for people ages 4-17 (full criteria)
at Oakland, California and other locations
study started
estimated completion



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.

Official Title

A Phase 2a, Open-label, Single and Multiple Dose Study to Evaluate the Pharmacokinetics, Safety, Tolerability, and Exploratory Treatment Effect of GBT440 in Pediatric Participants With Sickle Cell Disease


Sickle Cell Disease Anemia, Sickle Cell GBT440


You can join if…

Open to people ages 4-17

  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.

You CAN'T join if...

  1. Any one of the following requiring medical attention within 14 days of signing the

Informed Consent Form (ICF):

  • Vaso-occlusive crisis (VOC)
  • Acute chest syndrome (ACS)
  • Splenic sequestration crisis
  • Dactylitis
  • Requires chronic transfusion therapy
  • History of stroke or meeting criteria for primary stroke prophylaxis (history of two TCD measurements ≥ 200 cm/sec)
  • Transfusion within 30 days prior to signing the ICF


  • UCSF Benioff Children's Hospital Oakland in progress, not accepting new patients
    Oakland California 94609 United States
  • Children's Mercy Hospital Kansas City accepting new patients
    Kansas City Missouri 64108 United States


accepting new patients
Start Date
Completion Date
Global Blood Therapeutics
Phase 2
Study Type
Last Updated