RDP58 is a novel and potentially effective oral therapy for ulcerative colitis

Area of Science:

• Gastroenterology
• Pharmacology
• Immunology

Background:

• RDP58 is a novel d-amino acid decapeptide with anti-inflammatory properties.
• It functions by inhibiting pro-inflammatory cytokine synthesis via disruption of the MyD88-IRAK-TRAF6 signaling complex.
• Its potential in treating ulcerative colitis (UC) was investigated.

Purpose of the Study:

• To evaluate the efficacy and safety of RDP58 in patients with mild to moderate active ulcerative colitis.
• To compare different dosages of RDP58 against a placebo.

Main Methods:

• Two parallel, multicenter, double-blind, randomized concept studies were conducted.
• Study 1: 34 patients (mild-moderate UC) randomized to placebo or RDP58 100 mg.
• Study 2: 93 patients randomized to placebo, RDP58 200 mg, or RDP58 300 mg. Treatment success defined by clinical activity index at 28 days.

Main Results:

• RDP58 100 mg showed no significant difference in treatment success compared to placebo (29% vs 46%).
• Higher doses (200 mg and 300 mg) demonstrated significant treatment success (71% and 72% vs 43% for placebo, P=0.016).
• Histology scores improved significantly with higher RDP58 doses (P=0.002), while sigmoidoscopy scores showed non-significant improvements. Adverse events were comparable between groups.

Conclusions:

• RDP58 at doses of 200 mg or 300 mg is effective for mild to moderate ulcerative colitis.
• The 100 mg dose of RDP58 was not effective in this patient population.
• RDP58 is safe, well-tolerated, and represents a promising therapeutic option for UC due to its novel mechanism of action.