A randomized phase II trial with gemcitabine with or without pertuzumab (rhuMAb 2C4) in platinum-resistant ovarian cancer (OC): Preliminary safety data

Abstract

13001 Background: Pertuzumab (P), a humanized HER2 antibody, represents a new class of targeted agents called HER dimerization inhibitors (HDIs). P inhibits dimerization of HER2 with EGFR, HER3 and HER4, and subsequently inhibits signaling through MAP and PI3 kinases. Single agent P has demonstrated clinical benefit in advanced OC (ASCO 2005 abstract #5051). Methods: 40 pts with platinum-resistant OC (progressed within 6 months of receiving a platinum-based chemotherapy) were enrolled in this 1:1 randomized, double blind, placebo controlled trial of gemcitabine with or without P. Gemcitabine was administered IV on day 1 and 8 at 800 mg/m2 of a 21 day cycle. Blinded placebo or 420 mg P was administered IV on day 1. Gemcitabine was dose reduced for neutropenia or thrombocytopenia. P was not dose reduced. Results: 40 pts have been enrolled and treated with at least 1 cycle of gemcitabine in combination with blinded study drug. The median age was 58.5 (range 18–82); 26 had PS ECOG 0, 13 ECOG 1, 1 ECOG 2. The most common grade 3/4 events were neutropenia in 7 pts (17.5%), thrombocytopenia in 6 pts (15%), small bowel obstruction in 4 pts (10%), constipation in 3 pts (7.5%) and elevated ALT in 3 pts (7.4%). There was one grade 3 diarrhea, but no grade 3 or 4 rash. There were 4 serious adverse events (SAEs) attributed to study drug. These were a pleural effusion, thrombocytopenia, febrile neutropenia, and a deep vein thrombosis. Nine pts required one or two dose reductions of gemcitabine for hematological toxicity. Of 29 pts with post-baseline echo or MUGA values obtained, no pt had LVEF drop to <50%. The adverse events evaluated after 40 pts did not meet the prespecified criteria to call for an independent safety monitoring board evaluation of unblinded data. Conclusions: Preliminary safety data indicate that pertuzumab or placebo combined with gemcitabine is well tolerated with no unexpected additive toxicity. The nature and frequency of the adverse events are similar to what has been observed with either single agent gemcitabine or P. Updated data will be presented at ASCO. [Table: see text]