Bria-IMT Combo Elicits Overall Survival Benefit in Metastatic Breast Cancer

"The [Bria-IMT] early data are quite encouraging from both efficacy and tolerability standpoints,” according to Sara A. Hurvitz, MD.

Combining Bria-IMT with immune checkpoint inhibitor therapy produced positive overall survival (OS) data among patients with late-stage metastatic breast cancer, according to findings from a phase 2 trial (NCT03328026).¹

Among a group of patients who were most recently treated beginning in 2022, the median OS with the Bria-IMT combination was 15.6 months, and the median progression-free survival (PFS) was 4.1 months. According to a press release on these data, the median OS for comparable populations of patients has ranged from 6.7 to 9.3 months based on previously published literature. Patients enrolled on the phase 2 trial are receiving the same formulation of Bria-IMT that investigators are evaluating as part of the phase 3 BRIA-ABC trial (NCT06072612).

According to a previous report on data from the phase 2 study in December 2023, the median OS was 13.4 months among 54 patients.² Additionally, patients did not experience any toxicities associated with treatment discontinuation at this time.

“[OS] in patients with heavily pre-treated metastatic breast cancer is very poor. The [Bria-IMT] early data are quite encouraging from both efficacy and tolerability standpoints,” Sara A. Hurvitz, MD, a professor of medicine at Fred Hutch Cancer Center and the University of Washington, medical advisory board member for BriaCell, the developers of Bria-IMT, and breast cancer tumor chair for ONCOLOGY^® said in a press release on these data.¹

Investigators of this phase 2 study included 54 patients with heavily pre-treated metastatic breast cancer who received an average of 6 prior lines of treatment. Of these patients, 37 received the phase 3 formulation of Bria-IMT, and 25 received therapy following the COVID-19 pandemic when full study operations resumed.

In addition to Bria-IMT, study therapy consisted of pretreatment with low-dose cyclophosphamide, post-inoculation plus low-dose interferon, and retifanlimab (Zynyz) at 375 mg intravenously every 3 weeks.³

The trial’s primary end points included safety in terms of adverse effects (AEs), serious AEs, abnormalities in safety laboratory parameters, and QT interval. Secondary end points included objective response rate, non-progressive rate, and duration of response.

Patients 18 years and older with histologically confirmed recurrent and/or metastatic breast cancer not amenable to local treatment were eligible for enrollment on the study. Additional requirements for study entry included having a life expectancy of 4 months or longer and an ECOG performance status of 0 to 2.

Those who have received concurrent or recent chemotherapy, immunotherapy, or major surgery within 3 weeks of entry were ineligible for enrollment. Patients were also unsuitable for enrollment if they had radiotherapy within 14 days of entry, no adequate recovery from toxicities associated with prior surgical intervention, New York Heart Association stage 3 or 4 cardiac disease, or active autoimmune disease requiring systemic therapy within 2 years of entry. A history of colitis, non-infectious pneumonitis requiring systemic steroids, or current pneumonitis or interstitial lung disease was also grounds for exclusion from the trial.

“The Bria-IMT regimen is the only investigational drug we have seen to show these impressive survival numbers in [patients with] heavily pre-treated metastatic breast cancer who have [progressed on] numerous prior treatments including immune checkpoint inhibitors and antibody drug conjugates. These survival and clinical benefit data support BriaCell’s hypothesis of additive and/or synergistic effects of immune checkpoint inhibitors with Bria-IMT and drive the ongoing pivotal study of our combination regimen in the treatment of metastatic breast cancer,” Giuseppe Del Priore, MD, MPH, chief medical officer at BriaCell, concluded.¹

References

1. BriaCell reports positive overall survival (OS) in metastatic breast cancer. News release. BriaCell Therapeutics Corp. September 11, 2024. Accessed September 12, 2024. https://tinyurl.com/5n8v7ayd
2. BriaCell highlights outstanding topline survival and clinical benefit data in advanced metastatic breast cancer at the 2023 SABCS. News release. BriaCell Therapeutics Corp. December 6, 2023. Accessed September 12, 2024. https://tinyurl.com/52ey3y9k
3. Combination study of SV-BR-1-GM with retifanlimab. ClinicalTrials.gov. Updated October 6, 2023. Accessed September 12, 2024. https://tinyurl.com/mr38fdwn