STSP-0902: A Comprehensive Analysis of a Novel Fc-Fusion rhNGF Therapy in Ophthalmology and Male Infertility

Executive Summary

STSP-0902 is a novel, investigational biologic drug developed by Staidson (Beijing) Biopharmaceuticals Co., Ltd. It is engineered as a recombinant human nerve growth factor (rhNGF) Fc fusion protein, a molecular architecture designed to confer significant pharmacokinetic and tolerability advantages over first-generation neurotrophic therapies. The drug is being advanced through a unique dual-indication development strategy, targeting two distinct therapeutic areas with high unmet medical needs: neurotrophic keratitis (NK) in ophthalmology and asthenozoospermia/oligoasthenozoospermia in male infertility.

The mechanism of action for STSP-0902 is centered on its function as a potent agonist of the Tropomyosin receptor kinase A (TrkA). By activating this pathway, STSP-0902 mimics the action of endogenous nerve growth factor (NGF), promoting neuronal survival, differentiation, and regeneration. In neurotrophic keratitis, a degenerative corneal disease caused by impaired nerve function, STSP-0902 aims to restore corneal innervation, promote the healing of epithelial defects, and maintain ocular surface integrity. For male infertility, preclinical evidence indicates that TrkA activation by STSP-0902 stimulates the proliferation of germline and testicular support cells, suggesting a potential to directly improve spermatogenesis, sperm count, and motility.

The key innovation of STSP-0902 lies in its Fc fusion design. This modification is intended to extend the drug's in-vivo half-life, a feature confirmed in preclinical studies. This enhanced pharmacokinetic profile forms the basis of a clinical strategy in NK to reduce dosing frequency compared to the approved therapy, Cenegermin, potentially offering a significant improvement in patient convenience and adherence. Furthermore, preclinical models have consistently demonstrated that STSP-0902 elicits a reduced pain response compared to wild-type rhNGF, suggesting a superior tolerability profile.

The clinical development program is robust and strategically designed. For neurotrophic keratitis, STSP-0902 is in Phase 2 development (NCT06975748), with a trial designed to explicitly test a reduced, three-times-daily dosing regimen against a six-times-daily regimen, directly challenging the standard set by the incumbent therapy. For male infertility, a Phase 1b trial (NCT06948799) is underway, evaluating a subcutaneous injection formulation in the target patient population. This high-risk, high-reward program positions STSP-0902 as a potential first-in-class pharmacological treatment in a field dominated by procedural interventions.

In conclusion, STSP-0902 represents a sophisticated second-generation NGF therapeutic. In NK, it is positioned as a formidable "bio-better" competitor with the potential to disrupt the market through improved convenience and tolerability. In male infertility, it is a pioneering, first-in-class candidate that could establish a new treatment paradigm. Staidson Biopharmaceuticals' strategy of leveraging a single, well-engineered molecule to address two disparate and underserved markets exemplifies an efficient and ambitious approach to modern biopharmaceutical development.

Introduction to STSP-0902: A Novel Recombinant Human Nerve Growth Factor Fc Fusion Protein

Developer Profile: Staidson (Beijing) Biopharmaceuticals Co., Ltd.

STSP-0902 is an investigational new drug that was discovered and is being developed by its originator organization, Staidson (Beijing) Biopharmaceuticals Co., Ltd..[1] Staidson, also known by its stock name Shu Taishen (SHE: 300204), is an innovative biopharmaceutical company based in Beijing, China.[3] Founded in August 2002 and listed on the Shenzhen Stock Exchange in 2011, the company has established a complete and integrated industry chain encompassing research and development, manufacturing, quality management, and marketing.[4] Staidson focuses on developing innovative drugs, particularly biopharmaceuticals with independent intellectual property rights, to address unmet clinical needs.[4] The company's official corporate website is

www.staidson.com.[6] Staidson has also demonstrated its capacity for international collaboration through co-development agreements, such as its partnership with InflaRx N.V. concerning the anti-C5a antibody BDB-001, underscoring its engagement in the global biopharmaceutical landscape.[5]

Drug Class and Molecular Architecture: An Engineered Bio-better Approach

STSP-0902 is classified as a new molecular entity and belongs to the class of recombinant fusion proteins.[2] Specifically, its molecular architecture is that of a recombinant human nerve growth factor (rhNGF) Fc fusion protein.[1] This structure involves the genetic fusion of the biologically active rhNGF protein to the Fc (Fragment, crystallizable) region of a human immunoglobulin G (IgG) antibody.

