Emflaza deflazacort 30 mg Tablet, 30-count — NDC 52856-503-03 (Billing 52856-0503-03)

12 CLINICAL PHARMACOLOGY

12.1Mechanism of Action Deflazacort is a corticosteroid prodrug, whose active metabolite, 21-desDFZ, acts through the glucocorticoid receptor to exert anti-inflammatory and immunosuppressive effects. The precise mechanism by which deflazacort exerts its therapeutic effects in patients with DMD is unknown.

12.3Pharmacokinetics Absorption After oral administration in the fasted state, the median T max with deflazacort tablets or suspension is about 1 hour (range 0.25 to 2 hours). Food Effect: Co-administration of deflazacort tablets with a high-fat meal reduced C max by about 30% and delayed T max by one hour, relative to administration under fasting conditions, but there was no effect on the overall systemic absorption as measured by AUC. The bioavailability of deflazacort tablets was similar to that of the oral suspension.

The administration of deflazacort with food or crushed in applesauce did not affect the absorption and bioavailability of deflazacort. Distribution The protein binding of the active metabolite of deflazacort is about 40%. Elimination Metabolism Deflazacort is rapidly converted to the active metabolite 21-desDFZ by esterases after oral administration.

21-desDFZ is further metabolized by CYP3A4 to several other inactive metabolites, including 6β-hydroxy-21-desacetyl deflazacort. Excretion Urinary excretion is the predominant route of deflazacort elimination (about 68% of the dose), and the elimination is almost completed by 24 hours post dose. 21-desDFZ accounts for 18% of the eliminated drug in the urine.

Specific Populations Pediatric Patients The C max values (Geometric mean, %CV) of 21-desDFZ in children (ages 4-11, N=16) and adolescents (ages 12-16, N=8) was 206 ng/mL (95.6%) and 381 ng/mL (37.7%), respectively, on Day 1 after administration of 0.9 mg/kg deflazacort. The AUC inf (Geometric mean, %CV) of 21-desDFZ in children (ages 4-11, N=16) and adolescents (ages 12-16, N=8) was 400 ng•h/mL (87.5%) and 655 ng•h/mL (58.1%) on Day 1 after administration of 0.9 mg/kg deflazacort. Male and Female Patients There are no differences in the pharmacokinetics of 21-desDFZ between males and females.

Racial or Ethnic Groups There are no differences in the pharmacokinetics of 21-desDFZ between Caucasians and non-Caucasians. Patients with Renal Impairment In a study (N=16) comparing subjects with end stage renal disease (creatinine clearance less than 15 mL/min) with healthy matched controls, 21-desDFZ exposure was similar between the groups. Patients with Hepatic Impairment In a study (N=16) comparing subjects with moderate hepatic impairment (Child-Pugh Class B) with healthy matched controls, 21-desDFZ exposure was similar between the groups.

There is no experience in patients with severe hepatic impairment. Drug Interaction Studies In Vivo Assessment of Drug Interactions Compared to administration of deflazacort alone, administration of deflazacort following multiple doses of a strong CYP3A4 and Pgp inhibitor (clarithromycin) resulted in markedly higher C max , AUC last , and AUC inf values of 21-desDFZ. Geometric mean exposure (C max , AUC last , and AUC inf ) of 21-desDFZ ranged from 2.3-fold to 3.4-fold higher following administration of clarithromycin [see Dosage and Administration ( 2.5 )] .

Compared to administration of deflazacort alone, administration of deflazacort following multiple doses of a strong CYP3A4 inducer (rifampicin) resulted in markedly lower C max , AUC last , and AUC inf values of 21-desDFZ. Geometric mean exposures (C max , AUC la st , and AUC inf ) of 21-desDFZ were approximately 95% lower following administration of rifampin [see Drug Interactions ( 7.1 )] . 6β-Hydroxy-21-desacetyl deflazacort, a secondary and inactive metabolite, is not expected to cause any clinically meaningful interactions with the CYP enzymes or transporters.

In Vitro Assessment of Drug Interactions Drug-Metabolizing Enzyme Inhibition 21-desDFZ at clinically relevant concentrations did not… [Excerpted — this section continues on DailyMed.]

12.1Mechanism of Action Deflazacort is a corticosteroid prodrug, whose active metabolite, 21-desDFZ, acts through the glucocorticoid receptor to exert anti-inflammatory and immunosuppressive effects. The precise mechanism by which deflazacort exerts its therapeutic effects in patients with DMD is unknown.

12.3Pharmacokinetics Absorption After oral administration in the fasted state, the median T max with deflazacort tablets or suspension is about 1 hour (range 0.25 to 2 hours). Food Effect: Co-administration of deflazacort tablets with a high-fat meal reduced C max by about 30% and delayed T max by one hour, relative to administration under fasting conditions, but there was no effect on the overall systemic absorption as measured by AUC. The bioavailability of deflazacort tablets was similar to that of the oral suspension.

