Cosmo Completes Phase II Enrollment for Novel Rifamycin Enema in Distal Ulcerative Colitis
Key Insights
Cosmo N.V. (search) has completed enrollment of 77 patients across 24 European sites in its Phase II trial evaluating rifamycin enema (search) for distal ulcerative colitis (search) and ulcerative proctitis (search).
The investigational therapy features a bio-adhesive gel formulation designed to deliver rifamycin sodium directly to inflamed distal colon and rectal tissues.
The treatment addresses a significant unmet need affecting approximately 3.5 million patients worldwide, with topline results expected in fall 2026.
Cosmo N.V. (search) has successfully completed patient enrollment in its Phase II clinical trial evaluating rifamycin enema (search), a novel investigational therapy for distal ulcerative colitis (search) and ulcerative proctitis (search). The Dublin-based life sciences company enrolled 77 patients across 24 clinical sites in Europe, demonstrating strong investigator engagement and efficient study execution.
The Phase II study (EUCT number: 2023-506917-23-00) is designed to evaluate the safety and efficacy of rifamycin enema (search) in patients with distal ulcerative colitis (search) and ulcerative proctitis (search), with topline results expected in fall 2026.
Addressing Significant Unmet Medical Need
Distal ulcerative colitis (search) and ulcerative proctitis (search) represent clinically significant and underserved conditions affecting approximately 3.5 million patients worldwide. Current treatment options are often constrained by suboptimal topical efficacy or unnecessary systemic exposure, with the field experiencing limited innovation in topical rectal therapies, particularly in the United States where no new treatments have been approved for several years.
"Distal ulcerative colitis (search) and ulcerative proctitis (search) continue to represent a significant unmet medical need in daily clinical practice," said Professor Simon Travis, Professor of Clinical Gastroenterology at the University of Oxford and former President of the European Crohn's and Colitis Organization (search). "Approximately 70% of patients with ulcerative colitis (search) initially present with disease involving the rectum and distal colon, making this one of the most common forms of the disease encountered by gastroenterologists."
Novel Bio-Adhesive Gel Technology
Cosmo's investigational therapy contains rifamycin sodium as the active ingredient and is formulated to transform into a bio-adhesive gel after administration. This design allows targeted delivery of the active drug directly to the distal colon and rectum, where inflammation occurs.
The targeted delivery approach has the potential to represent a first-in-class advancement in the topical treatment of distal ulcerative colitis (search) and ulcerative proctitis (search). By combining rifamycin's antibiotic and anti-inflammatory properties with precision delivery, mucosal adherence, and a neutral pH formulation, the therapy is designed to improve local efficacy and tolerability.
Professor Travis noted that patients with proctitis are commonly excluded from Phase III programs of ulcerative colitis (search) therapies and are therefore not specifically represented in the approved labels of those products. "As a result, physicians continue to rely on treatment approaches that have seen little innovation for many years. Many patients experience persistent symptoms despite available therapies, underscoring the need for new treatments that directly target the site of inflammation."
Clinical and Strategic Implications
The novel approach could address two known causes of ulcerative colitis (search): inflammation and an imbalance in gut bacteria. "A therapy designed for precise delivery to the distal colon, with mucosal adherence of the gel and a neutral pH, could represent a new treatment paradigm," Travis added. "If confirmed in clinical trials, this approach has the potential to redefine how we manage patients with distal disease and proctitis in particular."
Giovanni Di Napoli, Chief Executive Officer of Cosmo, emphasized the strategic significance of the milestone. "This milestone reflects both strong execution and a clear strategic focus. We enrolled 77 patients across 24 sites on schedule, demonstrating strong investigator interest and the operational capabilities required to advance innovative therapies efficiently."
Di Napoli highlighted that Cosmo has a long-standing track record in gastroenterology and in developing targeted delivery technologies designed to act locally at the site of disease. "We believe this program represents an attractive value creation opportunity for Cosmo. It addresses a large and underserved segment of the ulcerative colitis (search) market with a differentiated, locally acting approach that has the potential to deliver meaningful clinical benefit while minimizing systemic exposure."
Disease Background
Distal ulcerative colitis (search) affects the descending colon, sigmoid colon, and rectum, while ulcerative proctitis (search) specifically affects the rectum alone. Patients frequently experience persistent symptoms despite available therapies, underscoring the need for more effective and targeted treatment approaches.
With topline results expected in fall 2026, Cosmo is approaching what Di Napoli described as "an important value inflection point for this program and for Cosmo."