Pfizer Inc. has announced positive topline results from a phase 2 study investigating tilrekimig (PF-07275315) in adults with moderate to severe atopic dermatitis.
The study met its primary efficacy endpoint, demonstrating a statistically significant increase in the percentage of participants achieving EASI-75 (≥ 75% reduction in the Eczema Area and Severity Index) at Week 16, compared to placebo. In stage 2 of the study, which evaluated monthly dosing regimens, tilrekimig showed competitive efficacy. The placebo-adjusted percentage of participants achieving EASI-75 at Week 16 was: 38.7% for the low tested dose; 51.9% for the middle-tested dose; and 49.4% for the high tested dose.
The two highest dose levels tested with tilrekimig suggest potentially meaningful improvements to approved standard of care biologics. Tilrekimig is an investigational trispecific antibody that simultaneously targets interleukin-4 (IL-4), interleukin-13 (IL-13), and thymic stromal lymphopoietin (TSLP), with the potential to be a once-monthly treatment option for multiple chronic inflammatory conditions driven by an overactive Type 2 (Th2) immune response, without affecting receptors on healthy cells.
“We are encouraged by the topline phase 2 results for tilrekimig, which show that combining the potent inhibition of IL-4/13 and TSLP pathways has the potential to deliver improved efficacy over the standard of care for atopic dermatitis,” said Mike Vincent, chief inflammation and immunology officer at Pfizer.
“We plan to advance a broad clinical development program for tilrekimig, a potential first-in-class trispecific antibody discovered at Pfizer, in atopic dermatitis and other Th2-mediated inflammatory diseases including asthma and COPD.”
Tilrekimig was well-tolerated with a favourable safety profile and no dose dependent safety signals; adverse event (AE) rates were comparable to placebo. The most common AEs were infections and infestations, skin and subcutaneous tissue disorders and general disorders, and administration site reactions. Three serious adverse events (SAEs) were observed, which were all considered to be unrelated to treatment. The observed frequency of conjunctivitis in this study was lower than rates reported with IL-4 receptor alpha inhibitors.
The phase 2 study is an ongoing randomised, double-blind, placebo-controlled trial in adults with moderate to severe atopic dermatitis. It is being conducted in four overlapping stages. Stage 1 tested a high dose of tilrekimig versus placebo. In addition, stage 1 included an arm testing a high dose of ompekimig (PF-07264660), an investigational trispecific antibody targeting IL-4, IL-13, and interleukin-33 (IL-33), versus placebo. Stage 1 has concluded and both tilrekimig and ompekimig groups met the primary endpoint. Stage 2 was a dose-ranging study in which participants received either tilrekimig or placebo, while stage 3 is an ongoing study in which participants who previously received biologic treatments receive either tilrekimig or placebo. Stage 4 is an ongoing dose-ranging study in which participants receive either ompekimig or placebo.
In addition to the ongoing phase 2 study in atopic dermatitis, Pfizer is studying tilrekimig in an ongoing phase 2 study in asthma and the company recently initiated a phase 2b/3 study of tilrekimig in chronic obstructive pulmonary disease (COPD). Phase 3 planning for atopic dermatitis is ongoing, with a pivotal study on track to start this year.