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SCD Root CauseAbout OxbrytaEfficacyEfficacyClinical Data | Ages ≥12 YearsClinical Data | Ages 4 to <12 YearsPatient ProfilesSafetyDosingAccess & SupportAccess & SupportAccess & SupportSign up
IndicationFull Prescribing InformationPatient Prescribing Information andInstructions for UsePatient Site
Oxbryta® (voxelotor) is the first and only hemoglobin S (HbS) polymerization inhibitor1Oxbryta® (voxelotor) is the first and only hemoglobin S (HbS) polymerization inhibitor1

How Oxbryta works

Blood smear imagery

Tab Number 3

Tab Number 4

Tab Number 5

Example

Oxbryta intervenes in the sickle cell disease (SCD) cascade, which may help red blood cell (RBC) health* by1,2:Oxbryta intervenes in the sickle cell disease (SCD) cascade, which may help red blood cell (RBC) health* by1,2:

BINDING

BINDING

Oxbryta directly binds to HbS molecules1,3

INHIBITING

INHIBITING

Dose-dependent binding of Oxbryta increases oxygen affinity, inhibiting HbS polymerization1

REDUCING

REDUCING

Nonclinical studies suggest Oxbryta may reduce RBC sickling1

Nonclinical studies also suggest Oxbryta may reduce whole blood viscosity1

IMPACTING

IMPACTING

The pivotal clinical trial†,‡ has shown that Oxbryta improves anemia§ and reduces hemolysis1,2,II

Defined by inhibition of RBC sickling and RBC deformability, and reduction of whole blood viscosity.1 Additional studies are required to assess the effect of voxelotor on red blood cell health.Data from the HOPE trial, a Phase 3, multicenter, randomized, double-blind, placebo-controlled trial of 274 patients aged 12-64 years. Patients were randomized to receive 1,500 mg/day of Oxbryta tablets (n=90), 900 mg/day of Oxbryta tablets (n=92), or placebo (n=92).1,2Oxbryta is approved under accelerated approval based on increase in hemoglobin (Hb). Continued approval for this indication may be contingent upon verification and description of clinical benefit in confirmatory trial(s).1As measured by a Hb increase of >1 g/dL from baseline to week 24 vs placebo (51% vs 7%) in patients ≥12 years of age (primary endpoint).1,2As demonstrated by statistically significant reductions in indirect bilirubin and percent reticulocyte count in patients ≥12 years of age (-26% and -25% placebo-adjusted mean change from baseline at 24 weeks, respectively; secondary endpoints).1,2See how Oxbryta worksSee how Oxbryta works
In a Phase 1/2 trial of patients with SCD, the percentages of sickled RBCs were evaluated in those treated with either voxelotor or placebo3In a Phase 1/2 trial of patients with SCD, the percentages of sickled RBCs were evaluated in those treated with either voxelotor or placebo3

Nonclinical studies suggest that voxelotor may inhibit RBC sickling. This Phase 1/2 trial was an unpowered proof-of-concept study.1,3

Data from this Phase 1/2 trial are not included in the Oxbryta USPI. The Phase 1/2 trial used lower doses of voxelotor than the FDA-approved dose of Oxbryta (1,500 mg daily). Effects of the 1,500-mg dose on RBC sickling have not been demonstrated. Results are presented for descriptive purposes; they offer supportive, but not conclusive, information, and may not translate into clinical benefit.

 Median percent change in sickled RBC count from baseline at day ≥903

Data from a Phase 1/2, randomized, double-blind, placebo-controlled study of voxelotor. Patients with SCD of type HbSS or HbSβ0 thalassemia aged 18-60 years were enrolled in either a 28-day cohort (n=38) or a 90-day cohort (n=16). Voxelotor was administered as multiple doses (500, 700, or 1,000 mg) for 28 days or multiple doses (700 or 900 mg) for 90 days before blood smears were created for analysis. Data shown are from the 90-day cohort.3

Percentage of sickled RBCs was analyzed from blood smears by 2 independent blinded readers. Six independent microscopy fields were randomly selected and >500 RBCs from ≥3 different fields were counted per blood smear. Elongated, crescent-shaped RBCs with tapering of opposite ends that culminated in a point were counted as sickled. Reductions in sickled RBCs of 73% and 79% from baseline were seen in patients receiving 700 mg and 900 mg voxelotor, respectively, when measured on or after day 90.3

HbSS = homozygous hemoglobin S; HbSβ0 = hemoglobin sickle beta zero.

Representative blood smears from the Phase 1/2 trial3,4Representative blood smears from the Phase 1/2 trial3,4

Data from this Phase 1/2 trial are not included in the Oxbryta USPI. The Phase 1/2 trial used lower doses of voxelotor than the FDA-approved dose of Oxbryta (1,500 mg daily). Effects of the 1,500-mg dose on RBC sickling have not been demonstrated. Results are presented for descriptive purposes; they offer supportive, but not conclusive, information, and may not translate into clinical benefit.

Representative blood smear images from the Phase 1/2, randomized, double-blind, placebo-controlled study of voxelotor in patients with SCD. Voxelotor was administered as multiple doses (500, 700, or 1,000 mg) for 28 days or multiple doses (700 or 900 mg) for 90 days before blood smears were created for analysis.3,4

Six independent microscopy fields were randomly selected for each blood smear. These images are representative of the 12 voxelotor-treated patients and 4 placebo-treated patients in the 90-day cohort.3,4

Voxelotor-treated patient with SCD (700 mg)3
Individual responses may vary. Voxelotor, baseline Voxelotor, day 90 Images adapted from Howard J, et al. Blood. 2019;133(17):1865-1875; with permission from Elsevier.

