The FDA on Tuesday on the combination of atezolizumab (Tecentriq) plus paclitaxel for first-line treatment of metastatic triple-negative breast cancer (TNBC), after the randomized IMpassion131 trial suggested a potential survival detriment.
Based on positive progression-free survival (PFS) data, the PD-L1 immune checkpoint inhibitor atezolizumab was granted accelerated approval last year in combination with nab-paclitaxel (Abraxane) for patients with metastatic or locally advanced, unresectable TNBC whose tumors express PD-L1. At the time, immature overall survival results favored the combination as well.
In , a multicenter phase III trial, paclitaxel plus atezolizumab failed to significantly improve PFS over paclitaxel and placebo in PD-L1-positive patients with metastatic breast cancer, and overall survival was numerically worse in the investigational arm for both the PD-L1-positive subgroup and the total population.
"FDA will review the findings of IMpassion131 and will communicate new information regarding the IMpassion131 results and any potential changes to prescribing information," the agency stated. "FDA is also evaluating the use of atezolizumab and paclitaxel in ongoing clinical trials for breast cancer and will recommend additional changes as appropriate."
The agency warned against replacing nab-paclitaxel with paclitaxel in routine clinical practice for this patient population but said, "Patients taking atezolizumab and paclitaxel for other approved uses should continue to take their medication as directed by their health care professional."
In early August, drugmaker the unfavorable mortality trend, but noted that data were immature and that the trial was not sufficiently powered for such an analysis.
This isn't the first time an accelerated approval for atezolizumab has been called into question. In 2018, the FDA issued a similar safety alert after the data safety and monitoring committee for the IMVIGOR130 trial found decreased survival with the immunotherapy alone (versus standard chemotherapy) in advanced bladder cancer patients with low PD-L1 expression levels.