Sydnexis Submits IPO Prospectus Following FDA Rejection of Phase 3-Successful Myopia Drug SYD-101

Recently, the U.S. FDA rejected the marketing application for SYD-101, a low-dose atropine eye drop from Sydnexis, Inc., which had been highly anticipated for slowing myopia progression in children aged 3 to 14. Despite being approved for marketing in Europe and meeting the primary efficacy endpoint in its Phase III clinical trial (STAR), the FDA still did not grant approval.

01Why Did the FDA Say “No”?

FDA's reasons in the Complete Response Letter (CRL) were very clear: although the Phase III STAR study supporting the SYD-101 application met its primary endpoint — the proportion of patients whose myopia progression was controlled within -0.75D aligned with expectations — the overall data was still insufficient to fully demonstrate the slowing effect of low-dose atropine on myopia in children. This statement clearly indicates that the core concern of the FDA is not about the drug’s safety or manufacturing process. In fact, in the CRL, the FDA did not mention any defects related to safety or product quality, which was also confirmed by Sydnexis, Inc. This means that the quality control during the drug’s manufacturing process and the assurance of safety during its use have both been recognized by the regulatory authority. The real issue lies in the fact that, from the FDA’s professional perspective, the current evidence of efficacy presented lacks strength and persuasiveness.

In - depth Analysis of FDA's Considerations: Industry Experts Suggest Higher Requirements for Data Comprehensiveness and Long - term Nature

Moreover, the FDA may have questions about the clinical significance of the study endpoints. Although the STAR study achieved its pre-specified primary endpoint, whether this endpoint can truly reflect the significant effect of the drug on controlling myopia in children in real clinical practice, whether it can effectively alter the progression of myopia in children, thereby reducing various risks associated with myopia, such as the risk of severe complications like retinopathy and glaucoma caused by high myopia, are all critical issues that the FDA needs to consider deeply when evaluating the drug's efficacy. If the study endpoint is merely a numerical achievement without establishing a strong connection to actual clinical benefits, then such study results would obviously be difficult to convince the FDA.

02 Behind the Drug

After delving into the reasons behind the FDA's stance on SYD-101, it is necessary to first understand the drug itself. What are its characteristics and advantages, and what potential and prospects does it hold in the field of myopia treatment?

SYD-101 is a low-dose atropine eye drop developed by Sydnexis, Inc. Its active ingredient, atropine sulfate, is an antimuscarinic agent with a long history of application in ophthalmology. The uniqueness of SYD-101 lies in its concentration of 0.1mg/mL. This low concentration is designed to ensure efficacy while minimizing potential side effects associated with higher concentrations of atropine. Additionally, SYD-101 features "enhanced ocular drug delivery properties," meaning the medication can be absorbed more effectively by ocular tissues, thereby improving therapeutic outcomes. Most notably, it possesses "room temperature stability," resolving the issue faced by traditional atropine eye drops that require refrigeration. In real-life scenarios, the refrigeration requirement for conventional atropine eye drops creates significant inconvenience for users, especially children at school or during travel, where maintaining refrigerated conditions can be challenging. SYD-101, which can be stored at room temperature, greatly enhances the portability and usability of the medication. Whether for daily school attendance, outings, or long-distance travel, neither children nor their parents need to worry about storage conditions, undoubtedly increasing patient adherence to the treatment.

This drug primarily targets children with annual myopia progression ≥0.5D and a degree of myopia between -0.5D and -6.0D. The method of use is relatively simple: once daily, one drop in each eye before bedtime. Its mechanism of action mainly involves inhibiting axial elongation to slow down the progression of myopia. Axial elongation is a key factor in the development of myopia; as the eye axis continues to lengthen, light cannot focus accurately on the retina, leading to a constant increase in myopia. SYD-101 works by acting on relevant receptors in the eye to suppress excessive axial growth, thereby achieving the goal of controlling myopia progression.

Supporting the SYD-101 application is the Phase III STAR study. This large-scale and rigorously designed study was conducted in children aged 3 to 14. The results were remarkable, not only meeting the primary endpoint — the proportion of patients with confirmed myopia progression of -0.75D met expectations — but also achieving statistical significance in key secondary endpoints, such as annual progression rates at 12, 24, and 36 months. Compared to the placebo group, children using SYD-101 showed a clear advantage in controlling myopia progression, reducing annual myopia progression by 30% over two years. These data fully demonstrate the effectiveness of SYD-101 in controlling myopia progression in children and lay a solid foundation for its approval in Europe.