This design is a deliberate and sophisticated protein engineering strategy that positions STSP-0902 not as a simple biologic or biosimilar, but as a "bio-better" therapeutic. The primary purpose of creating an Fc fusion protein is to improve upon the pharmacological properties of the native protein. By incorporating the Fc domain, the molecule is designed to have a significantly extended in-vivo half-life, enhanced stability, and potentially altered interactions with the immune system.[3] This approach aims to translate into a clinical profile with improved dosing convenience and better tolerability compared to first-generation, non-fused recombinant proteins.

Overview of Dual-Indication Development Strategy

Staidson is pursuing a distinctive and ambitious dual-track clinical development strategy for STSP-0902, targeting two entirely different therapeutic areas: Eye Diseases and Urogenital Diseases.[1] This approach leverages the drug's fundamental mechanism of action across different physiological systems.

• Ophthalmology: The lead and most advanced indication for STSP-0902 is Neurotrophic Keratitis (NK), a rare degenerative disease of the cornea. The program for this indication has progressed to Phase 2 clinical trials in China, utilizing a topical ophthalmic solution formulation of the drug.[1]
• Male Infertility: The secondary focus is on urogenital diseases, specifically the male infertility conditions of Asthenozoospermia (poor sperm motility) and Oligoasthenozoospermia (low sperm count and poor motility). For these indications, STSP-0902 is being developed as a systemic therapy and is currently in Phase 1 clinical development in China.[1]

This dual-indication strategy is a testament to the company's confidence in the broad therapeutic potential of the STSP-0902 molecule. By identifying a second, mechanistically plausible application for its asset, Staidson effectively maximizes the potential return on its research and development investment. This diversifies the drug's portfolio, mitigating the risk associated with relying on the success of a single clinical program and opening a path to two separate markets with significant unmet needs.

Mechanism of Action and Pharmacological Rationale

The Role of the Nerve Growth Factor (NGF) and TrkA Receptor Pathway

The therapeutic activity of STSP-0902 is rooted in its function as an NGF modulator and a specific agonist of the Tropomyosin receptor kinase A (TrkA).[1] Nerve Growth Factor is a critical endogenous neurotrophin, a type of protein essential for the growth, maintenance, differentiation, and survival of neurons, particularly sensory neurons.[11] NGF exerts its biological effects by binding to two distinct types of cell surface receptors: the high-affinity TrkA receptor and the low-affinity p75 neurotrophin receptor (p75NTR).[11]

The binding of NGF to the TrkA receptor is the primary pathway for its neurotrophic effects. This interaction causes the receptor to dimerize and auto-phosphorylate, initiating a cascade of downstream intracellular signaling pathways. These include the mitogen-activated protein kinase (MAPK) and phosphoinositide 3-kinase (PI3K) pathways, which are fundamental for regulating gene expression related to cell survival, growth, and plasticity.[12] By acting as a potent TrkA receptor agonist, STSP-0902 is designed to functionally replace or supplement deficient endogenous NGF, thereby stimulating these pro-survival and regenerative cellular processes.

Scientific Rationale in Corneal Homeostasis and Neuro-Regeneration (Neurotrophic Keratitis)

Neurotrophic Keratitis (NK) is a degenerative corneal disease fundamentally caused by damage to the trigeminal nerve, which results in impaired sensory innervation to the cornea.[12] This loss of nerve function disrupts the delicate homeostasis of the ocular surface, leading to a cascade of pathological events: a partial or complete loss of corneal sensation, a reduction in the rate of epithelial cell turnover and repair, and diminished reflex tear production.[12] The cornea becomes vulnerable to breakdown, leading to persistent epithelial defects (PEDs), ulceration, and, in severe cases, perforation and vision loss.

