This review was conducted by a team from Johns Hopkins University with expertise in the management of sickle cell disease, clinical trial methodology (including clinical trials of hematological agents), systematic literature review, epidemiological studies, and ethics and adherence research. External technical experts, including academic and clinical experts and representatives of patients and public interest groups, provided input regarding the selection and refinement of the questions to be examined and the relevant literature to be considered. The core team worked with the technical experts, the OMAR Consensus Panel chairman, and the AHRQ to develop the Key Questions (see page 1)