Camrelizumab in advanced or metastatic solid tumor patients with microsatellite instability–high/mismatch repair-deficient: Results from an open-label exploratory study.

Abstract

e15140 Background: PD-1 checkpoint inhibitor has been shown a significant effect in patients (pts) with microsatellite instability-high (MSI-H) or mismatch repair-deficient (dMMR) solid tumor. Herein, we assessed the efficacy and safety of camrelizumab, a PD-1 checkpoint inhibitor, in advanced or metastatic solid tumor pts with MSI-H/dMMR. Methods: Pts with MSI-H/dMMR solid tumor who had received at least one line of prior systemic chemotherapy were recruited in this single-arm exploratory study. Pts received camrelizumab (200mg, ivd, D1/2W) until disease progression or intolerable toxicity. Response was assessed every 8 weeks. The primary endpoint was objective response rate (ORR) according to RECIST v1.1 criteria. This study was registered at Chinese Clinical Trial Registry, ChiCTR-OIC-17013249. Results: From November 2017 to February 27, 2019, 12 eligible pts were recruited, which covered 9 cancer types. The median age was 58 (range 27-72) years; male/female was 58.3/41.7%. 11 pts were confirmed as MSI-H status, and 1 patient as d-MMR status. All pts were included in efficacy and safety analysis. 2 pts achieved complete response (CR), 6 pts partial response (PR), 4 pts stable disease (SD), yielding the ORR of 66.7% (95% CI: 34.9-90.1), and the disease control rate of 100% (95% CI 73.5-100) at best. What’s more, cancer types of CR pts covered rectal cancer and bladder cancer (1 patient each); PR pts included colon cancer, liver cancer, endometrial cancer, ureteric cancer, intrahepatic cholangiocarcinoma, and small intestine cancer (1 patient each); SD pts contained 3 colon cancer pts and 1 retroperitoneal leiomyosarcoma patient. The overall incidence of adverse incidences (AEs) was 100%. The incidence of Grade ≥3 AEs was 58.3%, which mainly included anemia (16.7%), increased γ-transglutaminase (16.7%), increased alkaline phosphatase (16.7%), increased blood bilirubin (16.7%). As of Oct 30, 2019, 11 pts were still on study medication. Conclusions: Camrelizumab resulted in encouraging objective response and tolerable toxicity in MSI-H/dMMR advanced or metastatic solid tumor. The survival benefits will be further observed. Clinical trial information: ChiCTR-OIC-17013249 .