Oculis (OCS) Phase 3 OCS-01 Trials Fail to Meet Endpoints in DME, Stock Plunges

Oculis Holding AG (Nasdaq: OCS) on May 31, 2026, said its Phase 3 DIAMOND-1 and DIAMOND-2 trials of OCS-01 eye drops for diabetic macular edema (DME) missed their primary endpoint of improving best corrected visual acuity at 12 weeks versus placebo. The trials also failed on all key secondary endpoints. Shares of Oculis plummeted more than 70% in premarket trading following the announcement. The company stated it will cease further development of OCS-01 for DME. The drug continues to be studied in dry eye disease and other ophthalmic indications, with data expected next year.