Oral drug candidate APX3330 showed a “favorable safety and tolerability profile” in patients with diabetes and diabetic retinopathy, according to research presented in a poster at Academy 2022.

APX3330 is an oral, small-molecule drug that targets Ref-1, co-author Ronil Patel, MS, vice president of business development and market strategy at Ocuphire Pharma, told Healio.

Originally developed for hepatic inflammation by Eisai, then for cancer by Apexian, Ocuphire licensed APX3330 from Apexian primarily for diabetic retinopathy, he said.

The researchers reported safety and tolerability in the 24-week, randomized, placebo-controlled, double-masked, multicenter ZETA-1 phase 2b clinical trial. Participants in the treatment group received 600 mg daily of APX3330.

Ninety-one out of 103 patients completed the trial, Patel said.

Adverse events were reported in 46 participants across both study arms, according to the poster. Twenty-two were thought to be related to the treatment, 18 of which were mild and included pruritis, rash, headache, dyspnea, vitreous floaters, various gastrointestinal symptoms, vertigo, urticaria and fatigue.

“We do not know yet if the adverse events were due to APX3330 or placebo,” Patel said.

Seven severe adverse events were reported in six participants, but they were deemed unrelated to either APX3330 or placebo, according to the study. Researchers also said that no major organ toxicities or vital sign abnormalities were seen.

“APX3330 has a good safety profile,” Patel said. “We just have to wait and see what the efficacy is.”

The efficacy endpoint is a two-step improvement in diabetic retinopathy severity score, he said.

“We’ll share the results soon,” Patel added. “We want to intervene before a patient needs injections.”