Litfulo From Pfizer Inc

The FDA has approved Ritlecitinib (Litfulo) oral capsules from Pfizer Inc to manage severe alopecia areata in individuals 12 years or older. The approval carries the limitation that ritlecitinib should not be used in combination with biologic immunomodulators, cyclosporine, other Janus kinase (JAK) inhibitors, or other potent immunosuppressants.¹

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Alopecia areata is an autoimmune disease that occurs when the immune system attacks the body’s hair follicles, resulting in hair loss on the body, face, or scalp. The condition affects approximately 7 million individuals in the United States and approximately 147 million individuals worldwide.²

PHARMACOLOGY AND PHARMACOKINETICS

Ritlecitinib irreversibly inhibits JAK3 and the tyrosine kinase expressed in the hepatocellular carcinoma kinase family. It reaches steady-state plasma concentrations after approximately 4 days of treatment and displays a mean terminal half-life of 1.3 to 2.3 hours.¹

DOSAGE AND ADMINISTRATION

The recommended dosage of ritlecitinib is 50 mg orally once daily. Treatment should not be initiated in patients with active tuberculosis (TB), hepatitis B, or hepatitis C or those with an absolute lymphocyte count (ALC) less than 500 cells/mm3 or a platelet count less than 100,000 cells/mm3. Before starting treatment with ritlecitinib, patients with latent TB or with a negative latent TB test result and a high risk for TB should begin preventive treatment for latent TB and immunizations should be brought up-to-date.¹

CLINICAL TRIALS

The efficacy and safety of ritlecitinib were evaluated in the double-blind, placebo-controlled, randomized, phase 2b/3 trial ALLEGRO (NCT03732807) of 718 patients 12 years or older with alopecia areata and a baseline scalp hair loss of 50% or more. Patients were randomly assigned to 1 of 7 treatment arms: 200 mg/d for 4 weeks followed by 50 mg/d for 44 weeks; 200 mg/d for 4 weeks followed by 30 mg/d for 44 weeks; 50 mg/d for 48 weeks; 30 mg/d for 48 weeks; 10 mg/d for 48 weeks; placebo for 24 weeks followed by 200 mg/d for 4 weeks then 50 mg/d for 20 weeks; or placebo for 24 weeks followed by 50 mg/d for 24 weeks. Results from the study found that at week 24, a statistically significant larger proportion of participants using ritlecitinib 50 mg had scalp hair loss less than or equal to 20% compared with those using placebo.^1,2

CONTRAINDICATIONS, WARNINGS, AND PRECAUTIONS

Ritlecitinib carries a boxed warning about the risk of serious bacterial, fungal, opportunistic, and viral infections, including TB. The warning also states that a higher rate of all-cause mortality, including sudden cardiovascular death and major adverse cardiovascular events, was observed during use with another JAK inhibitor when used in patients with rheumatoid arthritis and that malignant tumors and thrombosis have occurred in patients using ritlecitinib.

Treatment with ritlecitinib is contraindicated in patients with a known hypersensitivity to the medication or any of its components.

Serious hypersensitivity reactions have been observed in patients using ritlecitinib. Because treatment with ritlecitinib is associated with decreased lymphocyte and platelet counts, ALC and platelet count should be obtained before beginning therapy. Treatment discontinuation or interruption are recommended if ALC and platelet count abnormalities occur. The administration of live attenuated vaccines should be avoided during or shortly prior to beginning treatment. Ritlecitinib should not be used during breastfeeding or in patients with severe hepatic impairment.

Ritlecitinib is a CYP3A and CYP1A2 inhibitor. Additional monitoring and dose adjustments may be warranted when ritlecitinib is coadministered with CYP3A and CYP1A2 substrates, where small concentration changes may lead to serious adverse reactions. Ritlecitinib should not be used concomitantly with strong CYP3A inducers.

The most common adverse reactions were acne, atopic dermatitis, decreased red blood cell count, diarrhea, dizziness, folliculitis, headache, herpes zoster, increased blood creatine kinase level, pyrexia, rash, stomatitis, and urticaria.¹

About the Author

Monica Holmberg, PHARMD, BCPS, is a pharmacist in Phoenix, Arizona, and a Pharmacy Times contributor.

References

1. Litfulo. Prescribing information. Pfizer Inc; 2023. Accessed September 5, 2023. https://labeling.pfizer.com/ShowLabeling.aspx?id=19638
2. FDA approves Pfizer’s Litfulo (ritlecitinib) for adults and adolescents with severe alopecia areata. News release. Pfizer Inc. June 23, 2023. Accessed September 5, 2023. https://www.pfizer.com/news/press-release/press-release-detail/fda-approvespfizers-litfulotm-ritlecitinib-adults-and