Sugemalimab could be a new standard of care as consolidation therapy for patients with unresectable, stage III non-small cell lung cancer (NSCLC), according to a presentation at the IASLC 2022 World Conference on Lung Cancer.
In the phase 3 GEMSTONE-301 trial, sugemalimab improved progression-free survival (PFS), compared with placebo, when given after concurrent chemoradiotherapy (cCRT) or sequential chemoradiotherapy (sCRT).
Overall survival (OS) data are not yet mature, but there was a trend toward improvement in OS with sugemalimab as well.
“The results of the GEMSTONE-301 study suggest that sugemalimab could be safely and effectively used after concurrent or sequential chemoradiotherapy and should be a new standard of care in this setting for stage III, inoperable non-small cell lung cancer,” said Yi-Long Wu, MD, PhD, of Guangdong Lung Cancer Institute in China, who presented the study findings at the meeting.
GEMSTONE-301 (ClinicalTrials.gov Identifier: NCT03728556) included 381 patients with unresectable, stage III NSCLC and no disease progression after cCRT or sCRT. None of the patients had sensitizing EGFR, ALK, or ROS1 alterations.
Patients were randomly assigned 2:1 to a fixed intravenous dose of sugemalimab at 1200 mg (n=255) or placebo (n=126) every 3 weeks for up to 24 months.
At baseline, the median age was 61 years in the sugemalimab arm and 60 years in the placebo arm (overall range, 42-78 years). Most patients were men (92.5% and 91.3%, respectively), were current or former smokers (83.5% and 87.3%), had squamous histology (69.4% and 70.6%), and received a radiation dose of 60 Gy or higher (83.1% and 83.3%).
The primary endpoint was PFS by blinded independent review. The median follow-up for PFS was 27.1 months in the sugemalimab arm and 23.5 months in the placebo arm.
There was a significant improvement in PFS with sugemalimab in the overall cohort and when patients were separated by receipt of sCRT and cCRT.
Overall, the median PFS was 10.5 months with sugemalimab and 6.2 months with placebo (hazard ratio [HR], 0.65; 95% CI, 0.50-0.84; P =.0012). The 24-month PFS rate was 38.6% and 23.1%, respectively. The 36-month PFS rate was 26.1% and 0%, respectively.
Among patients who had received sCRT, the median PFS was 8.1 months with sugemalimab and 4.1 months with placebo (HR, 0.57; 95% CI, 0.38-0.87). Among patients who had received cCRT, the median PFS was 15.7 months with sugemalimab and 8.3 months with placebo (HR, 0.71; 95% CI, 0.50-1.00).
The OS data were not mature at the data cutoff, but there was a trend toward improvement in OS with sugemalimab. The median follow-up for OS was 27.1 months in the sugemalimab arm and 23.5 months in the placebo arm.
The median OS was not reached with sugemalimab and was 25.9 months with placebo (HR, 0.69; 95% CI, 0.49-0.97). The 24-month OS rate was 67.6% and 55.0%, respectively. The 36-month OS rate was 55.8% and 29.5%, respectively.
Among patients who had received sCRT, the median OS was not reached with sugemalimab and was 24.1 months with placebo (HR, 0.60; 95% CI, 0.34-1.05). Among patients who had received cCRT, the median OS was not reached with sugemalimab and was 32.4 months with placebo (HR, 0.75; 95% CI, 0.48-1.15).
Treatment-related adverse events (TRAEs) occurred in 78.4% of patients in the sugemalimab arm and 64.3% in the placebo arm. Grade 3 or higher TRAEs occurred in 11.4% and 5.6%, respectively. Serious TRAEs occurred in 17.3% and 8.7%, respectively.
The most common TRAEs in the sugemalimab arm were hypothyroidism, ALT/AST increase, hyperthyroidism, pneumonitis, and immune-mediated lung disease.
There were 12 fatal treatment-emergent adverse events in the sugemalimab arm and 3 in the placebo arm.
Disclosures: This research was supported by CStone Pharmaceuticals. Some study authors are employed by CStone Pharmaceuticals. Other authors declared relationships with a range of pharmaceutical companies.
Wu YL, Zhou Q, Chen M, et al. Sugemalimab vs placebo after cCRT or sCRT in pts with unresectable stage III NSCLC: Final PFS analysis of a phase 3 study. Presented at WCLC 2022. August 6-9, 2022. Abstract 968.