Bria-IMT Plus Immunotherapy Shows Early Promise in Breast Cancer Brain Metastasis

Giuseppe Del Priore, MD, MPH

The targeted cell-based immunotherapy Bria-IMT (SV-BR-1-GM) in combination with an immune checkpoint inhibitor elicited an antitumor response, including the complete resolution of a breast cancer metastasis in the right temporal lobe region of the brain, in a patient treated in a phase 1/2 trial (NCT03328026).¹

The patient’s temporal lobe tumor was no longer detectable via imaging taken at 8 and 11 months of treatment, and their eye-bulging orbital lesion has continued to shrink. This patient also experienced a sustained decrease in tumor markers, which confirmed the imaging results showing tumor reduction.

“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 [with metastatic breast cancer],” Giuseppe Del Priore, MD, MPH, chief medical officer of BriaCell, stated in a news release. “The protracted time on therapy, now 1 year, attests to the excellent tolerability of the Bria-IMT regimen in combination with an immune checkpoint inhibitor, which is being used in our pivotal phase 3 [BRIA-ABC] study [NCT06072612].”

Previously, at 2 months, this patient, who had progressed on 8 prior regimens, including antibody-drug conjugate therapy, had achieved an initial partial response in the brain lesion, and had no detectable disease following 8 and 11 months of treatment. At the time of the data release, the patient had completed 17 cycles of study treatment, had been enrolled in the study for 12 months, and continued to receive treatment with the Bria-IMT regimen.

A news release published in July 2024 stated that this patient achieved a median progression-free survival (PFS) of longer than 9.1 months, which was noted by BriaCell Therapeutics Corp. to be higher than the median PFS observed in other breast cancer studies.²

In 2021, BriaCell reported a similar case of a patient with advanced breast cancer who achieved a response to Bria-IMT–based treatment, including complete resolution of an eye-bulging orbital tumor after 6 months of treatment.³ This patient, who had 2+ HLA and grade 2 disease, experienced an overall survival (OS) of 21.4 months. Prior to treatment with Bria-IMT, this patient had received 12 regimens with 16 agents, including 13 chemotherapies.

Furthermore, a cohort of patients (n = 9) experienced an average OS of 12.0 months with Bria-IMT plus checkpoint inhibitors, including pembrolizumab (Keytruda) and retifanlimab-dlwr (Zynyz). Additionally, the average OS was 13.4 months in patients with 2+ HLA matches (n = 5), 12.1 months in those with 1+ HLA matches (n = 9), and 12.5 months in those with grade 1 or 2 tumors (n = 6).

“Bria-IMT’s potential therapeutic impact is unprecedented in metastatic breast cancer in a brain metastasis setting. Our clinical findings, demonstrating significant tumor shrinkage in metastatic brain legions, may transform the way we treat patients with [metastatic breast cancer] brain metastasis and offers hope to [patients with] cancer and their families fighting this devastating disease,” William V. Williams, MD, FACP, the president and chief executive officer of BriaCell, added in the October 2024 news release.¹ “These results support Bria-IMT as a potential new therapeutic option for patients with [metastatic breast cancer] brain metastasis. We look forward to evaluating the brain metastasis patient subgroup in our ongoing pivotal phase 3 study in metastatic breast cancer.”

The BRIA-ABC trial is 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.⁴

References

1. BriaCell reports 100% resolution of brain metastasis in breast cancer patient with “eye-bulging” tumor. News release. BriaCell. October 1, 2024. Accessed October 2, 2024. https://briacell.com/briacell-reports-100-resolution-of-brain-metastasis-in-breast-cancer-patient-with-eye-bulging-tumor/
2. BriaCell quadruples progression free survival (PFS) in patient with “eye-bulging” metastatic breast cancer. News Release. BriaCell. July 18, 2024. Accessed October 2, 2024. https://briacell.com/briacell-quadruples-progression-free-survival-pfs-in-patient-with-eye-bulging-metastatic-breast-cancer/
3. BriaCell reports 12.0 months overall survival benefit in advanced breast cancer; 100% resolution of ‘eye-bulging’ tumor. News release. BriaCell. June 2, 2021. Accessed October 2, 2024. https://briacell.com/briacell-reports-12-0-months-overall-survival-benefit-in-advanced-breast-cancer-100-resolution-of-eye-bulging-tumor/
4. Study of the Bria-IMT regimen and CPI vs physicians’ choice in advanced metastatic breast cancer. (BRIA-ABC). ClincialTrials.gov. Updated August 26, 2024. Accessed October 2, 2024. https://clinicaltrials.gov/study/NCT06072612