Clinical-stage biopharmaceutical company Kythera Biopharmaceuticals has reported positive interim results from a multi-centre, open-label Phase IIIb study of its investigational injectable drug for the reduction of unwanted submental fat (SMF), known as double chin.

ATX-101, a proprietary formulation of endogenous synthetic deoxycholic acid, is injected locally to cause proximal, preferential destruction of adipocytes, or fat cells, with minimal effect on surrounding tissue.

The study, which has treated more than 1,500 patients from a total of 2,500 enrolled patients, was designed to study the safety and efficacy of ATX-101 in reducing SMF.

"ATX-101, a proprietary formulation of endogenous synthetic deoxycholic acid, is injected locally to cause proximal, preferential destruction of adipocytes, or fat cells, with minimal effect on surrounding tissue."

The results of three months after the last ATX-101 treatment found that 87% of patients achieved at least a one-grade improvement from baseline on the Clinician-Reported Submental Fat Rating Scale (CR-SMFRS), while 83% achieved at least a one-grade improvement on the Patient-Reported Submental Fat Rating Scale (PR-SMFRS).

96% percent of patients had unchanged or improved skin laxity based on the clinician-rated Submental Skin Laxity Grading Scale (SMSLG), while 95% were satisfied with treatment based on the Global Post Treatment Satisfaction Scale.

In addition, adverse events were of mild to moderate intensity, transient and primarily associated with the treatment area.

University of South Florida board certified dermatologist and affiliate clinical professor and trial investigator Dr Susan Weinkle said; "The results of this study suggest that microinjections of ATX-101 can reduce submental fat without worsening skin laxity."

The company also announced study topline results, as announced in November 2012, which found out that 71.3% of subjects had at least a one-grade improvement on the CR-SMFRS / PR-SMFRS composite and 14% had at least a two-grade improvement on the same composite measure.

Kythera Biopharmaceuticals chief medical officer Dr Patricia Walker said; "These results, along with efficacy analyses in double-blind, placebo-controlled studies, support ATX-101 entering the market as potentially the first medical aesthetic drug approved for the reduction of submental fat."