CStone Pharmaceuticals (Suzhou) Co., Ltd. announced the updated results from two studies of its anti-PD-L1 monoclonal antibody sugemalimab (CS1001) at the 2020 Chinese Society of Clinical Oncology (CSCO) Annual Meeting. These two studies are 1) CS1001-201 clinical trial, which is designed to evaluate sugemalimab as monotherapy in patients with R/R ENKTL, and 2) CS1001-101 study aiming to evaluate sugemalimab in combination with chemotherapy for the treatment of GC/GEJ. As an investigational drug developed by CStone, sugemalimab has shown promising efficacy and safety results in a variety of solid tumors and lymphomas as demonstrated by the current study results and those reported previously including the recent positive topline results from a pivotal phase III trial in patients with stage non-small cell lung cancer (NSCLC).
CS1001-201 Study
CS1001-201 is a single-arm, multi-center, phase II pivotal study designed to evaluate the efficacy and safety of sugemalimab as a monotherapy for the treatment of R/R ENKTL. The primary endpoint of this study is ORR as assessed by the Independent Radiology Review Committee (IRRC), and its secondary endpoints include investigator-assessed ORR, CR rate as assessed by IRRC and the investigator, median duration of response (mDoR), progression-free survival (PFS) and OS. The study also evaluated the safety, pharmacokinetics (PK) and immunogenicity of sugemalimab.
As of July 1, 2020, a total of 43 patients were enrolled and received treatment. The demographic profile of patients at enrollment is similar to that of ENKTL patients: 74.4% of them had an ECOG score of 1; 72.1% had stage IV disease, and about a half (51.2%) have received second-line or above treatment
As a monotherapy, sugemalimab has demonstrated robust efficacy with a high CR rate and durable clinical benefits in terms of mDoR and OS, and a well-tolerated safety profile in R/R ENKTL patients
- The ORR of 38 evaluable patients was 44.7% with a CR rate as high as 31.6%. The mDoR was 16.8 months. Of all the 12 patients who achieved CR, 11 are still in continuous remission
-The mOS of the 43 patients who received study drug treatment was 19.7 months, and 1-year OS rate was 55.5%
- The most commonly reported study drug-related adverse event was fever; drug-related adverse events (AEs) of grade 3 or above were observed in 6 patients (14.0%); 10 patients (23.3%) had immune-related AEs, most of which were grade 1; and 3 patients (7.0%) experienced severe adverse events (SAEs) related to the study drug
CS1001-101 Study
CS1001-101 is a phase I study to evaluate the safety, tolerability, PK and anti-tumor activity of sugemalimab in patients with advanced solid tumors or lymphomas. At the 2020 CSCO annual meeting, CStone presented the proof of concept (PoC) data of phase 1b cohort study designed to evaluate sugemalimab in combination with XELOX (capecitabine and oxaliplatin) as first-line treatment for locally advanced or metastatic GC/GEJ. The primary endpoint of this study is the preliminary anti-tumor efficacy of this combination therapy.
Sugemalimab in combination with XELOX as a first-line treatment has shown robust anti-tumor activity, as well as a benigh safety and tolerability profile in patients with advanced GC/GEJ. Preliminary biomarker analysis showed that the therapeutic effect of this combination therapy was potentially associated with the PD-L1 expression level.
As of February 19, 2020, among the 29 patients included in the efficacy analysis set, 18 patients have achieved partial response (PR) and 6 patients have achieved stable disease (SD). The investigator-assessed ORR was 62.1%; the mDoR was 11.3 months; the mPFS was 8.3 months and the mOS was 17.0 months
26 patients in the efficacy analysis set have evaluable combined positive score (CPS) results. The analysis showed that the ORR of the subgroup with CPS ≥ 5 (19 patients) was 58%, the mDoR had not yet been reached, and that the mPFS was 13.3 months. In the subgroup with CPS <5 (7 patients), the reported ORR was 71%, the mDoR was 5.0 months, and the mPFS was 6.2 months
Dr. Jason Yang, Chief Medical Officer of CStone, said, "We are very pleased to see that sugemalimab, ...
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