• Temtokibart, LEO Pharma’s investigational IL-22RA1 antibody (formerly labelled as LEO 138559), reaches latest trial milestone.
  • Phase 2b initiation follows the completion of the Phase 2a trial, the results of which were presented at the American Academy of Dermatology (AAD) Annual Meeting earlier this year.1
  • The trial will be overseen by a steering committee featuring a selection of clinical experts.

BALLERUP, Denmark I October 11, 2023 I LEO Pharma A/S, a global leader in medical dermatology, has today announced the First Subject First Treatment (FSFT) milestone for the Phase 2b clinical trial for temtokibart, LEO Pharma’s IL-22RA1 antibody.2 The first patient dose was successfully administered on the 4th of October at the DermEdge Research Center in Ontario, Canada.

Temtokibart is an investigational monoclonal antibody currently in Phase 2 development for the treatment of moderate-to-severe atopic dermatitis (AD). The drug targets the IL-22RA1 receptor subunit thereby inhibiting the effect of the interleukin-22 (IL-22) cytokine – known to be elevated in patients with AD.1,3,4 As IL-22RA1 is also involved in IL-20 and IL-24 signalling, temtokibart potentially also inhibits the effects of those two cytokines; however, this is not yet fully understood.1

Following the completion of the Phase 2a trial,1 LEO Pharma has now initiated the LP0145-2240 trial. This is a Phase 2b, randomized, double-blind, placebo-controlled, multi-site, parallel-group, dose-finding trial to evaluate the efficacy and safety of different doses of subcutaneously administered temtokibart in adult subjects with moderate-to-severe AD.2

“We are committed to conducting clinical research to investigate potential new mechanisms of action,” said Kreesten Meldgaard Madsen, Chief Development Officer, Global Development LEO Pharma. “With this latest trial initiation, we continue to work towards potentially bringing additional treatments to people living with atopic dermatitis whose needs are not met by current treatments.”

“Despite advancements in the understanding of the disease, there are still patients that could benefit from additional treatment options for moderate-to-severe atopic dermatitis,” said Prof. Stephan Weidinger, Department of Dermatology and Allergy, University Hospital Schleswig-Holstein, Germany and international coordinating investigator (ICI) for the Phase 2b trial. “By targeting the IL-22 pathway, this trial could provide additional insights into the pathophysiology of atopic dermatitis.”

The Phase 2b trial will be overseen by a specialist steering committee, the purpose of which is to provide critical scientific guidance, oversee trial conduct and drive trial results, analysis and scientific communications.

The steering committee includes four international clinical experts:

  • Prof. Stephan Weidinger (Department of Dermatology and Allergy, University Hospital Schleswig-Holstein, Germany)
  • Prof. Emma Guttman-Yassky (Department of Dermatology, Icahn School of Medicine at Mount Sinai, New York, United States)
  • Prof. Michael Ardern-Jones (Department of Dermatology, Southampton General Hospital, University of Southampton, United Kingdom)
  • Dr Chih-ho Hong (Board certified dermatologist working in Greater Vancouver, BC Canada)

LEO Pharma and argenx jointly developed temtokibart under an exclusive option and research agreement. LEO Pharma obtained the license to temtokibart in 2022 and now assumes the responsibility to develop and commercialize the drug for inflammatory skin disorders, such as AD. The collaboration between LEO Pharma and argenx stands as a strong example of an external innovation sourcing model, which is a key pillar in LEO Pharma’s new Research and Development strategy.


About atopic dermatitis
Atopic dermatitis is a chronic, inflammatory skin disease characterized by intense itch and eczematous lesions.5 Atopic dermatitis is the result of skin barrier dysfunction and immune dysregulation, leading to chronic inflammation.6

About temtokibart
Temtokibart is an investigational monoclonal antibody that targets the IL-22RA1 receptor subunit, currently in Phase 2 development for the potential treatment of moderate-to-severe atopic dermatitis.1 It blocks the IL-22RA1 subunit and thereby inhibits the effects of the IL-22 cytokine, and potentially also to some extent the effects of IL-20 and IL-24.1 Temtokibart does not bind to the IL-22 cytokine itself.1 LEO Pharma has obtained a worldwide exclusive license to develop and commercialize temtokibart from argenx.

About LEO Pharma
LEO Pharma is a global company dedicated to advancing the standard of care for the benefit of people with skin conditions, their families and society. Founded in 1908 and majority owned by the LEO Foundation, LEO Pharma has devoted decades of research and development to advance the science of dermatology, and today, the company offers a wide range of therapies for all disease severities. LEO Pharma is headquartered in Denmark with a global team of 4,700 people, serving millions of patients across the world. In 2022, the company generated net sales of DKK 10.6 billion. Learn more at www.leo-pharma.com.


  1. Thaçi D, et al. Efficacy and safety of IL-22R inhibition in patients with moderate-to-severe atopic dermatitis: results from a phase 2a monotherapy trial. Presented at the 2023 American Academy of Dermatology Annual Meeting; March 17–21 2023; New Orleans, LA.
  2. ClinicalTrials.gov. National Library of Medicine (U.S.). A Trial to Evaluate the Efficacy and Safety of Different Doses of LEO 138559 in Adults With Moderate-to-severe Atopic Dermatitis. Identifier: NCT05923099 https://classic.clinicaltrials.gov/ct2/show/NCT05923099.
  3. Fujita H. The role of IL-22 and Th22 cells in human skin diseases. J Dermatol Sci. 2013;72(1):3-8.
  4. Czarnowicki T, He H, Krueger JG, Guttman-Yassky E. Atopic dermatitis endotypes and implications for targeted therapeutics. J Allergy Clin Immunol. 2019;143(1):1-11.
  5. Weidinger S, Novak N. Atopic dermatitis. Lancet. 2016;387(10023):1109-1122.
  6. Boguniewicz M, Leung DY. Atopic dermatitis: a disease of altered skin barrier and immune dysregulation. Immunol Rev. 2011;242(1):233-246.