immune system while the inhibited stem cells are in a weakened condition, the immune system, much more powerful now, can potentially come in and eliminate those inhibited stem cells,” said Dr. MacDonald, who is also a Professor in the Emory University School of Medicine Department of Pediatrics. “We’re aiming for a double knock-out, hitting the stem cells that you need to hit and eliciting an immune response at the same time.”
WP1066, currently being studied in adults at the MD Anderson Cancer Center, is the first drug of its kind to pack this powerful double punch. Drs. MacDonald and Dhodapkar, who is also an Associate Professor in the Emory University School of Medicine Department of Pediatrics, will study it in children with high-grade gliomas at the Aflac Cancer and Blood Disorders Center, including diffuse intrinsic pontine gliomas, medulloblastomas and ependymomas. Together, these tumors make up more than 90% of brain tumors in children, and all three have shown cancer-stem-cell dependency on STAT3, a key regulator of brain tumors in children. Children with more rare brain tumors and no effective treatment will also be eligible for the Phase 1 trial.
During the study, Drs. MacDonald and Dhodapkar will try to establish the proper dosage by testing toxicity and the maximum amount tolerated for each liquid treatment given orally, two weeks on and two weeks off, for up to a year. About 20 patients ages 3 to 25 will be tested over the course of two and a half years. Later, the Phase 2 trial will assess WP1066 alone or in combination with another therapy to optimize its effect. The team will also measure immune response after it is given.
“Immune therapy has revolutionized cancer therapy in both adults and kids,” Dr. MacDonald said. “The power of the immune system is far greater than any drug we could manufacture.”
Furthermore, as a targeted treatment, the STAT3 inhibitor will not damage healthy cells along with cancer cells like standard chemotherapy, potentially eliminating unwanted side effects such as nausea and vomiting. Developed by Moleculin Biotech Inc., WP1066 is the first drug to turn off STAT3 in all types of cancers tested, including brain, melanoma, pancreatic and ovarian. Dr. MacDonald discovered the STAT3 stem cell protein more than 20 years ago while trying to find the source of a growth factor known as PDGFR.
“The literature has shown for years that STAT3 is critical for supporting the survival of cancer stem cells,” Dr. MacDonald said. “Now, we have a drug that may target it.”