Pfizer's ritlecitinib hits goal in alopecia phase 3, setting up showdown with Lilly

Pfizer's alopecia therapy has been linked to a reduction in hair loss in early topline clinical data, setting the stage for a scrap with Eli Lilly and Incyte in the title fight for a potential blockbuster opportunity.

Ritlecitinib has met its primary endpoint in a phase 2b/3 clinical trial of patients with alopecia areata, Pfizer reported Wednesday. The update on the JAK3/TEC inhibitor comes months after Eli Lilly and Incyte reported late-phase success in alopecia.

There are currently no FDA-approved treatments for alopecia, an autoimmune disease characterized by hair loss, but multiple drugs could come to market in the indication over the coming years. Pfizer’s ritlecitinib joined Lilly and Incyte’s Olumiant on the list of drugs to hit the primary endpoint in pivotal alopecia trials on Wednesday—and Concert Pharmaceuticals is following closely behind.

RELATED: Lilly to seek industry-first FDA nod in autoimmune hair loss after Olumiant's 2nd trial win

Pfizer is yet to share numbers from the phase 2b/3, but the top-line overview is positive. The clinical trial randomized 719 people who had at least 50% scalp hair loss at baseline to receive placebo or one of three doses of ritlecitinib, with or without a high-dose induction period.

The trial linked the two higher ritlecitinib doses to statistically significant increases in the proportion of patients who had 20% or less scalp hair loss at 24 weeks. Pfizer said the third, lower dose was used for dose ranging and not tested for statistically significant efficacy compared to placebo.

Lilly and Incyte also looked at the proportion of patients with 20% or less scalp hair loss and plan to file for approval in the second half of the year. Around one-third of patients on Olumiant had 20% or less scalp hair loss at week 36, compared with just a few percent of their peers on placebo. Pfizer is yet to share the data needed to compare ritlecitinib to Olumiant in terms of efficacy.

Safety could be a key battleground, too. In other indications, Olumiant carries a black box warning for infections, malignancies and thromboses. Pfizer saw eight cases of mild to moderate shingles, one case of pulmonary embolism and two malignancies in patients who received ritlecitinib. There were no major adverse cardiac events, deaths or opportunistic infections in the study. 

RELATED: Concert's alopecia drug sails through phase 2; phase 3 on deck for 2020

Pfizer plans to combine the phase 2b/3 data with results from an ongoing long-term study to file for approval of ritlecitinib. The Big Pharma company has identified ritlecitinib as one of nine potential blockbusters it aims to launch by 2025.

As Pfizer sees it, ritlecitinib could rack up sales of more than $1 billion in alopecia alone. The drug is also in development in vitiligo, rheumatoid arthritis, ulcerative colitis and Crohn’s disease. Pfizer is up against more competitors in some of those indications but has been encouraged by midphase data generated to date.