A Pfizer drug that treats hair loss caused by alopecia areata is now approved by the FDA with a label that encompasses the treatment of patients at a young age, when symptoms of the autoimmune disorder often start to show.

The new Pfizer drug, ritlecitinib, brand name Litfulo, was approved late Friday for treating severe alopecia areata in patients age 12 and older. That’s a bigger range of patients than Eli Lilly can reach with its drug, Olumiant. A little more than a year ago, the FDA expanded Olumiant’s approval to include alopecia areata in adults, making that drug the first systemic treatment for the autoimmune disorder.

Alopecia areata is a condition in which the immune system attacks hair follicles, causing hair loss. While this loss most often occurs on the scalp, the condition can also lead to hair loss elsewhere on the body. This condition, which affects both males and females, can range from patchy to total body hair loss. While alopecia can start at any age, most patients who develop the condition start seeing hair loss while they are still young.

FDA approval of Litfulo is based on the results of a Phase 2b/3 study that enrolled 718 patients age 12 and older with 50% or greater scalp hair loss. Results showed that 23% of patients treated with the Pfizer drug had 80% or greater scalp hair coverage after six months of treatment compared to 1.6% of patients in the placebo group achieving that mark. The most common adverse effects reported in the study included headache, diarrhea, acne, and skin rash. The full results from this pivotal study were published in April in the journal The Lancet.

“With today’s approval, adolescents and adults who struggle with substantial hair loss have an opportunity to achieve significant scalp hair regrowth,” Angela Hwang, Pfizer’s chief commercial officer, said in a prepared statement.

Litfulo belongs to a class of drugs that block Janus kinases (JAKs), enzymes that play a role in autoimmune responses. The Pfizer small molecule is specifically designed to block JAK3. It also blocks signaling of receptors that are dependent on the hepatocellular carcinoma family of enzymes.

Lilly’s Olumiant is also a JAK inhibitor. This drug, licensed from Incyte, won its first FDA approval in 2018 for treating rheumatoid arthritis. Besides the alopecia indication, the drug is also approved for treating certain patients hospitalized with Covid-19 infection. For 2022, Eli Lilly reported $830.5 million in sales for Olumiant, down 26% from sales in the prior year. Lilly attributed the decline in part to lower sales of the drug for the treatment of Covid-19.

The entire JAK inhibitor drug class has fallen under FDA scrutiny for higher complication risks that include cardiovascular problems and cancer. Like Olumiant, the label of Pfizer’s Litfulo carries a black box warning that highlights these and other risks that are associated with these medications.

There are other companies vying to bring JAK-blocking drugs to the market for alopecia. Sun Pharma is in the mix with deuruxolitinib, a drug that blocks the JAK1 and JAK2 enzymes. Mumbai, India-based Sun added this molecule to its pipeline via the $576 million acquisition of Concert Pharmaceuticals earlier this year. But the drug has encountered a setback. In May, the FDA placed a partial clinical hold on tests of the drug after a pulmonary embolism was reported in a patient who received the high dose of the drug in an open-label extension study. Treatment with the high dose was stopped and those patients were transitioned to the lower dose.

Regulatory applications for Litfulo in alopecia areata are under review in other markets including China, the European Union, Japan, and the U.K. The molecule is also in late-stage clinical development for vitiligo, a different autoimmune condition that causes discolored skin patches that get bigger over time. Other potential indications that Pfizer is exploring for the drug include Crohn’s disease and ulcerative colitis.

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