Sirnaomics Achieves 100% Complete Response in Phase II Clinical Trial of STP705 for Treatment of Cutaneous Basal Cell Carcinoma

Data showed an excellent safety profile with no adverse events among the five subjects treated. Company continues to explore doses in the ongoing Phase II dose escalation study

GAITHERSBURG,Md and SUZHOU,China,Aug. 29,2022 -- Sirnaomics Ltd. (the "Company"or"Sirnaomics",stock code: 2257.HK),a leading biopharmaceutical company in discovery and development of RNAi therapeutics,announced today that the cohort receiving the 180μg dose level in the Phase II clinical trial of STP705 for the treatment of cutaneous basal cell carcinoma (BCC) achieved a 100% complete response (CR),indicating the promising viability of the treatment. STP705 is a siRNA (small interfering RNA) therapeutic that is composed of two siRNA oligonucleotides,targeting the expression of TGF-β1 and COX-2 mRNA,respectively.

Apart from achieving a 100% CR,the data among the five subjects treated in the cohort also showed improved or stable cosmetic results with an excellent safety profile (no adverse events) and no significant cutaneous skin reactions. The Company is continuing to explore doses in the ongoing dose escalation study and anticipates a final report in Q1 2023.

"The latest results from the Phase II clinical study of STP705 for BCC treatment,showing an incredible efficacy without any drug related AEs and SAEs,further validated the broad potential of this drug candidate for treatment of non-melanoma skin cancers and beyond",said Dr. Patrick Lu,PhD,founder,Chairman of the Board,Executive Director,President and CEO of Sirnaomics. "Based on the successes of both BCC and isSCC (cutaneous squamous cell carcinoma in situ) clinical studies,Sirnaomics is spearheading the development of the novel polypeptide-based siRNA therapeutics for various types of cancers."

"Achieving a 100% CR is a clear indication that our treatment has the potential to be an alternative to those treatments currently available to patients,which involve surgical excision of lesions," said Dr. Michael Molyneaux,MD,Executive Director and Chief Medical Officer of Sirnaomics. "To reduce the rate of scarring and achieve a superior cosmetic result compared to surgery could be a potential advantage for patients with BCC and other non-melanoma skin cancers."

The Phase II open label,dose escalation study will also expand the number of participating cohorts to continue to evaluate the safety,tolerability,and efficacy of various doses of STP705 administered as localized injections in patients with BCC. Additional information about this clinical trial is available at clinicaltrials.gov using the identifier: NCT04669808.

About Basal Cell Carcinoma

Basal cell carcinoma (BCC) is a type of nonmelanoma skin cancer (NMSC) that is associated with exposure to ultraviolet radiation from the sun. BCC is the most common form followed by squamous cell carcinoma (SCC),and while they have a lower metastatic potential,they can be locally aggressive and destructive of skin and surrounding structures. The estimated metastasis rate of BCC ranges from 0.0029% to 0.55%,and common metastatic sites are regional lymph nodes,lungs,bones,skin,and liver. In the U.S.,according to Incidence Estimate of Nonmelanoma Skin Cancer (Keratinocyte Carcinomas) in the U.S. Population,2012,the number of new cases of BCC is 2.4 million in 2020 and is projected to increase to 4.2 million in 2030. Standard treatments for BCC are standard surgical excision,Mohs micrographic surgery,topical cream treatments,cryosurgery,laser therapy,electro-desiccation,and radiation therapy. The various forms of surgical modalities carry significant cutaneous adverse events,risk of scar,infection,and bleeding. Currently,there are two drugs approved by U.S. Food and Drug Administration (FDA) for pre-metastatic BCC patients,which can cause skin reactions in some patients.

Treatment of BCC with STP705 shows benefits in cosmetic appearance,especially for patients with lesions on the head,face or neck,and clinical results demonstrate that STP705 has a high complete response compared with currently available topical treatments.

About STP705

Sirnaomics' leading 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 U.S. Food and Drug Administration (FDA) and the Chinese National Medical Products Administration (NMPA),including treatments of cholangiocarcinoma,non-melanoma skin cancer and hypertrophic scar. STP705 has also received Orphan Drug Designation for treatment of cholangiocarcinoma (CCA) and primary sclerosing cholangitis (PSC). STP705 is currently in seven clinical trials for different indications: a Phase IIb for squamous cell carcinoma in situ (isSCC),a Phase II for basal cell carcinoma (BCC),a Phase I/II for keloid scarring,a Phase I/II for hypertrophic scar (HTS),a Phase I/II for facial isSCC,a Phase I for liver cancer (basket),and a Phase I for medical cosmetology treatment.

About Sirnaomics

Sirnaomics is an RNA therapeutics biopharmaceutical company with product candidates in preclinical and clinical stages that focuses on the discovery and development of innovative drugs for indications with medical needs and large market opportunities. Sirnaomics is the first clinical-stage RNA therapeutics company to have a strong presence in both China and the United States,and also the first company to achieve positive Phase IIa clinical outcomes in oncology for an RNAi therapeutic for its core product,STP705. Learn more at www.sirnaomics.com.

Contact:

Michael Molyneaux,MBA

Executive Director and Chief Medical Officer,Sirnaomics

Email: MichaelMolyneaux@sirnaomics.com

Investor Relations:

Nigel Yip

Chief Financial Officer,Sirnaomics

Email: NigelYip@sirnaomics.com

US Media Contact:

Mark Corbae

Tel: +1 203 682 8288

Email: Mark.Corbae@westwicke.com

Asia Media Contact:

Bunny Lee

Tel: +852 3150 6707

Email: sirnaomics.hk@pordahavas.com