BriaCell Therapeutics' Bria-IMT (SV-BR-1-GM), a targeted cell-based immunotherapy, is showing early promise in treating metastatic breast cancer, including cases with brain metastasis. A patient in a phase 1/2 trial (NCT03328026) experienced complete resolution of a breast cancer metastasis in the brain's right temporal lobe after treatment with Bria-IMT in combination with an immune checkpoint inhibitor.
Complete Tumor Resolution
Imaging at 8 and 11 months showed no detectable tumor in the patient's temporal lobe, and an orbital lesion continued to shrink. Tumor marker levels also decreased, confirming the imaging results. "We believe that the complete tumor resolution in this patient with brain metastasis, plus other cases of significant anti-cancer clinical responses in our phase 2 patients with metastatic breast cancer brain metastasis, highlight the potential application of Bria-IMT in treating similar patients," stated Giuseppe Del Priore, MD, MPH, chief medical officer of BriaCell.
The patient had previously progressed on 8 prior regimens, including antibody-drug conjugate therapy, and had achieved an initial partial response in the brain lesion at 2 months. The patient completed 17 cycles of study treatment and had been enrolled in the study for 12 months at the time of the data release.
Survival Benefits
Data from the phase 2 trial (NCT03328026) showed a 1-year survival rate of 55% among patients with metastatic breast cancer. In a subset of patients undergoing treatment since 2022, the median overall survival (OS) with the Bria-IMT combination was 15.6 months, compared to a range of 6.9 to 9.8 months reported in prior literature for comparable patient groups. The median progression-free survival (PFS) in this group was 4.1 months.
Favorable Outcomes in Heavily Pretreated Patients
In a phase 1/2 study (NCT03328026), the addition of Bria-IMT to either retifanlimab-dlwr (Zynyz) or pembrolizumab (Keytruda) led to an overall survival benefit in heavily pretreated patients with advanced metastatic breast cancer. Among patients treated with the phase 3 formulation of Bria-IMT since 2022 (n = 25), the median overall survival (OS) was 15.6 months, and the median progression-free survival (PFS) was 4.1 months. These patients had received a median of 5.5 prior treatment lines (range, 2-13).
"The nearly 2-fold OS benefit we are seeing with the Bria-IMT regimen, together with the similar previously reported approximate doubling of PFS compared with literature controls, strongly support our belief that Bria-IMT could have a meaningful impact in the lives of heavily pretreated patients with metastatic breast cancer," said William V. Williams, president and chief executive officer of BriaCell.
Ongoing Phase 3 Trial
The BRIA-ABC trial (NCT06072612) is currently investigating Bria-IMT plus retifanlimab vs Bria-IMT monotherapy vs treatment of physician’s choice in patients with advanced metastatic or locally recurrent breast cancer for whom no approved alternative therapies are available. Interim results from the phase 3 study are expected in the second half of 2025.
"BriaCell’s clinical data supports our hypothesis that our regimen has prolonged survival in patients with metastatic breast cancer who otherwise have not responded to currently available treatments," said William V. Williams.
