Pfizer Korea will launch a new Janus kinase (JAK) inhibitor treatment Litfulo (ritlecitinib tosilate), and set to challenge the market for severe alopecia areata.

Previously launched Olumiant (baricitinib), the first drug approved in South Korea for treating adult patients with severe alopecia areata, has already settled in the market. The company will likely promote Litfulo's broader indication to treat adolescents over 12 years of age.

On March 5, Pfizer Korea hosted a press conference celebrating the launch of the severe alopecia areata treatment Litfulo. The company highlighted the clinical significance of the drug.

Litfulo is the first drug among alopecia areata treatments in South Korea to obtain approval for use in adolescent patients.

Alopecia areata is an autoimmune disease that causes hair loss in the scalp, face, and body in patches or complete loss of hair. It is an inflammatory and immune-mediated disease caused by the immune system attacking the body's hair follicles, leading to hair loss.

In South Korea, the number of patients treated for alopecia areata showed an increasing trend for the past 10 years, recording 154,380 patients in 2013 and 178,009 patients in 2023.

In most cases, alopecia areata without severe symptoms naturally recover and respond well to treatments. However, it has a high relapse rate, with about 40-80% of patients experiencing relapse within a year.

Dr. Chong Hyun Won, Professor in the Department of Dermatology at Asan Medical Center in Seoul, who attended the press conference, said, "About 100% of the patients with alopecia areata experience relapse within 20 years, so the disease has a high recurrence rate." Dr. Won explained, "It causes a substantial psychological burden on patients and is closely associated with mental health issues, such as depression, affecting the quality of life greatly."

However, the introduction of JAK inhibitors like Litfulo has changed the treatment settings. Previously, severe alopecia areata was treated with corticosteroids or cyclosporine. Analysis suggests that aggressive treatment is possible after the introduction of a new option.

"The launch of the new treatment provides hope for patients with unmet needs who suffered for a long time from alopecia areata. It is also meaningful to doctors, considering that a safe new option is now available," Dr. Won said.

The basis of approval for Litfulo was the global clinical study Phase 2b/3 ALLEGRO. The analysis results evaluating the primary endpoint, the patient ratio with a Severity of Alopecia Tool (SALT) score of 20 or below, showed that at week 24, 23% of the patient group had a SALT score less than 20, which was statistically significant treatment effectiveness compared to a 2% in the placebo group.

At week 48, the treatment group with a SALT score less than 20 was 43%, confirming significant treatment effectiveness than the placebo group (10%). This indicates that effectiveness increased over time.


When Olumiant was launched earlier, the alopecia areata had high unmet needs despite its non-reimbursed indication. It was evaluated that a higher-than-expected number of patients are opting for treatment.

In other words, since Olumiant already dominates the market, the company must strategize to promote Litfulo.

The most significant difference is the mechanism and indication. Unlike Olumiant, which targets JAK1 and 2, Litfulo primarily targets JAK3.

Also, Olumiant is used for adults aged 18 and older, whereas Lifulo is used to treat adolescents aged 12 years and above.

Dr. Won commented regarding this, "As of 2023, adolescents account for about 10% of the patients with alopecia areata, and the number can be lower with severity. However, the drug presents significance considering that earlier occurrence of alopecia areata may require longer treatment and has poor prognosis when relapse."

Furthermore, Dr. Won mentioned that it is too early to determine drug switching between existing treatments and new treatments.

"As drug switching requires the analysis of drug's effects and safety, a clear answer is not available at this point," he said. "We need confirmation of which patients can be better treated with existing treatment with longer safety."