The Atezo-Brain study evaluated atezolizumab combined with chemotherapy in patients with advanced non-small-cell lung cancer (NSCLC) with untreated brain metastases, a population traditionally excluded from trials.

This single-arm phase II clinical trial enrolled patients with advanced nonsquamous NSCLC with untreated brain metastases without neurologic symptoms or asymptomatic with medical treatment. Dexamethasone was allowed up to 4 mg once daily. Atezolizumab plus carboplatin and pemetrexed was given for four to six cycles followed by atezolizumab plus pemetrexed until progression for a maximum of 2 years. The primary end points were to determine the progression-free survival (PFS) rate at 12 weeks and the incidence of grade ≥3 adverse events during the first 9 weeks. Intracranial outcomes were assessed using response assessment in neuro-oncology brain metastases criteria.

Forty patients were enrolled and 22 (55%) were receiving corticosteroids at baseline. The overall 12-week PFS rate was 62.2% (95% credibility interval [CrI], 47.1 to 76.2). The rate of grade 3/4 adverse events during the first 9 weeks was 27.5%. Most neurologic events were grade 1 and 2 but five patients (12.5%) experienced grade 3-4 neurologic events. With a median follow-up of 31 months, intracranial median PFS was 6.9 months and response rate was 42.7% (95% CrI, 28.1 to 57.9). Systemic median PFS was 8.9 months and response rate was 45% (95% CrI, 28.1 to 57.9). The median overall survival (OS) was 11.8 months (95% CI, 7.6 to 16.9) and the 2-year OS rate was 27.5% (95% CI, 16.6 to 45.5).

Atezolizumab plus carboplatin and pemetrexed demonstrates activity in patients with advanced nonsquamous NSCLC with untreated brain metastases with an acceptable safety profile.