The scientific rationale for using STSP-0902 in NK is to directly address this underlying neurotrophic deficit. By delivering a functional TrkA agonist topically to the ocular surface, STSP-0902 is intended to stimulate the TrkA receptors present on corneal epithelial and nerve cells.[11] This activation is hypothesized to support the survival of remaining corneal nerves, promote the regeneration and re-innervation of the cornea, and enhance the healing of epithelial defects, thereby restoring the structural and functional integrity of the ocular surface.[3]

Scientific Rationale in Spermatogenesis and Male Reproductive Health (Asthenozoospermia)

The application of STSP-0902 to male infertility is a novel therapeutic concept grounded in preclinical findings. The rationale extends the known neurotrophic effects of NGF to the reproductive system. Preclinical experimental data has shown that STSP-0902 can bind to and activate the TrkA receptor pathway within testicular tissue.[9] This activation was observed to have a direct biological effect, promoting the proliferation of key cell populations essential for sperm production. These include germline cells (spermatogonia, the precursors to sperm) and testicular support cells (Sertoli cells), which are crucial for nurturing developing sperm.[9]

By stimulating these cell types, STSP-0902 is hypothesized to enhance the overall process of spermatogenesis. The anticipated clinical outcome is an improvement in key semen parameters, such as an increase in sperm concentration (addressing oligospermia) and an enhancement of sperm motility and vitality (addressing asthenozoospermia). This represents a potential pharmacological approach to directly treat the root causes of certain forms of male infertility.

The Strategic Importance of the Fc Fusion Design: Enhancing Pharmacokinetics and Tolerability

The decision to engineer STSP-0902 as an Fc fusion protein is a central element of its strategic design, intended to confer multiple pharmacological advantages that could translate into a superior clinical profile.

• Pharmacokinetics (PK): A primary limitation of many therapeutic proteins is their short circulating half-life, requiring frequent administration. The fusion of the Fc domain is a well-established strategy to overcome this. The Fc region of the molecule interacts with the neonatal Fc receptor (FcRn), a cellular receptor that salvages antibodies and Fc-fusion proteins from lysosomal degradation and recycles them back into circulation. This mechanism significantly extends the in-vivo half-life of the therapeutic protein.[10] Preclinical studies with the injectable formulation of STSP-0902 have explicitly confirmed this intended effect, demonstrating a "prolonged half-life" compared to wild-type human NGF.[9] This enhanced PK profile is critical for enabling less frequent dosing schedules, a key potential advantage for both the ophthalmic and systemic formulations.
• Tolerability: A significant and potentially differentiating feature of STSP-0902 is its improved tolerability profile observed in preclinical studies. Administration of NGF is often associated with pain, both at the site of injection and in the eye. Remarkably, preclinical data for both the ophthalmic and injectable formulations of STSP-0902 have shown a "reduced pain response" when compared directly with recombinant wild-type hNGF.[3] The precise mechanism for this pain reduction is not fully elucidated but may relate to the specific site modifications made during the drug's design or the way the larger Fc-fusion molecule interacts with pain-mediating receptors or local tissues. This feature represents a major potential clinical benefit, improving patient comfort and compliance.

This multi-purpose advantage derived from a single molecular modification is the cornerstone of the drug's value proposition. It simultaneously enhances pharmacokinetics to improve dosing convenience, and improves tolerability to enhance the patient experience, creating a strong basis for its competitive strategy.

Preclinical Evidence and Proof-of-Concept

The progression of STSP-0902 into clinical trials is supported by a compelling body of preclinical data generated in relevant animal models for both of its target indications. These studies have not only validated the drug's mechanism of action but have also provided the first evidence of its differentiating "bio-better" characteristics. The key findings from these foundational, proof-of-concept studies are summarized below.

Table 1: Summary of Preclinical Findings for STSP-0902

Parameter	Neurotrophic Keratitis (Rat Model)	Asthenozoospermia (Mouse Model)	Source Snippets
Mechanism	Activates TrkA receptor pathway, promotes nerve growth	Binds and activates TrkA receptor pathway	3
Efficacy	Improves corneal integrity, increases corneal nerve length, increases corneal sensory sensitivity	Promotes neurogenesis, proliferation of germline & testicular support cells, increases sperm count & vitality, reduces sperm deformity rate, improves testicular tubule structure	3
Pharmacokinetics	N/A (local administration)	Prolonged in-vivo half-life compared to wild-type hNGF	9
Tolerability	Reduced pain response compared to wild-type hNGF	Reduced pain reaction after injection compared to wild-type hNGF	3

The preclinical evidence provides a robust, dual-pronged validation of the core hypothesis behind STSP-0902's design. The data from the rat model of neurotrophic keratitis is particularly important, as it demonstrates that the fusion of the rhNGF moiety to the Fc domain does not compromise its fundamental biological activity.[3] The molecule successfully activated the TrkA pathway and promoted nerve growth, leading to tangible improvements in corneal integrity and sensory function. This finding was a critical de-risking step, confirming that the engineered protein retained its intended therapeutic effect at the site of action.

