Aobi Hatches, Tencent Invests! siRNA Innovative Drug Company Files for HKEX Listing Again

On March 31, 2026, Sirius Therapeutics submitted its Chapter 18A listing application to the Hong Kong Stock Exchange, officially marking the beginning of this young siRNA biotech company's second attempt to go public on the Hong Kong stock market. Goldman Sachs, Haitong International, and HSBC continued their support. The confidence of this young Biotech stems from the clinical progress of its core products, backing by prominent capital, and precise positioning in the billion-dollar chronic disease sector—it has broken away from the industry's overcrowded focus on rare diseases, prioritizing coagulation, cardio-metabolic conditions, and obesity as its core areas. Riding the wave of siRNA therapy’s shift toward chronic diseases, it aims to establish a firm foothold in the Hong Kong capital market.

Back in 2021, the global siRNA therapy field was still concentrated in the niche area of rare diseases, with most startups eager to break through by taking the "small but beautiful" route. It was during this time that Sirius Therapeutics was co-incubated and founded by OrbiMed and Creacion Ventures. From its inception, the company planted the seeds of "taking an unconventional path" — instead of focusing on rare diseases, it set its sights on three overlooked chronic disease tracks worth billions: coagulation, cardiometabolic conditions, and obesity.

In five years, from a blueprint to the second filing, Sirius Therapeutics has gradually built up its R&D, capital, and pipeline systems. Its growth is not only a microcosm of a Biotech startup but also carries the初心of Chinese nucleic acid drug companies advancing from followers to breakthrough players, from local to global. It also reflects the persistence and博弈of clinical-stage innovative drug companies between capital and technology.

In 2021, Sirius Therapeutics, starting with its dual headquarters in Shanghai and San Diego, was born with a global gene that allowed it to leap beyond the limitations of "local R&D" from the very beginning. By adopting the dual headquarters model of Shanghai and San Diego, it relied on the talent and industrial chain advantages of Shanghai to deepen domestic clinical trials and R&D implementation on one hand; on the other hand, it leveraged San Diego’s position as a global hub for nucleic acid technology to connect with cutting-edge international resources, quickly building up an R&D and clinical system covering China, the US, and Europe.

At its inception, Sirius Therapeutics clearly defined its core positioning: leveraging siRNA technology to address the pain points in chronic disease treatment. At that time, traditional chronic disease treatments faced challenges such as long medication cycles, poor compliance, and significant side effects, leaving unmet clinical needs that urgently required solutions. To this end, the company independently developed the PEPR® Precision Engineering High-Performance RNA Therapeutic Platform, integrating the entire chain of technologies including chemical modification and sequence design. Moreover, it took the lead in developing extrahepatic delivery systems, breaking the limitation of siRNA being effective only in the liver, thereby paving new avenues for long-acting treatments of chronic diseases.

The entrepreneurial journey is never smooth sailing. Continuous funding is required for research and development, while Biotech companies in the clinical stage have almost no revenue. Fundraising thus becomes the key to survival and growth. Sirius Therapeutics has maintained an accurate pace of capital flow from the very beginning, with each round of financing precisely aligned with critical milestones in pipeline R&D. This continuous influx of resources has provided a solid foundation for the company’s steady progress and the confidence to navigate through the R&D cycle.

In 2021, shortly after its establishment, the company completed its Series A financing round, led by founding shareholders Orbimed and Creacion Ventures. This funding, akin to "the first pot of gold," laid a solid foundation for building the initial R&D team, refining laboratory infrastructure, and advancing early-stage target screening. In October 2023, as the core product SRSD107 entered the clinical preparation phase, the company successfully closed a $60 million Series B financing round led by Hanking Capital, with continued support from existing shareholders. This funding directly propelled SRSD107 into the clinical stage, marking Sirius Therapeutics' official transition from "R&D accumulation" to the critical period of "clinical breakthrough."

By the end of 2023, Sirius Therapeutics' pipeline matrix had initially taken shape. In addition to its core product SRSD107, the company has also laid out multiple preclinical assets, consistently focusing on long-acting treatments for chronic diseases. While competitors were fiercely battling in niche rare disease fields, Sirius Therapeutics had quietly seized the blue ocean of siRNA for chronic diseases, paving the way for future development.

