Pfizer Announces Positive Top-Line Results from Phase 2b/3 Trial of Ritlecitinib in Alopecia Areata

Pfizer Inc. (NYSE: PFE) today announced positive top-line results from the Phase 2b/3 ALLEGRO trial evaluating oral once-daily ritlecitinib in patients with alopecia areata, an autoimmune disease driven by an immune attack on the hair follicles that causes hair loss on the scalp and can also affect the face and body.1,2 Ritlecitinib 50 mg and 30 mg achieved the primary efficacy endpoint of the study, namely the proportion of patients with less than or equal to 20 percent scalp hair loss after six months of treatment versus placebo.

“We are pleased by these positive results for ritlecitinib in patients with alopecia areata, a devastating and complex autoimmune disease for which there are currently no U.S. Food and Drug Administration (FDA) or European Medicines Agency approved treatments,” said Michael Corbo, PhD, Chief Development Officer, Inflammation & Immunology, Pfizer Global Product Development. “We look forward to bringing this potential new treatment option to patients living with alopecia areata as soon as possible.”

The Phase 2b/3 ALLEGRO trial met the primary efficacy endpoint of improving scalp hair regrowth. All participants entered the study with at least 50 percent scalp hair loss due to alopecia areata, as measured by the Severity of Alopecia Tool (SALT) score. A statistically significantly greater proportion of patients who took ritlecitinib 30 mg or 50 mg once-daily, with or without a four-week initial treatment of 200 mg once-daily, had 20 percent or less scalp hair loss (an absolute SALT score ≤20) after 24 weeks of treatment compared with placebo. This was followed by a 24-week extension period, during which all participants initially randomized to receive ritlecitinib continued on the same regimen, while participants who received placebo during the initial 24 weeks advanced to one of two regimens: 200 mg for four weeks followed by 50 mg for 20 weeks, or 50 mg for 24 weeks. The study also included a 10 mg dosing arm, which was assessed for dose-ranging and was not tested for statistically significant efficacy compared to placebo.

The safety profile seen with ritlecitinib was consistent with previous studies. Overall, the percentage of patients with adverse events (AEs), serious AEs and discontinuing due to AEs was similar across all treatment groups. The most common AEs seen in the study were nasopharyngitis, headache and upper respiratory tract infection. There were no major adverse cardiac events (MACE), deaths or opportunistic infections in the trial. Eight patients who were treated with ritlecitinib developed mild to moderate herpes zoster (shingles). There was one case of pulmonary embolism in the ritlecitinib 50 mg group, which was reported to have occurred on Day 169. There were two malignancies (both breast cancers) reported in the ritlecitinib 50 mg group, which were reported to have occurred on Day 68 and Day 195. Both participants were discontinued from the study.

Full results from this study will be submitted for future scientific publication and presentation. These data, together with data that will become available from ALLEGRO-LT, will form the basis for planned future regulatory filings.

Ritlecitinib is the first in a new investigational class of covalent kinase inhibitors that have high selectivity for Janus kinase 3 (JAK3) and members of the tyrosine kinase expressed in hepatocellular carcinoma (TEC) kinase family. In laboratory studies, ritlecitinib has been shown to block the activity of signaling molecules and immune cells believed to contribute to loss of hair in people with alopecia areata.3

Ritlecitinib, which was granted Breakthrough Therapy designation from the U.S. FDA for the treatment of alopecia areata in September 2018, is also being evaluated for vitiligo, rheumatoid arthritis, Crohn’s disease and ulcerative colitis.

About the Phase 2b/3 ALLEGRO Trial

This randomized, placebo-controlled, double-blind study investigated ritlecitinib in patients 12 years of age and older with alopecia areata (n=718). Patients included in the study had 50 percent or more hair loss of the scalp, including patients with alopecia totalis (complete scalp hair loss) and alopecia universalis (complete scalp, face and body hair loss), and were experiencing a current episode of alopecia areata that had lasted between six months and ten years. Patients were randomized to receive ritlecitinib 50 mg or 30 mg (with or without one month of initial treatment with once-daily ritlecitinib 200 mg), ritlecitinib 10 mg or placebo.

The primary endpoint was the proportion of patients with scalp hair regrowth in response to ritlecitinib treatment, based on an absolute SALT Score ≤20 at Week 24. SALT is a tool that measures the amount of scalp hair loss. The tool divides the scalp into standard regions, and each region contributes to the total SALT score, which ranges from 0 to 100. A SALT score of 0 corresponds to no scalp hair loss, while a SALT score of 100 corresponds to a total lack of hair on the scalp.4

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