AdvanTIG-105: a phase I dose escalation study of the anti-TIGIT monoclonal antibody ociperlimab in combination with tislelizumab in patients with advanced solid tumors

BACKGROUND: Ociperlimab, a novel, humanized monoclonal antibody (mAb), binds to T-cell immunoreceptor with immunoglobulin and immunoreceptor tyrosine-based inhibitory motif domains (TIGIT) with high affinity and specificity. Tislelizumab is an anti-programmed cell death protein 1 mAb. We report results from a phase I, first-in-human, dose escalation study evaluating the safety, pharmacokinetics (PK), and preliminary antitumor activity of ociperlimab plus tislelizumab in patients with advanced solid tumors. METHODS: Eligible patients previously treated with standard systemic therapy, or for whom treatment was not available or tolerated, received ociperlimab intravenously on Cycle (C) 1 Day (D) 1 and tislelizumab 200 mg intravenously on C1 D8. If tolerated, patients received ociperlimab plus tislelizumab 200 mg sequentially on D29 and every 3 weeks (Q3W) thereafter until discontinuation. Dose escalation for ociperlimab was planned with four dose levels (50 mg, 150 mg, 450 mg, and 900 mg) according to a 3+3 design. An additional dose level of ociperlimab 1800 mg was also assessed. Primary endpoints were safety, determination of the maximum tolerated (or administered) dose, and the recommended phase II dose (RP2D). Secondary endpoints included overall response rate (ORR), duration of response (DoR), disease control rate (DCR) (Response Evaluation Criteria in Solid Tumors version 1.1), PK, and biomarker analysis. RESULTS: At data cut-off (September 29, 2022), 32 patients had received ≥1 dose of ociperlimab plus tislelizumab 200 mg Q3W. The maximum administered dose was ociperlimab 1800 mg plus tislelizumab 200 mg Q3W. The median age of enrolled patients was 59.5 years (range: 31–79). Most patients (96.9%) experienced ≥1 treatment-emergent adverse event (TEAE); 62.5% of patients experienced ≥grade 3 TEAEs and 50.0% of patients experienced serious TEAEs. No dose limiting toxicity events were reported. The maximum tolerated dose was not reached. The RP2D was ociperlimab 900 mg plus tislelizumab 200 mg Q3W. Overall, ORR was 10.0%, median DoR was 3.6 months, and DCR was 50.0%. CONCLUSIONS: Ociperlimab plus tislelizumab was well tolerated in patients with advanced solid tumors, and preliminary antitumor activity was observed with 450 mg, 900 mg, and 1800 mg ociperlimab. Phase II/III trials of ociperlimab 900 mg plus tislelizumab 200 mg Q3W are underway in a range of solid tumors. TRIAL REGISTRATION NUMBER: NCT04047862.