cemiplimab

Overview

Cemiplimab (brand name Libtayo) is a fully human monoclonal antibody that targets programmed cell death protein-1 (PD-1), a key immune checkpoint receptor expressed on T cells and other immune effector cells. By blocking the interaction between PD-1 and its ligands PD-L1 and PD-L2, cemiplimab restores antitumor immune activity within the tumor microenvironment, enabling cytotoxic T cells to recognize and eliminate cancer cells that would otherwise evade immune surveillance. Developed by Regeneron Pharmaceuticals and Sanofi, cemiplimab was among the first anti-PD-1 therapies to receive approval from both the U.S. Food and Drug Administration (FDA) and the European Medicines Agency (EMA), initially for cutaneous squamous cell carcinoma (CSCC) and subsequently expanded to cover additional solid tumors including non-small cell lung cancer (NSCLC) and cervical cancer.

As an immune checkpoint inhibitor, cemiplimab belongs to the same mechanistic class as pembrolizumab and other anti-PD-1/PD-L1 agents. Its therapeutic value lies in reactivating exhausted T-cell responses against malignancies that exploit the PD-1 pathway to suppress antitumor immunity. Cemiplimab has demonstrated clinical utility both as monotherapy and in combination with chemotherapy or investigational agents, establishing it as a versatile backbone in the modern oncology treatment landscape across a range of tumor types including melanoma, CSCC, NSCLC, and recurrent cervical cancer.

Focus of Latest Publications

Recent publications on cemiplimab have focused on its use as a PD-1 checkpoint inhibitor in combination strategies and in real-world or follow-up analyses across several tumor types. In advanced skin cancers, a phase 1/2 study evaluated pegenzileukin, a pegylated non-alpha IL-2 variant, with cemiplimab in advanced or metastatic melanoma and cutaneous squamous cell carcinoma, building on earlier evidence that pegenzileukin combined with pembrolizumab showed initial efficacy and tolerable safety in advanced solid tumors. Another first-in-human program examined fianlimab, a LAG-3 monoclonal antibody, with cemiplimab; the dose-expansion cohorts reported safety and clinical activity data in advanced non-small cell lung cancer, clear cell renal cell carcinoma, head and neck squamous cell carcinoma, and cutaneous squamous cell carcinoma.

Several publications addressed cemiplimab in cutaneous squamous cell carcinoma and non-small cell lung cancer outside of early-phase combination studies. A retrospective cohort analysis of EMPOWER-CSCC-1 assessed extended follow-up in advanced cutaneous squamous cell carcinoma to better understand the long-term durability of responses after cemiplimab, while the French TOSCA study compared cemiplimab with historical systemic treatments in locally advanced or metastatic cutaneous squamous cell carcinoma, focusing on real-world effectiveness and safety. In advanced non-small cell lung cancer, a review of patient-reported outcomes from EMPOWER-Lung 1 summarized cemiplimab monotherapy versus chemotherapy in patients with PD-L1 expression of at least 50%, and a separate analysis evaluated the cost-effectiveness of cemiplimab plus chemotherapy versus pembrolizumab plus chemotherapy as first-line treatment for metastatic disease from a US payer perspective.

Cemiplimab has also been discussed in cervical cancer and in the broader context of resistance to PD-(L)1 blockade. A review of immunotherapy in cervical cancer noted that incorporation of immune checkpoint inhibitors such as pembrolizumab and cemiplimab into treatment has improved survival in locally advanced and recurrent/metastatic disease, while also emphasizing that primary and acquired resistance remain important limitations, particularly in low PD-L1 or immunologically “cold” tumors. In a separate publication on overcoming PD-(L)1 resistance, cemiplimab was mentioned as part of a preliminary strategy combining the ERAP1 inhibitor GRWD5769 with cemiplimab to target antigen processing and potentially mitigate resistance to PD-(L)1 blockade.

Key Publications

Jul Combos New and Old Counter PD-(L)1 Resistance, Treat Rare Cancers. (Cancer discovery, 2026, PMID 42240229): "The ERAP1 inhibitor GRWD5769 combined with cemiplimab, a PD-1 inhibitor, has shown preliminary promise in overcoming resistance to PD-(L)1 blockade by targeting antigen processing."
May Phase 1/2 study of pegenzileukin, a pegylated recombinant non-alpha IL-2, with cemiplimab for the treatment of advanced unresectable or metastatic skin cancers. (Journal for immunotherapy of cancer, 2026, PMID 42173654): "In this study, we evaluate pegenzileukin with cemiplimab for advanced or metastatic melanoma (MM) and cutaneous squamous cell carcinoma (CSCC)."
May Fianlimab, a human lymphocyte activation gene-3 monoclonal antibody, in combination with cemiplimab: Tumor-specific expansion cohorts in advanced malignancies. (Cancer, 2026, PMID 42028885): "The dose escalation phase of a first-in-human (FIH) study demonstrated acceptable safety and preliminary antitumor activity of fianlimab (anti-lymphocyte activation gene-3 [LAG-3]) as monotherapy and in combination with cemiplimab (anti-programmed cell death-1 [PD-1])."
Apr The game changer in the cervical cancer therapeutic landscape: immunotherapy. (Immunotherapy, 2026, PMID 41958269): "The incorporation of Immune Checkpoint Inhibitors such as pembrolizumab and cemiplimab in the CC treatment has led to significant improvements in survival."
Apr Cost-effectiveness of pembrolizumab plus chemotherapy vs cemiplimab plus chemotherapy for first-line metastatic non-small cell lung cancer: a US payer perspective using a matching-adjusted indirect comparison. (Journal of medical economics, 2026, PMID 41861397): "Recent clinical guidelines recommend pembrolizumab plus chemotherapy and cemiplimab plus chemotherapy as key first-line treatment options for metastatic non-small cell lung cancer (mNSCLC)."
Apr Review of patient-reported outcomes in EMPOWER-Lung 1 in patients with advanced non-small cell lung cancer treated with cemiplimab versus chemotherapy. (Cancer, 2026, PMID 41808570): "Patient-reported outcomes (PROs) for cemiplimab monotherapy versus chemotherapy from the EMPOWER-Lung 1 phase 3 clinical trial"
May Cemiplimab versus historical systemic treatments for locally advanced or metastatic cutaneous squamous cell carcinomas: Results from the French study TOSCA. (European journal of cancer (Oxford, England : 1990), 2026, PMID 41806521): "Cemiplimab an anti-programmed cell death receptor-1 antibody, was approved by the FDA and EMA for patients with locally advanced cutaneous squamous cell carcinoma (laCSCC) ineligible for curative surgery/radiotherapy or with metastatic (m) CSCC."
Apr Extended follow-up outcomes of patients with advanced cutaneous squamous cell carcinoma treated with cemiplimab on EMPOWER-CSCC-1: A retrospective cohort study. (Journal of the American Academy of Dermatology, 2026, PMID 41319712): "The international phase 2 EMPOWER-CSCC-1 study established the programmed cell death protein-1 inhibitor cemiplimab as standard of care for patients with locally advanced or metastatic cutaneous squamous cell carcinoma, however, long-term durability of responses are unknown."