Key Takeaways
- Boehringer Ingelheim advances oral diabetic macular edema (DME) therapy into Phase II: The THULITE trial will evaluate BI 1815368 as a potential first-in-class oral treatment for DME.
- Oral therapy aims to reduce treatment burden: BI 1815368 could offer an alternative to intravitreal injections, enabling at-home care and simultaneous treatment of both eyes.
- Building on Phase I safety data: Previous trials in healthy volunteers supported the progression of BI 1815368 into Phase II for patients with center-involved DME.
Boehringer Ingelheim announced that it has launched the Phase II THULITE trial (NCT06962839) to evaluate BI 1815368, a potential first-in-class oral treatment for diabetic macular edema (DME). The investigational compound is the fourth candidate from Boehringer Ingelheim’s eye health pipeline to advance to Phase II.1
Could an Oral Therapy Transform Treatment for Diabetic Macular Edema?
“DME is one of the most challenging complications of diabetes, and as vision worsens, people may lose their independence and rely more on loved ones,” said Dario Madani, CEO, PRO RETINA, in a press release. “Patients and caregivers may have to balance work, family obligations and other diabetes complications, while managing their eye condition. We need treatment options that could reduce this burden.”
THULITE Trial Design and Endpoints
- The randomized, double-masked, placebo-controlled THULITE trial will assess the efficacy, safety, and tolerability of BI 1815368 in approximately 300 patients with center-involved DME over a 48-week period.
- To be eligible, participants must have a diagnosis of type 1 or type 2 diabetes, an HbA1c level below 12%, and must be on a stable diabetes treatment regimen for at least 30 days prior to study entry.
- No major changes to diabetes medications should be planned at the time of screening or baseline.
- The primary endpoint of the trial is the gain of ≥10 Early Treatment Diabetic Retinopathy Study (ETDRS) letters compared with baseline in the study eye at week 48.
- Key secondary endpoints include the gain of ≥15 ETDRS letters compared with baseline in the study eye at week 48, occurrence of drug-related adverse events over the treatment period through the end of the trial, and the absolute change from baseline of central subfield foveal thickness as measured by spectral domain optical coherence tomography in the study eye at week 48.2
“An oral therapy for DME could represent a major step forward in its management,” trial principal investigator Charles C. Wykoff, MD, PhD, director of Research, Retina Consultants of Texas, research chair, Retina Consultants of America, in the press release. “A safe and effective systemic therapy would offer an important alternative to repeated intravitreal injections; it could enable more consistent initiation of care earlier in the disease process, improve treatment adherence and optimize quality of life for patients.”
Investigational Compound BI 1815368 Builds on Phase I Data
In 2024, the safety, tolerability, pharmacokinetics, and pharmacodynamics of BI 1815368 were evaluated in 26 healthy male patients in Japan in a Phase I trial (NCT06494774).3 An additional Phase I trial (NCT06655220) assessed whether taking BI 1815368 along with metformin affects the amount of metformin in the bloodstream, compared to when metformin is taken as a monotherapy.4
Addressing a Leading Cause of Vision Loss in Diabetes
According to Roche, approximately 750,000 people in the United States are currently living with DME. It is a leading cause of vision loss among the working-age populations of most developed countries. The risk of developing the condition increases as the severity of diabetic retinopathy increases, although it can occur at any stage.5
Boehringer’s Long-Term Vision for Eye Health Innovation
“At Boehringer Ingelheim, we are working towards a future where earlier intervention leads to long-term outcomes that prevent vision loss,” said Patrick Bussfeld, global head, medicine, eye health, Boehringer Ingelheim, in the press release.“One way we aim to achieve this is by developing oral treatments, which offer patients the ability to be more in control of their condition. By targeting the disease pathway systemically, we also have the potential to prevent DME in one eye while the other is being treated.”
References
Boehringer Ingelheim initiates Phase II study of BI 1815368, a potential first-in-class oral treatment for diabetic macular edema. Boehringer Ingelheim. July 7, 2025. Accessed July 7, 2025. https://www.boehringer-ingelheim.com/science-innovation/human-health-innovation/phase-ii-start-oral-treatment-diabetic-macular-edema
A Study to Test Whether BI 1815368 Helps People With an Eye Condition Called Diabetic Macular Edema. Clinicaltrials.gov. Accessed July 7, 2025. https://clinicaltrials.gov/study/NCT06962839
A Study to Test How Different Doses of BI 1815368 Are Tolerated and How BI 1815368 is Taken up in the Body of Healthy Japanese Men. Clinicaltrials.gov. Accessed July 7, 2025. https://clinicaltrials.gov/study/NCT06494774?term=NCT06494774&rank=1
A Study in Healthy Men to Test Whether BI 1815368 Influences the Amount of Metformin in the Body. Clinicaltrials.gov. Accessed July 7, 2025. https://clinicaltrials.gov/study/NCT06655220?term=NCT06655220&rank=1
Diabetic Macular Edema (DME) Fact Sheet. Genentech. Accessed July 7, 2025. https://www.gene.com/patients/disease-education/diabetic-macular-edema
