Phase II trial of surufatinib plus toripalimab for disease progression after first-line chemotherapy with platinum and fluoropyrimidine in advanced gastric or gastroesophageal junction adenocarcinoma.

Abstract

e16040 Background: Surufatinib is a novel small-molecule kinase inhibitor targeting VEGFRs, FGFR and CSF-1R, simultaneous targeting of angiogenesis through VEGFRs/FGFR1 and modulating tumor immune microenvironment through CSF-1R may be a uniquely potent strategy to enhance antitumor activity. Toripalimab is a monoclonal humanized IgG4 PD-1 antibody. Encouraging efficacy of surufatinib plus toripalimab treating patients with advanced solid tumors was reported at 2020 AACR. This is an ongoing, multicenter, open-label, single-arm, phase II study to evaluate the efficacy and safety of surufatinib in combination with toripalimab in various solid tumors. Here we report the results of patients with advanced gastric or gastroesophageal junction (GEJ) adenocarcinoma. Methods: Patients with histologically confirmed gastric or GEJ adenocarcinoma who have failed first-line of systemic chemotherapy were enrolled. Surufatinib 250 mg once a day (QD) will be orally administrated and toripalimab 240 mg will be intravenously administered every 3 weeks. Primary endpoint was the objective response rate (ORR) per RECIST v1.1. Results: As of Dec 31, 2020, a total of 21 gastric or GEJ adenocarcinoma patients were enrolled. The median age was 58 years old, and 81% of the patients were male. Median duration of treatment was 3 months (surufatinib, 3 months; toripalimab, 3 months). Among 15 patients with at least one post-baseline efficacy evaluation, 2 patients achieved confirmed partial response (PR), with 3 additional unconfirmed PR. And there were 6 in stable disease (SD), 3 in progressive disease (PD) and one not evaluable per RECIST v1.1. There were 5 in PR, 7 in SD and 2 in PD per irRECIST, respectively. The confirmed and unconfirmed ORR were 13.3% (95% CI: 1.7%-40.5%) and 33.3% (95% CI: 11.8%-61.6%), respectively. The disease control rate (DCR) was 73.3% (95% CI: 44.9%-92.2%) per RECIST v1.1. Median PFS was 3.71 months (95% CI: 1.41-unknown). 14.3% (3/21) of patients had treatment-related adverse events (TRAEs) of ≥ Grade 3. The most common TRAEs of ≥ Grade 3 were herpes zoster (4.8%), lymphopenia (4.8%), lymphocyte count decreased (4.8%), white blood cell count decreased (4.8%), liver injury (4.8%) and anaemia (4.8%). 4.8% (1/21) of patients had serious TRAEs. One patient died due to unknown reasons. Conclusions: Surufatinib plus toripalimab appeared to show encouraging activity in advanced gastric or GEJ adenocarcinoma with manageable safety profile. Such combination could be a promising strategy for advanced gastric or GEJ adenocarcinoma in the future. Clinical trial information: NCT04169672.