Alternative Cemiplimab Dosing Strategy Receives CHMP Recommendation in Multiple Cancer Types

The European Medicines Agency’s Committee for Medicinal Products for Human Use (CHMP) has issued a positive opinion recommending that an alternative dosing schedule for cemiplimab-rwlc (Libtayo) be approved for every indication currently authorized in the European Union (EU).¹

A final decision from the European Commission is expected in the coming months and would extend the schedule to all 6 approved EU indications. The EU approval would be based on pharmacokinetic and pharmacodynamic modeling and simulation, combined with clinical safety and efficacy data from the cemiplimab development program.

Under the extended regimen, patients would receive 350 mg of cemiplimab by 30-minute intravenous (IV) infusion every 3 weeks for the first 12 weeks, then 700 mg by 30-minute IV infusion every 6 weeks. The opinion also backs a shorter, 15- to 30-minute infusion for patients receiving 350 mg every 3 weeks who tolerated their first infusion at that dose over 30 minutes, which could reduce treatment time by as much as half.

What is the mechanism of action of cemiplimab?

Cemiplimab is a fully human immunoglobulin G4 monoclonal antibody directed against PD-1 that prevents the receptor from engaging PD-L1 and PD-L2.² Blocking that interaction enhances T-cell activity, including antitumor activity.

Which cemiplimab indications are approved in the EU?

Cemiplimab first received conditional marketing authorization in the EU on June 28, 2019, and moved to standard authorization on July 1, 2022.³ As monotherapy, it is approved for the treatment of adult patients with metastatic or locally advanced cutaneous squamous cell carcinoma (CSCC) who cannot undergo curative surgery or curative radiation, and as adjuvant therapy for those with CSCC at high risk of recurrence after surgery and radiation.^2,3 Other monotherapy indications include locally advanced or metastatic basal cell carcinoma after progression on, or intolerance to, a hedgehog pathway inhibitor; first-line treatment of non–small cell lung cancer (NSCLC) with PD-L1 expression on at least 50% of tumor cells and no EGFR, ALK, or ROS1 aberrations; and recurrent or metastatic cervical cancer that has progressed on or after platinum-based chemotherapy. In combination with platinum-based chemotherapy, cemiplimab is also approved as first-line treatment for patients with NSCLC with PD-L1 expression on at least 1% of tumor cells and no EGFR, ALK, or ROS1 aberrations. Both NSCLC indications cover metastatic disease and locally advanced disease in patients who are not candidates for definitive chemoradiation.

The 700-mg every-6-week option is already approved in the EU for the adjuvant treatment of patients with CSCC at high risk of recurrence, following an initial 12 weeks of 350 mg every 3 weeks.¹ For every other indication, the approved dose is 350 mg every 3 weeks as a 30-minute IV infusion.²

What data support every-6-week cemiplimab dosing?

The every-6-week schedule in patients with adjuvant CSCC was evaluated in the randomized, double-blind, placebo-controlled phase 3 C-POST trial (NCT03969004), in which 415 patients who had undergone surgery and radiation were randomly assigned 1:1 to receive cemiplimab (n = 209) or placebo (n = 206). In part 1, 334 patients were assigned to receive cemiplimab (n = 171) or placebo (n = 163) at 350 mg every 3 weeks for 12 weeks, then at 700 mg every 6 weeks for another 36 weeks. A further 81 patients were assigned to receive cemiplimab (n = 38) or placebo (n = 43) at 350 mg every 3 weeks for a maximum of 48 weeks.

At the primary analysis (data cutoff, October 4, 2024; median follow-up, 24.5 months with cemiplimab and 23.8 months with placebo), the median disease-free survival (DFS) was not reached with cemiplimab vs 49.4 months (95% CI, 48.5-not evaluable) with placebo (HR, 0.32; 95% CI, 0.20-0.51; P < .0001). DFS events occurred in 24 of 209 patients (11.5%) receiving cemiplimab and 65 of 206 patients (31.6%) receiving placebo. An updated analysis (data cutoff, April 7, 2025; median follow-up, 31 months with cemiplimab and 30 months with placebo) showed DFS events in 29 of 209 patients (13.9%) vs 68 of 206 patients (33.0%), respectively (HR, 0.35; 95% CI, 0.23-0.55).

Simulations in patients with high-risk CSCC illustrate how exposure differs by schedule. With 350 mg every 3 weeks for 12 weeks followed by 700 mg every 6 weeks, the mean steady-state cemiplimab concentrations ranged from a trough of 52.5 mg/L to an end-of-infusion peak of 233 mg/L, vs 66.3 mg/L to 154 mg/L with 350 mg every 3 weeks for 48 weeks. At 350 mg every 3 weeks in patients with solid tumors, the mean steady-state concentrations ranged from a trough of 59 mg/L to a peak of 171 mg/L.

References

1. Libtayo (cemiplimab) recommended for EU approval by the CHMP for updated dosing regimen across all approved cancer types. News release. Regeneron Pharmaceuticals, Inc. October 16, 2026. Accessed October 17, 2026. https://investor.regeneron.com/news-releases/news-release-details/libtayor-cemiplimab-recommended-eu-approval-chmp-updated-dosing
2. Libtayo: EPAR - product information. European Medicines Agency. First published July 5, 2019. Updated December 10, 2025. Accessed October 17, 2026. https://www.ema.europa.eu/en/documents/product-information/libtayo-epar-product-information_en.pdf
3. Libtayo. European Medicines Agency. Published July 5, 2019. Updated January 20, 2026. Accessed October 17, 2026. https://www.ema.europa.eu/en/medicines/human/EPAR/libtayo