Updated analysis from the ATEZO-BRAIN trial: Atezolizumab plus carboplatin and pemetrexed in patients with advanced nonsquamous non–small cell lung cancer with untreated brain metastases.

9010 Background: Atezolizumab plus chemotherapy was safe and yielded promising clinical outcome as frontline therapy for patients (pts) with advanced NSCLC with untreated brain metastases (BM) in the ATEZO-BRAIN study (NCT03526900). Methods: A multicenter single-arm phase II trial with a Bayesian design for evaluating the safety and efficacy of atezolizumab plus carboplatin with pemetrexed every 3 weeks for 4-6 cycles, followed by maintenance with pemetrexed plus atezolizumab in pts with stage IV non-squamous NSCLC without EGFR or ALK genetic alterations and untreated BM. Pts not presented neurologic symptoms at baseline; but anticonvulsants and dexamethasone (DXM) ≤ 4mg qd were allowed. Co-primary endpoints were safety and investigator-assessed progression-free survival (PFS) at 12 weeks according to RANO-BM and RECIST v1.1 for brain and systemic disease, respectively. Here we present the final data and an exploratory analysis based on PD-L1 expression and corticosteroid treatment at baseline. Results: Out of 40 pts included in the study, 22 (55%) were receiving DXM at baseline and 20 (50%) had positive expression of PD-L1. Sixteen (40%) pts had confirmed intracranial response based on RANO-BM (12 PR, 4 CR) and 19 (47.5%) pts achieved systemic response (all PR). Only 4 pts had discordant responses between the body and the brain. No differences were observed in the overall systemic and intracranial response rate according to the PD-L1 expression or the use of corticosteroids at baseline. As of December 31, 2021 (median follow-up, 20 months), the updated median (95% CI) systemic PFS was 8.9 (6.7 to 13.8) and intracranial PFS was 6.9 (4.7 to 11.9). Median (95% CI) OS was 13.6 (9.72 to not reached) and estimated 2-year OS rate (95% CI) was 30.5% (18.4 to 50.4). Median (95%CI) OS was longer for PD-L1 positive pts (16.2; 10.3 to not reached) compared to PD-L1 negative pts (10.7; 7.6 to not reached) but differences were not statistically significant due to the limited statistical power (HR = 0.99; 95% CI 0.35 to 2.12). No significant differences in OS were observed between pts receiving or not baseline DXM treatment. Treatment was well tolerated and no grade 5 toxicities were observed. Conclusions: In this updated analysis, treatment with atezolizumab plus carboplatin and pemetrexed yields a promising 2-year OS rate and intracranial response rate in patients with untreated BM from NSCLC, regardless of treatment with corticosteroids at baseline and PD-L1 expression. Clinical trial information: NCT03526900.