Voxelotor

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. 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). ( 1 )

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. See Table 2 for complete dosing recommendations. ( 2.4 ) 2.1 Recommended Dosage for Adults and Pediatric Patients 12 Years and Older The recommended dosage of OXBRYTA is 1,500 mg orally once daily. 2.2 Recommended Dosage for Pediatric Patients 4 Years to Less Than 12 Years For pediatric patients 4 years to less than 12 years, select the appropriate product (OXBRYTA tablets or OXBRYTA tablets for oral suspension) based on patient's ability to swallow tablets and patient's weight. The recommended dosage of OXBRYTA for pediatric patients 4 years to less than 12 years is shown in Table 1. Table 1: Recommended OXBRYTA Dosage in Pediatric Patients 4 Years to Less Than 12 Years Body Weight Recommended Dose (once daily) 40 kg or greater 1,500 mg 20 kg to less than 40 kg 900 mg 10 kg to less than 20 kg 600 mg 2.3 Recommended Dosage for Adults and Pediatric Patients 12 Years and Older with Hepatic Impairment The recommended dosage of OXBRYTA in adults and pediatric patients 12 years and older with severe hepatic impairment (Child Pugh C) is 1,000 mg orally once daily. No dosage adjustment of OXBRYTA is required for patients with mild or moderate hepatic impairment [ see Use in Specific Populations (8.6) and Clinical Pharmacology (12.3) ]. 2.4 Recommended Dosage for Pediatric Patients 4 Years to Less Than 12 Years with Hepatic Impairment The recommended dosage of OXBRYTA in pediatric patients 4 years to less than 12 years with severe hepatic impairment (Child Pugh C) is described in Table 2. No dosage adjustment of OXBRYTA is required for patients with mild or moderate hepatic impairment [see Use in Specific Populations (8.6) and Clinical Pharmacology (12.3) ] . Table 2: Recommended OXBRYTA Dosage in Pediatric Patients 4 Years to Less Than 12 Years with Severe Hepatic Impairment (Child Pugh C) Body Weight Recommended Dose (once daily) 40 kg or greater 1,000 mg (two 500 mg tablets) or 900 mg (three 300 mg tablets for oral suspension or three 300 mg tablets) 20 kg to less than 40 kg 600 mg 10 kg to less than 20 kg 300 mg 2.5 Recommended Dosage of OXBRYTA for Adults and Pediatric Patients 12 Years and Older When Used with Concomitant Strong or Moderate CYP3A4 Inducers CYP3A4 Inducers Avoid concomitant use of strong or moderate CYP3A4 inducers with OXBRYTA [see Drug Interactions (7.1) and Clinical Pharmacology (12.3) ] . If concomitant use of strong CYP3A4 inducers is unavoidable, the recommended dosage of OXBRYTA is 2,500 mg orally once daily. If concomitant use of moderate CYP3A4 inducers is unavoidable, the recommended dosage of OXBRYTA is 2,000 mg orally once daily. 2.6 Recommended Dosage of OXBRYTA for Pediatric Patients 4 Years to Less Than 12 Years When Used with Concomitant Strong or Moderate CYP3A4 Inducers CYP3A4 Inducers Avoid concomitant use of strong or moderate CYP3A4 inducers with OXBRYTA [see Drug Interactions (7.1) and Clinical Pharmacology (12.3) ] . If concomitant use of strong or moderate CYP3A4 inducers is unavoidable, see Table 3 for dosage. Table 3: OXBRYTA Recommended Dosage for Pediatric Patients 4 Years to Less Than 12 Years When Used with Concomitant Strong or Moderate CYP3A4 Inducers Body Weight Recommended Dose (once daily) Concomitant Use of Strong CYP3A4 Inducers Concomitant Use of Moderate CYP3A4 Inducers 40 kg or greater 2,500 mg (five 500 mg tablets) or 2,400 mg (eight 300 mg tablets for oral suspension or eight 300 mg tablets) 2,000 mg (four 500 mg tablets) or 2,100 mg (seven 300 mg tablets for oral suspension or seven 300 mg tablets) 20 kg to less than 40 kg 1,500 mg 1,200 mg 10 kg to less than 20 kg 900 mg 900 mg 2.7 Important Administration Instructions Administer OXBRYTA orally, once daily with or without food. If a dose is missed, or not administered entirely, resume dosing the following day. OXBRYTA may be given with or without hydroxyurea. OXBRYTA 300 mg and 500 mg Tablets Patients should swallow OXBRYTA tablets whole. Do not cut, crush, or chew the tablets. OXBRYTA 300 mg Tablets for Oral Suspension Patients should disperse tablets for oral suspension immediately before administration in a cup and in room temperature clear liquid (such as drinking water, clear soda, apple juice, clear electrolyte drinks, clear flavored drinks, or clear sports drinks) before swallowing. Do not swallow whole, cut, crush, or chew the tablets for oral suspension. Recommended Daily Dose Number of Tablets for Oral Suspension Minimum Recommended Volume of Clear Drink 300 mg 1 5 mL (1 teaspoon) 600 mg 2 10 mL (2 teaspoons) 900 mg 3 15 mL (3 teaspoons) 1,200 mg 4 20 mL (4 teaspoons) 1,500 mg 5 25 mL (5 teaspoons) 2,100 mg 7 35 mL (7 teaspoons) 2,400 mg 8 40 mL (8 teaspoons) • After the tablets start to disintegrate, swirl the contents of the cup until the tablets are dispersed, wait 1 to 5 minutes, swirl the contents of the cup again, and then orally administer the contents of the cup. The tablet(s) will not completely dissolve; there will still be small tablet clumps in the mixture. • Resuspend any residue left in the cup in more clear drink and administer. Repeat until no tablet residue is left in the cup. Tablets for oral suspension may be substituted for tablets in adults and pediatric patients 12 years and older with difficulty swallowing the tablets. Use the number of tablets for oral suspension needed to achieve the recommended dose.