The administration of deflazacort with food or crushed in applesauce did not affect the absorption and bioavailability of deflazacort. Distribution The protein binding of the active metabolite of deflazacort is about 40%. Elimination Metabolism Deflazacort is rapidly converted to the active metabolite 21-desDFZ by esterases after oral administration.

21-desDFZ is further metabolized by CYP3A4 to several other inactive metabolites, including 6β-hydroxy-21-desacetyl deflazacort. Excretion Urinary excretion is the predominant route of deflazacort elimination (about 68% of the dose), and the elimination is almost completed by 24 hours post dose. 21-desDFZ accounts for 18% of the eliminated drug in the urine.

Specific Populations Pediatric Patients The C max values (Geometric mean, %CV) of 21-desDFZ in children (ages 4-11, N=16) and adolescents (ages 12-16, N=8) was 206 ng/mL (95.6%) and 381 ng/mL (37.7%), respectively, on Day 1 after administration of 0.9 mg/kg deflazacort. The AUC inf (Geometric mean, %CV) of 21-desDFZ in children (ages 4-11, N=16) and adolescents (ages 12-16, N=8) was 400 ng•h/mL (87.5%) and 655 ng•h/mL (58.1%) on Day 1 after administration of 0.9 mg/kg deflazacort. Male and Female Patients There are no differences in the pharmacokinetics of 21-desDFZ between males and females.

Racial or Ethnic Groups There are no differences in the pharmacokinetics of 21-desDFZ between Caucasians and non-Caucasians. Patients with Renal Impairment In a study (N=16) comparing subjects with end stage renal disease (creatinine clearance less than 15 mL/min) with healthy matched controls, 21-desDFZ exposure was similar between the groups. Patients with Hepatic Impairment In a study (N=16) comparing subjects with moderate hepatic impairment (Child-Pugh Class B) with healthy matched controls, 21-desDFZ exposure was similar between the groups.

There is no experience in patients with severe hepatic impairment. Drug Interaction Studies In Vivo Assessment of Drug Interactions Compared to administration of deflazacort alone, administration of deflazacort following multiple doses of a strong CYP3A4 and Pgp inhibitor (clarithromycin) resulted in markedly higher C max , AUC last , and AUC inf values of 21-desDFZ. Geometric mean exposure (C max , AUC last , and AUC inf ) of 21-desDFZ ranged from 2.3-fold to 3.4-fold higher following administration of clarithromycin [see Dosage and Administration ( 2.5 )] .

Compared to administration of deflazacort alone, administration of deflazacort following multiple doses of a strong CYP3A4 inducer (rifampicin) resulted in markedly lower C max , AUC last , and AUC inf values of 21-desDFZ. Geometric mean exposures (C max , AUC la st , and AUC inf ) of 21-desDFZ were approximately 95% lower following administration of rifampin [see Drug Interactions ( 7.1 )] . 6β-Hydroxy-21-desacetyl deflazacort, a secondary and inactive metabolite, is not expected to cause any clinically meaningful interactions with the CYP enzymes or transporters.

In Vitro Assessment of Drug Interactions Drug-Metabolizing Enzyme Inhibition 21-desDFZ at clinically relevant concentrations did not inhibit CYP1A2, 2C9, 2C19, 3A4, UGT1A1, UGT1A4, UGT1A6, UGT1A9, or UGT2B7 and exhibited weak and not likely clinically meaningful inhibition for 2B6, 2C8, 2D6, and 3A4, UGT1A3 and UGT2B15. 6β-Hydroxy-21-desacetyl deflazacort at clinically relevant concentrations did not significantly inhibit CYP2C19, 3A4 1A2, 2B6, 2C8, 2C9, or 2D6.… [Excerpted — this section continues on DailyMed.]

6.1Clinical 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. In Study 1 [see Clinical Studies ( 14 )] , the adverse reactions that were associated with deflazacort treatment discontinuation, in decreasing order of frequency, were weight increased, obesity, cataract, and sleep disorder. Most Common Adverse Reactions in Clinical Studies Table 1 lists the adverse reactions that occurred in ≥ 5% of patients in the 0.9 mg/kg/day deflazacort-treated group and that occurred more frequently than in placebo patients in Study 1, which included patients with DMD between the ages of 5 and 15 years.

