Roche’s cancer immunotherapy drug Tecentriq (atezolizumab), a PD-L1 inhibitor, has received its fifth FDA approval, for advanced triple-negative breast cancer. Before this decision, no immunotherapies had been approved for any form of breast cancer.
The approval is only for locally advanced or metastatic triple-negative breast cancer expressing PD-L1, the molecule that locks onto PD-1 receptors on the surface of T cells. The PD-L1/PD-1 “handshake” blocks T cells from attacking the tumor. The first drugs that were developed to prevent the handshake, such as Bristol-Myers Squibb’s nivolumab and Merck’s pembrolizumab, target PD-1. Tecentriq binds with PD-L1, preventing the T-cell-sidelining handshake.
Despite all of the attention that immunotherapies have received, they help only a minority of patients. Data on overall survival aren’t final, but at last report, the Tecentriq patients with PD-L1-positive tumors had a median overall survival of 25 months, compared to 15.5 months for chemo-only patients.
Although the FDA approval was based on progression-free survival and on the fact that patients with triple-negative breast cancer have essentially no options, continued approval for triple-negative breast cancer “may be contingent upon verification and description of clinical benefit in a confirmatory trial(s),” Genentech, the Roche division that developed Tecentriq, said in a statement.
The American Cancer Society projects that about 40,000 people in the U.S. will be diagnosed with triple-negative breast cancer in 2019.
Source: STAT, March 8, 2019