Tencent-Backed Sirius Therapeutics Files for Hong Kong IPO with Leading siRNA Drug Pipeline

On September 28, Sirius Therapeutics, a developer of small nucleic acid drugs, submitted its prospectus to the Hong Kong Stock Exchange.

Sirius Therapeutics disclosed three small nucleic acid drug pipelines,Two of them correspond to the cardiovascular disease field, and one targets obesity.The core product is an FXI inhibitor anticoagulant drug, SRSD107, which secured an overseas licensing deal in May this year.Upfront payment of $95 million, other milestone payments exceed $800 million.

After the success of the "cholesterol-lowering miracle drug" inclisiran, MNCs such as Novartis have set their sights on China's small nucleic acid drug companies. In January last year and September this year, Novartis acquired the commercial rights to multiple cardiovascular pipelines from Argo for nearly 10 billion US dollars in total, directly pushing the small nucleic acid drug track to a climax.

Sirius TherapeuticsFormer WuXi AppTecVice PresidentJi Qunsheng founded in 2021In this wave of small nucleic acid drug trends, it has developed rapidly, raising 144 million US dollars in three rounds of financing, with a post-investment valuation of 253 million US dollars.

Shenzhen Tencent Computer System Co., Ltd. is one of the investors in Sirius Therapeutics.This is a rare direct investment by Tencent into an innovative pharmaceutical company.。

The Next Heavyweight Anticoagulant Drug

There are only a few small nucleic acid drugs that have been launched globally, and they are mainly for the treatment of rare diseases, so they have not received much attention before.Since the treatment field has expanded to chronic diseases, the prospects of small nucleic acid drugs have suddenly improved.

Novartis' Inclisiran sodium is the first small nucleic acid drug to enter the field of chronic disease treatment, used for long-acting lipid-lowering, and was approved for marketing in 2021. In 2024, Inclisiran sodium achieved sales of $754 million. In the first quarter of this year, Inclisiran sodium sales increased by 72% year-on-year.

Sirius Therapeutics is developing small nucleic acid drugs, also focusing on the cardiovascular chronic disease field. The company's core product is aSRSD107, an siRNA drug targeting coagulation factor XI, can be used for thrombotic and thromboembolic diseases.

Thrombosis is a trigger for a wide range of diseases, including atrial fibrillation, peripheral vascular disease, and venous thromboembolism. If fully developed, the market value would be significant. The current standard treatment for such diseases is oral Xa factor inhibitors, represented by apixaban.

Apixaban, developed by Bristol-Myers Squibb and Pfizer, has seen continuous sales growth since its launch, reaching $20.6 billion in sales in 2024. On the global top 10 best-selling drugs list, apixaban has outlasted "blockbuster drug" Humira and the world's first PD-1 inhibitor, nivolumab, yet it remains firmly at the forefront.It is the best-selling small molecule drug globally.

However, apixaban has a significant issue: the risk of bleeding.XI inhibitors can effectively solve bleeding problems., is expected to become the next super blockbuster in the anticoagulant field. Novartis, Bayer, and BMS/Johnson & Johnson's XI inhibitors have all initiated global Phase III clinical trials, while Hengrui's SHR-2004 has also launched Phase III clinical trials in China; Sirius Therapeutics' SRSD107 is an XI inhibitor based on the siRNA model,Only once or twice a year dosing required，Similar to inclisiran sodium, it has significant compliance advantages.

Currently, SRSD107 has advanced to the multi-center Phase II clinical trial and is expected to enter Phase III clinical trials in 2026. The Phase I clinical trial confirmed that a single subcutaneous administration of SRSD107 can reduce FXI levels by up to 95%, with effects lasting more than six months.

According to the prospectus, there are only four siRNA drugs targeting XI in the global R&D pipeline.Sirius Therapeutics' SRSD107 is in the second stage, just behind Ribo Biotech.

In May this year, Sirius Therapeutics licensed the U.S. commercial rights of this XI-targeted small nucleic acid drug to gene-editing company CRISPR, successfully expanding overseas while retaining the market in Greater China for itself.

Emerging Lipid-Lowering Targets

In addition to anticoagulant drugs, Sirius Therapeutics also hasSRSD216, an siRNA drug targeting Lp(a), for lipid-related diseases.

Lp(a) is an LDL-like molecule, and approximately 18%-35% of the population has elevated Lp(a) levels. Clinical studies have confirmed that the atherosclerotic capability of Lp(a) is 6.6 times higher than that of LDL. However, there are currently no drugs specifically targeting Lp(a). Existing lipid-lowering therapies, such as statins, are ineffective against it, and PCSK9 inhibitors can only reduce it to a small extent.

In the global development of chronic disease drugs, Lp(a) is an unavoidable target. In October last year and March this year,Lp(a) Small Molecule Inhibitors Developed by Shijiazhuang Pharmaceutical and Hengrui Have Successively Received Upfront Payments Exceeding $100 Million, licensed to AstraZeneca and Merck, has heated up the Lp(a) track.

The siRNA Lp(a) drug has been explored globally with Amgen and Eli Lilly taking the lead. Sirius Therapeutics' SRSD216 follows closely behind, ranking third in global progress. It is currently undergoing Phase IIa clinical trials simultaneously in China and the U.S., with BD opportunities potentially arising at any time.

Sirius Therapeutics has anotherThe candidate pipeline SRSD384 for obesity targets INHBE, not the popular GLP-1 series.Sirius Therapeutics stated that GLP-1 drugs face high discontinuation rates and side effects such as muscle loss and gastrointestinal reactions. SRSD384 is expected to address these issues. However, SRSD384 is not anticipated to enter clinical trials until next year.

The prospectus shows that as of the first half of this year, Sirius Therapeutics had over 600 million yuan in its account, indicating that its financial situation is not strained.