Table 1: Adverse Reactions that Occurred in ≥ 5% of Deflazacort-Treated Patients and Occurred More Frequently than in Placebo Patients with DMD (Study 1) 1 At 12 weeks placebo patients were re-randomized to receive either deflazacort or an active comparator. Adverse Reaction Deflazacort 0.9 mg/kg/d (N=51) % at 12 weeks Placebo (N=50) % at 12 weeks 1 Cushingoid appearance 33 12 Weight increased 20 6 Increased appetite 14 2 Upper respiratory tract infection 12 10 Cough 12 6 Pollakiuria 12 2 Nasopharyngitis 10 6 Hirsutism 10 2 Central obesity 10 4 Erythema 8 6 Irritability 8 4 Rhinorrhea 8 0 Abdominal discomfort 6 2 Common adverse reactions (≥ 5% of deflazacort-treated patients) that occurred over 52 weeks of exposure to deflazacort 0.9 mg/kg/day in Study 1 and at a higher rate than deflazacort 0.9 mg/kg/day in the 12-week placebo-controlled phase of the trial include Cushingoid appearance (60%), hirsutism (35%), weight increased (28%), erythema (28%), central obesity (25%), abdominal pain/abdominal pain upper (18% combined), pollakiuria (15%), constipation (10%), irritability (10%), abnormal behavior (9%), pyrexia (9%), back pain (7%), rash (7%), contusion (6%), nausea (6%), psychomotor hyperactivity (6%), epistaxis (6%), and skin striae (6%).

Study 1 also evaluated a higher dosage of deflazacort (1.2 mg/kg/day). Compared with the 0.9 mg/kg/day dosage, deflazacort 1.2 mg/kg/day over 52 weeks was associated with a higher incidence of certain adverse reactions, including Cushingoid appearance (69%), erythema (49%), hirsutism (37%), headache (34%), weight increased (32%), constipation (15%), abdominal pain upper (14%), skin striae (11%), acne (11%), and abdominal discomfort (8%). As there was no additional benefit with the 1.2 mg/kg/day dose of deflazacort, use of EMFLAZA 1.2 mg/kg/day is not recommended for the treatment of DMD [see Dosage and Administration ( 2.2 )] .

In an additional clinical study of two years duration with extended follow-up (Study 2), many of the same adverse reactions were observed. In addition, musculoskeletal events associated with long-term steroid use were also observed, including muscle weakness, tendon disorder, and osteopenia. Less Common Adverse Reactions Observed in Clinical Studies Other adverse reactions (≥ 1% frequency in any deflazacort treatment group and greater than placebo) that were observed during the 12-week placebo-controlled phase of Study 1 are shown below.

Eye Disorders: Lacrimation increased Gastrointestinal Disorders: Dyspepsia, nausea, gastrointestinal disorder General Disorders and Administration Site Conditions: Thirst Infections: Hordeolum, impetigo, influenza, otitis externa, pharyngitis, tooth abscess, urinary tract infection, viral infection Injury, Poisoning and Procedural Complications: Back injury, contusion, face injury, fibula fracture, greenstick fracture, heat exhaustion Investigations: Glucose urine present, heart rate irregular Musculoskeletal and Connective Tissue Disorders: Back pain, muscle spasms, myalgia, neck mass, neck pain, pain in extremity Nervous System Disorders: Dizziness, psychomotor hyperactivity Psychiatric Disorders: Affect lability, aggr… [Excerpted — this section continues on DailyMed.]

13 NONCLINICAL TOXICOLOGY

13.1Carcinogenesis, Mutagenesis, Impairment of Fertility Carcinogenesis In a published 2-year carcinogenicity study in rats, oral administration of deflazacort (0, 0.03, 0.06, 0.12, 0.25, 0.50, or 1.0 mg/kg/day) resulted in bone tumors (osteosarcoma and osteoma) of the head at 0.25 mg/kg/day, the highest evaluable dose. Doses higher than 0.25 mg/kg/day could not be evaluated for tumors because of a marked decrease in survival. In a 6-month carcinogenicity study in transgenic (Tg.RasH2) mice, oral administration of deflazacort (0, 2, 5, or 20 mg/kg/day in males; 0, 0.5, 2, or 5 mg/kg/day in females) resulted in an increase in stomach tumors (adenoma) at the highest dose tested in males and females.

Mutagenesis Deflazacort and 21-desDFZ were negative in in vitro (bacterial reverse mutation and human lymphocyte chromosomal aberration) assays and deflazacort was negative in an in vivo (rat micronucleus) assay. Impairment of Fertility Fertility studies in animals were not conducted with deflazacort. No effects on the male reproductive system were observed following oral administration of deflazacort to monkeys (0, 1.0, 3.0, or 6.0 mg/kg/day) for 39 weeks or rats (0, 0.05, 0.15, or 0.5 mg/kg/day) for 26 weeks.

Plasma 21-desDFZ exposures (AUC) at the highest doses tested in monkey and rat were 4 and 2 times, respectively, that in humans at the recommended human dose of EMFLAZA (0.9 mg/kg/day).