Study to Evaluate the Effect of GBT440 in Pediatrics With Sickle Cell Disease


This study consists of three parts, Parts A, B, and C. Part A is a single dose PK study in pediatric participants with Sickle Cell Disease. Part B is a multiple dose, safety, exploratory, efficacy, and PK study in adolescent Sickle Cell Disease participants who were 12-17 years of age. Part C is a multiple dose, safety, tolerability, and PK study, which includes the assessment of hematological effects and the effect on TCD flow velocity of GBT440 is pediatric participants with Sickle Cell Disease who are 4 to 17 years of age.


  • Sickle Cell Disease


Eligible Ages
Between 4 Years and 17 Years
Eligible Genders
Accepts Healthy Volunteers

Inclusion Criteria

  1. Male or female participants with homozygous hemoglobin SS (HbSS) or hemoglobin S beta0 thalassemia (HbS β0thal)
  2. A participant taking hydroxyurea (HU) may be enrolled if the dose has been stable for at least 3 months with no anticipated need for dose adjustment during the study and no sign of hematological toxicity.
  3. Hemoglobin (HB):
  4. Part A - No restriction
  5. Part B - Hb ≤ 10.5 g/dL
  6. Part C - Hb ≤ 10.5 g/dL
  7. Written informed parental/guardian consent and participant assent has been obtained per institutional review board (IRB)/Ethics Committee (EC) policy and requirements, consistent with International Council on Harmonisation (ICH) guidelines.
  8. For Part C only: Participants 12 to 17 years of age must have a TCD velocity of ≥ 140 cm/sec measured anytime during screening.

Exclusion Criteria

  1. Any one of the following requiring medical attention within 14 days of signing the Informed Consent Form (ICF):
  2. Vaso-occlusive crisis (VOC)
  3. Acute chest syndrome (ACS)
  4. Splenic sequestration crisis
  5. Dactylitis
  6. Requires chronic transfusion therapy
  7. History of stroke or meeting criteria for primary stroke prophylaxis (history of two TCD measurements ≥ 200 cm/sec)
  8. Transfusion within 30 days prior to signing the ICF

Study Design

Phase 2
Study Type
Intervention Model
Single Group Assignment
Primary Purpose
None (Open Label)

Arm Groups

ArmDescriptionAssigned Intervention
Subjects to receive daily oral dosing of GBT440 according to which Part (A, B, or C), the subject is participating in: Part A: Subjects to receive daily oral dosing of GBT440 for 1 day (single dose) Part B: Subjects to receive daily oral dosing of GBT440 for up to 24 weeks (multiple dose) Part C: Subjects to receive daily oral dosing of GBT440 for up to 48 weeks (1500mg or 1500mg equivalent dose)
  • Drug: GBT440
    GBT440 will be administered as oral capsules

Recruiting Locations

Children's National and nearby locations

Children's National Medical Center
Washington, District of Columbia 20010
Elaine Passley Curtis

More Details

Global Blood Therapeutics

Study Contact

Dan Rudin, MD
(650) 534-2574