First-line atezolizumab monotherapy versus single-agent chemotherapy in patients with non-small-cell lung cancer ineligible for treatment with a platinum-containing regimen (IPSOS): a phase 3, global, multicentre, open-label, randomised controlled study

Background: Despite immunotherapy advancements for patients with advanced or metastatic non-small-cell lung cancer (NSCLC), pivotal first-line trials were limited to patients with an Eastern Cooperative Oncology Group performance status (ECOG PS) 0-1 and a median age of 65 years or younger. We aimed to compare the efficacy and safety of first-line atezolizumab monotherapy with single-agent chemotherapy in patients ineligible for platinum-based chemotherapy.

Methods: This trial was a phase 3, open-label, randomised controlled study conducted at 91 sites in 23 countries across Asia, Europe, North America, and South America. Eligible patients had stage IIIB or IV NSCLC in whom platinum-doublet chemotherapy was deemed unsuitable by the investigator due to an ECOG PS 2 or 3, or alternatively, being 70 years or older with an ECOG PS 0-1 with substantial comorbidities or contraindications for platinum-doublet chemotherapy. Patients were randomised 2:1 by permuted-block randomisation (block size of six) to receive 1200 mg of atezolizumab given intravenously every 3 weeks or single-agent chemotherapy (vinorelbine [oral or intravenous] or gemcitabine [intravenous]; dosing per local label) at 3-weekly or 4-weekly cycles. The primary endpoint was overall survival assessed in the intention-to-treat population. Safety analyses were conducted in the safety-evaluable population, which included all randomised patients who received any amount of atezolizumab or chemotherapy. This trial is registered with ClinicalTrials.gov, NCT03191786.

Findings: Between Sept 11, 2017, and Sept 23, 2019, 453 patients were enrolled and randomised to receive atezolizumab (n=302) or chemotherapy (n=151). Atezolizumab improved overall survival compared with chemotherapy (median overall survival 10·3 months [95% CI 9·4-11·9] vs 9·2 months [5·9-11·2]; stratified hazard ratio 0·78 [0·63-0·97], p=0·028), with a 2-year survival rate of 24% (95% CI 19·3-29·4) with atezolizumab compared with 12% (6·7-18·0) with chemotherapy. Compared with chemotherapy, atezolizumab was associated with stabilisation or improvement of patient-reported health-related quality-of-life functioning scales and symptoms and fewer grade 3-4 treatment-related adverse events (49 [16%] of 300 vs 49 [33%] of 147) and treatment-related deaths (three [1%] vs four [3%]).

Interpretation: First-line treatment with atezolizumab monotherapy was associated with improved overall survival, a doubling of the 2-year survival rate, maintenance of quality of life, and a favourable safety profile compared with single-agent chemotherapy. These data support atezolizumab monotherapy as a potential first-line treatment option for patients with advanced NSCLC who are ineligible for platinum-based chemotherapy.

Funding: F Hoffmann-La Roche and Genentech Inc, a member of the Roche group.