LEO Pharma Reveals Positive Phase 2b Results for Temtokibart in Moderate-to-Severe Atopic Dermatitis

BALLERUP, Denmark, May 09, 2025 – LEO Pharma A/S, an established leader in the field of medical dermatology, has announced promising topline results from a phase 2b clinical trial investigating temtokibart. This investigational IL-22RA1 antagonist is being tested for its potential to treat adults suffering from moderate-to-severe atopic dermatitis (AD). The trial, a phase 2b study, was meticulously designed as a randomized, double-blind, placebo-controlled, multi-site, parallel-group, dose-finding study. The primary goal was to evaluate both the efficacy and safety of various doses of temtokibart, also known as LEO 138559, which is administered subcutaneously.

The trial successfully met its primary endpoint, showing a significant percentage improvement in the Eczema Area and Severity Index (EASI) from the start of the trial to Week 16 for the three highest doses in adults with moderate-to-severe AD. The treatment demonstrated a solid safety profile, being generally well-tolerated without showing dose dependency. Most adverse events recorded were non-serious, mild, or moderate and were not considered to be related to the treatment.

According to Dr. Jacob Pontoppidan Thyssen, Chief Scientific Officer & Executive Vice President, Science, Search & Innovation at LEO Pharma, there remain significant unmet needs for patients living with the complex immunological condition of atopic dermatitis. Dr. Thyssen emphasized the company's dedication to fundamentally improving patient outcomes and expressed optimism about the trial results. These findings highlight the distinctive mechanism of action of temtokibart, which targets the disease differently compared to existing treatments, potentially addressing unmet needs in conditions where the IL-22 pathway is crucial.

Temtokibart is an investigational monoclonal antibody aimed at treating moderate-to-severe AD by blocking the IL-22RA1 receptor subunit. This action inhibits the effects of the interleukin-22 (IL-22) cytokine, which is typically elevated in AD patients.

In collaboration with argenx, a global immunology company, LEO Pharma has been exploring innovative antibody-based treatments for chronic inflammation, a common factor in many skin conditions, since 2015. As part of this strategic partnership, temtokibart was co-developed, with LEO Pharma subsequently acquiring exclusive rights for its further development and commercialization.

LEO Pharma is in the process of collecting and analyzing the full data set from this trial. The company plans to present detailed findings from the phase 2b study in scientific forums and publications in the future.

Atopic dermatitis is a persistent, inflammatory skin disorder marked by severe itchiness and eczematous lesions. It arises from a combination of skin barrier dysfunction and immune system dysregulation, causing chronic inflammation. Key contributors to its pathophysiology include type 2 cytokines, such as IL-13, and an overproduction of IL-22.

Temtokibart, currently in phase 2 development, focuses on the IL-22RA1 receptor subunit. It blocks this subunit, reducing the effects of IL-22 and also impacting IL-20 and IL-24 signaling pathways. Notably, temtokibart does not bind directly to the IL-22 cytokine itself.

As a global leader in medical dermatology, LEO Pharma is dedicated to advancing skin health through innovative solutions and has a rich history of groundbreaking medical developments. The company supports over 100 million patients in more than 70 countries each year, driven by a commitment to improve lives worldwide.