In 2024, Sirius Therapeutics entered a phase of accelerated clinical development, with its core product SRSD107 taking center stage as the focal point of the company's IPO narrative. This long-acting siRNA anticoagulant drug targets coagulation factor XI (FXI) and carries the "game-changer" gene from its inception—traditional oral anticoagulants' biggest pain points are high bleeding risk, the need for long-term medication, and ineligibility for patients with renal insufficiency. By silencing FXI expression through RNA interference technology, SRSD107 can effectively reduce thrombosis risk while preserving the body’s fundamental hemostatic function, with the potential to redefine industry standards for anticoagulation therapy.

This year, SRSD107's clinical progress has hit the "fast-forward button," with Phase I clinical trials being conducted simultaneously in Australia and China. The company's R&D investment has remained consistently high, with a consolidated net loss of 342 million yuan in 2024, over 30% of which was allocated to SRSD107. This is all aimed at obtaining robust clinical data as soon as possible to pave the way for the product's breakthrough.

2025: A Pivotal Turning Point for Sirius TherapeuticsIn 2025, Sirius Therapeutics reached a critical turning point. Early in the year, Phase I clinical data for SRSD107 showed good single-dose tolerability, with FXI levels reduced by over 95%. The drug’s potent and long-lasting efficacy was fully validated, drawing significant attention from both investors and industry giants. In April, the company completed a $47.5 million Series B2 financing round, reaching a post-money valuation of $253 million. New investors included Boyuan Capital and Imagine Architecture Investment, a subsidiary of Shenzhen Tencent Computer System Co., Ltd., providing substantial resources for future development.

What truly established Sirius Therapeutics' foothold was the global co-development and co-commercialization (Co-Co) partnership reached in the same year with CRISPR Therapeutics, a giant in gene editing. This marked one of the few high-profile collaborations between a Chinese clinical-stage siRNA pharmaceutical company and a top-tier global biotech firm, breaking the traditional pattern of "passive licensing" for Chinese innovative drug companies in global partnerships. It enabled Sirius Therapeutics to take a crucial step in its global strategy and marked an important milestone in its growth journey.

This Co-Co partnership is not a simple resource alignment; its core logic is fundamentally different from the traditional License-out model. The two parties adopt a 50:50 sharing mechanism of "risk sharing, profit sharing," representing a truly equal partnership and marking Chinese pharmaceutical companies stepping out of the passive framework of "selling rights for cash." According to the agreement, CRISPR will pay an upfront fee of $95 million. Sirius Therapeutics can also receive over $800 million in upfront and milestone payments. Both parties will jointly promote the global clinical trials of SRSD107, with CRISPR responsible for commercialization in the U.S., while Sirius Therapeutics controls the Greater China market. Additionally, CRISPR has the priority license for two siRNA targets, and Sirius Therapeutics will receive corresponding benefits.

For Sirius Therapeutics, which is in the clinical stage, this collaboration provides comprehensive and highly targeted support. Financially, the substantial funding alleviates the pressure of clinical research and development, allowing the company to continuously invest more in R&D. Technically, leveraging CRISPR's R&D capabilities and pipeline complementarity accelerates the clinical progress of SRSD107 and enhances its own siRNA technology platform. Commercially, relying on CRISPR’s mature global network eliminates the need to build overseas channels from scratch, significantly shortening the product’s time to market, reducing overseas expansion costs, and increasing its global visibility. More importantly, the global clinical and commercial experience gained from this collaboration sets a valuable reference for the internationalization of China’s nucleic acid drugs and adds significant weight to its IPO efforts.

By September 2025, with the clinical progress of its core products, backing from prominent capital, and collaboration endorsements from industry giants, Sirius Therapeutics submitted its first application for a Chapter 18A listing to the Hong Kong Stock Exchange (HKEX). The aim was to access the capital markets to secure additional funding for subsequent clinical advancements and commercialization efforts. Despite not passing immediately after the initial submission, Sirius Therapeutics did not halt its efforts. Instead, it utilized the following six months to update financial data and refine clinical progress, thoroughly preparing for a second attempt.

