Efficacy and safety of sigvotatug vedotin, an investigational ADC, in NSCLC: Updated phase 1 results (SGNB6A-001).

Abstract

8521 Background: Integrin beta-6 (IB6), a tumor-associated membrane protein, plays an important role in pathogenesis and invasiveness and its expression correlates with poor outcomes. Sigvotatug vedotin (SV), formerly called SGN-B6A, is an IB6-directed ADC with encouraging activity in NSCLC in the Ph 1 study SGNB6A-001 (NCT04389632) (Hollebecque 2023). Here, we report updated efficacy and safety of SV in NSCLC. Methods: SGNB6A-001 is an open-label, multicenter, Ph 1 study evaluating the safety, pharmacokinetics (PK), and antitumor activity (cORR, DOR, and PFS per RECIST v1.1, and OS) of SV in patients (pts) with advanced solid tumors. Multiple dose regimens were explored during dose escalation (Part A). Dose expansion (Part B) is ongoing with selected regimens in various tumors including NSCLC. Parts C and D will evaluate SV in combination with pembrolizumab in NSCLC and HNSCC. Eligible pts had no therapeutic options (Part A) or had received platinum-based and anti-PD-(L)1 therapy unless contraindicated (Part B) and were dosed with the SV expansion regimens on D1 and D8 in a 21-day cycle (2Q3W; 1.2/1.25 mg/kg total body weight [TBW]) or D1 and D15 in a 28-day cycle (2Q4W; 1.5 mg/kg TBW, 1.8 mg/kg adjusted ideal body weight [AiBW]). Results: As of 01-Dec-2023, 306 pts had received SV; 113 pts with NSCLC received expansion regimens in Parts A and B. Prior lines of therapy and efficacy data for all pts with NSCLC and select subgroups are summarized in the table; cORR was 19.5% (95% CI, 12.6-28.0) in all pts with NSCLC and 32.5% (95% CI, 18.6-49.1) in pts with non-squamous (non-Sq)/taxane-naive NSCLC. Additional time-to-event data will be presented. Rates of TEAEs, ≥G3 TEAEs, SAEs, and TEAEs leading to discontinuation were 98.2%, 46.0%, 33.6%, and 13.3% in pts with NSCLC, and were consistent in all treated pts. The most common ≥G3 TEAEs in pts with NSCLC were dyspnea (9.7%), fatigue (7.1%), and neutropenia (5.3%). One pt with NSCLC had a treatment-related death (pneumonitis). PK variability across weight groups was lowest with 1.8 mg/kg AiBW 2Q4W. Conclusions: SV continues to demonstrate encouraging antitumor activity and a manageable safety profile in pts with NSCLC. Data at 1.8 mg/kg AiBW 2Q4W support initiation of the Ph 3 SGNB6A-002 study in 2/3L NSCLC (NCT06012435) and combination with pembrolizumab in earlier settings. Clinical trial information: NCT04389632 . [Table: see text]