CITRYLL PRESENTS POSITIVE DATA FROM PHASE I STUDY OF CIT-013 IN RHEUMATOID ARTHRITIS AT ACR CONVERGENCE 2025
- Phase I trial data in rheumatoid arthritis patients demonstrates favorable safety, encouraging clinical activity, and robust biomarker responses
- Data provides strong validation for the advancement of CIT-013 into Phase IIa studies
Oss, Netherlands – 27 October 2025 – Citryll, a biotech company pioneering a transformative approach to treating immune-mediated inflammatory diseases by targeting Extracellular Traps (ETs), has shared positive data from its first-in-human Phase I clinical trial of CIT-013 in participants with rheumatoid arthritis (RA) and healthy volunteers, as well as data from preclinical studies in three posters at the American College of Rheumatology (ACR) Convergence 2025, currently underway in Chicago.
The featured poster highlights findings from Citryll’s Phase I clinical trial of CIT-013 in participants with RA and healthy volunteers, which demonstrated that CIT-013 was generally well tolerated across all participants, with no serious treatment-related events reported. Importantly, clinically meaningful reductions in disease activity were seen in all active RA participants treated with CIT-013.
Two additional posters provided details from preclinical studies supporting the clinical program. The first outlines the use of radiolabelled CIT-013 as an imaging tool, with data indicating CIT-013 is a targeted therapy which accumulates specifically in inflamed tissue. The second evaluates calprotectin as a biomarker of disease activity, with a correlation seen between treatment response and serum calprotectin levels, supporting its use as a biomarker in RA.
Maarten Kraan, Chief Medical Officer of Citryll, commented, “Together, this data provides a compelling picture of CIT-013’s potential as a first-in-class therapeutic targeting ETs for the treatment of RA and other immune-mediated diseases. We are encouraged by the favorable safety and early efficacy signals observed in our Phase I study, validating our decision to advance CIT-013 through to Phase IIa studies. Additionally, the expanding body of translational evidence supports ET inhibition as a potential treatment option in autoimmune and inflammatory disease, strengthening our confidence in the ongoing clinical development program.”
A Phase IIa study – Citydream – is currently underway in RA, with an additional Phase IIa trial in hidradenitis suppurativa expected to start later this year.
POSTER DETAILS
Poster 1: Phase I Trial in Participants with Rheumatoid Arthritis and Healthy Volunteers with CIT-013, a First in Class NETosis Inhibitor
Date: 26 October 2025
Session: Rheumatoid Arthritis – Treatment Poster I
Abstract Number: 0493
Poster 2: Calprotectin Serum Levels: a potential neutrophil activation biomarker to monitor treatment response in Rheumatoid Arthritis
Date: 26 October 2025
Session: Rheumatoid Arthritis – Diagnosis, Manifestations, and Outcomes Poster I
Abstract Number: 0431
Poster 3: Radiolabelled anti-citrullinated histone antibody CIT-013 as a tool to visualize NET-rich inflamed joints in a collagen induced arthritic mouse model
Date: 27 October 2025
Session: Innate Immunity Poster
Abstract Number: 0928
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About CIT-013
CIT-013 is Citryll’s first-in-class monoclonal antibody targeting Extracellular Traps (ETs), a key driver of inflammation in RA and other immune-mediated diseases, which has yet to be addressed therapeutically. It has a unique dual mechanism of action, which enhances the clearance of existing ETs and inhibits the formation of new ETs. CIT-013 is highly selective for its epitope, minimizing off-target effects and representing a potentially transformative therapeutic strategy, going beyond individual pathway management and symptom treatment.
About Citryll
Citryll is pioneering a transformative approach to treating inflammatory diseases by targeting Extracellular Traps (ETs), a fundamental component of the inflammatory process that has yet to be addressed therapeutically.
Citryll is developing the first ET-targeting therapy and potentially creating a new class of therapeutics with broad applications across immune-mediated inflammatory diseases.
Our lead asset, CIT-013, is a first-in-class monoclonal antibody with a unique dual mechanism of action: it enhances the clearance of existing ETs and inhibits the formation of new ETs.
By addressing this key driver of inflammation, CIT-013 has the potential to offer a differentiated and comprehensive treatment option for conditions such as rheumatoid arthritis and hidradenitis suppurativa, where current therapies often fall short of providing adequate disease control.
Contacts
Citryll
Sjoerd van Gorp, COO / CFO
Email: info@citryll.com
Citryll Media Contacts
ICR Healthcare
Amber Fennell, Stephanie Cuthbert, Lucy Featherstone
Email: citryll@icrinc.com
