After a legal decision delayed its entry last fall, Sun Pharma has received the all-clear to tap into the U.S. alopecia market with its JAK inhibitor Leqselvi, teeing up a potential showdown with rival autoimmune meds from Eli Lilly, Incyte and Pfizer.

After Sun appealed an injunction handed down in New Jersey federal court in November that blocked Leqselvi’s U.S. launch, the U.S. Court of Appeals for the Federal Circuit on Wednesday ruled in favor of the Indian drugmaker. Sun is no longer under any court order delaying or restricting Leqselvi’s market debut, the company said in an April 10 filing (PDF) on the Bombay Stock Exchange.

Litigation is ongoing between Sun and Incyte Corporation, which brought a patent infringement lawsuit against Sun and its oral JAK inhibitor Leqselvi in 2024. Still, with the preliminary injunction no longer in effect, Sun will proceed with Leqselvi’s rollout stateside and says it plans to discuss launch plans “in due course of time.”

“We are pleased with this outcome and look forward to making this innovative treatment available for patients,” a Sun Pharma spokesperson told Fierce Pharma over email.

Leqselvi, which also goes by the generic moniker deuruxolitinib, won an FDA green light to treat adults with severe alopecia areata last July. The drug is a deuterated form of Incyte’s own JAK med Jakafi (ruxolitinib) and its topical counterpart Opzelura. Deuterated drugs replace hydrogen atoms with deuterium atoms to boost a medicine’s pharmacokinetic properties.

In last year’s lawsuit, Incyte alleged that Sun’s Leqselvi—which had been slated for a mid-October launch before the injunction—violated a patent known as ‘335, which covers the use of ruxolitinib to treat immune-related diseases, skin disorders, myeloid proliferative disorders and cancer.

Incyte’s legal team argued that Sun’s plan to sell Leqselvi at a lower price than Jakafi would promote off-label prescribing and trigger both price erosion for Jakafi and lost licensing royalties from Lilly on Olumiant—also a JAK inhibitor—in alopecia.

Naturally, Sun disagreed, branding Incyte’s off-label prescription concerns speculative as it pledged to appeal the injunction.

Alopecia is a common autoimmune disease that attacks the body’s hair follicles, causing patchy hair loss. Sun estimates that the condition affects around 700,000 people in the U.S., 300,000 of whom have the severe form of the disease.

Despite the disease’s prevalence, the first treatment specifically approved by the FDA in alopecia only arrived in 2022 with the green light for Lilly and Incyte’s Olumiant. About a year after that, Pfizer picked up an FDA nod in alopecia for its own JAK inhibitor Litfulo, which also goes by the name ritlecitinib.

Unlike Sun’s Leqselvi or Lilly and Incyte’s Olumiant, which are only approved in adults, Litfulo is approved to treat alopecia in both adults and kids over the age of 12.

For all of 2024, Lilly reported total Olumiant sales of $957 million. Under an established collaboration, Lilly pays Incyte tiered, double-digit royalties on worldwide net sales of the drug, which is also approved to treat COVID-19 and rheumatoid arthritis.

Pfizer, for its part, has yet to detail Litfulo’s performance directly in its financial reporting.