03 Insights from the Pediatric Myopia Track

FDA's Rejection of SYD-101 Approval Impacts the Booming Pediatric Myopia Drug Development Sector, Prompting Industry-wide Reevaluation of R&D Strategies and Directions. This Event Offers Significant Insights, Urging Us to Reflect on the Future Path of the Pediatric Myopia Field.

From a positive perspective, the FDA's decision sends a clear and strong signal: In the process of new drug development, merely proving that a drug is "effective" is far from enough. It is necessary to delve into "why it is effective" and convincingly demonstrate "the extent to which its effectiveness can change clinical practice." This will drive the entire industry to place greater emphasis on studying drug mechanisms of action in future research and development, no longer being satisfied with superficial efficacy data but instead exploring the principles of drug action at the molecular and cellular levels. This deeper understanding will provide a more solid theoretical foundation for drug efficacy.

In terms of future research and development directions, there are several key aspects worth focusing on. The first is the exploration of composite endpoints with stronger clinical persuasiveness. Traditional myopia drug development often focuses solely on a single indicator of myopia progression, such as changes in diopter. However, this single endpoint may not fully reflect the comprehensive impact of the drug on childhood myopia. In the future, it would be possible to link slowing myopia progression with reducing the risk of pathological changes associated with high myopia, such as incorporating the risks of severe complications like retinopathy and glaucoma into study endpoints. This approach would not only allow for a more comprehensive evaluation of the drug’s efficacy but also provide clinicians and patients with more valuable information, enabling them to clearly understand the actual benefits that drug treatment can offer.

Conducting longer-term and more real-world follow-up studies is also one of the important directions for the future. Myopia is a chronic condition, and its progression may last for several years or even decades. Current clinical trials are often short-term, making it difficult to comprehensively evaluate the long-term efficacy and safety of drugs. Therefore, longer-term follow-up studies are needed in the future to track changes in children's vision from the start of drug use into adulthood, as well as the long-term impact of the drugs on ocular structure and function. At the same time, studies should be as close as possible to real-world usage, taking into account various factors in children’s daily lives, such as academic pressure, outdoor activity time, and electronic device usage, which influence myopia progression, to more accurately assess the effectiveness of drugs in practical applications.

Optimizing formulation technology is also key to enhancing drug efficacy and patient compliance. Although SYD-101 has achieved certain breakthroughs in formulation technology, such as room temperature stability and enhanced ocular drug delivery properties, it still fails to meet FDA approval requirements. In the future, it will be necessary to further balance the relationship between efficacy, convenience, and side effects, and develop more advanced formulation technologies. For example, the drug's dosage form can be improved to make it more easily absorbed by the eye, reducing drug loss and waste; new drug carriers can also be explored to improve the drug’s stability and targeting while reducing side effects. Additionally, emerging technologies such as artificial intelligence and nanotechnology can be integrated to provide new ideas and methods for the development of myopia drugs.

Reviewing the Entire Journey of Myopia Drug Development for Children: From Initial Exploration of Atropine to the Emergence of Various New Drugs and Technologies Today

04 Conclusion

FDA's Rejection of SYD-101: A Setback or a Reflection of Scientific Rigor?The FDA's rejection of SYD-101 may appear to be a setback on the surface, but in reality, it reflects the rigor of scientific evaluation and regulatory scrutiny. In the field of children's health, the approval of any drug must be based on sufficient and reliable evidence. Although Sydnexis faces challenges, its commitment to cooperating with the FDA demonstrates corporate responsibility and offers hope for the future. As the global myopia problem becomes increasingly severe, drug therapies represented by low-dose atropine still hold broad prospects. We look forward to these innovative treatments, supported by more robust data, benefiting young patients in the near future.

Reference: Sydnexis Official Website

Editor: Liuli

Disclaimer: The views expressed in this article are solely those of the author and do not represent the position of PharmNet. We welcome exchanges and supplements in the comment section; if you need to reproduce the article, please be sure to indicate the author and source. If there are any issues involving the content, copyright, or other problems of the work, please leave a message on this platform, and we will handle it promptly.