Study of the Selective GlyT1 Inhibitor Bitopertin for Steroid-Refractory Diamond-Blackfan Anemia

Background: Diamond-Blackfan anemia (DBA) is an inherited disease that affects the bone marrow. People with DBA have chronic anemia that can be severe. Many must have frequent transfusions of red blood cells. Current treatments for DBA all have risks of serious side effects. Better treatments are needed. Objective: To test a new drug (bitopertin) in people with DBA. Eligibility: People aged 18 or older with DBA. Design: Participants will be screened. They will have a physical exam; they will have blood tests and a test of their heart function. They will have a bone marrow biopsy: An area of their hip will be numbed, and a needle will be inserted to remove a sample of tissue from inside the bone. Bitopertin is a pill taken by mouth. Participants will take the drug once a day every day for 8 months. They will start with a low dose of the drug; the dosage may increase gradually over time. They will keep a diary to record each dose. Participants will have blood tests every 4 weeks. This may be done in the clinic. Participants may also have telehealth visits; they can have blood drawn at a local lab and sent to the researchers. The bone marrow biopsy and other tests will be repeated after 8 months. Participants who have a positive response to bitopertin will be invited to enter an extended phase of the trial. They may continue to take the drug for 3 more years. Those who choose not to continue in the extended phase may have a follow-up visit 6 months after they stop taking the drug.