A Randomized, Double-blind, Placebo-controlled, Dose Ranging, Parallel, Multi-Centre, Phase II Study to Evaluate the Efficacy and Safety of MT921 in Subjects with Moderate to Severe Submental Fat.

BACKGROUND

Submental fat (SMF) is commonly treated with liposuction, surgery, or injectable drugs. Cholic acid, a primary bile acid, can induce lipolysis.

OBJECTIVES

To evaluate the efficacy and safety of MT921, an injectable cholic acid formulation, for reducing moderate to severe SMF.

METHODS

Subjects with moderate to severe SMF were randomized to receive MT921 1.0%/1.0 cm, MT921 1.5%/1.0 cm, MT921 1.5%/1.25 cm, or placebo. Primary endpoints were ≥1- and ≥2-grade improvements in clinician- and patient-assessed SMF Rating Scales at 4 weeks after the final treatment. Secondary endpoints included changes in SMFRS, patient satisfaction, Patient-Assessed Submental Fat Impact Scale, and SMF volume or thickness measured by MRI or calipers. Safety was assessed by adverse events, laboratory tests, and vital signs.

RESULTS

In groups 1, 2, 3, and 4, respectively, ≥1-grade improvement in clinician-assessed SMFRS was achieved by 72.73%, 88.64%, 79.07%, and 48.78% of subjects, and ≥1-grade improvement in patient-assessed SMFRS by 77.27%, 88.64%, 79.07%, and 46.34%. Compared with placebo, MT921 showed favorable improvements in SMFRS responses, patient satisfaction, PA-SMFIS, and caliper-measured SMF thickness. MRI-measured SMF volume decreased in MT921-treated groups but not in the placebo group. Adverse events were more frequent with MT921 but were mostly mild or moderate.

CONCLUSIONS

MT921 showed favorable efficacy signals for reducing moderate to severe SMF and was generally well tolerated. These findings support further evaluation of MT921, particularly the 1.5% formulation, in larger phase 3 trials with longer follow-up.