Maintaining vision for patients with neovascular (wet) age-related macular degeneration (AMD) often requires a grueling schedule of frequent intravitreal injections. Ocular Therapeutix is attempting to change this paradigm with AXPAXLI, an investigational axitinib hydrogel designed for long-term durability. On April 29, 2026, the company announced it has enrolled the first participant in the SOL-X long-term extension trial, a critical step in evaluating the drug’s safety and efficacy over several years.
- New Milestone: The SOL-X trial has officially begun with its first patient enrollment in April 2026.
- Trial Duration: SOL-X is a 36-month open-label extension study.
- Patient Eligibility: Enrollment is open to participants who completed the two-year follow-up in the SOL-1 or SOL-R trials.
- Treatment Goal: The study focuses on long-term safety and the potential for a disease-modifying impact in wet AMD.
Understanding the SOL-X Extension Trial
The SOL-X trial isn’t a standalone study but an extension of the company’s broader registrational program. It is designed to follow participants from the pivotal Phase 3 studies—SOL-1 and SOL-R—for an additional three years. By extending the observation period, researchers can determine if AXPAXLI maintains its effectiveness over time and how the retina responds to repeated dosing over a multi-year horizon.
Dosing and Monitoring Protocol
Participants in the SOL-X study will receive intravitreal AXPAXLI every 24 weeks at prespecified visits. To ensure patient safety and treatment efficacy, the protocol includes:
- Interim Assessments: Clinical evaluations every 12 weeks to monitor the state of the retina.
- Supplemental Therapy: Investigator-directed anti-VEGF therapy can be administered as needed if the patient’s condition requires immediate intervention.
The Science Behind AXPAXLI (OTX-TKI)
To understand why the SOL-X trial is significant, it’s important to understand what AXPAXLI is. Most current wet AMD treatments use anti-VEGF (vascular endothelial growth factor) agents to stop leaky blood vessels in the retina. However, these often require monthly or bimonthly injections, which creates a significant burden for patients and clinicians.
AXPAXLI uses a different approach. It is a tyrosine kinase inhibitor (TKI) delivered via a hydrogel. This hydrogel acts as a reservoir, slowly releasing the medication into the eye over a prolonged period. This mechanism aims to provide unmatched durability
, potentially reducing the number of injections a patient needs per year without sacrificing vision stability.
Context: The Path to FDA Approval
The SOL-X trial is the latest piece of a larger regulatory puzzle. Ocular Therapeutix has been aggressively pursuing FDA approval through two primary registrational trials:
SOL-1 (Superiority Trial)
The SOL-1 trial was designed to display that AXPAXLI is superior to existing treatments. In February 2026, reports indicated that the drug was more effective in helping patients maintain vision compared to the approved treatment Eylea. Post-hoc analyses presented in April 2026 reinforced the drug’s durability, showing robust control of central subfield thickness (CSFT).
SOL-R (Non-Inferiority Trial)
The SOL-R trial, which completed the randomization of 631 subjects in December 2025, is designed to demonstrate that AXPAXLI is at least as effective as current standards of care. Topline results for SOL-R are anticipated in the first quarter of 2027.
Comparing AXPAXLI to Current Standards
| Feature | Standard Anti-VEGF | AXPAXLI (Investigational) |
|---|---|---|
| Mechanism | Blocks VEGF protein | TKI via hydrogel reservoir |
| Injection Frequency | Often every 4–8 weeks | Targeting much longer intervals |
| Primary Goal | Fluid reduction/Vision stability | Durability and reduced burden |
Frequently Asked Questions
What is wet AMD?
Wet age-related macular degeneration occurs when abnormal blood vessels grow under the retina, leaking fluid and blood that cause rapid vision loss in the center of the eye.
Who can participate in the SOL-X trial?
Only patients who have already participated in and completed the two-year follow-up phase of the SOL-1 or SOL-R trials are eligible for the SOL-X extension.
Is AXPAXLI available for prescription now?
No. AXPAXLI is currently an investigational drug. Ocular Therapeutix plans to submit a New Drug Application (NDA) to the FDA pending the final results of its registrational trials.
Looking Ahead
The enrollment of the first patient in SOL-X marks a transition from proving that AXPAXLI works to proving that it works safely over the long term. If the 36-month data mirrors the positive results seen in the SOL-1 superiority trial, AXPAXLI could significantly reduce the treatment burden for millions of people living with wet AMD, moving the industry closer to a “treat-and-wait” model rather than a “constant-injection” cycle.