Simultaneously, the data from the asthenozoospermia mouse model provided powerful proof-of-concept for both the novel indication and the engineered advantages of the molecule.[9] The study confirmed that systemic administration of STSP-0902 could produce a significant biological effect in the testes, improving multiple parameters of sperm health and testicular structure. Crucially, this study also provided the first in-vivo evidence that the Fc fusion successfully prolonged the drug's half-life, validating the primary pharmacokinetic goal of the molecular engineering.

Perhaps the most compelling and consistent finding across both preclinical programs was the observation of a reduced pain response. Both the ophthalmic formulation in the rat NK model and the injectable formulation in the mouse asthenozoospermia model were shown to cause less pain than their wild-type rhNGF counterparts.[3] This consistent finding elevates the potential of STSP-0902 beyond being a mere "bio-better" in terms of dosing convenience to one that may also offer a superior safety and patient experience profile. This improved tolerability is a cornerstone of its potential competitive advantage in the marketplace.

Clinical Development Program for Neurotrophic Keratitis

Therapeutic Landscape and Unmet Needs in Neurotrophic Keratitis

Neurotrophic Keratitis (NK) is a rare, degenerative disease of the cornea resulting from impaired trigeminal innervation. The condition is typically staged according to the Mackie classification, which categorizes the disease into three levels of increasing severity based on epithelial and stromal involvement.[14] Stage 1 is characterized by epithelial irregularities, Stage 2 by a persistent epithelial defect (PED), and Stage 3 by corneal ulceration, stromal melting, and potential perforation.[14]

The standard of care for NK follows a stepwise approach aimed at protecting the ocular surface and promoting healing. Initial management includes intensive lubrication with preservative-free artificial tears, therapeutic bandage contact lenses, and the use of autologous serum eye drops.[13] For more severe or refractory cases, surgical interventions such as tarsorrhaphy (partial or complete eyelid closure) or amniotic membrane transplantation may be required.[13]

The therapeutic landscape was transformed by the approval of Cenegermin-bkbj (Oxervate), the first and only targeted pharmacological therapy for NK.[11] As a recombinant form of human nerve growth factor, Cenegermin directly addresses the underlying neurotrophic deficiency. Clinical trials demonstrated its efficacy in achieving complete corneal healing.[11] However, the treatment regimen for Cenegermin is exceptionally demanding, requiring patients to administer one drop to the affected eye six times per day at two-hour intervals for a full eight weeks.[12] This high-frequency dosing schedule represents a significant treatment burden and a major unmet need in the management of NK, creating challenges for patient adherence, quality of life, and overall treatment success.

Phase 1 Safety and Pharmacokinetics in Healthy Volunteers (NCT06597422 Analysis)

To establish the safety and pharmacokinetic profile of the STSP-0902 ophthalmic solution, Staidson initiated a Phase 1 clinical trial (NCT06597422).[1] This study is a randomized, double-blind, placebo-controlled trial designed to enroll 80 healthy adult subjects.[17] Its primary objectives are to evaluate the safety, tolerability, and pharmacokinetic (PK) characteristics of STSP-0902 following both single and multiple administrations.[17]

The trial features a sophisticated, multi-stage design. The initial stages involve single ascending dose (SAD) and multiple ascending dose (MAD) evaluations to determine a safe dose range.[18] A notable feature of this study is the inclusion of a dedicated tear PK study stage. This part of the trial is designed to measure the concentration of STSP-0902 directly in the tear film—the site of therapeutic action—in addition to measuring systemic absorption in the plasma.[17] This provides crucial data on local drug exposure and residence time on the ocular surface.

