An ongoing phase 0/1 clinical trial (NCT06072586) is evaluating the efficacy of BDTX-1535, a novel, brain-penetrant, fourth-generation EGFR inhibitor, in patients with recurrent high-grade glioma harboring oncogenic EGFR mutations. The study, led by researchers at the Ivy Brain Tumor Center, aims to address the limitations of previous EGFR-targeted therapies that failed due to poor blood-brain barrier penetration.
The trial's primary objective is to determine the extent of BDTX-1535 accumulation within tumor tissue. Patients demonstrating adequate drug penetration may be eligible for an expansion phase to continue treatment. Researchers are also employing a liquid biopsy program, sampling cerebrospinal fluid to monitor tumor evolution and identify potential resistance mechanisms.
Overcoming Challenges in Glioblastoma Treatment
EGFR has long been recognized as a relevant target in neuro-oncology, particularly in glioblastoma, where EGFR mutations are common. However, earlier attempts to target EGFR in brain tumors were hampered by the inability of drugs to effectively cross the blood-brain barrier. BDTX-1535 represents a new approach, specifically designed to overcome this obstacle.
"In neuro-oncology, people have been trying to target EGFR, which has been quite commonly mutated in glioblastoma, for a while," said Shwetal Mehta, PhD, deputy director and pre-clinical core leader at the Ivy Brain Tumor Center. "Normally, people don’t want to get into the space, but this drug that we are testing is a fourth-generation EGFR inhibitor. It’s brain-penetrant."
Monitoring Treatment Response and Resistance
The clinical trial incorporates a comprehensive approach to assess drug activity and identify potential resistance mechanisms. Researchers are analyzing pre- and post-treatment biopsies to evaluate the impact of BDTX-1535 on downstream EGFR signaling pathways. Additionally, the liquid biopsy program allows for real-time monitoring of tumor evolution through cerebrospinal fluid analysis.
"We have a whole new program of liquid biopsy where we sample cerebrospinal fluid from patients while they’re on treatment to see if the tumor is evolving or changing," Mehta explained. "If that can immediately give us an answer even before we start seeing symptoms of progression, we might see if there is a way to pivot, add a new therapy, and help these patients."
Future Directions in Brain Cancer Therapy
Beyond EGFR inhibition, the Ivy Brain Tumor Center is exploring other novel therapeutic strategies for brain cancer, including proteolysis targeting chimeras (PROTACs) and antibody-drug conjugates (ADCs). These approaches have shown promise in other areas of oncology and are now being investigated for their potential in treating brain tumors.
"Neuro-oncology is only now trying to test these things out, and we are uniquely situated to ask some of the important questions for these types of molecules," Mehta said. "That’s where our focus is going to be in the coming years, and we’re very excited about that."
