Primary endpoint of DFS met at first prespecified interim analysis, showing a 68% reduction in the risk of disease recurrence or death in patients with high-risk CSCC after surgery compared to placebo
Libtayo is the first and only immunotherapy to show a statistically significant and clinically meaningful benefit in high-risk CSCC in the adjuvant setting; a recent Phase 3 trial with Keytruda® failed in the same setting1
Libtayo is standard of care for certain patients with advanced CSCC
TARRYTOWN, NY, USA I January 13, 2025 I Regeneron Pharmaceuticals, Inc. (NASDAQ: REGN) today announced positive results from the Phase 3 C-POST trial, which demonstrated that adjuvant treatment with PD-1 inhibitor Libtayo® (cemiplimab) led to a statistically significant and clinically meaningful improvement in the primary endpoint of disease-free survival (DFS) in patients with high-risk cutaneous squamous cell carcinoma (CSCC) after surgery.
“While surgery is curative for most people living with cutaneous squamous cell carcinoma, many are burdened with a higher risk of recurrence that can lead to death or disfiguration,” said Danny Rischin, M.D., M.B.B.S., F.R.A.C.P., Research Lead, Head and Neck Cancer and Cutaneous SCC, Department of Medical Oncology at the Peter MacCallum Cancer Centre in Melbourne, Australia, and lead investigator of the trial. “At the first prespecified interim analysis, Libtayo achieved a remarkably high bar in improving disease-free survival in high-risk cutaneous squamous cell carcinoma. With no currently approved options in the adjuvant setting, these landmark results demonstrate Libtayo could represent a major advance in delaying recurrence in these vulnerable patients.”
C-POST enrolled 415 patients with high-risk CSCC who were randomized to receive either Libtayo or placebo for up to 48 weeks. The primary endpoint was DFS, defined as time from randomization to the first documented disease recurrence or death due to any cause. At the first prespecified interim analysis for DFS with a median duration of follow-up of 24 months (range: 2-64 months), Libtayo demonstrated a 68% reduction in the risk of disease recurrence or death, compared to placebo (hazard ratio: 0.32; 95% confidence interval: 0.20-0.51; p<0.0001).
Safety was assessed in 205 patients in the Libtayo arm and 204 patients in the placebo arm. Adverse events (AEs) of any grade occurred in 91% and 89% of patients in the Libtayo arm and the placebo arm, respectively. Grade ≥3 AEs occurred in 24% and 14% of patients in the Libtayo arm and the placebo arm, respectively. Treatment discontinuations due to adverse reactions occurred in 10% and 1.5% of patients in the Libtayo arm and the placebo arm, respectively. Two patients experienced an AE leading to death in each arm.
Following these interim results, C-POST will continue for additional follow-up, including an analysis of the key secondary endpoint of overall survival. Detailed results will be presented at an upcoming medical meeting and will be shared with regulatory authorities with a plan for U.S. Food and Drug Administration (FDA) submission in the first half of 2025.
“Regeneron has long been a pioneer in non-melanoma skin cancer research. Libtayo was the first PD-1 inhibitor approved for certain patients with advanced cutaneous squamous cell carcinoma and has become a standard of care in this setting,” said Israel Lowy, M.D., Ph.D., Clinical Development Unit Head, Oncology, at Regeneron. “With these results, Libtayo now has the potential to also transform the treatment of high-risk resectable cutaneous squamous cell carcinoma with adjuvant treatment. This trial is a testament to our unrelenting commitment to investigating areas where patient need remains high and to pursuing clinical research across diverse stages of skin cancer.”
The potential use of Libtayo described above is investigational, and its safety and efficacy has not been evaluated by any regulatory authority for this indication.
About the Phase 3 Trial
C-POST is an ongoing randomized, placebo-controlled, double-blind, multicenter, global Phase 3 trial investigating Libtayo versus placebo as adjuvant treatment for patients with features associated with a high-risk of CSCC recurrence and who have completed surgery and post-operative radiation therapy. Trial participants are at high risk of recurrence due to nodal features (extracapsular extension or ≥3 involved lymph nodes) and/or non-nodal features (in-transit metastases, T4 lesion, perineural invasion, or locally recurrent tumor with ≥1 additional poor prognostic features).
For the first 12 weeks, Libtayo 350 mg or placebo is administered intravenously every three weeks, followed by Libtayo 700 mg or placebo administered intravenously every six weeks for 36 weeks. The primary endpoint is DFS, and the secondary endpoints include freedom from locoregional recurrence, freedom from distant recurrence, overall survival, cumulative incidence of second primary CSCC tumors, and safety.
The Trans-Tasman Radiation Oncology Group (TROG), with Dr. Rischin as lead investigator, collaborated with Regeneron on protocol development. Trial sites included 24 TROG sites in Australia.
About Regeneron in Cancer
We aspire to turn revolutionary discoveries into medicines that can transform the lives of those impacted by cancer. Our team around the world is driven to solve the needs and challenges of those affected by one of the most serious diseases of our time.
Backed by our legacy of scientific innovation and a deep understanding of biology, genetics and the immune system, we’re pursuing potential therapies across more than 30 types of solid tumors and blood cancers. Our cancer strategy is powered by cutting-edge technologies and therapies that can be flexibly combined to investigate potentially transformative treatments for patients. Oncology assets in clinical development comprise nearly half of Regeneron’s pipeline, and include checkpoint inhibitors, bispecific antibodies and costimulatory bispecific antibodies. Our approved PD-1 inhibitor Libtayo serves as the backbone of many of our investigational combinations.
