Purpose: The phase II prospective, noncomparative BRAIN study (NCT00800202) investigated efficacy and safety of bevacizumab in chemotherapy-na⏠ve or pretreated patients with nonsmall cell lung cancer (NSCLC) and asymptomatic untreated brain metastases to provide data in this previously unexplored subgroup.Experimental Design: Patients with stage IV nonsquamous NSCLC, Eastern Cooperative Oncology Group performance status 0-1, and untreated, asymptomatic brain metastases received first-line bevacizumab (15 mg/kg) plus carboplatin (area under the curve Ă6) and paclitaxel (200 mg/m 2 ) every 3 weeks (B ĂŸ CP), or second-line bevacizumab plus erlotinib (150 mg/d; B ĂŸ E). Six-month progression-free survival (PFS) was the primary endpoint. The trial could be stopped if there were more than three (B ĂŸ CP) or more than two (B ĂŸ E) intracranial hemorrhages.Results: In first-line B ĂŸ CP cohort (n ÂŒ 67), 6-month PFS rate was 56.5% with a median PFS of 6.7 months [95% confidence interval (CI), 5.7-7.1] and median overall survival (OS) of 16.0 months. Investigator-assessed overall response rate (ORR) was 62.7%: 61.2% in intracranial lesions and 64.2% in extracranial lesions. Because of low enrolment (n ÂŒ 24), efficacy results for the second-line B ĂŸ E cohort were exploratory only; 6-month PFS rate was 57.2%, median PFS was 6.3 months (95% CI, 3.0-8.4), median OS was 12.0 months, and ORR was 12.5%. Adverse events were comparable with previous trials of bevacizumab. One grade 1 intracranial hemorrhage occurred and resolved without sequelae.Conclusions: The BRAIN study demonstrates encouraging efficacy and acceptable safety of bevacizumab with first-line paclitaxel and carboplatin in patients with NSCLC and asymptomatic, untreated brain metastases.