9MW2821, a nectin-4 antibody-drug conjugate (ADC), in patients with advanced solid tumor: Results from a phase 1/2a study.

Abstract

3013 Background: 9MW2821 is a monoclonal ADC that delivers monomethyl auristatin E to cells expressing Nectin-4. Nectin-4 is an adhesion molecule that highly expressed in variety of solid tumors, especially urothelial cancer (UC), cervical cancer (CC), esophageal cancer (EC) and breast cancer. Here we report the updated safety and efficacy data of 9MW2821. Methods: 9MW2821 was administered by intravenous infusion at doses of 0.33-1.5mg/kg on days 1, 8 and 15 of each 28-day cycle. The study included dose escalation, dose expansion and cohort expansion period which included UC, CC, EC, triple negative breast cancer (TNBC) and other Nectin-4 positive solid tumors that progressed after ≥1 systemic treatments (Tx). Primary objectives were assessment of safety and preliminary efficacy. Results: As of Jan 15, 2024, 260 patients (pts) were enrolled with doses ranging from 0.33 to 1.5mg/kg. Only 1 out of 6 pts in 1.5mg/kg group had dose limiting toxicity (grade 4 neutropenia lasted more than 5 days). The maximum tolerated dose was not reached up to 1.5mg/kg and the RP2D was selected as 1.25mg/kg for tolerance. 240 pts were enrolled at dose of 1.25mg/kg. The most common TRAEs of 1.25mg/kg dose group (≥20%, all grade/≥5%, ≥G3) were white blood cell (WBC) count decreased (50.8%, 23.3%), neutrophil count decreased (46.3%, 27.9%), anemia (43.8%, 8.3%), aspartate aminotransferase increased (42.1%, 2.9%), alanine aminotransferase increased (35.4%, 2.1%), asthenia (32.1%, 2.9%), rash (30.0%, 5.0%), decreased appetite (28.8%, 1.3%), nausea (26.7%, 0%), hyperglycemia (25.4%, 2.1%), platelet count decreased (24.2%, 4.6%), alopecia (24.2%, 0%), hypoaesthesia (22.5%, 1.7%), constipation (21.3%, 0%), vomiting (20.9%, 1.3%), hypertriglyceridemia (20.4%, 2.1%), gamma-glutamyltransferase increased (15.8%, 5.4%). Among 190 pts treated with 9MW2821 at 1.25mg/kg or above and reached tumor assessment, objective response rate (ORR) and disease control rate (DCR) was 35.3% and 78.4%, respectively. 37 UC pts, 45 CC pts, 27 EC pts and 16 TNBC pts were enrolled at 1.25mg/kg and evaluable for tumor assessment. Median prior lines of Tx were 2 (range, 1-4). All UC, 51% CC and 93% EC pts progressed after platinum-based chemotherapy and immune checkpoint inhibitors, respectively. Objective responses were also observed in pts with other solid tumor types. Conclusions: The data indicated encouraging efficacy of 9MW2821 in advanced UC, CC, EC and TNBC. 9MW2821 is the first Nectin-4 targeting ADC showed antitumor activity in patients with CC, EC and TNBC. The safety profile showed adequate tolerability. Clinical trial information: NCT05216965 . [Table: see text]