A Single Arm, Open Label, Phase 1/2 Study to Evaluate the Pharmacokinetics and Safety of Etavopivat in Pediatric Patients With Sickle Cell Disease
The purpose of this study is to evaluate the pharmacokinetics and safety of etavopivat in paediatric participants with sickle cell disease (SCD). Participants will receive etavopivat and will be enrolled in a staggered manner, starting with the oldest age group and followed sequentially by younger cohorts after review of pharmacokinetic and safety data from the preceding cohort. All participants will undergo a 24-week primary treatment period followed by a 72-week extension treatment period to further evaluate long-term safety and pharmacokinetics of etavopivat. The total duration of the study will be approximately 96 weeks.
• Type of Participant and Disease Characteristics
‣ Patient's parent, legal guardian, or legal representative has provided documented informed consent and patients have provided age-appropriate assent
⁃ Age greater than or equal to (≥) 6 months and lesser than (\<) 18 years of age at time of enrollment, according to the enrolling cohort:
• Cohort 1: age 12 to \< 18 years (adolescents)
∙ Cohort 2: age 6 to \< 12 years
∙ Cohort 4: age 6 months to \< 2 years
⁃ Patient has confirmed diagnosis of SCD
‣ • Documentation of SCD genotype (HbSS, HbSβ0-thalassemia or other sickle cell syndrome variants) based on prior history of laboratory testing. Molecular genotyping is not required. SCD genotype may be determined from the results of Hb electrophoresis, high-performance liquid chromatography (HPLC), or similar testing. Note that Hb electrophoresis is performed by the local laboratory at Screening.
⁃ Hemoglobin ≥ 5.5 and lesser than or equal to (≤) 10.5 grams per deciliter (g/dL)
⁃ Pediatric patients with severe SCD, as defined by at least 1 of the following:
• 2-15 episodes of documented VOC within the 12 months prior to screening. Documentation must exist in the patient's medical record prior to screening. Events based solely on patient recall without supporting documentation should not be counted towards eligibility.
∙ Hospitalization for any SCD-related complication in the last 12 months prior to starting study treatment
∙ Proteinuria, defined as an albumin:creatinine ratio (ACR) \> 100 mg/g on 2 measures (separated by ≥ 1 month) as an indicator of early renal disease
∙ History of a conditional TCD in the last 12 months prior to starting study treatment, but not currently being treated with chronic transfusion therapy (applicable to participants \> 2 years of age). Conditional TCD is defined as a TAMMV of 170-199 cm/s by TCD or 155-184 cm/s by imaging TCD (TCDi).
⁃ For participants taking hydroxyurea (HU), the dose of HU (mg/kg) must be stable (no more than a 20% change in dosing) for at least 90 days prior to start of study treatment with no anticipated need for dose adjustments during the study, in the opinion of the Investigator
⁃ Patients on crizanlizumab or L-glutamine treatment at the time of consent may be eligible if they:
• Have been on a stable dose for ≥ 12 months at the time of consent (ie, no changes to the dose except for changes to weight or for safety reasons)
∙ For patients on crizanlizumab, have been ≥ 80% compliant with the planned regimen during the 12 months prior to the time of consent
⁃ Female patients of childbearing potential who are using acceptable methods of contraception and agree not to donate ova from study start to 90 days after the last dose of study drug, and male patients who are willing to use acceptable methods of contraception and agree not to donate sperm, from study start to 90 days after the last dose of study drug.