The primary outcome measures for the trial are safety, assessed by the incidence and severity of adverse events, and pharmacokinetics, measured by the concentration of STSP-0902 in plasma and tears over time.[17] A key secondary outcome is immunogenicity, which will be evaluated by measuring the incidence of anti-drug antibodies (ADAs) against STSP-0902 in the plasma.[17] The study began in October 2024 and has an estimated completion date of May 2025.[17] As of the latest update, the trial is active but no longer recruiting participants.[1]

Phase 2 Efficacy and Safety Trial in Patients (NCT06975748 Deep-Dive Analysis)

Building on the Phase 1 data, Staidson has advanced STSP-0902 into a pivotal Phase 2 clinical trial (NCT06975748) to assess its efficacy and safety in the target patient population.[1] This is a multicenter, randomized, double-blind, placebo-controlled study that plans to enroll 48 patients with moderate to severe NK.[19] Eligible patients are adults between 18 and 80 years of age diagnosed with Mackie Stage 2 (PED) or Stage 3 (corneal ulcer) NK, with a corneal defect of at least 2 mm in diameter and demonstrably reduced or absent corneal sensitivity.[19]

The design of this trial is particularly strategic, as it is structured to directly investigate the potential for a more convenient dosing regimen. The study randomizes patients on a 1:1:1 basis into three main dosing groups, with each group having a 3:1 allocation of active drug to placebo.[19] The intervention arms are:

1. Low Dose STSP-0902, administered 3 times daily for 8 weeks.
2. Low Dose STSP-0902, administered 6 times daily for 8 weeks.
3. High Dose STSP-0902, administered 3 times daily for 8 weeks.
4. Placebo, administered either 3 or 6 times daily for 8 weeks to match the active arms.

This design is explicitly engineered to test whether a reduced, three-times-daily dosing frequency can achieve efficacy comparable to a six-times-daily regimen, which mirrors the approved dosing for Cenegermin. Success in a three-times-daily arm would provide strong clinical evidence for a significant competitive advantage based on improved patient convenience and adherence.

The trial's primary endpoint is safety, focusing on the incidence of ocular and systemic adverse events.[19] The secondary endpoints are robustly designed to capture efficacy from multiple angles. These include the percentage of subjects who achieve complete corneal healing (assessed by fluorescein staining), quantitative changes in corneal sensitivity, changes in Best Corrected Visual Acuity (BCVA), and patient-reported outcomes on visual function via the National Eye Institute Visual Function Questionnaire-25 (NEI-VFQ-25).[19] The trial is currently in the recruiting phase.[1]

Clinical Development Program for Male Infertility

Therapeutic Landscape and Unmet Needs in Asthenozoospermia and Oligoasthenozoospermia

Asthenozoospermia (characterized by reduced sperm motility) and oligoasthenozoospermia (a combination of low sperm count and reduced motility) are among the most common causes of male infertility.[20] Despite their prevalence, the therapeutic landscape for these conditions is notably devoid of effective, approved pharmacological agents that directly improve sperm parameters.

The current standard of care is largely procedural and diagnostic rather than therapeutic.[22] Management begins with a comprehensive evaluation to identify and treat any underlying reversible causes, such as hormonal imbalances or varicoceles (which may be corrected surgically).[20] Lifestyle modifications, including dietary changes, exercise, and cessation of smoking and excessive alcohol consumption, are also recommended.[20] However, for a majority of cases, which are idiopathic, the primary path to conception relies on the use of Assisted Reproductive Technologies (ART).[20] These techniques, such as Intrauterine Insemination (IUI) and In Vitro Fertilization with Intracytoplasmic Sperm Injection (IVF-ICSI), bypass the issue of poor sperm quality but are invasive, costly, and do not treat the underlying male factor infertility.[24] Consequently, there is a profound and long-standing unmet medical need for a pharmacological therapy that can directly enhance spermatogenesis and improve sperm quality, potentially enabling couples to conceive naturally or to improve their success rates with less invasive forms of ART.

