Oral Metformin for Treatment of ABCA4 Retinopathy
Background: ABCA4 retinopathy is a genetic disease in which the ABCA4 protein is absent or faulty. It can cause waste material to collect in the eye and may cause cells to die. The cell death can lead to vision loss. Researchers want to see if an oral drug called metformin can help.
Objective: To see if metformin is safe and possibly helps to slow the rate of ABCA4 retinopathy.
Eligibility: People age 12 and older who have ABCA4 retinopathy and have problems with their vision.
Design: Participants will be screened under a separate protocol. Participants will have a medical and family history. They will complete a questionnaire about their vision and daily activities. They will have a physical exam. They may have blood drawn through a needle in the arm. Participants will have an eye exam. Their pupils may be dilated with eye drops. Their retina may be photographed. Participants will have a visual field test. They will sit in front of a large dome and press a button when they see a light within the dome. Participants will have an electroretinogram. It examines the function of the retina. They will sit in the dark for 30 minutes. Then their eyes will be numbed with eye drops. They will wear contact lenses that can sense signals from the retinas. They will watch flashing lights. Participants will have optical coherence tomography. This non-invasive procedure makes pictures of the retina. Participants will have fundus autofluorescence. A bright blue light will be shone into their eye. Participants will take metformin by mouth for 24 months. Participants will have study visits every 6 months. Participation will last for at least 36 months....
⁃ To be eligible, the following inclusion criteria must be met, where applicable.
⁃ Participant must be at least 12 years of age.
⁃ Participant (or legal guardian) must understand and sign the protocol s informed consent document.
⁃ Participant must have at least one definite pathogenic or likely pathogenic mutation in ABCA4 and a typical clinical presentation of Stargardt disease and phenotypic presentation of ABCA4 retinopathy in both eyes.
⁃ Participant must have at least two years of natural history data from at least four data points (a) The separation between any two consecutive data points must be at least six months (b) The most recent data point must be at least 4.5 months and no more than 16 months prior to the baseline visit (c)
• Potential participants with three natural history data points may be enrolled to obtain their fourth natural history data point on protocol.
∙ The separation between any two consecutive data points may fall short of 6 months by no more than 45 days; however, the total separation among the data points must allow for at least two years of natural history data.
∙ Potential participants with four or more natural history data points completed off protocol, all of which having occurred more than 16 months prior to the baseline visit, may be enrolled to complete an additional natural history data point on protocol within the required timeframe from the baseline visit.
⁃ Participant must agree to adhere to Lifestyle Considerations throughout study duration.
⁃ Any female participant of childbearing potential must have a negative urine pregnancy test at screening and be willing to undergo urine pregnancy tests throughout the study.
⁃ Any female participant of childbearing potential must:
∙ Have had a surgical sterilization OR
‣ Completely abstain from intercourse OR
‣ Practice at least one form of contraception while actively taking IP on the study and at least one week after IP discontinuation OR
‣ Have a partner who had a surgical sterilization OR
‣ Have a partner who practices one form of contraception while the female participant is actively taking IP and at least one week after the female participant discontinues IP.
⁃ Any male participants must:
• Have had a surgical sterilization OR
• Completely abstain from intercourse OR
• Practice at least one form of contraception while actively taking IP on the study and at least for 3 months after IP discontinuation OR
• Have a partner who had a surgical sterilization OR
• Have a partner who practices one form of contraception while the male participant actively takes IP and at least 3 months after the male participant discontinues IP.
∙ Acceptable forms of surgical sterilization include: vasectomy, hysterectomy, or tubal ligation.
‣ Acceptable methods of contraception include: hormonal contraception (i.e., birth control pills, injected hormones, dermal patch or vaginal ring), intrauterine device, or barrier methods (diaphragm, condom) with spermicide.