SAFFRON-104: a phase Ib/II study of sitravatinib alone or with tislelizumab in advanced hepatocellular carcinoma and gastric cancer/gastroesophageal junction cancer.

Background: Sitravatinib is a spectrum-selective tyrosine kinase inhibitor targeting TAM (TYRO3, AXL, MER), VEGFR-2, KIT, and MET. SAFFRON-104 (NCT03941873) was a multicohort phase Ib/II study investigating sitravatinib with/without tislelizumab, an anti-programmed cell death protein 1 (PD-1) antibody, in patients with advanced hepatocellular carcinoma (HCC) or gastric cancer/gastroesophageal junction cancer (GC/GEJC).

Methods: Eligible patients had histologically/cytologically confirmed advanced HCC or GC/GEJC. Phase I determined the recommended phase II dose (RP2D) of sitravatinib with/without tislelizumab. Phase II evaluated sitravatinib monotherapy in patients with pretreated HCC, and sitravatinib plus tislelizumab in anti-PD-(L)1-naïve or -treated HCC and anti-PD-(L)1-naïve GC/GEJC. Primary endpoints were safety/tolerability (phase I) and objective response rate (ORR) (phase II).

Results: At data cutoff (March 31, 2023), 111 patients were enrolled; 102 were efficacy-evaluable (median study follow-up 9.1 months [range: 0.7-36.9]). The RP2D of sitravatinib was determined as 120 mg orally once daily. In patients receiving sitravatinib monotherapy and sitravatinib in combination with tislelizumab, grade ≥ 3 treatment-related adverse events occurred in 14 (51.9%) and 42 (50.0%) patients, respectively. The ORR was 25% (95% confidence interval [CI]: 8.7-49.1) in patients with pretreated HCC receiving sitravatinib monotherapy. In patients receiving sitravatinib with tislelizumab, the ORR was 11.5% (95% CI 2.4-30.2) with anti-PD-(L)1-naïve HCC, 9.5% (95% CI 1.2-30.4) with anti-PD-(L)1-treated HCC, and 16.1% (95% CI 5.5-33.7) in patients with anti-PD-(L)1-naïve GC/GEJC.

Conclusions: Sitravatinib with/without tislelizumab was generally well tolerated and showed preliminary antitumor activity in patients with advanced HCC and GC/GEJC.