Aldeyra Therapeutics has started enrolling patients in the Phase III GUARD clinical trial of ADX-2191 to prevent proliferative vitreoretinopathy (PVR), a rare retinal disease.

PVR develops as an inflammatory fibroproliferative condition that causes severe retinal scarring and blindness. An estimated 40% to 50% of PVR patients experience severe uncorrectable vision loss and 76% have at least moderate vision loss that cannot be corrected.

The disorder, which lacks approved treatments, is known to complicate up to 10% of retinal detachment surgeries and about 50% of open-globe injury surgeries.

ADX-2191 is being developed to treat the disorder by inhibiting cell growth and reducing scar formation. It holds US Food and Drug Administration (FDA) fast track and orphan drug designations to prevent PVR.

Aldeyra Therapeutics president and CEO Todd Brady said: “Initiation of patient enrolment in the GUARD trial marks an important step toward our goal of improving clinical outcomes for the thousands of patients with this rare but devastating condition.

“Today, the only option for patients who develop PVR is surgery, which fails in a significant number of cases. ADX-2191 is a new therapeutic approach with the potential to prevent vision loss from recurrent retinal detachments.”

The two-part, multi-centre, randomised, controlled, adaptive GUARD study compared the efficacy of intravitreal ADX-2191 injections to standard-of-care in preventing PVR.

The primary outcome measure is the recurrent retinal detachment rate over 24 weeks after retinal detachment surgery associated with PVR or open-globe injury.

The Phase III trial will also measure the best-corrected visual acuity (BCVA) change from baseline as the secondary outcome. It is expected to be completed in December 2022.

In March this year, Aldeyra announced positive results from the Phase III ALLEVIATE study of reproxalap in allergic conjunctivitis patients.