Sirnaomics Ltd, a biopharmaceutical company in discovery and development of RNAi therapeutics, announced the interim results of an ongoing Phase I clinical trial of STP705, an siRNA (small interfering RNA) drug candidate, for fat reduction in adults undergoing abdominoplasty. According to the company, the initial results of the STP705 Phase I trial appear to indicate that the use of STP705 in the treatment of unwanted fat is safe and show clear signs of efficacy.

STP705 Phase I Clinical Trial Results

This interim efficacy results reportedly examined efficacy data from six participants that were scheduled to undergo abdominoplasty. Each participant was treated with STP705 doses of 120 μg, 240 μg and 320 μg at volume per injection of either 0.5 ml or 1.0 ml per injection site as well as placebo consisting of normal saline. The test article administration area was the central to lower abdomen region designated for abdominoplasty and participants received a single injection per site up to three injections of test article approximately 28 days apart.

Participants in the safety review were examined for the presence of and severity of Local Skin Reactions (LSR) including erythema, edema, and bruising over a time frame as well as the incidence (severity and causality) of any adverse events for a time frame of approximately 98 days. Secondary analysis looked at histological evidence of fat changes that would be seen in fat tissue remodeling such as fat inflammation, panniculitis, fibrosis, and fat necrosis. Statistical analysis was performed with non-parametric one-way ANOVA using Kruskal-Wallis test and Dunn’s multiple comparison test.

The interim analysis results include data from six participants with 42 tissue samples in total. There were no significant adverse events and all tissue samples examined in this review using variables doses of STP705 showed histological evidence suggestive of fat remodeling. Based on the histological scoring and panniculitis + fat necrosis ranking, a dose-dependent effect was observed for all treatment groups comparing to the placebo group with statistical significance (P < 0.05). The 240 μg at the volume of 1.0 ml treatment group has demonstrated the most potent activity.


Mark Nestor, MD, PhD, director of the Center for Clinical and Cosmetic Research and the Center for Cosmetic Enhancement, Aventura, Fla, a voluntary professor in the Division of Plastic Surgery at the University of Miami, Miller School of Medicine and the principal investigator (PI) of the Phase I clinical study commented, “The initial data from the Phase I trial appears to indicate that the use of STP705 in the treatment of unwanted fat is safe and shows clear signs of efficacy. Safety has been examined in the first of three subjects and histology of the injected areas post abdominoplasty has been evaluated. Regarding histology, there is a clear difference in many of the specimens between the placebo, and the subjects injected with STP705. We look forward to completing this first study and analyzing all the results in the near future.”

Michael Molyneaux, MD, executive director and chief medical officer at Sirnaomics, added, “Interim data from our clinical study of STP705 for fat reduction indicate that subjects that have received various doses of STP705 show clear histologic evidence of fat changes that would be observed in fat remodeling. The safety results were very encouraging with no systemic adverse events and no significant local skin or tissue changes. This finding is very important when selecting a product that will be used for non-surgical fat remodeling and the fact that there was clear histological evidence of fat remodeling in a dose dependent manner is very encouraging as we move into Phase II of the program. We anticipate final study report sometime in Q3 2023 after which time, we will request a meeting with the FDA to determine the path to approval for the program.”

This study is the Group’s first attempt to apply an RNAi therapeutic candidate for localized fat remodeling and Sirnaomics reportedly plans to use the information from this study to expand into the treatment of submental fat and other areas of noninvasive fat remodeling. According to the company, the positive interim results have better informed the Group about the later stage development of STP705 in the medical aesthetics category. The company adds that together with the positive results from STP705 for treatment of squamous cell carcinoma in situ (isSCC) and basal cell carcinoma (BCC), the Group has successfully leveraged the proof-of-concept human data from STP705. According to Sirnaomics, this advancement in fat remodeling is expected to open up a new therapeutic area of medical aesthetics for Sirnaomics’ pipeline and has received very positive responses from the market.

Results Encourage Further Work

“The interim results of this Phase I clinical study have brought a strong enthusiasm using RNAi drug for medical aesthetic treatment. This novel non-invasive fat-reduction option potentially offers millions of people with unwanted fat on their bodies, which are resistant to diet and exercise and influenced by aging and genetics, a unique way to address those all-too-common conditions,” said Patrick Lu, PhD, founder, chairman of the board, executive director, president and chief executive officer of Sirnaomics. “During our preclinical studies with a well-defined animal model, we found that STP705 demonstrated superior efficacy and safety, compared to a commercially available injection drug for the same indication. This observation encourages us not only to explore the utility of STP705 for medical aesthetics but also to advance it to become a best-in-class drug candidate for fat-remodeling.”

Additional information about this clinical trial is available at using the identifier: NCT05422378.