Atezolizumab monotherapy has a good overall response rate (ORR) and favorable safety profile in patients with advanced PD-L1 expressing non-small cell lung cancer (NSCLC), according to a study published in the Journal of Clinical Oncology.1

Additional therapies are required for patients with NSCLC as first- and second-line chemotherapies inadequately prolong survival. Atezolizumab and other immune checkpoint inhibitors have demonstrated efficacy and improved survival in various cancers.

For the phase II BIRCH trial (ClinicalTrials.gov Identifier: NCT02031458), researchers assigned 659 patients to 3 cohorts determined by treatment status; patients in cohort 1 were treatment naive for advanced NSCLC, patients in cohort 2 had failed one platinum-based regimen, and patients in cohort 3 had failed at least 2 prior chemotherapy regimens. Patients received intravenous (IV) atezolizumab at a dose of 1200 mg every 3 weeks.

Study eligible patients were divided into subgroups by percentage of PD-L1 positive tumor cells (TC) (TC3 > 50% or TC2 > 5% but < 50%) and the percentage of the tumor area stained positive by PD-L1 positive tumor-infiltrating immune cells (IC) (IC3 > 10% or IC2 > 5% but < 10%).

At the minimum 12 month follow-up, the ORR was 22%, 19%, and 18% in cohorts 1, 2, and 3, respectively. Complete response was achieved in 1%, 2%, and 2% of patients in cohorts 1, 2, and 3, respectively. The ORR was 31%, 26%, and 27% in the TC3 and IC3 subgroups in cohorts 1, 2, and 3, respectively. Responses were observed regardless of KRAS or EGFR mutation status.

The median OS was 23.5 months (26.9 months for TC3/IC3 patients), 15.5 months, and 13.2 months in cohorts 1, 2, and 3, respectively.

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Atezolizumab was well tolerated by study patients. Safety profiles were consistent across the 3 cohorts and with previous clinical studies for atezolizumab.

Reference

  1. Peters S, Gettinger S, Johnson ML, et al. Phase II trial of atezolizumab as first-line or subsequent therapy for patients with programmed death-ligand 1-selected advanced non-small-cell lung cancer (BIRCH). J Clin Oncol. 2017 Jun 13. doi: 10.1200/JCO.2016.71.9476