New uses of IDO inhibitors: treatment for diabetic retinopathy and macular degeneration

Lead investigator: Alexander J. Muller, PhD, Lisa Laury-Kleintop, PhD

Unmet need

Diabetic retinopathy (DR) and the “wet” form of age-related macular degeneration (AMD) are increasing in incidence worldwide. These retinopathies are caused by the pathogenic growth of blood vessels (angiogenesis) on the surface of the retina, obscuring vision. Present treatments are laser therapy or injectable drugs that block VEGF, which stimulates formation of new blood vessels. However, these treatments are not fully effective. For example, up to 30% of patients receiving anti-VEGF are non-responders, and long-term treatment actually may be deleterious in treating DR. Thus, there remains a need for drugs or biologics to safely and effectively treat these common retinopathies.

The global number of cases of AMD are expected to grow from 196 million in 2020 to 288 million in 2040 (Wong, et al; see reference). About 4.2 million U.S. adults have DR, and 655,000 have vision-threatening DR, according to the CDC.


For companies developing IDO/TDO inhibitors in clinical trials, this technology could expand the scope of marketable applications for this drug class to encompass the field of ophthalmology.

Unique attributes

As part of their pioneering studies of IDO enzymes as targets for immunotherapeutic development, LIMR scientists discovered that the IDO1 enzyme also contributes significantly to inflammatory vasculogenesis. Exploring this direction, they defined a new use for IDO inhibitors to treat retinopathies that are driven by formation of pathogenic blood vessels. This new use expands clinical applications for IDO inhibitors as potential medicines in ophthalmology.

Clinical applications

This new use of IDO inhibitors could expand their clinical applications as medicines in ophthalmology.

Stage of development

Preclinical proof of concept for repositioning this drug class has been achieved, including with two clinical stage IDO inhibitors.

Intellectual property

New use for IDO1 inhibitors (daily oral monotherapy): Patent pending.

Collaboration opportunity

Efficacy evaluation of IDO inhibitors alone or in combination with anti-VEGF, laser, or other modalities used to treat retinopathy, to improve management of DR, AMD, retinopathy of prematurity.

Relevant publications


Institutional contact: George C. Prendergast, PhD, LIMR President and CEO, 484.476.8475, [email protected]

IP manager contact: Heather Rose, PhD, JD, VP of Technology Licensing and Startups, Thomas Jefferson University, 215.503.0770, [email protected]