To complement our extensive in-house capabilities, we collaborate with patients, healthcare providers, governments, biopharma companies and each other to further our shared goals. Together, we are united in the mission to serve as a beacon of transformation in cancer care.
About Libtayo
Libtayo is a fully human monoclonal antibody targeting the immune checkpoint receptor PD-1 on T cells and was invented using Regeneron’s proprietary VelocImmune® technology. By binding to PD-1, Libtayo has been shown to block cancer cells from using the PD-1 pathway to suppress T-cell activation. Libtayo has been approved by regulatory authorities in more than 30 countries in one or more indications, including for certain adult patients with advanced basal cell carcinoma (BCC), advanced CSCC, advanced non-small cell lung cancer (NSCLC) and advanced cervical cancer.
In the U.S., the generic name for Libtayo in its approved indications is cemiplimab-rwlc, with rwlc as the suffix designated in accordance with Nonproprietary Naming of Biological Products Guidance for Industry issued by the U.S. FDA. Outside of the U.S., the generic name of Libtayo in its approved indications is cemiplimab.
The extensive clinical program for Libtayo is focused on difficult-to-treat cancers. Libtayo is currently being investigated in trials as a monotherapy, as well as in combination with either conventional or novel therapeutic approaches for other solid tumors and blood cancers. These potential uses are investigational, and their safety and efficacy have not been evaluated by any regulatory authority.
U.S. FDA-approved Indications
Libtayo is a prescription medicine used to treat:
- People with a type of skin cancer called cutaneous squamous cell carcinoma (CSCC) that has spread or cannot be cured by surgery or radiation.
- People with a type of skin cancer called basal cell carcinoma (BCC) when your BCC cannot be removed by surgery (locally advanced BCC) or when it has spread (metastatic BCC) and have received treatment with a hedgehog pathway inhibitor (HHI), or cannot receive treatment with a HHI.
- Adults with a type of lung cancer called non-small cell lung cancer (NSCLC).
- LIBTAYO may be used in combination with chemotherapy that contains a platinum medicine as your first treatment when your lung cancer has not spread outside your chest (locally advanced lung cancer) and you cannot have surgery or chemotherapy with radiation, or your lung cancer has spread to other areas of your body (metastatic lung cancer), and your tumor does not have an abnormal “EGFR,” “ALK,” or “ROS1” gene.
- LIBTAYO may be used alone as your first treatment when your lung cancer has not spread outside your chest (locally advanced lung cancer) and you cannot have surgery or chemotherapy with radiation, or your lung cancer has spread to other areas of your body (metastatic lung cancer), and your tumor tests positive for high “PD-L1,” and your tumor does not have an abnormal “EGFR,” “ALK,” or “ROS1” gene.
It is not known if Libtayo is safe and effective in children.
Please see full Prescribing Information, including Medication Guide.
About Regeneron’s VelocImmune Technology
Regeneron’s VelocImmune technology utilizes a proprietary genetically engineered mouse platform endowed with a genetically humanized immune system to produce optimized fully human antibodies. When Regeneron’s co-Founder, President and Chief Scientific Officer George D. Yancopoulos was a graduate student with his mentor Frederick W. Alt in 1985, they were the first to envision making such a genetically humanized mouse, and Regeneron has spent decades inventing and developing VelocImmune and related VelociSuite® technologies. Dr. Yancopoulos and his team have used VelocImmune technology to create a substantial proportion of all original, FDA-approved or authorized fully human monoclonal antibodies. This includes Dupixent® (dupilumab), Libtayo, Praluent® (alirocumab), Kevzara® (sarilumab), Evkeeza® (evinacumab-dgnb), Inmazeb® (atoltivimab, maftivimab and odesivimab-ebgn) and Veopoz® (pozelimab-bbfg). In addition, REGEN-COV® (casirivimab and imdevimab) had been authorized by the FDA during the COVID-19 pandemic until 2024.
About Regeneron
Regeneron (NASDAQ: REGN) is a leading biotechnology company that invents, develops and commercializes life-transforming medicines for people with serious diseases. Founded and led by physician-scientists, our unique ability to repeatedly and consistently translate science into medicine has led to numerous approved treatments and product candidates in development, most of which were homegrown in our laboratories. Our medicines and pipeline are designed to help patients with eye diseases, allergic and inflammatory diseases, cancer, cardiovascular and metabolic diseases, neurological diseases, hematologic conditions, infectious diseases, and rare diseases.
Regeneron pushes the boundaries of scientific discovery and accelerates drug development using our proprietary technologies, such as VelociSuite®, which produces optimized fully human antibodies and new classes of bispecific antibodies. We are shaping the next frontier of medicine with data-powered insights from the Regeneron Genetics Center® and pioneering genetic medicine platforms, enabling us to identify innovative targets and complementary approaches to potentially treat or cure diseases.
For more information, please visit www.Regeneron.com or follow Regeneron on LinkedIn, Instagram, Facebook or X.
1 Data not yet published. https://www.merck.com/news/merck-provides-update-on-phase-3-keynote-867-and-keynote-630-trials/ . All trademarks used are the property of their respective owners. The studies had differences in trial design specifics and no head-to-head comparisons have been conducted.
SOURCE: Regeneron Pharmaceuticals
