An Extension Study to Further Evaluate the Safety, Tolerability of GBT440 in Patients With Sickle Cell Disease Who Participated in the Study GBT440-001

This is an open label, single arm study which enrolled 5 subjects with SCD who previously participated in the GBT440-001 study (NCT02285088).

Dosing of study drug was 2 to 6 months, depending on subject's dose assignment in the last administration of study drug in GBT440-001 (NCT02285088).

The primary objective of the study was to evaluate the safety and tolerability of up to a total of 6 months dosing of subjects with SCD who participated in the GBT440-001 study (NCT02285088).