Deutivacaftor

12.1 Mechanism of Action Vanzacaftor and tezacaftor bind to different sites on the CFTR protein and have an additive effect in facilitating the cellular processing and trafficking of select mutant forms of CFTR (including F508del- CFTR) to increase the amount of CFTR protein delivered to the cell surface compared to either molecule alone. Deutivacaftor potentiates the channel open probability (or gating) of the CFTR protein at the cell surface. The combined effect of vanzacaftor, tezacaftor and deutivacaftor is increased quantity and function of CFTR at the cell surface, resulting in increased CFTR activity as measured both by CFTR mediated chloride transport in vitro and by sweat chloride in patients with CF. CFTR Chloride Transport Assay in Fischer Rat Thyroid Cells Expressing Mutant CFTR Protein Effects of vanzacaftor/tezacaftor/deutivacaftor on chloride transport for mutant CFTR protein was determined in Ussing chamber electrophysiology studies using a panel of Fischer Rat Thyroid (FRT) cell lines stably expressing CFTR protein from individual mutations. Vanzacaftor/tezacaftor/deutivacaftor increased chloride transport in FRT cells expressing select CFTR mutations, as identified in Table 5. The threshold that the treatment-induced increase in chloride transport must exceed for the mutant CFTR protein to be considered responsive is ≥10% of normal over baseline. This threshold was used because it is expected to predict clinical benefit. For individual mutations, the magnitude of the net change over baseline in CFTR-mediated chloride transport in vitro is not correlated with the magnitude of clinical response. CFTR Chloride Transport Assay in Human Bronchial Epithelial Cells Expressing Mutant CFTR Protein Homozygous and heterozygous N1303K- Human Bronchial Epithelial (HBE) cells showed greater chloride transport in the presence of vanzacaftor/tezacaftor/deutivacaftor than F508del/F508del- HBE cells treated with tezacaftor/ivacaftor which has shown clinical benefit

1 INDICATIONS AND USAGE ALYFTREK is indicated for the treatment of cystic fibrosis (CF) in patients 6 years of age and older who have at least one F508del mutation or another responsive mutation in the cystic fibrosis transmembrane conductance regulator ( CFTR ) gene (see Table 5 ) [see Clinical Pharmacology (12.1) ]. If the patient's genotype is unknown, an FDA-cleared CF mutation test should be used to confirm the presence of at least one indicated mutation. ALYFTREK is a combination of deutivacaftor, a CFTR potentiator, tezacaftor, and vanzacaftor indicated for the treatment of cystic fibrosis (CF) in patients aged 6 years and older who have at least one F508del mutation or another responsive mutation in the CFTR gene. ( 1 , 12.1 ) If the patient's genotype is unknown, an FDA-cleared CF mutation test should be used to confirm the presence of at least one indicated mutation. ( 1 , 12.1 )

2 DOSAGE AND ADMINISTRATION Prior to initiating ALYFTREK obtain liver function tests (ALT, AST, alkaline phosphatase, and bilirubin) in all patients. Monitor liver function tests every month during the first 6 months of treatment, then every 3 months during the next 12 months, then at least annually thereafter. ( 2.1 , 5.1 ) Recommended Dosage for Adult and Pediatric Patients Aged 6 Years and Older (with fat-containing food) ( 2.2 ) Age Weight Once Daily Oral Dosage 6 to less than 12 years old Less than 40 kg Three tablets of vanzacaftor 4 mg/tezacaftor 20 mg/deutivacaftor 50 mg Greater than or equal to 40 kg Two tablets of vanzacaftor 10 mg/tezacaftor 50 mg/deutivacaftor 125 mg 12 years and older Any Weight Two tablets of vanzacaftor 10 mg/tezacaftor 50 mg/deutivacaftor 125 mg Should not be used in patients with severe hepatic impairment. Use not recommended in patients with moderate hepatic