Kodiak Sciences Inc. announced the completion of enrollment in its GLOW2 Phase 3 clinical trial evaluating tarcocimab tedromer for the treatment of diabetic retinopathy (DR). The company has exceeded its enrollment target, randomizing more than 250 patients into the study.
"With its 48-week duration of treatment, all patients are expected to complete their primary endpoint visits by the end of January 2026, and we expect to announce topline clinical data in 1Q 2026," said Victor Perlroth, M.D., Chief Executive Officer of Kodiak Sciences.
Trial Design and Significance
The GLOW2 Phase 3 study is designed as a confirmatory registrational trial following the successful GLOW1 study, which met its primary endpoint and all key secondary endpoints with high statistical significance. The new trial mirrors GLOW1's design with one notable enhancement: an additional loading dose to provide greater dosing flexibility for healthcare providers.
In the double-masked, randomized study, patients receive either sham injections or tarcocimab via intravitreal injection at baseline, Week 4, Week 8, Week 20, and Week 44. The primary endpoint measures the proportion of eyes improving by at least 2 steps on the Diabetic Retinopathy Severity Scale (DRSS) from baseline at Week 48.
Dr. Allen Hu, principal investigator at Cumberland Valley Retina Consultants and top enroller in the GLOW2 study, highlighted the potential impact of tarcocimab: "Fewer than 1% of subjects with diabetic retinopathy are treated today due to high treatment burden associated with frequent injections needed with today's approved therapies. If diabetic retinopathy is left untreated, the majority of patients—and this is millions of patients—will experience disease progression and develop vision-threatening complications."
Addressing Unmet Needs in Diabetic Retinopathy
Diabetic retinopathy affects approximately 10 million of the 36 million American adults living with diabetes. Despite this high prevalence, current treatment options require frequent injections, resulting in extremely low treatment rates among eligible patients.
The GLOW1 study demonstrated tarcocimab's potential to transform this treatment landscape. At one year, 41.1% of evaluable patients on tarcocimab showed at least a 2-step improvement on the DRSS versus just 1.4% in the sham group (p<0.0001). The drug also demonstrated an 89% reduction in the development of sight-threatening complications and a 95% risk reduction in the development of diabetic macular edema.
"With only 4 doses in Year 1 and every 6-month dosing in every patient, the GLOW1 data showed us as a community that tarcocimab can potentially achieve strong efficacy both in treating existing disease and preventing disease progression in diabetic retinopathy," Dr. Hu noted. "If GLOW2 mirrors these results, I believe tarcocimab as a biologic with twice yearly dosing in all patients can change the treatment landscape in diabetic retinopathy and help millions of patients."
Broader Development Program
Tarcocimab is being developed as a "mainstay" intravitreal biologic monotherapy with flexible dosing intervals ranging from 1 to 6 months. The drug is built on Kodiak's proprietary Antibody Biopolymer Conjugate (ABC) Platform.
Beyond GLOW2, Kodiak is also conducting the DAYBREAK Phase 3 study of tarcocimab in wet age-related macular degeneration (wet AMD). The company plans to wait for DAYBREAK topline data, expected in Q2 2026, before filing a single Biologics License Application (BLA) for tarcocimab covering wet AMD, DR, and Retinal Vein Occlusion (RVO).
"GLOW2 is our second registrational study in diabetic retinopathy and if there is a successful outcome, we anticipate having a regulatory package for tarcocimab that is ready to file," said Dr. Perlroth. "We remain focused on completing enrollment in our ongoing DAYBREAK Phase 3 study to broaden the efficacy profile for tarcocimab in wet age-related macular degeneration."
Enhanced Formulation
Both the GLOW2 and DAYBREAK studies utilize tarcocimab's enhanced 50 mg/mL formulation containing both conjugated and unconjugated antibody, designed to balance immediacy and durability of effect. This formulation represents an advancement in Kodiak's ABC Platform technology.
The DAYBREAK study incorporates learnings from prior pivotal trials and features individualized dosing every 4 to 24 weeks on an as-needed basis following four monthly loading doses. This approach uses a treat-to-dryness strategy that more closely resembles retina specialists' practice patterns.
For diabetic retinopathy patients, the potential for a twice-yearly dosing regimen could dramatically improve treatment adherence and outcomes, addressing a significant unmet need in ophthalmology and potentially benefiting millions of patients at risk of vision loss.
