P658 Safety and efficacy of MH002, an optimized live biotherapeutic product, for the treatment of mild to moderate ulcerative colitis: a first-in-disease, double-blind, randomized clinical trial

Background Treatment options for patients with mild to moderate ulcerative colitis (UC) failing 5-ASA are limited. MH002 is an optimized consortium of 6 non-pathogenic, well-characterized commensal bacteria with immune modulating, wound healing and gut barrier protective effects. This study evaluated the safety, efficacy, and mechanistic effects of MH002 in mild to moderate UC. Methods In this 2:1-randomized, double-blind, placebo-controlled first-in-disease study (EudraCT 2020-001355-33), 45 patients with mild to moderate active UC (Modified Mayo Score [MMS] =4-8 but including Mayo Endoscopic Sub-score [MES] ≥2) received treatment with 400mg MH002 or placebo (PBO) once daily for 8 wks. Full colonoscopies with biopsies were performed at baseline and wk8, biopsies and endoscopy videos were scored by blinded central readers. The primary endpoint was the rate of treatment-emergent adverse events (TEAEs). Exploratory efficacy endpoints included clinical remission (MMS ≤2 with all sub-scores ≤1 and rectal bleeding sub-score =0), endoscopic improvement (MES ≤1), and UC-100 and biomarker normalisation (C-reactive protein [CRP] ≤5mg/L, faecal calprotectin [FCP] ≤250mg/kg). Changes from baseline (CFBL) in MES and stool consistency (Bristol Stool Form Scale) were also evaluated. Results MH002 was safe and well tolerated: a TEAE was reported in 11/31 (35%) patients with MH002 and in 8/14 (57%) with PBO. Most TEAEs were mild and unrelated to study treatment. Early discontinuations (7/45; 16%) occurred similarly in both groups. At wk8, patients achieved clinical remission, endoscopic improvement, and biomarker improvements at higher rates with MH002 vs PBO (Table 1). Clinical remission rates were 14% for MH002 vs 7% for PBO (Per-protocol Set [PPS]: 18% vs 0%). Significant differences in favour of MH002 over PBO were seen in the CFBL for MES at wk8 (P=0.05, 1-sided Wilcoxon) and for stool consistency at wk2 (P=0.0057, 1-sided Student t). In total, 14/45 (31%) and 36/42 (86%) patients had elevated CRP and FCP levels at baseline, resp. Of these, more patients treated with MH002 achieved normalisation at wk8 (CRP: 60% vs 25%; FCP: 36% vs 15%). Decreases in FCP and stool consistency with MH002 were observed as early as wk2 and were greater than with PBO through wk8 (Fig 1). Conclusion MH002 treatment was safe and well tolerated and resulted in clinically meaningful improvements in disease activity and inflammatory parameters. MH002 therefore represents a promising new treatment for mild to moderate UC patients insufficiently controlled with 5ASA. These results warrant further development in a phase 2/3 study.