KYTHERA Biopharmaceuticals Announces Results from Open-Label Study for ATX-101

KYTHERA Biopharmaceuticals Announces Results from Open-Label Study for ATX-101

KYTHERA Biopharmaceuticals, Inc.Investor & Media ContactHeather Rowe Tel: (818) 587-4559

(NASDAQ: KYTH) today announced interim study results from Study ATX-101-11-26, a multicenter, open-label, long-term study to evaluate the safety of , a facial injectable drug for the reduction of submental fat (SMF), which commonly presents as an unwanted double chin.

“We are pleased that the open-label study results further support the safety profile of ATX-101 for the reduction of submental fat and are consistent with our previous Phase II and the European Phase III trials,” said Patricia S. Walker, M.D., Ph.D., KYTHERA’s Chief Medical Officer. “These findings add to our robust clinical database of over 1,500 subjects treated with ATX-101 in our clinical development program for the reduction of submental fat.”

This study captured subjects who received ATX-101 (2 mg/cm) for up to six treatments spaced 28 days apart. The interim results included subjects who had completed Visit 9, or three months after last injection, which is the same study endpoint as the ongoing U.S. and Canadian Phase III pivotal trials. Final study results will be analyzed following completion of the study, which is 12 months after last injection.

In this study, ATX-101 was found to be well tolerated and the observed overall safety profile was consistent with findings from previous Phase II and European Phase III clinical trials. Adverse events were mostly mild to moderate, and transient. The most common adverse events were bruising, numbness, pain, swelling, redness, induration, itching and nodule formation. These adverse events were limited to the injection site and were temporally associated with treatment.

Although not designed to measure efficacy, the interim results from this open-label Study 26 were also consistent with the efficacy results observed in previous studies of similar design. Mean changes from baseline in submental fat measured 12 weeks after last injection were -1.3 on the Clinician-Reported Submental Fat Rating Scale (CR-SMFRS) and -1.2 on the Patient-Reported Submental Fat Rating Scale (PR-SMFRS). Additionally, 71.3% of subjects had at least a 1-grade improvement on the CR-SMFRS / PR-SMFRS composite and 14.0% had at least a 2-grade improvement on the same composite measure.

KYTHERA currently expects to submit additional details from this study for presentation at a future medical meeting.

This multicenter, open-label study enrolled 165 subjects in 21 dermatology and plastic surgery centers in the United States. In this study subjects at least 18 years of age with stable body weight, and body mass index (BMI) of less than 40.0 and with a presence of SMF rated by both clinicians and subjects as moderate, severe or extreme (rated 2, 3 or 4 on the CR-SMFRS and PR-SMFRS) and considered undesirable by the subject (as characterized by a score of 0, 1, or 2 on the Subject Self-Ratings Scale, or SSRS) received 2 mg/cm ATX-101 for up to six treatment visits.

ATX-101 is a proprietary formulation of synthetic sodium deoxycholate, a well-characterized component of human bile that is naturally occurring in the body to promote the breakdown of dietary fat. ATX-101 is designed to be a locally-injected drug that causes proximal, preferential destruction of adipocytes, or fat cells, with minimal effect on surrounding tissue. Based on clinical trials conducted to date, ATX-101 has exhibited significant, meaningful and durable results in the reduction of submental fat, which commonly presents as an undesirable “double chin.” These results correspond with subject satisfaction measures demonstrating meaningful improvement in perceived chin appearance.

In August 2010, Bayer signed a licensing and collaboration development agreement with KYTHERA, thereby obtaining development and commercialization rights to ATX-101 outside of the U.S. and Canada. Bayer recently completed two pivotal Phase III trials of ATX-101 in Europe for the reduction of submental fat. Topline results from these trials were reported in the second quarter of 2012. KYTHERA completed enrollment in its pivotal Phase III clinical program for ATX-101 in more than 1,000 subjects, randomized to ATX-101 or placebo, in 70 centers across the United States and Canada in August 2012. The Company expects to release top-line results in mid-2013.

KYTHERA Biopharmaceuticals, Inc. is a clinical-stage biopharmaceutical company focused on the discovery, development and commercialization of novel prescription products for the aesthetic medicine market. KYTHERA’s product candidate, ATX-101, is a potential first-in-class, injectable treatment currently in Phase III clinical development for the reduction of submental fat, which commonly presents as an undesirable “double chin.” KYTHERA also maintains an active research interest in hair and fat biology, pigmentation modulation and facial contouring. Find more information at .