OXBRYTA Film-coated tablet Ref.[9906] Active ingredients: Voxelotor

5.1 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 [see Adverse Reactions (6.1)].

If hypersensitivity reactions occur, discontinue OXBRYTA and administer appropriate medical therapy. Do not reinitiate OXBRYTA in patients who experience these symptoms with previous use.

5.2 Laboratory Test Interference

OXBRYTA administration may interfere with measurement of Hb subtypes (HbA, HbS, and HbF) by high-performance liquid chromatography (HPLC) [see Drug Interactions (7.3)]. If precise quantitation of Hb species is required, chromatography should be performed when the patient is not receiving OXBRYTA therapy.

The following clinically significant adverse reaction is discussed in other sections of the labeling: Hypersensitivity Reactions [see Contraindications (4)].

Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice.

The safety of OXBRYTA was evaluated in the HOPE trial based upon 88 patients who received OXBRYTA 1,500 mg and 91 patients who received placebo orally once daily [see Clinical Studies (14)]. Seventy-four patients received OXBRYTA 1,500 mg once daily for ≥24 weeks and 65 patients for ≥48 weeks.

In patients who received OXBRYTA 1,500 mg once daily the median age was 24 years (range:12-59); 65% female; 66% Black or African American and 23% Arab/Middle Eastern; and 65% receiving hydroxyurea at baseline.

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.

Dosage modifications (dose reduction or dosing interruption) due to an adverse reaction occurred in 41% (36/88) of patients who received OXBRYTA. Most frequent adverse reactions requiring dosage interruption occurring in more than one patient who received OXBRYTA 1,500 mg included diarrhea, headache, rash, and vomiting.

The safety profile observed in pediatric patients 12 to <17 years of age treated with OXBRYTA was similar to that seen in adult patients.

The most common adverse reactions occurring in ≥10% of patients treated with OXBRYTA 1,500 mg with a difference of >3% compared to placebo are summarized in Table 2.

Table 2. Adverse Reactions (≥10%) in Patients Receiving OXBRYTA with a Difference Between Arms of >3% Compared to Placebo in HOPE:

* Adverse reactions were Grades 1 or 2 except for Grade 3 diarrhea (1), nausea (1), rash (1), and rash generalized (3)
^† Abdominal pain (grouped PTs) included the following PTs: abdominal pain and upper abdominal pain
^‡ Rash (grouped PTs) includes the following PTs: rash, urticaria, generalized rash, maculo-papular rash, pruritic rash, papular rash, erythematous rash, and vesicular rash

Clinically relevant adverse reactions occurring in <10% of patients included:

• Drug hypersensitivity

7.1 Effect of Other Drugs on Voxelotor

Strong CYP3A4 Inhibitors or Fluconazole

Co-administration of strong CYP3A4 inhibitors or fluconazole may increase voxelotor plasma concentrations and may lead to increased toxicity. Avoid co-administration of OXBRYTA with strong CYP3A4 inhibitors or fluconazole and replace these drugs with alternative drugs when possible [see Clinical Pharmacology (12.3)]. Decrease the OXBRYTA dosage when co-administration with a strong CYP3A4 inhibitor or fluconazole is unavoidable [see Dosage and Administration (2.3)].

Strong or Moderate CYP3A4 Inducers

Co-administration of strong or moderate CYP3A4 inducers may decrease voxelotor plasma concentrations and may lead to reduced efficacy.

Avoid co-administration of OXBRYTA with strong or moderate CYP3A4 inducers. Increase the OXBRYTA dosage when co-administration with a strong or moderate CYP3A4 inducer is unavoidable [see Dosage and Administration (2.3)].

7.2 Effect of Voxelotor on Other Drugs

Voxelotor increased the systemic exposure of midazolam (a sensitive CYP3A4 substrate) [see Clinical Pharmacology (12.3)]. Avoid co-administration 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).

