Sirnaomics, Inc., a wholly owned subsidiary of Sirnaomics Ltd. (2257.HK) and a trailblazer in RNAi therapeutics, today announced the successful completion of its Phase 1 clinical study (SRN-707-001) of STP707, with the Clinical Study Report (CSR) formally submitted to the U.S. Food and Drug Administration (FDA). The milestone underscores the program’s progress and validates STP707’s breakthrough PNP platform IV delivery, exceptional safety profile, and tumor microenvironment targeting capability – key advancements for treating advanced/metastatic solid tumors refractory to standard therapy.

STP707, powered by Sirnaomics’ proprietary histidine-lysine polypeptide (HKP+H) nanoparticle platform, is the first RNAi therapy to demonstrate safe IV administration with effective tumor microenvironment targeting in a Phase 1 setting. Unlike conventional RNAi therapeutics limited to liver delivery, STP707’s unique formulation reaches extra-hepatic tumors across multiple sites (e.g., pancreas, colon, ovary, head and neck) – addressing a critical unmet need for patients with refractory cancers.

The multicenter Phase 1 study, conducted across 8 sites with 49 enrolled patients, evaluated six dose levels (3 mg to 48 mg) and delivered compelling safety data. STP707 was universally well-tolerated, with 100% of patients completing at least one dose. Treatment-related adverse events (TRAEs) were predominantly mild to moderate (Grade 1-2), including manageable chills, fatigue, and nausea, with no dose-dependent toxicity observed. Only 1 dose-limiting toxicity (DLT) was reported, and just 8.2% of serious adverse events were treatment-related. Notably, liver function markers (AST/ALT) showed no targeted toxicity, confirming the delivery advantage of the HKP+H platform.

Beyond safety and delivery, STP707 demonstrated meaningful clinical activity: 35.7% of evaluable patients achieved stable disease (SD), slowing progression in a heavily pretreated population with limited treatment options. This disease control, paired with the feasibility of weekly IV infusions, reinforces STP707’s potential as a versatile therapeutic candidate.

“Completing Phase 1 and submitting the CSR to the FDA marks a pivotal milestone for STP707 and our PNP platform,” said H. Fai Poon, Chief Executive Officer at Sirnaomics. “We have not only demonstrated that our PNP platform can efficiently deliver siRNA via IV administration to safely target extra-hepatic tissues, but also submitted comprehensive safety data for our PNP platform to support the FDA’s review. The successful completion of this study validates our strategic approach to addressing unmet medical needs in refractory solid tumors, while also confirming the druggability and favorable safety profile of our PNP delivery platform. This breakthrough opens new avenues for the future development of our platform, and we are eager to advance it to the next stage of clinical development.”

With the CSR submitted, Sirnaomics is positioned to initiate discussions with the FDA to define the Phase 2 development strategy, building on STP707’s proven IV delivery, non-liver targeting, and strong safety profile. The company remains committed to accelerating access to this transformative therapy for patients with limited treatment options.

About Sirnaomics

Sirnaomics Ltd.(HK: 2257), known as Asia's "First RNAi Therapeutics Stock," is a clinical-stage global biopharmaceutical company specializing in RNA interference technology. Utilizing its dual core technology platforms and diverse pipeline, the company is at the forefront of developing RNAi therapies to drive industry growth.

Sirnaomics has two proprietary delivery platforms:

1. Polypeptide Nanoparticle (PNP) Platform: An extrahepatic delivery platform enabling precise targeting of tissues such as skin, adipose tissue, and muscle.
2. GalAhead™ Delivery Platform: A liver-targeted delivery system with clear IP and long-acting administration capabilities.

The company is also an industry leader with its innovative linker-free, dual-target RNAi technology. Sirnaomics' robust pipeline addresses oncology, local fat reduction, medical aesthetics, and cardiovascular diseases, with multiple products in clinical trials. Beyond its internal development, Sirnaomics embraces an open-collaboration strategy, integrating its technology platforms to support the broader industry and benefit patients worldwide.