Quadriga BioSciences Reports Promising Phase IIa Results for QBS72S in Breast Cancer Leptomeningeal Disease
Key Insights
Quadriga BioSciences (search) announced positive Phase IIa interim results for QBS72S, showing 90%, 60%, and 40% survival rates at 1, 3, and 12 months respectively in breast cancer patients with leptomeningeal disease.
The LAT1-targeted chemotherapeutic demonstrated both radiographic stability and improvements in neurologic symptoms, with 4 out of 10 patients surviving beyond 12 months.
QBS72S was well tolerated in heavily pre-treated patients and addresses a critical unmet need, as leptomeningeal disease currently has no approved treatments and typically carries a 2-4 month survival expectation.
Quadriga BioSciences (search) announced encouraging Phase IIa interim results for QBS72S, a novel chemotherapeutic designed to cross the blood-brain barrier, in breast cancer patients with leptomeningeal disease (LMD). The data, presented at the 7th Quadrennial World Federation of Neuro-Oncology Societies and 30th Annual Meeting of the Society for Neuro-Oncology in Honolulu, Hawaii, showed survival rates of 90%, 60%, and 40% at 1, 3, and 12 months respectively.
Clinical Trial Results
The single-arm, open-label study conducted by Stanford University School of Medicine's Department of Neurosurgery evaluated QBS72S in patients with LMD, a deadly cancer complication with no approved treatments and an expected survival of 2-4 months. The Phase IIa results demonstrated both radiographic and symptomatic improvements, with two long-term responders identified among the patient cohort.
"The Phase IIa results provide important early clinical signals that reinforce the potential of QBS72S to meaningfully impact outcomes for patients with LMD," said Gordon Ringold, Ph.D., CEO of Quadriga BioSciences (search). "Seeing radiographic stability alongside improvements in neurologic and physical symptoms, as well as survival beyond 12 months in 4 out of 10 patients, is very encouraging."
Mechanism of Action and Drug Design
QBS72S represents a first-in-class chemotherapeutic agent that mimics an aromatic amino acid for cellular uptake by the L-type amino acid transporter 1 (LAT1). This design enables the drug to cross the blood-brain barrier and selectively target rapidly growing cancer cells. Once inside the cell, QBS72S causes double-stranded DNA breaks resulting in cell death. Most aggressive cancers express high LAT1, which is commonly associated with poor prognoses.
Addressing Unmet Medical Need
Leptomeningeal disease occurs when cancer cells spread to the membranes surrounding the brain and spinal cord, leading to significant neurologic symptoms, rapid clinical decline, and poor prognosis. Breast cancer is one of the most common solid tumors to spread to the brain, making LMD a serious and challenging complication.
"Available treatment options remain limited, in part due to challenges with drug delivery across the blood-brain barrier," said Ron Weitzman, M.D., CMO of Quadriga BioSciences (search). "The clinical findings presented at WFNOS-SNO suggest that QBS72S reaches the cancer cells and may offer meaningful benefit for patients with advanced metastatic disease."
Study Design and Future Development
The Phase 2 open-label clinical trial is designed to assess safety, tolerability and efficacy of QBS72S in patients with brain metastases from breast cancer. The study will recruit up to 35 patients with the primary objective of determining preliminary efficacy through overall response rate. Secondary endpoints include progression-free survival, overall survival, duration of response, and adverse events.
QBS72S was well tolerated in heavily pre-treated patients, supporting continued development to address the critical unmet need in metastatic breast cancer. The findings reinforce Quadriga BioSciences (search)' commitment to advancing QBS72S toward a potential therapeutic option for patients with leptomeningeal disease and other central nervous system manifestations of metastatic breast cancer.