Overview
11 DESCRIPTION OXBRYTA contains voxelotor, a hemoglobin S polymerization inhibitor. The chemical name of voxelotor is 2-hydroxy-6-((2-(1-isopropyl-1 H -pyrazol-5-yl)pyridin-3-yl)methoxy)benzaldehyde with a molecular formula of C 19 H 19 N 3 O 3 and a molecular weight of 337.4. The chemical structure of voxelotor is: Voxelotor is a white-to-yellow-to-beige compound in crystalline Form II of its...
Mechanism of Action
12 CLINICAL PHARMACOLOGY 12.1 Mechanism of Action Voxelotor is a hemoglobin S (HbS) polymerization inhibitor that binds to HbS with a 1:1 stoichiometry and exhibits preferential partitioning to red blood cells (RBCs). By increasing the affinity of Hb for oxygen, voxelotor demonstrates dose-dependent inhibition of HbS polymerization. Nonclinical studies suggest that voxelotor may inhibit RBC sickling, improve RBC deformability, and reduce whole blood viscosity. 12.2 Pharmacodynamics The pharmacodynamic effect of voxelotor treatment demonstrated a dose-dependent increase in Hb oxygen affinity as determined by the change in p50 (partial pressure of oxygen at which Hb oxygen saturation of 50% is achieved) that was linearly correlated with voxelotor exposure.
Indications
- 1 INDICATIONS AND USAGE OXBRYTA is indicated for the treatment of sickle cell disease (SCD) in adults and pediatric patients 4 years of age and older. This indication is approved under accelerated approval based on increase in hemoglobin (Hb) [see Clinical Studies (14) ] . Continued approval for this indication may be contingent upon verification and description of clinical benefit in confirmatory trial(s). OXBRYTA is a hemoglobin S polymerization inhibitor indicated for the treatment of sickle cell disease in adults and pediatric patients 4 years of age and older.
Common Doses
- 500 mg
- 000 mg
- 900 mg
- 600 mg
Dosage
2 DOSAGE AND ADMINISTRATION OXBRYTA can be taken with or without food. ( 2.7 ) Recommended dosage: • Adults and pediatric patients 12 years and older: 1,500 mg orally once daily. ( 2.1 ) • Pediatric patients 4 to less than 12 years: Dosing with OXBRYTA is based on body weight. See Table 1 for complete dosing recommendations. ( 2.2 ) Recommended dosage for severe hepatic impairment (Child Pugh C) : • Adults and pediatric patients 12 years and older: 1,000 mg orally once daily. ( 2.3 ) • Pediatric patients 4 to less than 12 years: Reduce the dose of OXBRYTA based on body weight.
Contraindications
- 4 CONTRAINDICATIONS OXBRYTA is contraindicated in patients with a history of serious drug hypersensitivity reaction to voxelotor or excipients. Clinical manifestations may include generalized rash, urticaria, mild shortness of breath, mild facial swelling, and eosinophilia [see Warnings and Precautions (5.1) and Adverse Reactions (6.1) ]. Prior drug hypersensitivity to voxelotor or excipients. ( 4 )
Side Effects
- 6 ADVERSE REACTIONS The following clinically significant adverse reaction is discussed in other sections of the labeling: • Hypersensitivity Reactions [see Contraindications (4) and Warnings and Precautions (5.1) ]. Most common adverse reactions (incidence ≥10% with a difference of >3% compared to placebo) are headache, diarrhea, abdominal pain, nausea, rash, and pyrexia. ( 6.1 ) Most common adverse reactions (incidence >10%) reported in pediatric patients 4 to 3% compared to placebo are summarized in Table 4.
Interactions
- 7 DRUG INTERACTIONS • Sensitive CYP3A4 Substrates: Avoid coadministration of sensitive CYP3A4 substrates with a narrow therapeutic index. ( 7.2 ) • Strong or moderate CYP3A4 Inducers: Avoid coadministration with strong or moderate CYP3A4 inducers. If unavoidable, increase the dose of OXBRYTA. ( 2.5 , 2.6 , 7.1 ) 7.1 Effect of Other Drugs on Voxelotor Strong or Moderate CYP3A4 Inducers Coadministration of strong or moderate CYP3A4 inducers may decrease voxelotor plasma and whole blood concentrations and may lead to reduced efficacy.