Efficacy and safety of farletuzumab, a humanized monoclonal antibody to folate receptor alpha, in platinum-sensitive relapsed ovarian cancer subjects: Final data from a multicenter phase II study.

Abstract

5001 Background: Farletuzumab (MORAb-003) is a humanized monoclonal antibody to folate receptor alpha, which is overexpressed in most epithelial ovarian cancers (EOC), but largely absent on normal tissue. The phase I study showed signs of activity and did not reach an MTD. Methods: 54 subjects with platinum-sensitive EOC in first relapse received weekly farletuzumab either as single agent (SA) or in combination with carboplatin (AUC 5-6) and taxane (P/T) q 21 days for 6 cycles, followed by farletuzumab maintenance. 28 subjects with asymptomatic CA125 relapse received SA farletuzumab. Subjects could receive P/T plus farletuzumab after SA. 26 subjects with symptomatic relapse entered the combination arm directly and 21 subjects entered after SA. Primary endpoints were normalization of CA125 and Objective Response Rate. Duration of each subject's second response was compared to the duration of their own first response. Results: Farletuzumab was well-tolerated as SA as well as without additive toxicity to P/T. Preliminary data show that of the 44 evaluable subjects who received farletuzumab with P/T, 89% normalized CA-125. In 9/44 (21%) treated subjects, the second remission has been equal to, or longer, than the first remission. There was an unexpectedly high response rate among subjects with a first progression-free interval of <12 months, comparable to that in subjects with a first progression-free interval of >12 months (Table). Conclusions: Preliminary data for this study indicated that farletuzumab with P/T significantly increases objective response rate compared to historic data for P/T alone in platinum-sensitive first-relapsed ovarian cancer subjects and increases the duration of second remission compared to first remission. Combination therapy: Response by length of first progression-free interval First progression-free interval <12 months (n=12) ≥12 months (n=32) CA125 normalization 92% 84% RECIST responder (CR + PR) 64% 71% RECIST patient benefit (CR + PR + SD) 100% 90% Author Disclosure Employment or Leadership Position Consultant or Advisory Role Stock Ownership Honoraria Research Funding Expert Testimony Other Remuneration Morphotek Morphotek Morphotek Morphotek