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STX-478 Demonstrates Promise in Heavily Pre-Treated Patients With PI3Kα-Mutated Solid Tumors
Alberto Montero, MD, University Hospitals Seidman Cancer Center, Cleveland, Ohio, discusses phase 1/2 study results which demonstrated that STX-478, a first-in-human mutant-selective PI3Kα inhibitor, shows promising activity among patients with heavily pre-treated PI3Kα-mutated solid tumors.
Dr Montero presented these results at the 2024 European Society of Medical Oncology (ESMO) Congress in Barcelona, Spain.
Transcript:
I am Alberto Montero, I'm a breast medical oncologist and the director of breast medical oncology at University Hospital Seidman Cancer Center in Cleveland, Ohio, and I'm here at ESMO.
My presentation today involved STX-478, which is an oral, mutation specific, PI3Kα inhibitor that preferentially targets the kinase and helical domain mutated tumors. In our presentation we showed in the phase 1 trial, the drug was escalated to 160 milligrams, and the maximally tolerated dose of this drug was 100 milligrams and at different dose ranges we showed that we saw several responses.
The overall response rate for the overall cohort was approximately 21% and in metastatic ER-positive breast cancer, which represented about half of all patients, the overall response rate was 23%. We saw very few severe toxicities. [It’s] important to note that we didn't see any of the typical wild-type toxicities that we observe with other PI3Kα inhibitors. We didn't have any patient with any grade 3/4 hyperglycemia, mucositis, rash, or diarrhea.
I'm very excited about this data because it shows the advantage of utilizing a mutation specific inhibitor of PI3Kα, which is a very commonly mutated gene in cancer.
Source:
Montero AJ, Giordano A, Jhaveri K, et al. First-in-human results of STX-478, a mutant-selective PI3Kα inhibitor, in advanced solid tumor patients. Presented at 2024 ESMO Congress. September 13-17, 2024. Abstract LBA27
