Efficacy and safety of chemotherapy (CT) {+/-} pertuzumab (P) for platinum-resistant ovarian cancer (PROC): AGO-OVAR 2.20/ENGOT-ov14/PENELOPE double-blind placebo-controlled randomized phase III trial.

5504 Background: Adding P to gemcitabine (GEM) for PROC improved progression-free survival (PFS) in a subset of patients (pts) with low tumor HER3 mRNA expression [Makhija 2010]. Methods: Eligible pts had recurrent PROC (progression [PD] during/within 6 mo of completing ≥ 4 platinum cycles) with centrally tested low tumor HER3 mRNA expression (concentration ratio ≤ 2.81 by qRT-PCR on cobas z480) and ≤ 2 prior CT lines. Investigators (INVs) chose CT (topotecan [TOP], paclitaxel [PAC] or GEM); recruitment was capped to ensure similarly sized CT cohorts. Pts were stratified by chosen CT, prior anti-angiogenic therapy and platinum-free interval ( < 3 vs 3–6 mo) and randomized 1:1 to CT with either placebo or P 840→420 mg q3w until PD/unacceptable toxicity. The primary objective was to determine if independent review committee (IRC)-assessed PFS was superior with P + CT vs placebo + CT. The prespecified primary PFS analysis after 109 blinded IRC-assessed PFS events in 154 planned pts provided 95% power to dete...