Oculis Holding AG Announces Completion of Last Patient Visit in Phase 3 Diamond Program with OCS-01 Eye Drops for Treatment of Diabetic Macular Edema

Published: 2026-04-20 11:52:52 ET OCS

Published on 04/20/2026 at 11:52 am EDT

Oculis Holding AG announced completion of the final patient visit in the OCS-01 Phase 3 DIAMOND program in diabetic macular edema (DME). Last patient visits for both OCS-01 Phase 3 DIAMOND trials (total 800+ patients) are complete, with topline results expected in June 2026. A non-invasive topical treatment for diabetic macular edema (DME) has the potential to address significant unmet needs for early treatment intervention and for inadequate responders to the current standard of care.

OCS-01 aims to transform the treatment paradigm as the first topical treatment for DME, a leading cause of vision loss in the working-age population in most developed countries. The last patient in the DIAMOND (DIAbetic Macular edema patients ON a Drop) program, consisting of two Phase 3, double-masked, randomized, multi-center trials to evaluate the efficacy and safety of OCS-01 eye drops in patients with DME following 52 weeks of treatment, completed the final study visit in April 2026. Both registrational 52-week trials were initiated upon the positive findings from Stage 1 of the DIAMOND program, in which patients treated with OCS-01 experienced significant improvements in visual acuity and a rapid reduction of edema.

Oculis expects to report topline data from both pivotal trials in June, followed by a potential NDA submission in Fourth Quarter 2026. Despite available invasive therapies, an estimated 1 million patients out of the 1,800,000 people diagnosed with DME in the U.S. remain untreated or underserved. Significant unmet medical needs remain for early treatment intervention and inadequate responders to the standard of care.

An analysis of real-world evidence from the IRIS Registry showed that approximately 60% of newly diagnosed DME patients remained untreated one year after diagnosis. Furthermore, according to the DRCR Retina Network Protocol I, an estimated 40% of treated DME patients have an inadequate response to the current standard of care. This suboptimal response reflects DME?s multifactorial pathophysiology, which also involves inflammatory pathways, underscoring the need for alternative therapeutic approaches.

OCS-01 is intended to be strategically positioned to capture this significant opportunity by providing a non-invasive, topical eye drop for those requiring early intervention and a versatile option for patients who do not respond to existing injections, thereby potentially expanding the current market estimated at $3 billion in the U.S. alone. Leveraging Oculis? proprietary technology, OCS-01 is an OPTIREACH formulation of high concentration dexamethasone eye drop.

It is being developed as an eye drop to treat the retina to offer a non-invasive treatment alternative for diabetic macular edema (DME). This route of administration enables easy access to treatment in the early stages of the disease and can be used in combination with other therapies in later stages. In contrast, all currently available treatments require invasive delivery methods, such as intravitreal injections or ocular implants, to reach the retina.

The OPTIREACH solubilizing formulation technology addresses the main limitations of conventional eye drops by improving the solubility of lipophilic drugs, increasing the residence time on the eye surface and thereby, enabling the drug passage from the eye surface to the posterior segment of the eye. Oculis? OCS-01 is being developed with the aim to transform the current treatment paradigm in DME as a non-invasive topical treatment option.

OCS-01 is an investigational drug in Phase 3 development that has not received regulatory approval for commercial use in any country. DME is the leading cause of visual loss and legal blindness in patients with diabetes. Currently, it is estimated to affect around 37 million people worldwide and, with the rise of diabetes, the prevalence is expected to increase to 53 million by 2040.

DME is an irreversible and progressive complication of diabetic retinopathy and is related to consistently having high blood sugar levels that damage nerves and blood vessels in the macula, the area of the retina responsible for sharp vision. DME occurs when blood vessels in the retina swell, and then leak, leading to a fluid build-up (edema) into the retina. There remains a significant need for safe, efficacious, and less burdensome treatments for DME patients.

The DIAMOND-1 (DIAbetic Macular edema patients ON a Drop) and DIAMOND-2 trials are Phase 3, double-masked, randomized, multi-center trials which are evaluating the efficacy and safety of OCS-01 eye drops in patients with DME. Oculis enrolled over 800 patients across both pivotal trials who were randomized 1:1 to receive OCS-01 or vehicle six times daily for the 6-week induction phase and then three times daily through week 52 for the maintenance phase. The primary endpoint is change in best corrected visual acuity early treatment diabetic retinopathy study (BCVA ETDRS) letter score at Week 52 compared with baseline.

Secondary endpoints include percentage of patients with =15-letter gain in BCVA and change in central subfield thickness (CST), both at Week 52 compared with baseline. Both trials were initiated upon the positive findings from Stage 1 of the DIAMOND program, which was announced in the Second Quarter of 2023.