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 <12 years are pyrexia, vomiting, rash, abdominal pain, diarrhea, and headache. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Pfizer Inc. at 1-800-438-1985 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch . 6.1 Clinical Trials Experience 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. Adults and Pediatric Patients 12 Years and Older The safety of OXBRYTA was evaluated in the HOPE trial based on data from 88 patients with SCD who received OXBRYTA 1,500 mg and 91 patients who received placebo orally once daily [see Clinical Studies (14.1) ] . Seventy-four patients received OXBRYTA 1,500 mg once daily for ≥24 weeks, 65 patients for ≥48 weeks, and 63 patients completed the 72-week treatment period. In patients who received OXBRYTA 1,500 mg once daily the median age was 24 years (range:12 to 59 years); 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 adverse reactions occurred in 14% (12/88) of patients who received OXBRYTA 1,500 mg. The adverse reactions requiring dosage modification included rash (4.5%), diarrhea (3.4%), headache (2.3%), nausea (2.3%), abdominal pain (1.1%), and drug hypersensitivity (1.1%). The safety profile observed in pediatric patients 12 to <17 years treated with OXBRYTA in the HOPE trial 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 4. Table 4: Adverse Reactions (≥10%) in Patients Receiving OXBRYTA with a Difference Between Arms of >3% Compared to Placebo in HOPE Adverse Reaction Adverse reactions were Grades 1 or 2 except for Grade 3 headache (2), diarrhea (1), nausea (1), rash (1), and rash generalized (3) OXBRYTA 1,500 mg (N=88) Placebo (N=91) Headache 32% 25% Diarrhea 23% 11% Abdominal Pain Abdominal pain (grouped PTs) includes the following PTs: abdominal pain, lower abdominal pain, and upper abdominal pain 23% 16% Nausea 19% 10% Rash Rash (grouped PTs) includes the following PTs: rash, urticaria, generalized rash, macular rash, maculo-papular rash, pruritic rash, and papular rash 15% 11% Pyrexia 15% 8% Clinically relevant adverse reactions occurring in <10% of patients included: • Drug hypersensitivity 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 [see Clinical Studies (14.2) ] . 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. 6.2 Postmarketing Experience The following adverse reactions have been identified during postapproval use of OXBRYTA. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure: • Drug reaction with eosinophilia and systemic symptoms (DRESS), Pruritis, Angioedema (including swelling of eyelid, face edema, lip swelling, and periorbital swelling).

