Evaluation of Tonabersat for DME | NCT05727891

ID	Type	Description	Link
UG1EY014231	U.S. NIH Grant/Contract		View source

Status Module

Record Verification Date

Dec 2025

Overall Recruitment Status or Expanded Access Status

Active, not recruiting

Last Known Status

Not provided

Delayed Posting

Not provided

Why Stopped

Not provided

Expanded Access Info

Start Date

May 2, 2023Actual

Primary Completion Date

Jun 27, 2025Actual

Completion Date

Jan 2026Estimated

First Submitted Date

Feb 6, 2023

First Submission Date that Met QC Criteria

Feb 6, 2023

First Posted Date

Feb 14, 2023Actual

Results Waived

Not provided

Results First Submitted Date

Not provided

Results First Submitted that Met QC Criteria

Not provided

Results First Posted Date

Not provided

Certification/Extension (aka Delayed Results) First Submitted Date

Not provided

Certification/Extension First Submitted that Passed QC Review

Not provided

Certification/Extension First Posted Date

Not provided

Last Update Submitted Date

Dec 5, 2025

Last Update Posted Date

Dec 11, 2025Actual

Name	Class
National Institutes of Health (NIH)	NIH
National Eye Institute (NEI)	NIH
Juvenile Diabetes Research Foundation	OTHER

Description Module

Brief Summary

This randomized clinical trial will evaluate the effect of tonabersat compared with placebo on central subfield thickness (CST) in eyes with center-involved diabetic macular edema (CI-DME) and good visual acuity.

Detailed Description

The primary objective is to assess the effects of tonabersat, an orally administered Connexin43 hemichannel inhibitor, on central subfield thickness (mean change) compared with placebo in eyes with CI-DME and good visual acuity at 6 months.

Exploratory objectives will evaluate biomarkers of kidney function for potential benefit. Furthermore, this phase 2 study is being conducted to determine whether the conduct of a phase 3 trial has merit and provide information on outcome measures needed to design a phase 3 trial.

Design Module

Study Type

Interventional

Number of References to an Expanded Access Study

Not provided

Expanded Access Types

Not provided

Patient Registry

Not provided

Target Follow-Up Duration

Not provided

Phases

Phase 2

Interventional Study Design

Allocation

Biospecimen

No data available

No data is available for this block.

Enrollment

128Estimated

Arms/Interventions Module

Arm Groups

Label	Type	Description	Intervention Names
Placebo	Placebo Comparator		Other: Placebo
Tonabersat (80 mg)	Active Comparator		Drug: Tonabersat

Interventions

Name	Type	Description	Arm Group Labels	Other Names
Tonabersat	Drug	Two pills of Study Drug (80 mg tonabersat) is taken orally once daily. It is recommended the Study Drug be taken at bedtime. The first dose (two pills) will be taken at bedtime on the day the participant is randomized.

Outcomes Module

Primary Outcomes

Measure	Description	Time Frame
Mean change in central subfield thickness		6 months

Secondary Outcomes

Measure	Description	Time Frame
Mean change in retinal volume from baseline		6 months
Percentage of eyes central subfield thickness below optical coherence machine- and sex-specific threshold for DME and at least a 10% decrease from baseline	Composite outcome, gender-specific spectral domain optical coherence tomography equivalent of 250 µm on Zeiss Stratus optical coherence tomography

Other Outcomes

Not provided

Eligibility Module

Eligibility Criteria

Key Inclusion Criteria

Adults with type 1 or 2 diabetes mellitus
At least one eye with:
- Best corrected E-ETDRS visual acuity letter score ≥ 74 (i.e., 20/32 or better)
- Ophthalmoscopic evidence of center-involved DME in study eye confirmed by central subfield thickness on spectral domain OCT
- Zeiss Cirrus: ≥ 290 µm in females, ≥ 305 µm in males
- Heidelberg Spectralis: ≥ 305 µm in females, ≥ 320 µm in males
  - Recruitment will be monitored with a goal to have equal proportions in the following categories above the CI-DME thresholds: <75 μm, 75 μm to <175 μm, ≥175 μm
Media clarity, pupillary dilation, and study participant cooperation sufficient for adequate OCT

Key Exclusion Criteria

Macular edema is considered to be due to a cause other than DME
Major ocular surgery within prior 4 months, or anticipated after randomization
History of focal/grid laser or other ocular surgical, intravitreal, or peribulbar treatment for DR or DME within prior 1 year, and no more than 4 anti-VEGF injections within prior 3 years
Anticipated need to treat DME or DR during the first 6 months, or anticipated need for cataract surgery during study period
Any history of vitrectomy
Systemic anti-VEGF or pro-VEGF treatment within 12 months prior to randomization
History of chronic renal failure requiring dialysis or kidney transplant
History of moderate to severe hepatic impairment, including known liver function test (LFT) values > 3x's the upper limit of normal

Accepts Healthy Volunteers

Sex

All

Sex/Gender Based

Not provided

Sex/Gender Description

Not provided

Minimum Age

18 Years

Maximum Age

Not provided

Standard Ages

AdultOlder Adult

Study Population

Not provided

Sampling Method

Not provided

Facility	Status	City	State	ZIP	Country	Contacts
Retina Associates of Southern California		Huntington Beach	California	92647	United States
Loma Linda University