Autosomal dominant best vitelliform macular dystrophy (BVMD) or autosomal recessive bestrophinopathy (ARB) Eye Diseases
Conditions
Interventions
Sponsors
Eligibility
Inclusion criteria
Inclusion criteria: 1. Participants capable of giving informed consent 2. Age 18 - 65 years old 3. Best corrected visual acuity recorded as better than hand movements at recruitment 4. Clinical and molecular diagnosis of ARB or BVMD 5. Able to speak and understand English
Exclusion criteria
Exclusion criteria: 1. Participation in other CTIMP in the last 12 weeks 2. Pregnant or breastfeeding 3. Liver morbidity 4. Treatment for acute hyperammonaemia 5. Unable to speak and understand English 6. Urea cycle disorder 7. Known hypersensitivity to phenylbutyrate 8. Reduced phenylbutyrate absorption due to pancreatic insufficiency or intestinal malabsorption 9. Contraindicated concomitant medications: 9.1. Treatment with probenecid (which may inhibit the renal excretion of metabolites of 4PBA including phenylacetylglutamine and phenylacetate) 9.2. Treatment with drugs with a narrow therapeutic index that are substrates of CYP3A4 (4PBA weakly induces CYP3A4 in humans and so may decrease the systemic exposure to drugs that are its substrates of CYP3A4 e.g., alfentanil, quinidine, cyclosporine) 9.3. Treatment with midazolam (4PBA can decrease the systemic exposure of midazolam)
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| EOG LP:DT ratio measured using electrooculogram on Days 8 and 36. These measurements will determine if the primary objective has been achieved (measurable effect of dosing at the end of the dosing period). | — |
Secondary
| Measure | Time frame |
|---|---|
| EOG LP:DT ratio measured using electrooculogram on Days 1 and 29 (baseline periods 1 and 2) and on Day 57. These measurements will determine whether the secondary objective has been achieved (return to baseline value following cessation of dosing) | — |
Countries
England, United Kingdom