Sirnaomics Announces Peer-Reviewed Publication of Phase IIa Clinical Results for STP705 in Adult Patients with Cutaneous Squamous Cell Carcinoma In Situ in the Journal of Drugs in Dermatology

Gaithersburg, Maryland, USA and Suzhou, ChinaJune 16, 2022/PR Newswire/ --Sirnaomics Ltd.（"Sirnaomics", Stock Code: 2257.HK), is a leading biopharmaceutical company focused on the discovery and development of RNAi therapeutics. Sirnaomics announced that the results of the Phase IIa clinical trial of STP705 for the treatment of in situ squamous cell carcinoma of the skin (isSCC) were peer-reviewed and published in the May 2022 issue of the *Journal of Drugs in Dermatology*."JDD"）。The study on "Safety and Efficacy of TGF-β1 and COX-2 Gene Silencing Therapy in Adults with In Situ Squamous Cell Carcinoma of the Skin" shows that STP705 demonstrated good safety and tolerability in treating patients with in situ squamous cell carcinoma of the skin.

The main results of this original research paper present a single-center, randomized, dose-escalation cohort study that evaluates the safety and efficacy of different doses of STP705 administered intradermally for the treatment of patients with in situ squamous cell carcinoma of the skin. STP705 is a TGF-β1 and COX-2 dual-target histidine-lysine polypeptide (siRNA/HKP) nanoparticle gene silencing therapy. The primary endpoint was the proportion of participants achieving complete histological clearance. Twenty-five participants received different doses of STP705, with 19 participants (76%) achieving histological clearance. The histological clearance rates were 80% in the 30 μg treatment group and 100% in the 60 μg treatment group. The study results indicate that STP705 is currently one of the less invasive, safe, and effective treatments for in situ squamous cell carcinoma of the skin. It is recommended that future studies use doses of 30 μg per administration and 60 μg per administration.

At the 2021 Fall Clinical Dermatology Conference held last year, Dr. Brian Berman, Professor of Dermatology at the University of Miami Miller School of Medicine, member of the American Academy of Dermatology Board of Directors, and Principal Investigator of the clinical study of STP705 for the treatment of isSCC, presented a detailed report on the clinical development and trial results of STP705. After the presentation, an on-site survey was conducted among more than 2,000 attendees to assess whether STP705 for isSCC meets medical needs in clinical practice and whether there is a willingness to use this innovative drug. The survey results showed that the dermatologists present gave the clinical application of STP705 a perfect score. During the same conference, in the Gore Range Capital Skin Health Innovation Competition, Sirnaomics' STP705 was selected as one of the three preferred projects.

"The number of currently approved non-surgical treatments for isSCC is limited. Our research findings indicate that STP705 has the potential to become a viable treatment option for patients with non-surgical, non-melanoma skin cancer. Publications and investigative results further validate the clinical application potential of this novel siRNA therapy," said Dr. Michael Molyneaux, Executive Director and Chief Medical Officer of Sirnaomics. "Excessive gene expression of TGF-β1 and COX-2 is closely associated with the development of SCC, with TGF-β1 playing a significant role in tumor progression. By using RNAi-based therapies such as STP705, these genes can be silenced, and we may be able to halt the proliferation of isSCC through this non-invasive treatment approach. This study provides strong support for that argument, and we plan to continue evaluating the 30μg and 60μg doses in future research."

Dr. Yang Lu, Founder, Chairman of the Board, Executive Director, President and Chief Executive Officer of Sirnaomics, stated: "The Phase IIa clinical study results of the company's candidate product STP705 for the treatment of isSCC were published in a peer-reviewed journal with a clinical focus, along with positive feedback from clinical dermatologists, further enhancing our confidence in advancing STP705 for the treatment of various types of non-melanoma skin cancers. This prevalent cancer has over 5 million new cases annually in the United States. Surgical removal of tumors in patients carries risks of disease progression, metastasis, recurrence, as well as infection, hematoma, or scarring. These patients need an alternative and non-invasive treatment option. This is why we are driving the evaluation of STP705’s significant application potential in clinical trials."