Conditions: Diabetic Retinopathy
Keywords: diabetic retinopathy diabetes diabetic eye studies
Allocation: RANDOMIZED | Intervention model: PARALLEL
Enrollment: 33
Healthy volunteers: no

Brief summary:
This 24 month randomized research study will evaluate whether doxycycline can slow the deterioration or improve retinal function among patients with mild to moderate non-proliferative diabetic retinopathy.

Detailed description:
The objective of this proof-of-concept study is to investigate whether doxycycline can slow the deterioration or improve retinal function among patients with mild to moderate NPDR (with abnormal retinal function defined as a foveal sensitivity \< 30.91 dB on Matrix frequency doubling perimetry \[FDP\]). Based on results of the END DR Study, the primary visual function endpoint in the POC 2 Study will be performance on the Matrix Frequency Doubling Technology Perimeter. This test was the most sensitive to NPDR of the visual function endpoints the investigators evaluated in the END DR Study. This selection is aggressive because the investigators lack natural history data to estimate the 2-year rate of change in the endpoint; in fact, a major output of this POC 2 Study will be 2-year natural history data using several visual function endpoints. The investigators are enrolling patients who have moderate dysfunction; that is, patients who fall outside the 95% confidence interval of normal performance on FDP. These patients will have the opportunity to improve their FDP performance to "normal" levels as well as progress to more severe FDP impairment associated with more advanced disease. Secondary endpoints include visual acuity, contrast sensitivity, visual field, and dark adaptation. The tests will be performed in the Ophthalmology Department of the Penn State College of Medicine. The 24-month proof-of-concept clinical study will involve a prospective, randomized, double-masked clinical trial including 60 adult patients with type 1 or type 2 diabetes who have mild to moderate NPDR (ETDRS levels 20 to 43), and in whom retinal photocoagulation is not anticipated (by the investigator) within the subsequent 2 years. Participants will be randomized to receive either doxycycline monohydrate 50mg or an identical placebo once daily for 24 months.

Arms:
arm 1: None arm 2: Placebo

Interventions: intervention 1: doxycycline monohydrate intervention 2: Placebo
Intervention descriptions: intervention 1: 50 mg intervention 2: Cellulose Placebo Capsule

Protocol document: