Nitisinone for Type 1B Oculocutaneous Albinism

• INCLUSION CRITERIA:

To be eligible, the following inclusion criteria must be met, when applicable.

• Participant must be 18 years of age or older.
• Participant must understand and sign the protocol s informed consent document.
• Participant must have normal renal function, liver function, and platelet counts or have mild abnormalities no greater than grade 1 as defined by the Common Terminology Criteria for Adverse Events v4.0 (CTCAE).
• Any female participant of childbearing potential must have a negative pregnancy test at screening and must be willing to undergo pregnancy testing immediately prior to the start of the investigational product and while on the investigational product.
• Any female participant of childbearing potential and any male participant able to father children must have (or have a partner who has) had a hysterectomy or vasectomy, be completely abstinent from intercourse, or must agree to practice two effective methods of contraception while taking the investigational product and for at least two months following the last dose of investigational product. Acceptable methods of contraception include:
• Hormonal contraception (i.e., birth control pills, injected hormones, dermal patch, or vaginal ring),
• Intrauterine device,
• Barrier methods (diaphragm, condom) with spermicide, or
• Surgical sterilization (tubal ligation).
• Participant must have OCA1B, as defined by ALL (a-d) of the following criteria:
• Participant has ophthalmic signs or symptoms of albinism, including:
• Bilateral visual acuity E-ETDRS EVA letter score of less than or equal to 83 (i.e., Snellen equivalent of 20/25 or worse) that is not attributable to any other pathology.
• Bilateral iris transillumination that can be seen in clinical photographs.
• Predominant contralateral decussation of ganglion cell axons, as determined by pattern visual evoked potential (VEP).
• Participant has at least one definitive mutation in the OCA1 gene (tyrosinase).
• Participant has no definitive mutations in the OCA2 gene.

EXCLUSION CRITERIA

• Participant is pregnant or breast-feeding.
• Participant is a male AND has a definitive mutation in the OA1 gene.
• Participant has any of the following abnormal laboratory test results:
• Serum potassium 500 U/L,
• Hemoglobin 150 microM,
• ESR > 100 mm/h, and/or
• Serum T4 > 15 microg/dL OR Serum T4 3 cm below the right costal margin.
• Participant has a muscle disease.
• Participant is currently taking a medication known to cause elevated liver function tests including statins/HMG-Co-A reductase inhibitors (e.g., lovastatin, simvastatin); anti-epileptic medications (e.g., carbamazepine, phenytoin, phenobarbital); tetracycline or its derivatives, if used chronically; acetaminophen, if used daily/chronically; amiodarone; and any other medications with known significant liver toxicity.