TRIAL FAIL

Oculis's OCS-01 eye drop misses primary endpoint in DME despite thickness benefit

Both Phase 3 DIAMOND trials failed on visual acuity at week 52, and Oculis said it will not pursue an FDA filing for OCS-01 in diabetic macular edema.

By AppliedXLMay 29, 2026Trial NCT06172257

Executive Summary

Oculis's Phase 3 DIAMOND-2 trial of its topical eye drop for diabetic macular edema missed its primary visual-acuity endpoint at one year, even as a secondary imaging measure of retinal swelling improved.
Oculis will not pursue an FDA filing for this drug in this indication, closing the regulatory path for a therapy that aimed to be the first topical option for a disease currently treated mostly by eye injections.
The result illustrates a split outcome: the drug moved a structural biomarker without producing the functional vision gain regulators require, and the sponsor's public framing leaned on the biomarker result after the functional endpoint failed.
The disclosure lands in a diabetic macular edema field still built around anti-VEGF injections, where no oral or topical small molecule has yet established a mechanism-driven vision benefit.

The result

Oculis reported on May 29, 2026 that the primary endpoint, mean change in best corrected visual acuity from baseline to week 52, was not met in either of its two Phase 3 DIAMOND trials of OCS-01, an ophthalmic small-molecule glucocorticoid receptor agonist. The key secondary endpoint, the proportion of patients gaining 15 or more letters of visual acuity, also was not met in both trials. The trial registered under NCT06172257 analyzed 401 patients against a target of 401, with no shortfall in enrollment. Oculis+1

Probability of Success

Endpoint Met99%

Completes98%

Clinical Significance47%

Regulatory97%

The secondary signal

Retinal thickness, measured by optical coherence tomography, showed a persistent reduction with OCS-01 versus vehicle at all visits in DIAMOND-2 and at all visits except week 52 in DIAMOND-1. Oculis Chief Executive Officer Riad Sherif said the company was "naturally disappointed that the sustained reduction in retinal thickness observed across both trials didn't translate into BCVA improvement at week 52". The structural improvement without a matching functional gain is the split result that defines this readout: the drug measurably reduced swelling but did not restore vision by the trial's own yardstick. Oculis

Safety and regulatory path

OCS-01 was well tolerated with no unexpected adverse events, and its safety profile was consistent with prior trials. Based on the results, Oculis said it does not plan to pursue an FDA regulatory filing for OCS-01 in diabetic macular edema at this time. The company said it will instead direct resources to its Privosegtor PIONEER program in optic neuropathies and its Licaminlimab PREDICT-1 trial in dry eye disease. Oculis

Design and stakes

The double-masked, randomized, two-arm DIAMOND-2 trial ran at sites in the United States, Argentina, India and Puerto Rico, enrolling patients with central subfield thickness of at least 310 micrometers by imaging at screening. Oculis had framed the drug as a potential first topical alternative to the anti-VEGF injections that dominate treatment for diabetic macular edema, a disease where an estimated 1 million of 1.8 million diagnosed U.S. patients remain untreated or undertreated, according to the company's April 2026 release. That unmet-need framing does not change the week 52 result; the trial's own primary measure did not move. NCT06172257+1

Competitive setting

The diabetic macular edema field is populated almost entirely by anti-VEGF biologics: Genentech's faricimab, Roche's ranibizumab, and Alvotech's aflibercept are among agents in active trials, all targeting VEGF-A or related pathways rather than the glucocorticoid receptor OCS-01 targets. Oculis's own earlier-stage dexamethasone program (NCT05066997) is the closest mechanism comparator on record, sharing the same small-molecule modality and glucocorticoid receptor target. No other industry trial in this indication shares OCS-01's target-and-mechanism combination, leaving the readout as the only completed test of this approach in the disease to date. NCT06172257

This analysis was produced using AI-assisted reporting systems, AppliedXL data, and official public records. These systems undergo editorial review, quality checks, and regular audits by human experts. Errors may still occur, as with any automated system. Always consult the linked primary sources. Read our AI Editorial Policy.