On March 31, 2026, Sirius Therapeutics filed its second listing application with the Hong Kong Stock Exchange. After six months of refinement, this young Biotech company has quietly undergone a transformation. SRSD107 has completed the first dosing in a Phase II clinical trial in Europe, with two Phase II trials simultaneously initiated in China, and key data is expected to be released in the second half of the year. The company holds cash and cash equivalents amounting to 1.173 billion yuan, sufficient to sustain operations for 37 months, ensuring short-term liquidity without concern. Its pipeline portfolio has been further enhanced, forming a structure of "1 core product + 2 key products + 18 preclinical assets." SRSD216 (targeting Lp(a)) is advancing synchronously in Phase IIa clinical trials in both China and the U.S., while SRSD384 (for obesity) has entered the IND submission stage, with impressive preclinical data.

Under the Glare of the Spotlight, Challenges Are Equally Prominent. As a clinical-stage Biotech, Sirius Therapeutics currently has no drug sales revenue and is projected to accumulate losses of nearly 600 million yuan between 2024 and 2025. The characteristics of "high R&D, high losses, and high financing" remain pronounced—this is also an inevitable phase in the growth journey of all innovative pharmaceutical companies. The FXI inhibitor track where SRSD107 is positioned has become increasingly competitive: Novartis, Bayer, and Bristol-Myers Squibb’s antibody and small-molecule FXI inhibitors have entered Phase III clinical trials, while Hengrui Medicine's similar product is also advancing into Phase III trials domestically, all ahead of SRSD107 in terms of progress. At the same time, traditional oral anticoagulants like apixaban have achieved global sales exceeding $20 billion, establishing solid clinical usage habits and market barriers. For SRSD107 to break through, it must use more compelling clinical data to demonstrate its differentiated advantages of lower bleeding risk and longer dosing intervals.

In terms of cash flow, the current funds are sufficient. However, as clinical progress deepens, R&D investment will continue to increase. The proceeds from this IPO will be entirely used for R&D and operations, focusing on advancing the three core products through clinical trials while also promoting the development of extrahepatic delivery systems and supplementing working capital. Recognition from the capital market will become a key support for Sirius Therapeutics to continue its growth.

In terms of equity structure, a diverse and strong lineup of shareholders backs the company: OrbiMed holds approximately 40.46% as the controlling shareholder, Creacion Ventures holds 20.23%, H&Q Capital and Shenzhen Tencent Computer System Co., Ltd.'s Imagine Architecture Investment hold 10.72% and 8.14%, respectively, while CEO Qunsheng Ji holds 5.87%. The synergy between top-tier healthcare funds and industry capital provides financial and resource support for its long-term development, also making the market optimistic about its future.

From its quiet establishment in 2021, to clinical breakthroughs in 2023, to capital infusion and partnerships with industry giants in 2025, and finally to its second listing application in 2026, the five-year journey of Sirius Therapeutics epitomizes Chinese innovative pharmaceutical companies deeply exploring frontiers and boldly entering the billion-dollar track. It coincides with the critical window of siRNA therapy's expansion into chronic diseases, whose features of long-acting and low compliance burden perfectly align with the industry trend of chronic disease management. Its dual-headquarter global layout and equal cooperation model with international giants also conform to the core valuation logic of HKEX Chapter 18A biotech companies.

Today, this company, which has only been established for five years, is standing at the doorstep of the Hong Kong stock market, carrying the overseas ambitions of China's siRNA innovative pharmaceutical enterprises. Its second attempt is not only crucial to its own fate but also impacts China's话语权 in the global chronic disease sector for nucleic acid drugs. If it successfully goes public and advances the commercialization of its core products, Sirius Therapeutics could become a new benchmark for Chinese nucleic acid drug companies going global, providing a reference for more Chinese innovative pharmaceutical enterprises to expand internationally.

IPO is just the starting point, and there is still a long way to go for subsequent clinical advancement and commercialization. The alignment between clinical timelines and capital consumption, the differentiated advantages of core products, and breaking through competition in a crowded track are all challenges that Sirius Therapeutics must face. Undeniably, it has already seized the initiative in the chronic disease siRNA field and built up sufficient confidence.

Five Years to Sharpen a Sword, Setting Off Again Today. In the blue ocean market of global chronic disease siRNA therapies, whether Sirius Therapeutics can break the industry pattern and achieve dual breakthroughs in technology and commercialization, becoming a new benchmark for innovative pharmaceutical companies in China, is something the entire market is watching with anticipation.