These images are representative Wright-Giemsa stains from a voxelotor-treated patient at baseline and at day 90 showing the decrease in sickled RBCs observed after 90 days of treatment with voxelotor 700 mg QD. Six independent microscopy fields were randomly selected for each blood smear. These images are representative of the 12 voxelotor-treated patients in the 90-day cohort.3

Placebo-treated patient with SCD3,4
Individual responses may vary. Placebo, baseline Placebo, day 90

These images are representative Wright-Giemsa stains from a placebo-treated patient at baseline and at day 90. Six independent microscopy fields were randomly selected for each blood smear. These images are representative of the 4 placebo-treated patients in the 90-day cohort.3,4

 Next: Oxbryta efficacy Oxbryta efficacy LoadingReferences:Oxbryta Full Prescribing Information. South San Francisco, CA: Global Blood Therapeutics, Inc.; 08/2023.Vichinsky E, Hoppe CC, Ataga Kl, et al. A phase 3 randomized trial of voxelotor in sickle cell disease. N Engl J Med. 2019;381(6):509-519. doi:10.1056/NEJMoa1903212Howard J, Hemmaway CJ, Telfer P, et al. A phase 1/2 ascending dose study and open-label extension study of voxelotor in patients with sickle cell disease. Blood. 2019;133(17):1865-1875. doi:10.1182/blood-2018-08-868893Data on file. Pfizer Inc. Get the latest information about Oxbryta delivered to your inbox Sign upLoading

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PP-LTV-USA-2392
Indications and UsageOxbryta 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). Continued approval for this indication may be contingent upon verification and description of clinical benefit in confirmatory trial(s).
Important Safety InformationCONTRAINDICATIONS
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.

WARNINGS AND PRECAUTIONS
Hypersensitivity Reactions
Serious hypersensitivity reactions after administration of Oxbryta have occurred in <1% of patients treated. Clinical manifestations may include generalized rash, urticaria, mild shortness of breath, mild facial swelling, and eosinophilia.

Drug reaction with eosinophilia and systemic symptoms (DRESS) has been reported in postmarketing experience with Oxbryta. Patients who develop a combination of skin rash, fever, peripheral eosinophilia, and internal systemic organ involvement (e.g., hepatic, renal, pulmonary) while receiving Oxbryta should undergo medical evaluation.

Advise patients of the signs and symptoms of severe hypersensitivity reactions, including DRESS. If hypersensitivity reactions occur, discontinue Oxbryta and administer appropriate medical therapy. Do not reinitiate Oxbryta in patients who experience these symptoms with previous use.

Laboratory Test Interference
Oxbryta administration may interfere with measurement of Hb subtypes (HbA, HbS, and HbF) by high-performance liquid chromatography (HPLC). If precise quantitation of Hb species is required, chromatography should be performed when the patient has not received Oxbryta therapy in the immediately preceding 10 days.

ADVERSE REACTIONS
Clinical Trials Experience
Adults and Pediatric Patients 12 Years of Age and Older
Serious adverse reactions occurred in 3% (3/88) of patients receiving Oxbryta 1,500 mg, which included headache, drug hypersensitivity, and pulmonary embolism occurring in 1 patient each. Permanent discontinuation due to an adverse reaction (Grades 1-4) occurred in 5% (4/88) of patients who received Oxbryta 1,500 mg.

The most common adverse reactions occurring in ≥10% of patients treated with Oxbryta 1,500 mg with a difference of >3% compared to placebo: Headache (32% vs. 25%), Diarrhea (23% vs. 11%), Abdominal Pain (23% vs. 16%), Nausea (19% vs. 10%), Rash (15% vs. 11%), and Pyrexia (15% vs. 8%).

Pediatric Patients 4 to <12 Years
The safety of Oxbryta in pediatric patients 4 to <12 years with SCD was evaluated in an open-label, Phase 2 study. In this study, 45 patients 4 to <12 years of age received doses of Oxbryta tablets for oral suspension based on weight at baseline. Thirty-five patients received Oxbryta for 24 weeks and 26 patients for 48 weeks. The most common adverse reactions (>10%) reported in pediatric patients 4 to <12 years were pyrexia (36%), vomiting (33%), rash (20%), abdominal pain (18%), diarrhea (18%), and headache (18%).

The overall safety profile of Oxbryta in pediatric patients 4 to <12 years was similar to that seen in adults and pediatric patients 12 years and older.

DRUG INTERACTIONS
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. Avoid coadministration of Oxbryta with strong or moderate CYP3A4 inducers. Increase the Oxbryta dosage when coadministration with a strong or moderate CYP3A4 inducer is unavoidable.

Sensitive CYP3A4 Substrates
Voxelotor increased the systemic exposure of midazolam (a sensitive CYP3A4 substrate). Avoid coadministration of Oxbryta with sensitive CYP3A4 substrates with a narrow therapeutic index. If concomitant use is unavoidable, consider dose reduction of the sensitive CYP3A4 substrate(s).

USE IN SPECIFIC POPULATIONS
Lactation
Because of the potential for serious adverse reactions in the breastfed child, including changes in the hematopoietic system, advise patients that breastfeeding is not recommended during treatment with Oxbryta, and for at least 2 weeks after the last dose.

Recommended Dosage for Hepatic Impairment
Severe hepatic impairment increases voxelotor exposures. For severe hepatic impairment (Child Pugh C) reduce dose to 1,000 mg orally once daily for adults and pediatric patients ≥12 years. Dose reduction for pediatric patients 4 to <12 years is dependent on body weight (please refer to Table 2 in the Full Prescribing Information).

Please see Full Prescribing Information for more information about Oxbryta.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). Continued approval for this indication may be contingent upon verification and description of clinical benefit in confirmatory trial(s).

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