Sirnaomics Doses First Patient in Phase Ⅱb Study of STP705 for Treatment of Squamous Cell Skin Cancer



Company Expects to Report Interim Clinical Data of the Phase 2 in Second Half of 2021


Sirnaomics, Inc., a biopharmaceutical company engaged in the discovery and development of RNAi therapeutics against cancer and fibrotic diseases, today announced dose administration for the first patient in a Phase 2b study of the company’s drug candidate, STP705, for the treatment of squamous cell skin cancer in situ (isSCC). STP705 is a siRNA (small interfering RNA) therapeutic that takes advantage of a dual-targeted inhibitory property and polypeptide nanoparticle (PNP)-enhanced delivery to directly knock down both TGF-β1 and COX-2 gene expression.


The randomized, double-blind, placebo-controlled Phase 2b study is evaluating the safety and efficacy of intralesional injection of STP705 in up to 100 adult patients with isSCC. This portion of the trial will further evaluate the two most efficacious dosing regimens of 30 ug and 60 ug. The primary endpoint of this trial is the proportion of participants with histological clearance of treated isSCC lesion at the end of treatment. Histological clearance will be defined as the absence of detectable evidence of isSCC tumor cell nests as determined by central pathology review.


“For many patients with isSCC, surgery is still considered the only viable treatment option, so with our first patient dosed in this Phase 2b study, we’ll be able to observe the efficacy of STP705, which has to the potential to be a non-surgical, non-invasive alternative,” said Michael Molyneaux M.D., Chief Medical Officer. “Our interim readout later this year will guide our clinical development for this indication.”   


“After a high rate of patients achieved histological clearance in the Phase 2a study of STP705 for isSCC, we’re looking forward to seeing the results of our Phase 2b study as we begin patient dosing,” said Patrick Lu, Ph.D., founder, President and CEO of Sirnaomics. “The anticipated clinical readout in the second half of 2021 will provide more insights into the potential of STP705 for the treatment of non-melanoma skin cancer and the impact of RNAi therapeutics in oncology.”


Additional information about this clinical trial is available at using the identifier: NCT04844983.






About Non-melanoma Skin Cancer and Squamous Cell Carcinoma In Situ 

Skin cancer is the most common type of all cancers diagnosed each year in the United States. It is estimated that nearly half of cancers diagnosed every year will be skin cancers. Over the past decade, the incidence of skin cancers has increased dramatically. According to the JAMA Dermatology paper (Rogers, et. al. JAMA Dermatol. 2015151(10):1081-1086), an estimated 3.3 million people in the US suffer from non-melanoma skin cancer (NMSC) along with 5.43 million people that are currently living with cancer lesions.


Squamous cell carcinoma in situ, also called Bowen disease, is the earliest form of squamous cell skin cancer (SCC). Along with basal cell carcinoma, SCC is one of two major subtypes of NMSC. The key driver for development of SCC is ultraviolet rays from the sun. It is believed that development of SCC is linked closely to genomic perturbations, genetic mutations, and altered expression of key molecules (e.g., overexpression of TGF-β1 and COX-2) that impacts squamous cell lineage commitment and terminal differentiation.


Surgery is the currently the most common treatment option for the treatment of NMSC. The various forms of surgical modalities carry significant cutaneous adverse events, risk of scar, infection and bleeding. Surgery can also have a significant recurrence rate. As a result, there is a high unmet need for an FDA approved local injection therapy that is safe and effective.




About STP705

Sirnaomics’ product candidate, STP705, is a siRNA (small interfering RNA) therapeutic that takes advantage of a dual-targeted inhibitory property and polypeptide nanoparticle (PNP)-enhanced delivery to directly knock down both TGF-β1 and COX-2 gene expression. The product candidate has received multiple IND approvals from both the US FDA and Chinese NMPA, including treatments of cholangiocarcinoma, nonmelanoma skin cancer and hypertrophic scar. STP705 has also received Orphan Drug Designation for treatment of cholangiocarcinoma and primary sclerosing cholangitis. A Phase 2a study of STP705 for treatment of squamous cell skin cancer (isSCC) in adult patients demonstrated positive efficacy and safety results, with 76% of all patients (19/25) achieving complete histologically clearance and the two optimal dosing ranges achieving 90% histological clearance of tumor cell in the lesion. No significant or serious adverse events, including no significant cutaneous skin reactions, were reported in the study, and the company was able to define a clear therapeutic window in advance of later stage studies.




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About Sirnaomics, Inc.

Sirnaomics, Inc., a leading privately held biopharmaceutical company for discovery and development of RNAi therapeutics, is a Delaware corporation headquartered in Gaithersburg, Maryland, USA, with subsidiaries in Suzhou and Guangzhou, China. The Company’s mission is to develop novel therapeutics to alleviate human suffering and advance patient care in areas of high unmet medical need. The guiding principles of the company are: Innovation, Global Vision with a Patient Centered focus. Members of the senior management team have a great deal of combined experience in the biopharmaceutical industry, financial, clinical and business management in both the USA and China. The company is supported by funding from institutional investors and corporate partnerships. Sirnaomics has developed a strong portfolio of intellectual property with an enriched product pipeline. The therapeutic areas of focus include oncology and anti-fibrotic therapeutics. Learn more at