Consolidation sugemalimab prolongs PFS in unresectable stage III NSCLC

Patients with unresectable stage III non-small cell lung cancer experienced a sustained advantage in progression-free survival after treatment with consolidation sugemalimab.

Treatment with sugemalimab appears to be a safe and effective option after concurrent chemoradiotherapy and short-term chemoradiotherapy and may be considered standard of care for unresectable stage III non-small cell lung cancer, according to the results of the Final progression-free survival (PFS) from the phase 3 GEMSTONE-301 study (NCT03728556) which was presented at the 2022 World Conference on Lung Cancer.

The data indicated that after a median follow-up of 27.1 months versus 23.5 months in the sugemalimab and placebo arms, respectively, the blinded independent central review (BICR) PFS rates were 60.4% and 71.4% (RR: 0.65; 95% CI, 0.50-0.84). The median PFS was 10.5 months (95% CI, 8.3-17.1) in the sugemalimab arm versus 6.2 months in the placebo arm. Additionally, PFS rates were higher with sugemalimab at 12 months (49.5% versus 32.3%, respectively), 24 months (38.6% versus 23.1%) and 36 months (26.1% versus 0.0%).

When assessing PFS by type of chemoradiotherapy, investigators reported rates of 73.3% and 92.7% after treatment with sugemalimab and placebo, respectively, after a median follow-up of 30.6 months and 27.8 months in both arms in patients treated with short-term radiotherapy. The median PFS in the sugemalimab arm was 8.1 months (95% CI, 3.4-10.6) and 4.1 months (95% CI, 2.1-6.1) in the placebo. Additionally, the PFS rates at 12 months, 24 months, and 36 months in both arms were 38.8% versus 12.7%, 30.5% versus 7.6%, and 18.1% versus 0.0 %, respectively.

“Concomitant chemoradiotherapy followed by immunotherapy is the standard of care for patients with unresectable stage III pulmonary NSCLC. [However], nearly 50% did not receive concurrent chemoradiotherapy and only received sequential chemoradiotherapy,” explained Yi-Long Wu, MD, tenured professor at Guangdong Provincial People’s Hospital, Academy of Guangdong Medical Sciences and Guangdong Lung Cancer Institute. “Furthermore, only 45% had received concurrent chemoradiotherapy in Europe, 35% in Belgium, 55% in the Netherlands and 45% in the UK.”

Among patients treated with concurrent chemoradiotherapy, PFS rates were 53.8% and 61.2% after a median of 22.4 months and 20.0 months of follow-up in the sugemalimab and placebo arms, respectively. The median PFS was 15.7 months (95% CI, 9.0-24.4) for the sugemalimab cohort and 8.3 months (95% CI, 5.8-24.8) for the placebo. At 12, 24, and 36 months, PFS rates in the sugemalimab and placebo groups were 54.8% versus 42.1%, 42.5% versus 34.0%, and 34.1% versus 0.0%, respectively.

The trial included a total of 381 patients who were randomized 2:1 to receive either intravenous sugemalimab at a dose of 1200 mg every 3 weeks or intravenous placebo every 3 weeks until 24 months. The population included patients with stage III disease who had not progressed after concurrent chemoradiotherapy or short-term radiotherapy. Additional inclusion criteria included an ECOG performance status of 0 or 1 and no known sensitization of EGFR, ALKWhere ROS1 alterations. Patients were stratified by performance status, type of chemoradiotherapy, and total dose of radiotherapy.

The primary endpoint of the study was PFS by BICR, and secondary endpoints included overall survival (OS), investigator-assessed PFS, overall response rate, duration of response, time to distant metastasis, safety and pharmacokinetics.

In terms of other outcomes, the OS rate in the sugemalimab arm was 33.3% after a median follow-up of 27.1 months and 42.9% after a median follow-up of 23.5 months (HR, 0. 69; 95% CI, 0.49-0.97) . Median OS was not achieved (NR; 95% CI, 31.0-NR) in the sugemalimab arm versus 25.9 months (95% CI, 21.2-NR) in the placebo arm. OS rates for the sugemalimab arm versus placebo at 12, 24, and 36 months were 86.0% versus 83.2%, 67.6% versus 55.0%, and 55.8% versus 29.5% , respectively.

Safety results indicated that almost all patients experienced treatment-related adverse events (TEAEs) in the sugemalimab and placebo arms (97.3% versus 96.0%, respectively). Serious TEAEs occurred in 78.4% and 27.8% of patients in the sugemalimab and placebo arms, respectively. In addition, 31.0% of those in the sugemalimab cohort and 28.6% in the placebo cohort experienced grade 3 to 5 TEAEs. Permanent discontinuation of treatment was required in 16.1% and 4.8 % of patients, respectively, and 4.7% and 2.4% of patients died as a result of TEAE. The most common grade 3 or higher TEAEs in the sugemalimab arm were immune-mediated lung disease, rash, hypothyroidism, and pneumonitis compared to pneumonitis and anemia in the control group.

Reference

Wu Yl. Sugemalimab vs placebo after cCRT or sCRT in patients with unresectable stage III NSCLC: final analysis of PFS from a phase 3 study. Presented at the 2022 World Conference on Lung Cancer; August 6-9, 2022; Vienna, Austria; abstract 968.

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