Oculis Holding AG announced that patient enrollment is officially complete for both of its phase 3 DIAMOND trials evaluating OCS-01, its lead investigational candidateOCS-01, for the treatment of diabetic macular edema (DME).
First things first: OCS-01
OCS-01 is a novel, high-concentration (15 mg/ml) formulation of dexamethasone that utilizes Oculis’ OPTIREACH solubilizing nanoparticle technology.
Quick refresher: OPTIREACH is a proprietary platform designed to enable the formulation of drugs as non-invasive topical treatments (eye drops) by improving the solubility of lipophilic drugs (which is crucial for drug absorption, distribution, and overall effectiveness).
Watch this video for a rundown on how it works.
https://vimeo.com/937733775
And what’s the intended result of this technology for OCS-01?
The idea is for the eye drop-formulated drug to have increased solubility as well as an extended amount of residence time on the eye surface, leading to:
- Less frequent administration for the front-of-the-eye
- Drug passage from the eye surface to the posterior segment for retinal diseases
Now to OCS-01’s clinical indications.
To note: The formulation is currently under clinical investigation for two potential indications:
- DME (our topic of discussion)
- Post-op inflammation and pain following cataract surgery
- See here for phase 3 findings, reported in April 2024
And this DME program.
The phase 3 DIAbetic Macular edema patients ON a Drop (DIAMOND) trials include 800+ DME patients across 119 global clinical sites randomized 1:1 in the following setups:
- DIAMOND-1 (NCT05066997)
- n = 497 (estimated; aged 18-85)
- Stage 1: OCS-01 dosed with dexamethasone 6 times per day for 6 weeks followed by 3 times per day for 6 weeks
- Stage 2: OCS-01 dosed alone 6 times per day for 6 weeks followed by 3 times per day for 46 weeks
- Note: First patient was dosed in January 2024
- n = 497 (estimated; aged 18-85)
- DIAMOND-2 (NCT06172257)
- n = 350 (estimated; aged 18-85)
- OCS-01 dosed alone and with dexamethasone for the following setup:
- Dosed 6 times per day for 6 weeks followed by 3 times per day for 6 weeks
- OCS-01 dosed alone and with dexamethasone for the following setup:
- n = 350 (estimated; aged 18-85)
Both are designed as double-masked, randomized, multicenter studies evaluating the efficacy and safety of OCS-01 for DME patients.
And what’s being measured?
The primary endpoint for each trial is the change in best-corrected visual acuity Early Treatment Diabetic Retinopathy (BCVA ETDRS) letter score at Week 52.
Secondary endpoints extend to:
- Percentage of patients with ≥15-letter gain in BCVA
- Change in central subfield thickness
Got it. Any clinical data from these studies yet?
Yes! Oculis released positive topline data from stage 1 of the DIAMOND-1 trial in May 2023.
- To note: The first stage’s primary target included identifying an optimal dosing regimen of OCS-01 as well as that aforementioned primary efficacy endpoint.
The crux of the data: As we previously reported, OCS-01 met its primary endpoint, demonstrating a statistically significant improvement in BCVA ETDRS score (check out the numbers) and a strong visual gain in the treatment arm.
Give me a few more numbers.
The percentage of patients who achieved ≥15-letter improvement in BCVA from baseline at Week 6 extended to:
- 25.3% of OCS-01-treated patients
- 9.8% of vehicle-treated patients
And the percentage of patients that continued this improvement until Week 12 (p = 0.009):
- 27.4% OCS-01-treated patients
- 7.5% vehicle-treated patients
See more data highlights here.
Sounds promising … so what’s next for these trials?
Per Clinical Trials, both studies are slated to end in June 2026.
Oculis is planning for topline data readout in Q2 2026.
And the plan down the road?
The company intends to use the pivotal data from DIAMOND-1 and DIAMOND-2 to support an eventual new drug application (NDA) submission to the FDA and—ultimately—regulatory approval.
If successful in this: OCS-01 would become the “first topical eye drop for the treatment of DME and address unmet medical needs for early treatment intervention or for patients with inadequate response to anti-VEGF therapy,” Oculis stated.