Phase 1b Safety, PK, and Immunogenicity Trial (NCT06948799 Analysis)

To explore the potential of STSP-0902 in this area of high unmet need, Staidson has initiated a Phase 1b clinical trial (NCT06948799).[1] This is a randomized, double-blind, placebo-controlled, multiple ascending dose (MAD) study designed to evaluate a subcutaneous injection formulation of STSP-0902.[25] The primary objectives are to assess the safety, tolerability, pharmacokinetics, and immunogenicity of the drug when administered systemically.[25]

A critical and strategic feature of this trial is its participant population. Unlike typical Phase 1 studies conducted in healthy volunteers, this trial specifically enrolls male subjects with a confirmed diagnosis of oligoasthenozoospermia, defined by a sperm concentration of less than 15 million/mL and/or a progressive sperm motility of less than 32%.[25] This decision to conduct the study in the target patient population, even at this early stage, is highly significant. While the primary endpoints are safety and PK, this design allows for the collection of exploratory pharmacodynamic data through semen analysis.

The trial employs a sequential, dose-escalation design, with cohorts of participants randomized to receive either a low, middle, or high dose of STSP-0902 via subcutaneous injection, or a dose-matched placebo.[25] This approach will establish a safe and tolerable dose range for future efficacy studies.

The male infertility program for STSP-0902 represents a high-risk, but potentially transformative, "blue ocean" strategy. Success in this indication would not only be first-in-class but could fundamentally disrupt the multi-billion dollar ART market by offering a pharmacological alternative. The decision to study the drug in patients with the condition in Phase 1b is a calculated move. While the translational leap from preclinical mouse models to human efficacy is substantial and carries a high risk of failure, this trial design provides an opportunity to obtain early pharmacodynamic signals. Any positive trend observed in sperm count or motility, even as an exploratory measure, would serve as a major de-risking event for the entire program, generating significant validation and attracting substantial investor and partner interest. This justifies the high-risk approach by providing a clear, near-term path to a critical go/no-go decision point.

Strategic Analysis and Future Outlook

STSP-0902 is a strategically engineered molecule with a thoughtfully designed clinical program that positions it to compete in one therapeutic area and potentially create an entirely new market in another. Its value proposition is built upon a foundation of advanced protein engineering aimed at delivering clinically meaningful improvements over existing and potential therapies.

Table 2: Competitive Profile: STSP-0902 vs. Cenegermin (Oxervate) for Neurotrophic Keratitis

Feature	STSP-0902 (Investigational)	Cenegermin (Oxervate) (Approved)	Potential Advantage for STSP-0902
Molecular Structure	rhNGF Fc Fusion Protein	Recombinant Human NGF	Fc fusion designed for improved PK/stability.
Mechanism of Action	TrkA Receptor Agonist	TrkA Receptor Agonist	Identical primary mechanism.
Approved Dosing	TBD (Phase 2 testing 3x/day & 6x/day)	6 times per day for 8 weeks	Potential for ≥50% reduction in dosing frequency.
Tolerability (Pain)	Preclinically showed reduced pain response	Ocular pain is a known side effect	Potential for a superior side effect profile.
Development Stage	Phase 2 (for NK)	Approved (US FDA 2018)	N/A (Follower)

The competitive landscape in neurotrophic keratitis is defined by a single approved targeted therapy, Cenegermin. While effective, its demanding six-times-daily dosing regimen is a significant liability. The entire clinical and preclinical strategy for STSP-0902 appears designed to exploit this weakness. The Fc fusion architecture provides a strong mechanistic basis for a prolonged duration of action, and the Phase 2 trial is explicitly designed to validate a less frequent, three-times-daily dosing schedule. If this trial demonstrates that a 3x/day regimen is non-inferior or superior to a 6x/day regimen, STSP-0902 will have a powerful, clinically validated advantage in patient convenience and adherence. Combined with the preclinical signal of reduced pain, STSP-0902 is strongly positioned as a "bio-better" and a "fast-follower" with the potential to capture significant market share from the incumbent.

Development Trajectory, Potential Milestones, and Anticipated Challenges

The future development of STSP-0902 will proceed along two parallel paths, each with distinct milestones and challenges.

