Voxelotor

DAE Class; Rx

Common Brand Names; Oxbryta

• Hemoglobin Oxygen-Affinity Modulators

Voxelotor is a hemoglobin S (HbS) polymerization inhibitor that binds to HbS with a 1:1 stoichiometry and exhibits preferential partitioning to RBCs

By increasing the affinity of Hb for oxygen, voxelotor demonstrates dose-dependent inhibition of HbS polymerization

Nonclinical studies suggest voxelotor may inhibit RBC sickling, improve RBC deformability, and reduce whole blood viscosity

Indicated for treatment of sickle cell disease

Hypersensitivity; clinical manifestations may include generalized rash, urticaria, mild shortness of breath, mild facial swelling, and eosinophilia

>10%

Adults and adolescents ≥12 yr

• Headache (32%)
• Diarrhea (23%)
• Abdominal pain (23%)
• Nausea (19%)
• Rash (15%)
• Pyrexia (15%)

Pediatrics 4-11 yr

• Pyrexia (36%)
• Vomiting (33%)
• Rash (20%)
• Abdominal pain (18%)
• Diarrhea (18%)
• Headache (18%)

1-10%

Adults and adolescents ≥12 yr

• Drug hypersensitivity (<10%)

<1%

Adults and adolescents ≥12 yr

• Serious hypersensitivity

Postmarketing Reports

Drug reaction with eosinophilia and systemic symptoms (DRESS), pruritis, angioedema (including swelling of eyelid, face edema, lip swelling, and periorbital swelling)

Voxelotor may interfere with laboratory measurement of Hb subtypes (HbA, HbS, and HbF) by high-performance liquid chromatography (HPLC)

Hypersensitivity reactions

• Drug reaction with eosinophilia and systemic symptoms (DRESS) reported in postmarketing experience
• Patients who develop a combination of skin rash, fever, peripheral eosinophilia, and internal systemic organ involvement (eg, hepatic, renal, pulmonary) while receiving therapy should undergo medical evaluation
• Advise patients of the signs and symptoms of severe hypersensitivity reactions, including DRESS
• If hypersensitivity reactions occur, discontinue treatment and administer appropriate medical therapy; do not reinitiate therapy in patients who experience these symptoms with previous use

Drug interaction overview

• Strong or moderate CYP3A4 inducers

  • Avoid coadministration with strong or moderate CYP3A4 inducers
  • Increase voxelotor dose if unable to avoid

• Effect of voxelotor on other drugs

  • Voxelotor increased the systemic exposure of midazolam (a sensitive CYP3A4 substrate)
  • Avoid co-administration with sensitive CYP3A4 substrates with a narrow therapeutic index
  • Consider dose reduction of the sensitive CYP3A4 substrate(s) if unable to avoid

Pregnancy

Data are not available regarding use in pregnant women to evaluate for drug-associated risk of major birth defects, miscarriage, or adverse maternal or fetal outcomes

Lactation

Data are not available on the presence of voxelotor in human milk, effects on the breastfed child, or effects on milk production

Voxelotor was detected in milk in lactating rats; plasma concentrations of voxelotor in pregnant rats were higher than the concentration in milk

Advise women not to breastfeed during treatment and for at least 2 weeks after the last dose

Sickle Cell Disease

Indicated for treatment of sickle cell disease

1500 mg PO qDay

May take with or without hydroxyurea

Dosage Modifications

Renal impairment

• Mild, moderate, or severe: No dose adjustment required
• End-stage renal disease: Not studied

Hepatic impairment

• Mild-to-moderate (Child-Pugh A or B): No dose adjustment required
• Severe (Child-Pugh C): Decrease to 1000 mg (tablets) PO qDay or 900 mg (tablets for oral suspension) PO qDay

CYP3A4 inducers

• Avoid coadministration of strong or moderate CYP3A4 inducers
• If unable to avoid, adjust dose
• Strong CYP3A4 inducers: Increase to 2500 mg PO qDay
• Moderate CYP3A4 inducers: Increase to 2000 mg PO qDay

Voxelotor