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Testing BI 764524 for treating diabetic retinopathy

CRIMSON: A Multicentre, Randomised, Sham-controlled (and Active Controlled in the USA), Double-masked, 72-week Trial to Study the Safety, Tolerability, Pharmacokinetics, and Efficacy of 3 Dosing Regimens of Intravitreal BI 764524 in Patients With Moderately Severe to Severe Non-proliferative Diabetic Retinopathy

Phase 2 Interventional Boehringer Ingelheim · NCT06321302

This study is testing a new eye treatment called BI 764524 to see if it can help adults with moderate to severe diabetic retinopathy improve their eye health.

Quick facts

PhasePhase 2
Study typeInterventional
Enrollment178 (estimated)
Ages18 Years and up
SexAll
SponsorBoehringer Ingelheim Industry-sponsored
Locations79 sites (Phoenix, Arizona and 78 other locations)
Trial IDNCT06321302 on ClinicalTrials.gov

What this trial studies

This clinical trial is designed for adults with moderate to severe non-proliferative diabetic retinopathy. Participants will be randomly assigned to one of five groups, where they will receive varying doses of BI 764524 or a sham control over the course of one year. Some participants in the U.S. will also receive aflibercept, a standard treatment for diabetic retinopathy, to compare its effectiveness. The study aims to evaluate the efficacy of BI 764524 in improving eye health in individuals with this condition.

Who should consider this trial

Good fit: Ideal candidates are adults aged 18 and older with moderate to severe non-proliferative diabetic retinopathy and specific visual acuity criteria.

Not a fit: Patients with mild diabetic retinopathy or those with uncontrolled diabetes may not benefit from this study.

Why it matters

Potential benefit: If successful, this treatment could significantly improve vision and quality of life for patients suffering from diabetic retinopathy.

How similar studies have performed: Previous studies have shown promise in treating diabetic retinopathy with similar approaches, but this specific treatment is being evaluated for the first time.

Eligibility criteria

Show full inclusion / exclusion criteria 
General inclusion criteria

* Diagnosis of DM under regular treatment with Haemoglobin A1c (HbA1c) (glycated haemoglobin) (HbA1c) \<12%
* Age ≥18 years at time of signing Informed Consent Form

Ocular inclusion criteria: study eye

* Moderately severe to severe non-proliferative diabetic retinopathy (NPDR) (Diabetic Retinopathy Severity Scale (DRSS) 47 to 53) based on early treatment diabetic retinopathy study (ETDRS) 7-field grading as confirmed by the central reading centre (CRC) at screening
* Presence of retinal non-perfusion (RNP) as assessed by ultra-widefield fluorescein angiography (UWF-FA) defined as an area ≥12.5 square millimeter (mm²) (approximately ≥5 disc areas) within a circular area with a 17.5 millimeter (mm) radius centred to the fovea as confirmed by the CRC at screening
* Visual acuity: best corrected visual acuity (BCVA) letter score of ≥49 letters (approximate Snellen equivalent of 20/100 or better) using ETDRS chart at starting distance of 4 meter (m) at screening
* Sufficiently clear ocular media, adequate pupillary dilation, and fixation to permit quality fundus imaging

Main exclusion criteria in study eye:

* Evidence of active retinal neovascularisation (NV) on clinical exam and/or ultra-widefield colour fundus photography (UWF-CFP) within the ETDRS 7-field, confirmed by the CRC grading

  -- Neovascularisations outside of the ETDRS 7-field on ultra-widefield imaging may be included if this condition, based on the assessment of the investigator, does not require acute treatment
* Evidence of active NV of the iris (small iris tufts are not an exclusion) or in the anterior chamber angle
* Prior pan-retinal photocoagulation (PRP) (defined as ≥100 burns placed previously outside of the posterior pole)
* CI-DME, defined as a central subfield thickness (CST) ≥320 micrometer (μm) (men)/305 μm (women), measured by Heidelberg Spectralis optical coherence tomography (OCT)), in the study eye as confirmed by the CRC at screening
* Previous treatment in the study eye for NPDR and/or diabetic macular edema (DME) with intravitreal (IVT) anti-vascular endothelial growth factor (VEGF) (including anti-VEGF/Ang2) drugs within 6 months prior to Day 1. The number of patients with history of an IVT anti-VEGF treatment is limited to approximately 50 randomised patients. Once this number has been achieved, any patients with previous IVT treatment will be excluded
* Any previous IVT treatment other than anti-VEGF, including steroids
* Refractive error of more than -8 dioptres of myopia (spherical equivalent) in the study eye. For patients having undergone refractive or cataract surgery in the study eye, the preoperative refractive error should be used.
* Any concurrent or past ocular condition in the study eye which, in the judgement of the investigator, could:

  * Require medical or surgical intervention during the study period to prevent or treat vision loss (e.g. advanced cataract, history of retinal detachment or macular hole (Stage 3 or 4) in the study eye)
  * Could likely contribute to a significant loss of BCVA during the study period if left untreated (e.g. advanced epiretinal membrane and/or vitreomacular traction, active or history of optic neuritis in either eye)
  * Contraindicate the use of the investigational drug, or may render the patient at high risk for treatment complications (e.g. active infectious or non-infectious conjunctivitis/keratitis in either eye; history of recurrent infectious or inflammatory ocular disease in either eye (e.g. uveitis)
  * May affect interpretation of the study results (e.g. central atrophy of the retinal pigment epithelium or photoreceptors; age-related macular degeneration, hereditary retinal degenerative diseases, myopic macular degeneration, past, current or planned use of medications known to be toxic to the retina, lens or optic nerve (e.g. deferoxamine, chloroquine/hydrochloroquine, chlorpromazine, phenothiazines, tamoxifen, nicotinic acid, and ethambutol); history of central serous chorioretinopathy, ischemic optic neuropathy or retinal vascular occlusion

Where this trial is running

Phoenix, Arizona and 78 other locations

+29 more sites — see ClinicalTrials.gov for the full list.

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
View on ClinicalTrials.gov → Find more trials like this →
Conditions Diabetic Retinopathy
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.