How QA102's oral mechanism could reshape treatment for intermediate dry AMD

Age-related macular degeneration (AMD) remains one of the leading causes of irreversible vision loss worldwide, yet treatment options for earlier-stage disease, particularly intermediate dry AMD, have remained limited. Most approved therapies target late-stage disease or require repeated intravitreal injections, leaving a significant gap for the millions of patients who are losing vision before they ever qualify for treatment. The QA102-CS201 phase 2 study (NCT05536752) of QA102, an investigational oral therapy for intermediate dry AMD, is challenging that paradigm with a novel mechanism rooted in the connection between gut bacteria and retinal inflammation—targeting harmful gut bacteria and inhibiting complement-driven retinal inflammation to slow drusen progression and geographic atrophy (GA) growth from the inside out.

In this Q&A, Sunil S. Patel, MD, PhD, ophthalmologist at Abilene Surgery Center in Texas, speaks with Ophthalmology Times and dives deeper into the phase 2 data for QA102 presented at the Association for Research in Vision and Ophthalmology Annual Meeting in Denver, Colorado, from May 3 to 7, 2026. Patel explains the significance of a 59.2% numerical reduction in drusen volume and what that means in the context of a study not powered to detect it, why meeting the GA area growth rate end point—now a US Food and Drug Administration (FDA)–recognized benchmark since the approval of pegcetacoplan injection (Syfovre; Apellis Pharmaceuticals, Inc.)—is a meaningful signal for the field, and what a phase 3 program needs to address to bring this therapy to patients. The exchange offers clinicians an early but substantive look at a mechanism that could reframe how the field thinks about treating AMD before it reaches its most devastating stages.

This interview has been edited for length and clarity.

Ophthalmology Times: QA102 is described as "first-in-class" but does not disclose its mechanism. Can you discuss how QA102 is thought to act on drusen biology or the complement/lipid/oxidative stress pathways implicated in AMD progression—and why an oral approach might confer pharmacokinetic advantages over intravitreal delivery for earlier-stage disease?

Sunil S. Patel, MD, PhD: Recent data suggest that cell barriers become dysfunctional and weaken with age. This includes the intestinal lining of the gut and the blood-retinal barrier in the eye. This allows bacteria and other microbes to enter the bloodstream from the GI [gastrointestinal] tract and make their way into the eye. Researchers have identified bacteria in the retina in patients with age-related macular degeneration, and we know that microbes activate the complement system in the eye and can cause an inflammatory response, including drusen formation. Studies also show that dysbiosis [an imbalance in gut flora] may predispose patients to AMD.

Data suggest that the spread of pathogens [such as bacteria or viruses] from the GI tract to retinal tissue activates an inflammatory response, with activation of complement, amyloid-β, and other immune activation molecules. This immune response can damage the retinal cells, leading to retinal degeneration and AMD. This hypothesis was evaluated in mice with a CRB1 mutation, where mutations in the CRB1 gene do not only affect the retina; they also compromise the integrity of the intestinal epithelial barrier in the gut.¹ This failure allows intestinal bacteria to translocate out of the lower gastrointestinal tract and travel to the retina, where they trigger secondary retinal degeneration and cause drusen-like lesions in mice.

Under this theory, pathogens move from the gut to the retina and may contribute to AMD. Reducing pathogen exposure to the gut could limit their spread to the retina and slow retinal degeneration and AMD progression. QA102 was developed to work through 2 mechanisms: as an antimicrobial that targets harmful gut bacteria and as an anti-inflammatory agent that inhibits complement activation and other inflammatory responses in the retina.

In the phase 1 clinical study, we demonstrated that the systemic exposure of QA102 is low, indicating that QA102 acts locally in the gut. Therefore, QA102 provides an oral approach to treat AMD without the potential systemic risk of drug-drug interaction.

Ophthalmology Times: The 59.2% reduction in drusen volume did not reach statistical significance on the primary end point, yet the drusen growth rate and GA area growth rate secondaries did. From a trial design standpoint, was the study adequately powered for these end points, and how should clinicians interpret positive signals on secondary measures when the primary fails?

Patel: Drusen volume was not an FDA-approved end point when this phase 2 study began in 2022, and it was not yet clear which clinical end point would be most sensitive to treatment or how the FDA would view it. We therefore selected drusen volume as the primary end point and included several key secondary end points. Although the primary end point did not reach statistical significance, QA102 showed a strong dose-dependent numerical trend toward reducing drusen volume, with a P value of .089.

GA area growth rate became an FDA-approved end point when Syfovre was approved in 2023. In our phase 2 study, we met this clinical end point with statistical significance. In addition, the study is not adequately powered. In the phase 3 study, we believe both end points can reach statistical significance.

Ophthalmology Times: For an oral chronic therapy in an older population likely on polypharmacy, what specific systemic safety signals and drug-drug interactions should be prioritized in a phase 3 program, and what would an adequate safety disclosure look like at this stage of development?

Patel: Since the drug has an antimicrobial effect and works in the gut as well as the eye, the most frequent adverse effects we saw were gastrointestinal, mostly mild or moderate diarrhea [14.7% overall occurrence]. These resolved off the medication and were not dose dependent, but rather may be due to hypersensitivity. Patients should be told about these potential adverse effects, and we may want to consider excluding patients with a history of recurrent diarrhea or specific GI illnesses in the next trial.

Reference

1. Peng S, Li JJ, Song W, et al. CRB1-associated retinal degeneration is dependent on bacterial translocation from the gut. Cell. 2024;187(6):1387-1401.e13. doi:10.1016/j.cell.2024.01.040