impairment unless the benefit outweighs the risk. If used, no dose adjustment is recommended. Liver function tests should be closely monitored. ( 2.4 , 5.1 , 6.1 , 8.7 ) See full prescribing information for dosage modifications for concomitant use of ALYFTREK with strong or moderate CYP3A inhibitors. ( 2.3 , 5.6 , 7.1 ) 2.1 Recommended Laboratory Testing Prior to ALYFTREK Initiation and During Treatment Prior to initiating ALYFTREK, obtain liver function tests (ALT, AST, alkaline phosphatase, and bilirubin) for all patients. Monitor liver function tests every month during the first 6 months of treatment, then every 3 months for the next 12 months, then at least annually thereafter. Consider more frequent monitoring for patients with a history of liver disease, elevated liver function tests at baseline, or a history of elevated liver function tests with drugs containing elexacaftor, tezacaftor, and/or ivacaftor [see Warnings and Precautions (5.1) and Use in Specific Populations (8.7) ]. 2.2 Recommended Dosage The recommended ALYFTREK dosage in adult and pediatric patients aged 6 years and older is provided in Table 1. Administer ALYFTREK orally (swallow the tablets whole) with fat-containing food, once daily, at approximately the same time each day [see Clinical Pharmacology (12.3) ]. Examples of meals or snacks that contain fat are those prepared with butter or oils or those containing eggs, peanut butter, cheeses, nuts, whole milk, or meats. Table 1: Recommended Dosage of ALYFTREK in Adult and Pediatric Patients Aged 6 Years and Older Age Weight Once Daily Oral Dosage 6 to less than 12 years old Less than 40 kg Three tablets of vanzacaftor 4 mg/tezacaftor 20 mg/deutivacaftor 50 mg (total dose of vanzacaftor 12 mg/tezacaftor 60 mg/ deutivacaftor 150 mg) Greater than or equal to 40 kg Two tablets of vanzacaftor 10 mg/tezacaftor 50 mg/deutivacaftor 125 mg (total dose of vanzacaftor 20 mg/tezacaftor 100 mg/ deutivacaftor 250 mg) 12 years and older Any weight Two tablets of vanzacaftor 10 mg/tezacaftor 50 mg/deutivacaftor 125 mg (total dose of vanzacaftor 20 mg/tezacaftor 100 mg/ deutivacaftor 250 mg) 2.3 Dosage Modification for Strong or Moderate CYP3A Inhibitors Table 2 describes the recommended dosage modification for ALYFTREK when used concomitantly with strong or moderate CYP3A inhibitors [see Warnings and Precautions (5.6) ] . Administer ALYFTREK orally (swallow the tablets whole) with fat-containing food, once daily, at approximately the same time each day [see Clinical Pharmacology (12.3) ]. Table 2: Dosage Modification for Concomitant Use of ALYFTREK with Strong or Moderate CYP3A Inhibitors in Adult and Pediatric Patients Aged 6 Years and Older Age Weight Moderate CYP3A Inhibitors Strong CYP3A Inhibitors 6 to less than 12 years old Less than 40 kg Two tablets of vanzacaftor 4 mg/tezacaftor 20 mg/deutivacaftor 50 mg every other day (total dose of vanzacaftor 8 mg/tezacaftor 40 mg/deutivacaftor 100 mg) Two tablets of vanzacaftor 4 mg/tezacaftor 20 mg/deutivacaftor 50 mg once a week (total dose of vanzacaftor 8 mg/tezacaftor 40 mg/deutivacaftor 100 mg) Greater than or equal to 40 kg One tablet of vanzacaftor 10 mg/tezacaftor 50 mg/deutivacaftor 125 mg every other day One tablet of vanzacaftor 10 mg/tezacaftor 50 mg/deutivacaftor 125 mg once a week 12 years and older Any weight One tablet of vanzacaftor 10 mg/tezacaftor 50 mg/deutivacaftor 125 mg every other day One tablet of vanzacaftor 10 mg/tezacaftor 50 mg/deutivacaftor 125 mg once a week 2.4 Recommended Dosage for Patients with Hepatic Impairment Severe Hepatic Impairment (Child-Pugh Class C) : ALYFTREK should not be used in patients with severe hepatic impairment (HI) (Child-Pugh Class C). Moderate Hepatic Impairment (Child-Pugh Class B) : The use of ALYFTREK in patients with moderate HI (Child-Pugh Class B) is not recommended. Use of ALYFTREK should only be considered in patients with moderate HI when there is a clear medical need, and the benefit outweighs the risk. If used, the recommended dosage in patients with moderate HI is the same as for patients with n

