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Consolidation with sugemalimab improves progression-free survival (PFS), compared with placebo, in patients with unresectable, stage III non-small cell lung cancer (NSCLC) who have not progressed after chemoradiotherapy, phase 3 results suggest.
The results were presented at the European Society for Medical Oncology (ESMO) Congress 2021 by Yi-Long Wu, MD, of the Guangdong Lung Cancer Institute in Guangzhou, China.
In the phase 3 GEMSTONE-301 trial (ClinicalTrials.gov Identifier: NCT03728556), Dr Wu and colleagues evaluated the efficacy and safety of sugemalimab as consolidation therapy in patients with unresectable, stage III NSCLC whose disease did not progress after concurrent chemoradiotherapy (cCRT) or sequential chemoradiotherapy (sCRT).
The study included 381 patients from 50 sites in China. The patients were randomly assigned 2:1 to receive sugemalimab at 1200 mg every 3 weeks (255 patients) or matched placebo (126 patients).
At baseline, the median age was 61 years (range, 46-78 years) in the sugemalimab arm and 60 years (range, 42-73 years) in the placebo arm. Most patients were men (93% and 91%, respectively), had received cCRT (66% and 67%, respectively), and had squamous cell carcinoma (69% and 68%, respectively).
Stage IIIB disease was the most common (57% in the sugemalimab arm and 52% in the placebo arm), followed by stage IIIA disease (29% and 25%, respectively).
At a median follow-up of 14 months, the median PFS was 9.0 months with sugemalimab and 5.8 months with placebo (hazard ratio [HR], 0.64; 95% CI, 0.48-0.85; P =.0026).
The 12-month PFS rate was 45.4% in the sugemalimab arm and 25.6% in the placebo arm. At 18 months, the PFS rates were 38.8% and 23.3%, respectively.
Among patients who had received prior sCRT, the median PFS was 8.1 months with sugemalimab and 4.1 months with placebo (HR, 0.59; 95% CI, 0.39-0.91). In patients who received cCRT, the median PFS was 10.5 months and 6.4 months, respectively (HR, 0.66; 95% CI, 0.44-0.99).
The overall survival (OS) data were immature, but a trend toward survival benefit was observed with sugemalimab. The median OS was not reached in the sugemalimab arm and was 24.1 months in the placebo arm (HR, 0.44; 95% CI, 0.27-0.73).
At 24 months, the OS rate was 78.0% in the sugemalimab arm and 50.7% in the placebo arm.
The incidence of grade 3-5 treatment-emergent adverse events (AEs) was similar between the treatment arms — 24.3% with sugemalimab and 23.8% with placebo. Grade 3-5 immune-related AEs occurred in 4.7% and 0.8% of patients, respectively.
“The results of the GEMSTONE-301 study suggest that sugemalimab is an effective consolidation therapy for patients with unresectable, stage III non-small cell lung cancer who have not progressed following cCRT or sCRT,” Dr Wu said.
Disclosures: This research was supported by CStone Pharmaceuticals. Some study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of disclosures.
Wu YL, Zhou Q, Chen M, et al. GEMSTONE-301: A randomized, double-blind, placebo-controlled, phase III study of sugemalimab in patients with unresectable stage III non-small cell lung cancer (NSCLC) who had not progressed after concurrent or sequential chemoradiotherapy (CRT). Presented at: European Society for Medical Oncology (ESMO) Congress 2021; September 16-21, 2021. Abstract LBA43.