This will be an open-label, dose escalating study with a starting dose of 2mg. Up to 4 additional cohorts will be enrolled at subsequently higher doses of 4mg, 8mg, 16mg, and 32mg.~Cohort 1 - Two (2) patients will be enrolled at the 2mg dose level for 8 weeks of treatment. After both patients have received at least 4 weeks of treatment, if there are no adverse events >Grade 1 that are related (possibly, probably, or definitely) to the study drug, then the study will proceed to the next dose level.~Cohort 2 - Two (2) patients will be enrolled at the 4mg dose level for 8 weeks of treatment. After both patients have received at least 4 weeks of treatment, if there are no adverse events >Grade 1 that are related to the study drug, then the study will proceed to the next dose level.~Cohort 3 - Three (3) patients will be enrolled at the 8mg dose level for 8 weeks of treatment. After all patients have received at least 4 weeks of treatment, if <2 patients experience a related adverse event >Grade 1, then the study will proceed to the next dose level.~Cohort 4 - Three (3) patients will be enrolled at the 16mg dose level for 8 weeks of treatment. After all patients have received at least 4 weeks of treatment, if <2 patients experience a related adverse event >Grade 1, then the study will proceed to the next and final dose level.~Cohort 5 - Three (3) patients will be enrolled at the 32mg dose level for 8 weeks of treatment.~Additional cohorts may be explored at 12 and 24mg dose levels if deemed appropriate based on safety and activity parameters.~If there are any adverse events >Grade 1 that are related (possibly, probably, or definitely) to study drug, at the 4mg cohort or >2 patients in any subsequent cohort, the dose may be decreased to that for the previous cohort and an additional 3 patients (up to a total of 5 or 6) may be enrolled into that previous cohort. Additionally, if HbF levels, as a percent of total Hb, increase to >15% in any cohort, the cohort can be expanded by an additional 3 patients, as well as continuing to the next cohort if safety parameters have been met.~Approximately 6 to 30 patients may be enrolled for the entire study. Patients are eligible to enroll in a higher cohort of the study after a minimum of one month washout from AB1 dosing, if their HbF levels return to baseline (<8.6%) and the investigator deems the patient eligible.
This will be an open-label, dose escalating study with a starting dose of 2mg. Up to 4 additional cohorts will be enrolled at subsequently higher doses of 4mg, 8mg, 16mg, and 32mg. Each dose will be taken orally, once daily, for 8 weeks.