12.3 Pharmacokinetics Voxelotor is absorbed into plasma and is then distributed predominantly into RBCs due to its preferential binding to Hb. The major route of elimination of voxelotor is by metabolism with subsequent excretion of metabolites into urine and feces. The PK are linear and voxelotor exposures increased proportionally with either single or multiple doses (Table 5) in whole blood, plasma, and RBCs. Steady-state after repeated administration is reached within 8 days and exposures of voxelotor are consistent with accumulation predicted based on single dose data in patients with SCD. Table 5: Pharmacokinetics Parameters of Voxelotor in Plasma and Whole Blood Based on the 72-week population pharmacokinetic analysis. PK Parameter Voxelotor 1,500 mg Geometric Mean (%CV) Plasma PK AUC 0-24h (μg∙hr/mL) 278 (28.4) C max (µg/mL) 14 (24.5) Half-life (hours) 38.7 (30.2) Whole Blood PK AUC 0-24h (μg∙hr/mL) 3,830 (33.5) C max (µg/mL) 180 (31) In healthy subjects, voxelotor exposures were comparable when administered as tablet for oral suspension dispersed in water or as oral tablet swallowed whole. Absorption The median plasma and whole blood T max of voxelotor after oral administration is 2 hours. The mean peak concentrations in whole blood and RBCs are observed between 6 and 18 hours after oral administration. Effect of Food A high-fat, high-calorie meal increased voxelotor AUC by 42% and C max by 45% in whole blood relative to AUC and C max in the fasted state. Similarly, AUC increased by 42% and C max increased by 95% in plasma. Distribution Voxelotor apparent volume of distribution of the central compartment and peripheral compartment are 333 L and 72.3 L in plasma, respectively. Protein binding is 99.8% in vitro. The blood-to-plasma ratio is approximately 17:1 in patients with SCD. Elimination The geometric mean (%CV) terminal elimination half-life of voxelotor in patients with SCD is 38.7 hours (30.2%) with concentrations in plasma, whole blood, and RBCs declining in parallel. The apparent oral clearance of voxelotor was estimated as 6.1 L/h in plasma in patients with SCD. Metabolism In vitro and in vivo studies indicate that voxelotor is extensively metabolized through Phase I (oxidation and reduction), Phase II (glucuronidation) and combinations of Phase I and II metabolism. Metabolism of voxelotor is mediated by CYP3A4, CYP3A5, CYP2B6, CYP2C19, CYP2C9, UGT1A1, and UGT1A9. Excretion Following the administration of radiolabeled voxelotor, approximately 62.6% of the dose and its metabolites are excreted into feces (33.3% unchanged) and 35.5% in urine (0.08% unchanged). Specific Populations No clinically significant differences in the pharmacokinetics of voxelotor were observed based on age (12 to 59 years), sex, body weight (28 to 135 kg), or mild to severe renal impairment (creatinine clearance [CLcr] 15-89 mL/min). Pediatric Patients The pharmacokinetic exposures of voxelotor in whole blood and plasma were similar between pediatric patients 4 to <17 years and adults following the recommended dosage [see Dosage and Administration (2) ] . Patients with Renal Impairment There was no clinically significant effect of renal function on the excretion of voxelotor. Following a single 900 mg dose of voxelotor, whole blood exposures in subjects with severe renal impairment (eGFR <30 mL/min/1.73 m 2 ) were 25% lower compared to healthy controls. The unbound plasma concentrations were comparable. OXBRYTA has not been evaluated in patients with end stage renal disease requiring dialysis. Patients with Hepatic Impairment The voxelotor AUC in whole blood were 14% and 15% higher in subjects with mild and moderate hepatic impairment (Child Pugh A and B) and 90% higher in subjects with severe hepatic impairment (Child Pugh C) compared to subjects with normal hepatic function. Patients with HbSC Genotype Voxelotor steady state whole blood AUC and C max were 50% and 45% higher in HbSC genotype patients (n=11) compared to HbSS genotype (n=220) patients and voxelotor steady state plasma AUC and C max were 23% and 15% higher in HbSC genotype patients compared to HbSS genotype patients. Drug Interaction Studies Clinical Studies and Model-Informed Approaches Effect of Strong CYP3A4 Inhibitors on Voxelotor: concomitant use of OXBRYTA with itraconazole increased voxelotor AUC in healthy subjects by 11%. Effect of Strong or Moderate CYP3A4 Inducers on Voxelotor : concomitant use of OXBRYTA with rifampin (a strong CYP3A4 inducer) is predicted to decrease voxelotor AUC in patients by up to 40%, and efavirenz (a moderate CYP3A4 inducer) is predicted to decrease voxelotor AUC in patients by up to 24%. Effect of Acid Reducing Agents on Voxelotor: coadministration of omeprazole (proton pump inhibitor) with OXBRYTA did not alter voxelotor exposure. Effect of Voxelotor on CYP450 Enzymes: in vivo voxelotor inhibits CYP3A4, but not CYP1A2, CYP2C9, CYP2C19, CYP2C8, or CYP2D6. The observed exposure increase of the CYP3A4 substrate midazolam in healthy subjects was 1.6-fold and the predicted increase in patients after multiple dosing is 2.5-fold. Effect of Voxelotor on P-gp : concomitant use of OXBRYTA with digoxin (a P-gp substrate) did not alter digoxin to a clinically relevant extent. In Vitro Studies CYP Enzymes: voxelotor is a reversible and time-dependent inhibitor as well as an inducer of CYP2B6. Transporter Systems : voxelotor is not an inhibitor of P-gp, BCRP, OATP1B1, OATP1B3, OCT2, OAT1, OAT3, MATE1, MATE2-K, or BSEP. Voxelotor is not a substrate of P-gp, BCRP, OATP1A2, OATP1B1, OATP1B3, or BSEP.