The agency indicated that the use of atezolizumab (Tecentriq) and paclitaxel in patients with previously untreated, inoperable, locally advanced, or metastatic triple negative breast cancer was not effective in treating the disease.
The FDA issued an alert notifying health care professionals, oncology clinical investigators, and patients that a clinical trial studying the use of atezolizumab (Tecentriq) and paclitaxel in patients with previously untreated, inoperable, locally advanced, or metastatic triple negative breast cancer (TNBC) failed to meet its primary end point in effectively treating the disease.1
The multicenter, randomized, double-blind, placebo-controlled phase 3 IMpassion131 study assessed the efficacy and safety of atezolizumab in combination with paclitaxel compared to placebo plus paclitaxel in 651 individuals with previously untreated, inoperable, locally advanced, or metastatic TNBC.2 Patents were randomized 2:1 to receive the atezolizumab combination or placebo plus paclitaxel.
The primary end point was progression-free survival (PFS) per investigator assessment (RECIST 1.1) in a PD-L1-positive population of patients, followed by intention-to-treat (ITT) populations. Key secondary end points included overall survival (OS), objective response rate, and duration of response in the PD-L1-positive and ITT populations.
Ultimately, the combination treatment with atezolizumab and paclitaxel did not significantly reduce the risk of cancer progression and death compared with placebo and paclitaxel in the PD-L1-positive population of patients. Additionally, interim OS results favored paclitaxel plus placebo over paclitaxel plus atezolizumab in both the PD-L1-positive population and ITT population.
Currently, this treatment combination is not approved for use in patients with breast cancer. However, atezolizumab in combination with paclitaxel protein-bound (Abraxane) is already approved for the treatment of adult patients with metastatic TNBC whose tumors express PD-L1, as determined by an FDA-approved test. Continued approval for this indication may be contingent upon proven benefit of the treatment combination in additional trials.
Given the study results, the FDA indicated that health care professionals should not replace paclitaxel protein-bound with paclitaxel in clinical practice. Additionally, patients already taking atezolizumab and paclitaxel for other approved uses should continue to take their medication as directed by their provider.
Moving forward, the FDA will review the findings of the IMpassion131 study and will communicate new information regarding the study results, as well as any potential changes to prescribing information. The FDA is also evaluating the use of atezolizumab and paclitaxel in ongoing clinical trials for breast cancer and will recommend additional changes as necessary.
1. FDA alerts health care professionals and oncology clinical investigators about efficacy and potential safety concerns with atezolizumab in combination with paclitaxel for treatment of breast cancer [news release]. Published September 8, 2020. Accessed September 8, 2020. https://www.fda.gov/drugs/drug-safety-and-availability/fda-alerts-health-care-professionals-and-oncology-clinical-investigators-about-efficacy-and
2. Roche provides update on Phase III study of Tecentriq in combination with paclitaxel for people with metastatic triple-negative breast cancer [news release]. Basel. Published August 6, 2020. Accessed September 8, 2020. https://www.roche.com/media/releases/med-cor-2020-08-06.htm..htm