Background: Classical Hodgkin’s lymphoma (cHL) is characterized by chromosome 9p24.1 alterations and PD-1 ligand overexpression. Sintilimab, a programmed death-1 checkpoint inhibitor, has demonstrated efficacy in relapsed/refractory cHL after the primary analysis of the ORIENT-1 study. Here, we report the updated safety and efficacy prolines after extended follow-up. Methods: ORIENT-1 is a multicenter, single-arm, phase II study in China. Classical Hodgkin’s lymphoma patients who had failed ≥2 lines of systemic therapy, including autologous hematopoietic stem cell transplantation (HSCT) were enrolled. Sintilimab, 200 mg IV was given every 3 weeks, until disease progression, death, unacceptable toxicity, or withdrawal from study. The primary endpoint was objective response rate (ORR) assessed by an independent radiological review committee (IRRC) according to 2007 IWG criteria. Results: 96 patients were treated. As of the data cutoff on 16 October, 2018 72.9% of patients were continuing treatment with a median follow-up of 14 months. Median number of treatment cycles was 20 (range: 1 to 26). ORR was 85.4% (82/96, 95%CI: 76.7 to 91.8) based on IRRC review. Twenty-eight patients (29.2%) achieved complete response (CR) by PET scan. At the time of analysis, 59 out of 82 patients who had achieved complete or partial response continued to have an on-going response. The median duration of response (DoR) and progression free survival (PFS) have not been reached. The most common treatment-related adverse event (TRAE) was pyrexia (40.6%, 39/96), 92.3% of which was grade 1 or 2. The most common grade 3 or 4 TRAEs were pyrexia (3.1%) and anemia (3.1%). One death occurred which was not considered treatment related. Conclusions: ORIENT-1 study has the largest cohort of cHL patients in China treated with a PD-1. In addition to a high rate of response, sintilimab also demonstrated durable efficacy and favorable long-term safety profile after extended follow-up. Clinical trial information: NCT03114683