A Phase 2, Open Label, Multiple Dose Escalation Study to Evaluate the Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of Voxelotor in Patients With Sickle Cell Disease

About the study

This is a dose escalation study to evaluate the safety and tolerability of voxelotor at daily
doses of 1500 mg to 3000 mg in participants with sickle cell disease (SCD). The study is
designed to include 2 separate cohorts. In Cohort A participants will undergo up to 4 periods
of voxelotor administration at progressively higher dose levels from 1500 mg until either a
maximum tolerated dose (MTD) or 3000 mg orally daily is reached. Cohort B (following Cohort
A) will assess the tolerability and safety of doses higher than 1500 mg administered without

Study point of contact

Theresa Thuener
+1 650 741 7710
Will Tappe, MD
(650) 825-4678


6 United Kingdom sites


18 to 60 Years




Phase 2

Study type








participation requirements

– Male or female with sickle cell disease

– Documentation of SCD genotype HbSS or HbSB0

– Age 18 to < 60 years, inclusive - Participants, who if female and of child bearing potential, agree to use highly effective methods of contraception or practicing abstinence from study start to 30 days after the last dose of study drug, and who if male, agree to use barrier methods of contraception or practice abstinence from study start to 30 days after the last dose of study drug - Participant has provided documented informed consent

participation restrictions

– More than 10 vaso-occlusive crises (VOCs) within 12 months of screening that required
a hospital, emergency room, or clinic visit

– Female participant who is breast feeding or pregnant

– Hospitalized for sickle cell crisis or other vaso-occlusive event prior to 30 days of
dosing (ie, a vaso-occlusive event cannot be within 30 days prior to dosing)

– Participants with known active hepatitis A, B, or C or who are known to be human
immunodeficiency virus (HIV) positive

– Severe renal dysfunction or on chronic dialysis

– History of malignancy within the past 2 years prior to treatment Day 1 requiring
chemotherapy and/or radiation (with the exception of local therapy for non-melanoma
skin malignancy)

– History of unstable or deteriorating cardiac or pulmonary disease within 6 months
prior to consent including but not limited to the following:

– Participated in another clinical trial of an investigational agent or medical device
within 30 days or 5 half-lives of date of informed consent, whichever is longer, or is
currently participating in another trial of an investigational agent or medical device

– Inadequate venous access as determined by the Investigator/site staff

– Ongoing or recent (within 2 years) substance abuse

– Inability to undergo magnetic resonance imaging (MRI) or cardiopulmonary exercise test
(CPET) assessments (Cohort B only)

– Known allergy to voxelotor


  • London, United Kingdom, Guy's and St Thomas' NHS Foundation Trust [Recruiting]
  • London, United Kingdom, Guy's Hospital [Recruiting]
  • London, United Kingdom, Hammersmith Hospital [Recruiting]
  • London, United Kingdom, Homerton University [Recruiting]
  • London, United Kingdom, King's College Hospital [Recruiting]
  • London, United Kingdom, Royal London Hospital, Barts Health NHS Trust [Recruiting]
Last updated 2020-03-13