7.3 Laboratory Test Interference

OXBRYTA administration may interfere with measurement of Hb subtypes (HbA, HbS, and HbF) by HPLC [see Warnings and Precautions (5.2)]. If precise quantitation of Hb species is required, chromatography should be performed when the patient is not receiving OXBRYTA therapy.

Risk Summary

There are no available data on OXBRYTA use in pregnant women to evaluate for a drug-associated risk of major birth defects, miscarriage or adverse maternal or fetal outcomes. In animal reproduction studies, oral administration of voxelotor to pregnant rats and rabbits during organogenesis at exposures up to 2.8-times (rats) and 0.3-times (rabbits) the exposure at the maximum recommended human dose resulted in no adverse developmental effects (see Data).

The estimated background risk of major birth defects and miscarriage for the indicated population is approximately 14% and up to 43%, respectively. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes.

There are adverse effects on maternal and fetal outcomes associated with sickle cell disease in pregnancy (see Clinical Considerations). OXBRYTA should only be used during pregnancy if the benefit of the drug outweighs the potential risk.

Clinical Considerations

Disease-Associated Maternal and/or Embryo/Fetal Risk

Women with sickle cell disease have an increased risk of adverse pregnancy outcomes for the mother and the fetus. Pregnant women are at greater risk for vasoocclusive crises, pre-eclampsia, eclampsia, and maternal mortality. For the fetus, there is an increased risk for intrauterine growth restriction, preterm delivery, low birth weight, and perinatal mortality.

Data

Animal Data

In embryo-fetal development studies, voxelotor was administered orally to pregnant rats at 15, 50, and 250 mg/kg/day (gestation days 7 through 17) and rabbits at 25, 75, and 150 mg/kg/day (gestation days 7 through 19) through organogenesis. Maternal toxicity was observed at the highest dose levels in these studies equivalent to 2.8-times (rats) and 0.3-times (rabbits) the exposures in patients receiving OXBRYTA at the recommended daily dose. There was no evidence of adverse developmental outcomes in rats or rabbits.

In a pre- and postnatal development study, voxelotor was administered orally to pregnant rats at 15, 50 and 250 mg/kg/day (gestation day 6 through lactation day 20). Maternal gestational body weights were decreased at 250 mg/kg/day, which continued to the end of lactation. The findings in offspring included reduced survival and reduced body weights throughout lactation, weaning and maturation. The effects in offspring were observed at the maternal dose of 250 mg/kg/day with an exposure approximately 2.8-times the exposure in patients at the recommended dose.

Risk Summary

There are no data on the presence of voxelotor in human milk, the effects on the breastfed child, or the 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. When a drug is present in animal milk, it is likely that the drug will be present in human milk. The concentration of voxelotor in animal milk does not necessarily predict the concentration of drug in human milk. 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.

The safety and effectiveness of OXBRYTA for sickle cell disease have been established in pediatric patients aged 12 years and older. Use of OXBRYTA for sickle cell disease is supported by evidence from an adequate and well-controlled study in adults and pediatric patients (HOPE trial). The HOPE trial enrolled a total of 26 pediatric patients aged 12 to <17 years, in which 12 pediatric patients received OXBRYTA 1,500 mg once daily and 14 pediatric patients received OXBRYTA 900 mg once daily [see Adverse Reactions (6.1), Clinical Pharmacology (12.3), and Clinical Studies (14)]. The safety and efficacy of OXBRYTA in pediatric patients below the age of 12 years have not been established.

Pharmacokinetics, safety and efficacy in pediatric patients 12 years to <17 years were similar to that observed in adults [see Dosage and Administration (2), Clinical Pharmacology (12.3) and Clinical Studies (14)].

The adverse reactions observed in pediatric patients 12 to <17 years treated with OXBRYTA were similar in type and frequency to those observed in adults [see Adverse Reactions (6.1)].

Clinical studies of OXBRYTA did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects.

Severe hepatic impairment increases voxelotor exposures [see Clinical Pharmacology (12.3)]. Reduce OXBRYTA dose [see Dosage and Administration (2.2)].