2005^ Background: GBM has a high disease burden and poor prognosis, and impacts negatively on HRQoL. Symptomatic therapies for GBM, such as corticosteroids (CS), may impact patient status negatively Methods: AVAglio, a randomized, double-blind, placebo (P)-controlled trial in patients (pts) ≥18 yrs with newly diagnosed GBM, evaluated the addition of Bv or P (10mg/kg, q2w) to 6 wks of T (75mg/m2/d) + RT (2Gy, 5d/wk) followed by 28 treatment-free days, then 6 cycles of T (150–200 mg/m2/d, 5d q4w) with Bv or P (10 mg/kg, q2w), and then single-agent Bv or P (15 mg/kg, q3w) until disease progression (PD)/unacceptable toxicity. Co-primary endpoints were investigator-assessed PFS and overall survival. Secondary endpoints included HRQoL (EORTC QLQ-C30 and BN20, with 5 prespecified domains based on relevance in GBM). HRQoL time to definitive deterioration (TDD) was defined as time from randomization to ≥10 point deterioration from baseline with no subsequent improvement, PD, or death. Exploratory endpoints included KPS and CS use. Results: Baseline characteristics were well balanced. Bv significantly prolonged PFS (HR 0.64, 95% CI 0.55–0.74, p<0.0001; median 10.6 vs 6.2 mo) and delayed TDD in HRQoL compared with P (p<0.0001; Table). Functional independence (KPS ≥ 70%) was maintained during PFS in both arms (median Bv vs P: 9 vs 6 mo). Among pts on CS (≥ 2mg) at baseline, discontinuation (≥ 5 consecutive days) was more frequent with Bv than P (66% vs 47%). In pts off CS at baseline (< 2mg), time to CS initiation was significantly longer with Bv than P (HR 0.71, 95% CI 0.57–0.88; median 12.3 vs 3.7 mo). Conclusions: Addition of Bv to RT/T provided a clinically meaningful and statistically significant PFS improvement associated with stable/improved HRQoL and KPS, and reduced CS requirement. Clinical trial information: NCT00943826. [Table: see text]