• Neurotrophic Keratitis Program: The most critical near-term milestone is the data readout from the Phase 2 trial (NCT06975748). A positive result, particularly one that supports the efficacy and safety of the three-times-daily dosing arm, would be a major value inflection point and would trigger the planning for a pivotal Phase 3 study. The primary challenge in this indication will be to demonstrate a sufficiently compelling clinical profile—combining efficacy, improved convenience, and better tolerability—to persuade clinicians and payers to adopt a new therapy over an established, albeit imperfect, one.
• Male Infertility Program: The immediate milestone for this program is the completion of the Phase 1b trial (NCT06948799) and the subsequent analysis of its safety, tolerability, and pharmacokinetic data. However, the most eagerly anticipated data will be the exploratory analysis of semen parameters. The fundamental challenge for this program is the high degree of translational risk; efficacy in a mouse model does not guarantee success in humans. A positive signal in sperm count or motility from the Phase 1b study would be a massive de-risking event and a powerful catalyst for advancing the program into Phase 2 efficacy trials. Conversely, a lack of such a signal would likely lead to a re-evaluation or discontinuation of this high-risk endeavor.

Market Potential and Concluding Expert Assessment

STSP-0902 is a well-conceived, second-generation NGF therapeutic backed by a clear and intelligent clinical development strategy. The molecule's design and the structure of its clinical trials reflect a deep understanding of the competitive landscapes in its target indications.

In the neurotrophic keratitis market, STSP-0902 is poised to be a strong competitor. Its potential for a significantly reduced dosing burden and an improved tolerability profile are clinically meaningful advantages that could drive rapid adoption if validated in late-stage trials. It has the potential to become the new standard of care based on a superior overall product profile.

In the male infertility market, STSP-0902 represents a high-risk, paradigm-shifting opportunity. The field has been without significant pharmacological innovation for decades. While the probability of success is inherently lower than in the NK program, a positive outcome would be transformative. A successful drug would create an entirely new market, offering hope to millions of couples and establishing STSP-0902 as a first-in-class, blockbuster asset.

Overall, Staidson's development of STSP-0902 is a noteworthy case study in strategic biopharmaceutical R&D. It demonstrates how advanced protein engineering can be leveraged to create a single molecule capable of competing effectively in an existing market while simultaneously pioneering a new one. The dual-indication approach balances the more predictable path of a "bio-better" with the high-reward potential of a first-in-class therapeutic, creating a diversified and compelling asset portfolio.

Appendix

Table 3: Comprehensive Overview of Active STSP-0902 Clinical Trials

NCT Identifier	Phase	Indication	Formulation	Population	Key Objectives	Status (as of research)
NCT06975748	Phase 2	Neurotrophic Keratitis	Ophthalmic Solution	48 NK Patients (Stage 2/3)	Evaluate efficacy (corneal healing) and safety of 3x/day vs. 6x/day dosing	Recruiting
NCT06597422	Phase 1	Safety/PK Study	Ophthalmic Solution	80 Healthy Volunteers	Evaluate safety, tolerability, and PK in plasma and tears	Active, not recruiting
NCT06948799	Phase 1b	Astheno/Oligoasthenozoospermia	Subcutaneous Injection	Males with low sperm count/motility	Evaluate safety, tolerability, PK, and immunogenicity of multiple ascending doses	Recruiting

