Mufemilast advances to phase 3 following positive phase 2 results in UC

Mufemilast, a small molecule inhibiting phosphodiesterase type 4 (PDE4), was associated with favourable clinical remission and response rates in patients with moderate-to-severe ulcerative colitis (UC) in a randomised phase 2 trial. The agent was generally well tolerated, and a phase 3 trial is now being planned to further investigate its potential in this population.

In a phase 2 study, Dr Charles Jones (Tianjin Hemay Pharmaceuticals, China) and colleagues evaluated the investigational phosphodiesterase-4 inhibitor mufemilast among 91 Chinese patients with moderate-to-severe UC. Participants were randomised 1:1:1 to receive mufemilast 45 mg twice daily, mufemilast 60 mg twice daily, or placebo. “All participants had received ≥1 prior conventional or advanced therapy,” added Dr Jones. The primary endpoint was the clinical remission rate at week 12 [1].

At week 12, clinical remission rates were 35.5%, 43.3%, and 9.7% in the 45 mg, 60 mg, and placebo groups, respectively (P=0.031; P=0.004). The corresponding clinical response rates were 87.1%, 80.0%, and 41.9%, while mucosal healing was achieved in 41.9%, 66.7%, and 16.1% of participants, respectively. “The effect of mufemilast appeared consistent across biologic-naïve and biologic-experienced participants, although the sample size was too small to draw solid conclusions from this finding,” Dr Jones commented.

Overall, mufemilast was well tolerated; 1 participant experienced a serious adverse event related to the study drug (varicose phlebitis), and 2 other participants discontinued treatment due to adverse events: 1 case of combined headache, dizziness, nausea, and restlessness, and 1 case of lower limb pain.

“Mufemilast demonstrated promising safety and efficacy in this phase 2 trial,” concluded Dr Jones. “A phase 3 trial in China is planned to assess the long-term efficacy and safety of mufemilast in patients with UC.”

1. Jones CR, et al. A phase 2 multicentre, randomised, double-blind, placebo-controlled induction trial in Chinese patients with moderate to severe ulcerative colitis. LB07, Hot off the press: IBD treatment, UEG Week, 4–7 October 2025, Berlin, Germany.

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Posted on 1 December 20251 December 2025