Two Phase 1 Clinical Studies Evaluating the Cumulative Irritation and Contact Sensitization on Intact and Abraded Skin of MBN-101, a Novel Antimicrobial Product in Development for Diabetic Foot Ulcer Infection

Background: MBN-101, a novel product in a new class of antimicrobial compounds with unique, broad-spectrum activity against bacteria and biofilm, is in clinical development for the topical treatment of chronic diabetic foot ulcer infections and local/intrasurgical treatment of orthopedic infections.

Methods: Two standardized IRB-approved (Gallatin Institutional Review Board) Phase 1 clinical studies were performed according to FDA/CDER guidance to investigate whether repeated daily application with MBN-101 to the intact and abraded skin of healthy volunteers caused local irritation or allergic contact sensitization. The 30-subject skin irritation study demonstrated that repeated (daily) application, resulting in continuous topical exposure to MBN-101 at five concentrations (25 to 2500 µg/mL) for 21 days, produced significantly (p<0.05) less skin irritation than the positive control (0.1% sodium lauryl sulfate, SLS) and was not significantly (p<0.05) different from vehicle control or negative control (0.9% NaCl). Exposed sites were visually evaluated daily, based on a standardized scoring scale of skin condition (erythema, edema, papules). The sum of daily scores yielded a total cumulative score (TCS) for each subject.

Results: The mean of TCSs from all 30 subjects resulted in scores for intact/abraded skin of 17.5/23.6 for 0.9% NaCl; 32.3/43.7 for SLS; 18.1/22.9 for vehicle control; and 14.7-17.5/18.2-20.4 for all MBN-101 concentrations. MBN-101 (2500 µg/mL) was subsequently evaluated in a 209-subject skin sensitization study comprised of 9 sequential applications for 48-72 hours each for 21 days of continuous exposure (induction phase), a 2-week rest phase with no MBN-101 exposure, and a final 48-hour re-exposure (challenge phase). MBN-101 was non-irritating and no sensitization was observed on intact and abraded skin over a 72-hour period following the single re-exposure.

Conclusion: These data demonstrate very low potential for irritation and sensitization, supporting the safety and further development of MBN-101 for treatment of chronic wounds including diabetic foot ulcer infection and other topical/local infectious conditions.