The approval is based off of progression-free survival data from the IMpassion130 study and represents the first approved immunotherapy regimen for breast cancer.
The FDA has granted accelerated approval for atezolizumab (Tecentriq) in combination with nab-paclitaxel (Abraxane) for the treatment of adults with unresectable locally advanced or metastatic triple-negative breast cancer—a form of breast cancer with few treatment options—who express programmed death ligand-1 (PD-L1). The combination is the first approved immunotherapy regimen for breast cancer.
The agency also approved the VENTANA PD-L1 Assay as the first companion diagnostic for identifying which patients should receive atezolizumab.
The approval was based off of progression-free survival (PFS) data from the phase 3 IMpassion130 study, which demonstrated that among 902 patients who had not received previous chemotherapy for metastatic disease, the combination reduced the risk of disease worsening or death by 40%.
“The Tecentriq regimen is an exciting new treatment for certain people living with metastatic triple-negative breast cancer, a difficult-to-treat disease,” said Hayley Dinerman, executive director, Triple Negative Breast Cancer Foundation, in a statement. “Chemotherapy alone has been the mainstay of treatment for many years, so it’s encouraging to now have an immunotherapy combination available for people with PD-L1 positive disease.”
During the study, patients were randomized to receive either atezolizumab 840 mg or placebo on days 1 and 15 of every 28-day cycle, plus nab-paclitaxel 100 mg/m2 on days 1, 8, and 15 of every 28-day cycle. For patients treated with the atezolizumab combination, median PFS was 7.2 months, compared with a median PFS of 5.5 months among patients receiving chemotherapy alone. Among patients expressing PD-L1, median PFS was 7.4 months for patients receiving the atezolizumab combination and 4.8 months for patients receiving chemotherapy alone.
The objective response rate (ORR) among patients receiving the atezolizumab combination was 53% while ORR among patients receiving chemotherapy alone was 33%. While overall survival data are immature, an interim analysis showed that median overall survival was 25 months and 15.5 months, respectively.
Throughout the study, the most common grade 3 or 4 side effects included neutropenia, tingling or numbness in the hands and feet, low blood potassium level, pneumonia, and low red blood cell count.
According to the FDA, continued approval of this combination in this treatment setting is contingent upon a confirmatory trial.