Overview of Libtayo, First New FDA-Approved Drug for Metastatic Cutaneous Squamous Cell Carcinoma (CSCC) Everyday Health MenuNewslettersSearch Cancer Overview of Libtayo First New FDA-Approved Drug for Metastatic Cutaneous Squamous Cell Carcinoma CSCC When Surgery or Radiation Isn t an Option By Susan K. TreimanMedically Reviewed by Thomas Urban Marron, MD, PhDReviewed: July 17, 2020Medically ReviewedLibtayo belongs to a category of drugs called checkpoint inhibitors, which help the immune system fight cancer. Photo Courtesy of SanofiLibtayo (pronounced lihb-TAY-oh) falls into a category of drugs called checkpoint inhibitors, which help the immune system fight cancer. Libtayo (cemiplimab-rwlc, pronounced seh-MIP-lih-mab) is a type of drug known as a human monoclonal antibody. It targets the immune checkpoint receptor PD-1 (programmed cell death protein-1) and has become the standard of care for some forms of metastatic cutaneous squamous cell carcinoma (CSCC) over the last 18 months, and has shown promise in treating other cancers, too. Libtayo acts on a cellular pathway known as PD-1, blocking it and allowing the immune system to recognize and fight cancer cells. Since its approval, tests conducted on other cancers that use the same pathway have yielded promise. Those include the more common basal cell carcinoma, and non-small-cell lung cancer. Libtayo won U.S. Food and Drug Administration (FDA) approval in September 2018 for those with metastatic or locally advanced cancers who are not candidates for curative surgery or radiation. With four thousand prescriptions written since then, the drug has successfully halted or reversed CSCC for some patients with no other viable treatment options, doing so with few or minor side effects relatively quickly. “We generally know within two or three months if we will get a benefit from Libtayo,” says Svetomir N. Markovic, MD, PhD, an oncologist at Mayo Clinic in Minneapolis, who frequently uses the medication. So far, the drug’s effects have been enduring. “Our follow-up in our trials shows cancers maintaining or improving two or three years out,” says Daren Kwok, spokesman for the U.S.-based Regeneron, one of the drug’s codevelopers. CSCC A Rising Concern Metastatic cutaneous squamous cell carcinoma, the second-most frequently diagnosed skin cancer, is a nonmelanoma cancer of the squamous cells (pronounced either SKWAY-muss or SKWAH-muss) of the epidermis, the skin’s outermost layer. Roughly 95 percent of CSCC cases are curable by tumor removal. Treatments are less effective when CSCC invades deeper skin layers (“advanced” CSCC) and when it spreads to other areas (“metastatic” CSCC). CSCC claims 15,000 lives a year in the United States, according to the Skin Cancer Foundation (SCF). (6) The disease is among the few malignancies not registered in the cancer research database. It affects between 800,000 and one million people, as detailed at a December 2018 OncLive conference. A study published in the Journal of the American Academy of Dermatology projected 700,000 new diagnoses annually, with numbers increasing as the population ages. (5) Before Libtayo dominated CSCC treatment, few drugs were effective for cases that did not respond to tumor removal. “There were some medications being used off-label, but their response rates were pretty low,” says Emily S. Ruiz, MD, MPH, director of the High-Risk Skin Cancer Clinic at Dana Farber and Brigham and Women’s Cancer Center in Boston. “This drug has definitely changed the landscape for those patients,” Dr. Ruiz says. In clinical trials, Libtayo achieved an almost 50 percent response rate for metastatic CSCC, as reported by Regeneron Sanofi Genzyme. New Potential Treatments Early research using Libtayo on other T-cell-inhibiting cancers that, like CSCC, carry many genetic mutations, (known as a high tumor mutational burden) are yielding promise. They include basal cell carcinoma, which is even more common than CSCC, and non-small-cell lung cancer. More than four million cases of basal cell cancer are diagnosed each year in the United States, most believed due to sun exposure. In addition, the non-small-cell cancer accounts for at least 80 percent of lung cancers, according to the American Cancer Society. Dosage Information for Adults Libtayo is administered intravenously over 30-minute periods every three weeks until the disease responds or there is some kind of unacceptable reaction. The recommended dose is 350 milligrams (mg) per treatment. (1) What Are the Side Effects of Libtayo Libtayo is “very well-tolerated,” Ruiz says, “but it’s important to know that all immune