Clinical Trial: Long-Term Study of Nitisinone to Treat Alkaptonuria

Study Status: Completed
Recruit Status: Completed
Study Type: Interventional




Official Title: Long-Term Clinical Trial of Nitisinone in Alkaptonuria

Brief Summary:

This 3-year study will examine the safety and effectiveness of long-term use of nitisinone (Orfadin) for treating joint problems in patients with alkaptonuria, an inherited disease in which a compound called homogentisic acid accumulates. The excess homogentisic acid causes arthritis and limited joint movement. It can also cause heart valve damage and kidney stones.

Patients between 30 and 80 years of age with alkaptonuria may be eligible for this study. Patients must have hip involvement, but at least one remaining hip joint. Candidates are recruited from among patients enrolled in protocol 00-HG-0141, "Clinical, Biochemical, and Molecular Investigations into Alkaptonuria." Participants may enter both protocols simultaneously.

Participants are randomly assigned to one of two treatment groups: one group takes their regular medicines plus a 2-mg nitisinone capsule daily; the other group takes only their regular medicines. Patients taking nitisinone have blood tests to measure liver function 2 weeks and 6 weeks after starting treatment. Before starting therapy, all patients are admitted to the NIH Clinical Center for 4-5 days to undergo the following procedures:

  • Medical history and physical examination
  • 24-hour urine collection to test for sugar, protein, and other molecules
  • Blood tests for liver and thyroid function, blood counts, and blood chemistries
  • Blood and urine tests to measure tyrosine and other amino acids and homogentisic acid
  • Bone x-rays
  • Spiral CT (computed tomography) of the abdomen to detect kidney stones
  • Eye examin