Abstract
TPS5637 Background: The treatment of recurrent epithelial ovarian cancer remains a challenge, particularly for tumors with low to moderate expression levels of FRα. Luveltamab tazevibulin (luvelta) is an anti–FRα-targeting antibody-drug conjugate with a stable cleavable linker and a 3-aminophenyl hemiasterlin warhead (DAR=4), which induces cytotoxic and immunologic cell death. Luvelta was designed to treat multiple cancers with a broad range of FRα expression. Luvelta demonstrated preliminary antitumor activity in women with recurrent ovarian cancer, selected for FRα expression level of ≥25% at any intensity (tumor proportion score [TPS]). In PROC, this cutoff represents an estimated 80% of patients (pts). In a phase 1 study of luvelta in relapsed ovarian cancer, the overall response rate (ORR) was 37.5% with a median duration of response (DOR) of 5.5 months and a median progression-free survival (PFS) of 6.1 months. ORR was higher at 5.2 mg/kg compared with 4.3 mg/kg (43.8% vs 31.3%). The safety profile was manageable, with the most common grade ≥3 adverse events consisting of neutropenia, arthralgia, and anemia (Oaknin et al. J Clin Oncol 2023;41[16 suppl]:5508). These results support further investigation in pts with PROC whose tumors have a broad range of FRα expression. Herein, we describe a phase 2/3 pivotal study (REFRaME-01)of luvelta in this pt population. Methods: This randomized, global, open-label, 2-part phase 2/3 pivotal study has been designed to assess the efficacy and safety of luvelta vs investigator’s choice (IC) chemotherapy in pts with recurrent PROC expressing FRα (NCT05870748). Eligible pts are adults (≥18 years) with relapsed PROC, 1–3 prior lines of therapy (which must include bevacizumab), measurable disease, Eastern Cooperative Oncology Group performance status ≤1, and TPS for FRα expression ≥25% using Ventana validated IHC assay. Part 1 (phase 2) consists of a luvelta dose-optimization stage in which pts are randomized 1:1 to receive intravenous (IV) luvelta every 3 weeks (Q3W) at 4.3 mg/kg or IV luvelta Q3W at 5.2 mg/kg with prophylactic G-CSF for 2 cycles followed by 4.3 mg/kg luvelta from cycle 3 onward. Part 1 data will be used to select the optimal dosing regimen. In part 2 (phase 3) ~550 pts will be enrolled and randomized 1:1 to the optimal luvelta dosing regimen or IC chemotherapy (gemcitabine, paclitaxel, pegylated liposomal doxorubicin, or topotecan). Primary endpoints are PFS and ORR, with response evaluated per RECIST v1.1. Secondary endpoints include overall survival, DOR, safety, and quality of life. Clinical trial information: NCT05870748 .