therapies can cause side effects.” Regeneron and Sanofi report on the Libtayo website that serious adverse reactions occurred in about 28 percent of patients, resulting in a halt to the medication in 5 percent of all patients. The most common nonserious reactions were fatigue, rash, and diarrhea. (1) Other adverse reactions can include:Immune-mediated pneumonitis (inflammation of the lungs, which can lead to coughing or shortness of breath)Immune-mediated colitisImmune-mediated hepatitisImmune-mediated endocrinopathies, including adrenal insufficiency, hypophysis, hypothyroidism, hyperthyroidism, and type 1 diabetesImmune-mediated nephritis with renal dysfunctionImmune-mediated dermatologic reactionOther neurological, ocular, gastrointestinal, musculoskeletal, and connective tissue reactions, and hematological side effects (1) Because Libtayo can cause the immune system to attack normal organs and tissues in any area of the body, each patient must undergo blood work periodically while taking the drug to track liver and thyroid function. Other side effects, such as diarrhea or abdominal pain, may not be detected via blood tests. It is important that patients report all symptoms and changes to their doctor. (1) Libtayo should not be used by pregnant women as it can harm a fetus. Lactating women should wait four weeks after the medication is discontinued before breastfeeding. (1) Clinical Trial and Safety Information Libtayo won FDA approval based on data collected from a multicenter, open-label, nonrandomized phase 2 trial and two advanced CSCC multicenter, open-label, nonrandomized phase 1 trials. The trials represent the largest prospective data set in advanced CSCC. A total of 108 patients (75 with metastatic disease and 33 with locally advanced disease) were included in the evaluation. The patients received 3 milligram per kilogram (mg/kg) of Libtayo via intravenous infusion every two weeks over a 48-week period. Treatment continued until either tumor growth was arrested, a reaction caused the patient to discontinue the medication, or the planned treatment was completed. Patient responses were evaluated every eight weeks. At the conclusion, nearly one-half of the participants — 47.2 percent — experienced partial shrinkage or complete disappearance of their tumors. Tumors did not regrow immediately following the clinical trials. Prevention of CSCC The biggest CSCC risk factor is sun exposure, often over a lifetime. Avoiding the sun, using effective sunscreens, and eschewing tanning beds are the best preventions, particularly if initiated early in life and practiced consistently. Those who are fair-skinned, work outdoors, live in the southern and central United States, or are geriatric are likelier to develop CSCC. “The incidence is increasing, with the number of skin cancer patients over 65 now reaching an all-time high,” says Ruiz. Libtayo is a much-needed addition to the treatment arsenal, say both Ruiz and Dr. Markovic. “CSCC is a rare disease. The medical community went and asked whether treatments similar to those used in melanoma could work here too,” Markovic says. “Fortunately, the answer was ‘yes,’ and there were companies willing to make the investment to study this.” NEWSLETTERS Sign up for our Cancer Care Newsletter SubscribeBy subscribing you agree to the Terms of Use and Privacy Policy. Editorial Sources and Fact-Checking Libtayo Can Help Your Immune System Fight Advanced CSCC. Libtayo.FDA Approves Libtayo (Cemiplimab) for a Type of Skin Cancer. American Cancer Society. October 8, 2018.Librayo (Cemiplimab) Approved for Advanced Cutaneous Squamous Cell Carcinoma in the European Union. Sanofi. July 1, 2019.Libtayo Injection. Regeneron. September 2018.Karia P, Han J, Schmults CD. Cutaneous Squamous Cell Carcinoma: Estimated Incidence of Disease, Nodal Metastasis, and Deaths From Disease in the United States, 2012. Journal of the American Academy of Dermatology. February 4, 2013.The Skin Cancer Foundation Comments on FDA Approval of Libtayo (Cemiplimab-RWLC), for the Treatment of Advanced Cutaneous Squamous Cell Carcinoma (CSCC). Skin Cancer Foundation. October 1, 2018.Skin Cancer Prevention. Skin Cancer Foundation.Show Less The Latest in Cancer New Guidelines Recommend Best Uses of Acupuncture Massage and Other Non-Drug Treatments for Cancer PainLeading organizations say complementary therapies such as reflexology and hypnosis may provide pain relief for some cancers.By Susan K. TreimanOctober 4, 2022 Is Chemotherapy Bringing You Down Research shows that chemotherapy can cause depression. 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