A Study to Test Whether BI 1815368 Helps People With an Eye Condition Called Diabetic Macular Edema

A Randomised, Double-masked, Placebo-controlled Trial to Evaluate the Efficacy, Safety, and Tolerability of Oral BI 1815368 in Participants With Centre-involved Diabetic Macular Edema for 48 Weeks of Treatment (THULITE)

This study is open to adults 18 and older with an eye condition called diabetic macular edema. People are required to have a specific type of diabetic macular edema called centre-involved diabetic macular edema (CI-DME) to take part. The purpose of this study is to find out whether a medicine called BI 1815368 improves sight in people with CI-DME and to find the most suitable dose.

This study has 2 parts. In the first part, participants are put into 2 groups of equal size randomly, which means by chance. One group takes BI 1815368 tablets and the other group takes placebo tablets. Placebo tablets look like BI 1815368 tablets but do not contain any medicine. In the second part, participants are put into 4 groups of equal size randomly. 3 groups take different daily doses of the study medicine, BI 1815368, while 1 group takes placebo. All participants take tablets twice a day for about 11 months.

Participants are in the study for about 1 year. During this time, they visit the study site 16 times. At visits, doctors check the participant's vision and collect information on any health problems. They take detailed pictures of the eye. The changes over time are compared between the groups to see if the treatment works.

Inclusion criteria:

• ≥18 years of age
• Diagnosis of diabetes mellitus (DM) (type 1 or type 2), Haemoglobin A1C (HbA1c) <12% treated with stable medication for at least 30 days prior to Day 1; no already-set plans for major changes in DM medication (e.g. start of new medication) at the time of screening and baseline
• Centre-involved diabetic macular edema (CI-DME) confirmed on spectral domain optical coherence tomography (SD-OCT) with central subfield foveal thickness (CST) ≥320 µm in the study eye at screening
• Best corrected visual acuity (BCVA) visual acuity Early Treatment Diabetic Retinopathy Study (ETDRS) letter score in the study eye between 24 and 78 (Snellen equivalent range 20/320 to 20/32) at screening Further inclusion criteria apply.

Exclusion criteria:

• Macular edema considered to be due to other causes than CI-DME in the study eye
• Proliferative diabetic retinopathy or iris neovascularisation (including the anterior chamber angle) in the study eye
• Any intravitreal (IVT) anti-vascular endothelial growth factor (VEGF) treatment within 4 months before Day 1 (other than faricimab or aflibercept 8mg), and within 6 months before Day 1 for faricimab or aflibercept 8 mg, and/or more than 4 prior IVT injections with anti-VEGF treatment in total in the study eye
• Any history of panretinal photocoagulation, macular laser photocoagulation, vitreoretinal surgery, IVT or periocular corticosteroid treatment (within 12 months before Day 1), history of fluocinolone ophthalmic implant or dexamethasone IVT implant before Day 1, or topical steroid or NSAID treatment (within 30 days before Day 1)
• Active ocular inflammation of any history of intraocular inflammation within 1 year
• Aphakia or total absence of the posterior capsule; Yttrium aluminium garnet (YAG) laser capsulotomy in the study eye is permitted if more than 2 months prior to Day 1 Further exclusion criteria apply.