Works cited

1. STSP-0902 - Drug Targets, Indications, Patents - Patsnap Synapse, accessed October 5, 2025, https://synapse.patsnap.com/drug/e6d4a1e6ea8d4fa0bcac8b8c4d3ed0f1
2. STSP 0902 - AdisInsight - Springer, accessed October 5, 2025, https://adisinsight.springer.com/drugs/800079503
3. Shu Taishen (300204.SZ): STSP-0902 eye drops (used to treat ..., accessed October 5, 2025, https://www.moomoo.com/news/post/36486400/shu-taishen-300204-sz-stsp-0902-eye-drops-used-to
4. Staidson Company Profile & Introduction - moomoo, accessed October 5, 2025, https://www.moomoo.com/stock/300204-SZ/company
5. InflaRx Announces Amendment of Co-Development Agreement and Additional Equity Investment by Staidson in Connection with Regulatory Filing in China for Anti-C5a-Antibody for Treatment of COVID-19, accessed October 5, 2025, https://www.inflarx.de/Home/Investors/Press-Releases/Press-Release~2022-12-InflaRx-Announces-Amendment-of-Co-Development-Agreement-and-Additional-Equity-Investment-by-Staidson-in-Connection-with-Regulatory-Filing-in-China-for-Anti-C5a-Antibody-for-Treatment-of-COVID-19~.html
6. Staidson(Beijing) BioPharmaceuticals Co., Ltd. | Pharmaceutical Manufacturer Profile & Drug Portfolio - Echemi, accessed October 5, 2025, https://www.echemi.com/drugs-manufacturer/ep2505167707.html
7. Staidson (Beijing) Biopharmaceuticals Co., Ltd. - Drug pipelines, Patents, Clinical trials - Patsnap Synapse, accessed October 5, 2025, https://synapse.patsnap.com/organization/834fab3812b42014b670ddc9294820e3
8. InflaRx N.V., accessed October 5, 2025, https://www.inflarx.de/docroot/ementals-secfilings/generated/0001140361-22-046454.pdf
9. Staidson (300204.SZ): STSP-0902 Injection Obtains Clinical Trial ..., accessed October 5, 2025, https://www.moomoo.com/news/post/39917918/staidson-300204-sz-stsp-0902-injection-obtains-clinical-trial-notification
10. Pipeline - Powerful Science – Meaningful Medicines – Changing Lives | 89bio, accessed October 5, 2025, https://89bio.com/pipeline/
11. for patients with neurotrophic keratitis 1,2 - Oxervate, accessed October 5, 2025, https://oxervate.com/hcp/
12. Cenegermin - StatPearls - NCBI Bookshelf, accessed October 5, 2025, https://www.ncbi.nlm.nih.gov/books/NBK573069/
13. Neurotrophic Keratitis - StatPearls - NCBI Bookshelf, accessed October 5, 2025, https://www.ncbi.nlm.nih.gov/books/NBK431106/
14. Diagnosing and Treating Neurotrophic Keratopathy - American Academy of Ophthalmology, accessed October 5, 2025, https://www.aao.org/eyenet/article/diagnosing-treating-neurotrophic-keratopathy
15. NK Presentation – How Neurotrophic Keratitis Presents - Know NK, accessed October 5, 2025, https://knownk.com/nk-progression/
16. Breaking down neurotrophic keratitis - EyeWorld, accessed October 5, 2025, https://www.eyeworld.org/2021/breaking-down-neurotrophic-keratitis/
17. Study Details | NCT06597422 | A Study of STSP-0902 Ophthalmic ..., accessed October 5, 2025, https://www.clinicaltrials.gov/study/NCT06597422?term=AREA%5BConditionSearch%5D(%22Keratitis%22)%20AND%20SEARCH%5BLocation%5D(AREA%5BLocationCountry%5DChina)&rank=3
18. A Study of STSP-0902 Ophthalmic Solution in Healthy Subjects - ClinicalTrials.Veeva, accessed October 5, 2025, https://ctv.veeva.com/study/a-study-of-stsp-0902-ophthalmic-solution-in-healthy-subjects
19. NCT06975748 | A Phase II Study of STSP-0902 Ophthalmic Solution in Patients With Neurotrophic Keratitis | ClinicalTrials.gov, accessed October 5, 2025, https://clinicaltrials.gov/study/NCT06975748
20. Asthenozoospermia Causes, Symptoms & Treatment | Indira IVF, accessed October 5, 2025, https://www.indiraivf.com/blog/asthenozoospermia-causes-symptoms-treatment
21. 11. male infertility - EAU Guidelines on Sexual and Reproductive Health - Uroweb, accessed October 5, 2025, https://uroweb.org/guidelines/sexual-and-reproductive-health/chapter/male-infertility
22. Diagnosis and Treatment of Infertility in Men: AUA/ASRM Guideline, accessed October 5, 2025, https://www.auanet.org/guidelines-and-quality/guidelines/male-infertility
23. Diagnosis and treatment of infertility in men: AUA/ASRM guideline part I, accessed October 5, 2025, https://www.asrm.org/practice-guidance/practice-committee-documents/diagnosis-and-treatment-of-infertility-in-men-auaasrm-guideline-part-i-2020/
24. Oligoasthenozoospermia: Causes, Symptoms & Treatments, accessed October 5, 2025, https://www.aksigenivf.com/oligoasthenozoospermia-treatment-meaning
25. A Study to Evaluate the Safety and Tolerability of Multiple Dose of STSP-0902 in Healthy Subjects - ClinicalTrials.Veeva, accessed October 5, 2025, https://ctv.veeva.com/study/a-study-to-evaluate-the-safety-and-tolerability-of-multiple-dose-of-stsp-0902-in-healthy-subjects