Fianlimab (LAG-3 Inhibitor) Combined with Libtayo® (cemiplimab) Demonstrates Greater than 60% Response Rates in Two Independent Cohorts of Patients with Advanced Melanoma Naïve to PD-1 or PD-L1 Inhibitors

Positive clinical data presented in a mini-oral session at ESMO

Safety profile of the combination was generally similar to Libtayo monotherapy

TARRYTOWN, NY, USA I September 12, 2022 I Regeneron Pharmaceuticals, Inc. (NASDAQ: REGN) today announced the presentation of positive data from multiple expansion cohorts of an initial Phase 1 trial for an investigational combination of LAG-3 inhibitor fianlimab and PD-1 inhibitor Libtayo® (cemiplimab) in advanced melanoma. The results were shared in a mini-oral session at the European Society for Medical Oncology (ESMO) Congress 2022 in Paris.

"After regulatory approvals of our PD-1 inhibitor Libtayo in two advanced non-melanoma skin cancers, we are expanding our efforts in dermato-oncology to address advanced melanoma," said Israel Lowy, M.D., Ph.D., Senior Vice President, Translational and Clinical Sciences, Oncology at Regeneron. "Combining LAG-3 and PD-1 inhibition has shown promise in advanced melanoma but achieving response rates above 50% has been challenging. In two independent dose expansion cohorts from a Phase 1 clinical trial of patients naïve to PD-1 or PD-L1 inhibitors, our LAG-3 inhibitor fianlimab combined with Libtayo demonstrated greater than 60% response rates. Notably, the safety profile for this combination appears in line with Libtayo monotherapy. A Phase 3 trial in first-line metastatic melanoma is currently enrolling patients, and we look forward to opening additional trials with this combination in the near future."

Data presented at ESMO were from three dose expansion cohorts in advanced melanoma, including two that enrolled patients who had not previously been treated with a PD-1 or PD-L1 inhibitor (PD-1/PD-L1-naïve) and one of patients who had received prior PD-1 or PD-L1 inhibitor therapy (PD-1/PD-L1-experienced). The objective response rate (ORR) in the PD-1/PD-L1-experienced cohort was 13%. Results from the PD-1/PD-L1-naïve cohorts were as follows:

  • In updated results for one cohort (n=40), a 62.5% ORR (25 of 40 patients; 6 complete reponses [CR], 19 partial responses [PR]). Median duration of response (DOR) was not reached (range: 12 months to not evaluable [NE]) and the median progression-free survival (PFS) was 24 months (95% confidence interval [CI], 4 months to NE), per Kaplan-Meier estimates.
  • In a newly presented independent confirmatory cohort (n=40), a 65% ORR (26 of 40 patients; 1 CR, 25 PRs). The median DOR (range: 6 months to NE) and median PFS (95% CI, 7.5 to NE) were not reached, per Kaplan-Meier estimates.

Tumor responses were based on RECIST 1.1 criteria and per investigator assessment. AEs of any grade in the two PD-1/PD-L1-naïve cohorts (n= 80) occurred in 96% of patients, with 29% considered serious. The most common immune-mediated AEs in ≥15% patients were rash (n=19) and pruritus (n=12). AEs that were ≥grade 3 occurred in 40% of patients. The treatment discontinuation rate due to AEs was 16%, with two deaths considered possibly related to treatment (colitis and cardiac shock).

The potential use of fianlimab and Libtayo described above is investigational, and safety and efficacy of this combination have not been evaluated by any regulatory authority.

About Regeneron in Oncology
At Regeneron, we're applying more than three decades of scientific innovation with the goal of developing paradigm-changing therapies for patients with cancer. Our oncology portfolio is built around two foundational approaches – our approved PD-1 inhibitor Libtayo and investigational bispecific antibodies – which are being evaluated both as monotherapies and in combination with emerging therapeutic modalities. Together, they provide us with unique combinatorial flexibility to develop potentially synergistic treatments for a wide range of solid tumors and blood cancers.

If you are interested in learning more about our clinical trials, please contact us (This email address is being protected from spambots. You need JavaScript enabled to view it. or 844-734-6643) or visit our clinical trials website.

About fianlimab
Fianlimab is a fully human monoclonal antibody targeting the immune checkpoint receptor LAG-3 on T cells and was invented using Regeneron's proprietary VelocImmune® technology. In melanoma, LAG-3 expression on cancer cells is associated with therapeutic resistance to PD-1 inhibitors. Fianlimab is being investigated in combination with Regeneron's PD-1 inhibitor Libtayo to determine whether concurrent blockade of LAG-3 and PD-1 can help overcome this resistance and release the brakes on T cell activation.

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. In the U.S. and other countries Libtayo is indicated in certain patients with advanced basal cell carcinoma (BCC), advanced cutaneous squamous cell carcinoma (CSCC) and advanced non-small cell lung cancer (NSCLC), as well as in advanced cervical cancer in Canada and Brazil. As of July 1, 2022, Libtayo is developed and marketed globally by Regeneron. 

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. Food and Drug Administration (FDA). Outside of the U.S. the generic name of Libtayo in its approved indication 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 advanced CSCC that has spread or cannot be cured by surgery or radiation.
  • A type of skin cancer called BCC:
    • That cannot be removed by surgery (locally advanced BCC) and have received treatment with a hedgehog pathway inhibitor (HHI), or cannot receive treatment with an HHI.
    • That has spread (metastatic BCC) and have received treatment with an HHI, or cannot receive treatment with an HHI. This use is approved based on how many patients responded to treatment and how long they responded. Studies are ongoing to provide additional information about clinical benefit.
  • A type of lung cancer called NSCLC. Libtayo may be used 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.

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 approximately one in five of all original, FDA-approved or authorized fully human monoclonal antibodies. This includes REGEN-COV® (casirivimab and imdevimab), Dupixent® (dupilumab), Libtayo® (cemiplimab-rwlc), Praluent® (alirocumab), Kevzara® (sarilumab), Evkeeza® (evinacumab-dgnb) and Inmazeb™ (atoltivimab, maftivimab and odesivimab-ebgn).

SOURCE: Regeneron Pharmaceuticals

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