Abstract 954P
Background
In EMPOWER-Lung 3 (NCT03409614), a double-blind randomised phase 3 study of patients (pts) with advanced squamous or non-squamous NSCLC without EGFR, ALK or ROS aberrations, 1L cemiplimab + chemo demonstrated improved overall survival (OS) versus chemo alone (hazard ratio [HR] 0.71, P=0.014), a safety profile consistent with those previously reported for cemiplimab and chemo, and a favourable pt-reported outcome (PRO). Here, we report a post hoc subgroup analysis of pts with laNSCLC (Stage IIIb/c) who are not candidates for definitive concurrent chemoradiotherapy.
Methods
In EMPOWER-Lung 3, pts were randomised 2:1—stratified by histology and programmed cell death-ligand 1 (PD-L1) expression—to receive cemiplimab 350 mg or placebo (PBO) every 3 weeks for 108 weeks plus 4 cycles of chemo until progression, followed by pemetrexed maintenance as appropriate. Primary endpoint was OS. Secondary endpoints included progression-free survival (PFS), objective response rate (ORR), duration of response (DOR) and PROs. Data cutoff for this subgroup analysis was 14 Jun 2021.
Results
Of 466 trial pts, 69 pts (14.8%) had laNSCLC. At median follow-up of 16.7 months (range 9.0–24.0), cemiplimab + chemo provided significantly better PFS (12.5 vs 6.2 months) and numerically longer OS (21.9 vs 13.8 months) than PBO + chemo. ORR was 57.8% with median DOR of 16 months with cemiplimab + chemo, versus 33.3% and 4.2 months, respectively, with PBO + chemo (Table). Incidence of Grade ≥3 treatment-emergent adverse events was 42.2% with cemiplimab + chemo and 25.0% with PBO + chemo. Table: 954P
| Cemiplimab + chemo (n=45) | PBO + chemo (n=24) | |
| Age, median (range), years | 62.0 (39–82) | 63.0 (52–77) |
| Squamous, n (%) | 23 (51.1) | 13 (54.2) |
| Non-squamous, n (%) | 22 (48.9) | 11 (45.8) |
| Follow-up duration, median (range), months | 16.7 (9.0–24.0) | 17.9 (10.6–23.4) |
| OS, median (95% CI), months | 21.9 (14.1–23.2) | 13.8 (10.3–NE) |
| HR (95% CI) | 0.54 (0.25–1.15); P=0.107† | |
| PFS, median (95% CI), months | 12.5 (8.2–18.1) | 6.2 (4.3–6.4) |
| HR (95% CI) | 0.34 (0.19–0.62); P=0.0002† | |
| ORR, % (95% CI) | 57.8 (42.2–72.3) | 33.3 (15.6–55.3) |
| CR, n (%) | 1 (2.2) | 0 |
| PR, n (%) | 25 (55.6) | 8 (33.3) |
| KM estimated DOR, median (95% CI), months | 16.0 (10.6–NE) | 4.2 (3.0–10.3) |
†Nominal P value. CR, complete response; KM, Kaplan-Meier; NE, not evaluable; PR, partial response.
Conclusions
In pts with laNSCLC, 1L cemiplimab + chemo provided significant improvement in PFS, numerically longer OS, higher ORR, and longer durable response than control. The safety profile was consistent with that reported in the overall population of this study.
Clinical trial identification
NCT03409614.
Editorial acknowledgement
Medical writing support was provided by Daniel M Himmel, PhD, of Prime, Knutsford, UK.
Legal entity responsible for the study
Regeneron Pharmaceuticals, Inc., and Sanofi.
Funding
Regeneron Pharmaceuticals, Inc., and Sanofi.
Disclosure
E. Kalinka-Warzocha: Financial Interests, Personal, Other, Honoraria: Merck Sharp & Dohme, Bristol-Myers Squibb, Nektar, Pfizer, Roche, AstraZeneca, Amgen, Regeneron Pharmaceuticals. K.D. Penkov: Financial Interests, Personal, Other, Honoraria: AstraZeneca, Merck Sharp & Dohme, Nektar, Pfizer, Regeneron Pharmaceuticals, Inc., and Roche; Financial Interests, Personal, Advisory Role: Nektar. X. He, R. Quek, J. Pouliot, F. Seebach, I. Lowy, G. Gullo, P. Rietschel: Financial Interests, Personal, Full or part-time Employment: Regeneron Pharmaceuticals, Inc. ; Financial Interests, Personal, Stocks/Shares: Regeneron Pharmaceuticals, Inc. All other authors have declared no conflicts of interest.