Rifamycin 1% enema is a new in situ gelling bioadhesive formulation containing Rifamycin sodium which is being developed for the treatment of mildly to moderately active distal Ulcerative Colitis (UC) and Proctitis.
A recent review published in literature estimated that, at disease on-set, about 70% of patients have ulcerative proctitis and/or distal UC[1].
The innovative enema solution combines three different polymers to achieve a solution to gel transition upon rectal administration.
The formulation is liquid at room temperature and, at body temperature, transitions to a gel characterized by bio-adhesiveness to the target tissue, allowing for prolonged residency time in the target organ.
The active ingredient (Rifamycin SV) is a topical antibiotic with peculiar pharmacological activities, which represents a step forward compared to the current standard of care. Rifamycin SV is more effective in killing the bad bacteria as compared to the normal microbioma of the colon (it is an “eubiotic”).
A specific published study[2] demonstrated that the delivery of the active substance by commercial enemas is suboptimal because they deliver low amounts of the active ingredient (less than 10% of the whole dose) to the rectum and most of the content is delivered to the distal colon. This represents a major issue, as the rectum is always inflamed in patients who have distal UC. To solve this issue, we conceived a new delivery system, which includes a customized cannula characterized by an apical hole for the delivery of the content to the distal colon and lateral holes for an optimized delivery to the rectum.
A Phase II Proof-of-Concept study was initiated in April 2024. It is expected that approximately 120 patients will be enrolled in the trial at ~23 centers in 7 European countries.
This is a randomized, double-blind, placebo-controlled study designed in accordance with EMA and FDA guidelines, involving colonoscopy with biopsy at study entry and at the end to confirm disease extent and severity, and a centralized endoscopic and histological review.
The Rifamycin 1% enema and the delivery device are objects of several patent applications.
A new formulation technology: Rifamycin 1% enema
[1] Ref.: M. Fumery et al. Clin Gastroenterol Hepatol. 2018 March; 16(3): 343–356
[2] Ref.: van Bodegraven et al., Aliment Pharmacol Ther 1996; 10: 327-332