Oculis drops plans for diabetic macular edema drug after Phase III miss

The Zug-based company said the DIAMOND-1 and DIAMOND-2 trials did not show a statistically meaningful improvement in best corrected visual acuity after 52 weeks of treatment compared with vehicle. The result is particularly damaging because visual acuity was the primary endpoint of the programme and the basis for a potential regulatory filing.

OCS-01, a high-concentration dexamethasone eye drop formulation, had been developed as a non-invasive alternative in a field still largely dominated by intravitreal injections. Diabetic macular edema is a complication of diabetic retinopathy in which fluid accumulates in the macula, causing swelling and vision loss. Current treatment is typically based on anti-VEGF therapies or corticosteroids administered by injection into the eye, creating a clear rationale for a topical product if it could deliver clinically meaningful improvements in vision.

That promise was not confirmed in the pivotal trials. Oculis said OCS-01 produced a “substantial and persistent” reduction in retinal thickness, a sign that the drug had a biological effect on macular swelling. However, this did not translate into the required improvement in vision. The key secondary endpoint, the proportion of patients gaining at least 15 letters in best corrected visual acuity, was also not met in either study.

The company said OCS-01 was well tolerated and no unexpected adverse events were observed. But the safety profile was not enough to rescue the programme. Oculis said it does not currently plan to submit OCS-01 for FDA approval in diabetic macular edema.

Priority reset

The decision reshapes the company’s development priorities. Oculis said it will focus its financial and operational resources on its late-stage pipeline, including Privosegtor in optic neuropathies and Licaminlimab in dry eye disease. Privosegtor is being studied in the PIONEER registrational programme for optic neuritis and non-arteritic anterior ischemic optic neuropathy, while Licaminlimab is in the PREDICT-1 registrational trial using a genotype-based approach in dry eye disease.

Investors reacted sharply to the news. Oculis shares closed at $29.65 on Nasdaq on 28 May, before the announcement. They fell to about $22.71 at the next close and were trading around $15.66 intraday on 1 June, implying a fall of roughly 47% from the pre-announcement level. The reaction suggests that investors had assigned significant value to the DME opportunity and now see the company’s near-term story shifting away from OCS-01.

Oculis said it remains well financed despite the setback. The company reported $278m in cash, cash equivalents and short-term investments as of 31 March 2026, which it said should fund operations into the second half of 2029. That runway gives Oculis time to advance its remaining late-stage assets, but the failure of DIAMOND removes what could have been a differentiated topical entry into a large retinal disease market.