First Immunotherapy Approved for Patients with Advanced or Metastatic Triple-Negative Breast Cancer Expressing PD-L1

In March 2019, the FDA accelerated the ap­proval of the immunotherapy Tecentriq (atezol­izumab; from Genentech), a PD-L1 inhibitor, for use in combination with Abraxane (paclitaxel protein-bound; from Celgene) in adults with locally advanced or metastatic triple-negative breast cancer whose tumors cannot be removed by surgery (un­resectable) and express PD-L1, as identified by an FDA-approved test.

At the same time, the FDA approved the VENTANA PD-L1 (SP142) Assay, which is a companion diagnostic test used to identify patients with this type of breast cancer who are appropriate candidates for treatment with Tecentriq.

This approval was based on results of the clinical trial called IMpassion130, an international study that included 902 patients with unresectable, locally advanced or metastatic triple-negative breast cancer who had not received chemotherapy for metastatic disease. The VENTANA PD-L1 (SP142) Assay was used to identify patients whose tumors expressed PD-L1.

In patients whose tumors expressed PD-L1, the average time without cancer progression was 7.4 months for those who received Tecentriq in combination with Abraxane compared with 4.8 months among patients who received placebo plus Abraxane. Overall, 53% of the patients who received Tecentriq plus Abraxane responded to treatment compared with 33% of the patients who received Abraxane plus placebo.

The most common adverse reactions that occurred in 20% or more of patients with the immunotherapy plus chemotherapy combination included hair loss, peripheral neuropathies, fatigue, nausea, diarrhea, anemia, constipation, cough, headache, neutro­penia, vomiting, and reduced appetite. This approval represents the first time that the FDA approved an immune checkpoint inhibitor for the treatment of patients with triple-negative breast cancer.