6 ADVERSE REACTIONS The following clinically significant adverse reactions are discussed in greater detail in other sections of the labeling: Drug-Induced Liver Injury and Liver Failure [see Warnings and Precautions (5.1) ] Hypersensitivity Reactions, Including Anaphylaxis [see Warnings and Precautions (5.2) ] Patients Who Discontinued or Interrupted Elexacaftor-, Tezacaftor-, or Ivacaftor-Containing Drugs Due to Adverse Reactions [see Warnings and Precautions (5.3) ] Intracranial Hypertension [see Warnings and Precautions (5.4) ] Cataracts [see Warnings and Precautions (5.7) ] Most common adverse reactions to ALYFTREK (≥5% of patients and at a frequency higher than ELX/TEZ/IVA by ≥1%) were cough, nasopharyngitis, upper respiratory tract infection, headache, oropharyngeal pain, influenza, fatigue, increased ALT, rash, increased AST, and sinus congestion. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Vertex Pharmaceuticals Incorporated at 1-877-634-8789 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 clinical practice. The adverse reactions data below are from clinical trials of ALYFTREK in patients 6 years of age and older with CF with at least one responsive CFTR mutation who were able to tolerate ELX/TEZ/IVA. Adverse reactions data in patients who previously discontinued or interrupted ELX/TEZ/IVA due to adverse reactions are not available . Adverse Reactions in Patients Aged 12 Years and Older with CF The safety of ALYFTREK is based on 480 patients with CF aged 12 years and older who have at least one F508del mutation or another responsive mutation in the CFTR gene in two, 52-week, active-controlled trials (Trials 1 and 2) [see Clinical Studies (14) ]. In both trials, patients received a fixed-dose combination drug containing elexacaftor, tezacaftor, and ivacaftor (ELX/TEZ/IVA) in a 4-week run-in period and then were subsequently randomized to continue ELX/TEZ/IVA (elexacaftor 200 mg/tezacaftor 100 mg/ivacaftor 150 mg in the morning and ivacaftor 150 mg in the evening) or receive ALYFTREK (vanzacaftor 20 mg/tezacaftor 100 mg/deutivacaftor 250 mg) once daily. Patients with a history of prior intolerance to ELX/TEZ/IVA (i.e., patients who discontinued or interrupted treatment due to adverse reactions) were excluded. Trials 1 and 2 were not designed to evaluate meaningful comparisons of the incidence of adverse reactions between the ALYFTREK and ELX/TEZ/IVA treatment groups. For additional information regarding ELX/TEZ/IVA adverse reactions, refer to ELX/TEZ/IVA Prescribing Information. In Trial 1 and Trial 2 combined, the proportion of patients who discontinued treatment prematurely due to adverse reactions were 3.8% and 3.7% in ALYFTREK and ELX/TEZ/IVA treatment groups, respectively. Serious adverse reactions that occurred more frequently with ALYFTREK treatment than with ELX/TEZ/IVA treatment that occurred in 2 or more patients (≥0.4%) were influenza (1.5%), increased AST (0.4%), increased GGT (0.4%), depression (0.4%), and syncope (0.4%). Table 3: Adverse Reactions Occurring in ≥5% of ALYFTREK-Treated Patients and ≥1% Higher than ELX/TEZ/IVA-Treated Patients Aged 12 Years and Older with CF Who Had at Least One F508del Mutation or Responsive Mutation in the CFTR Gene (Trials 1 and 2) Adverse Reactions ALYFTREK N=480 ELX/TEZ/IVA N=491 Abbreviations: ALT, alanine aminotransferase; AST, aspartate aminotransferase; ELX, elexacaftor; IVA, ivacaftor; TEZ, tezacaftor Cough Cough is composed of several similar terms including productive cough. 120 (25%) 116 (24%) Nasopharyngitis 102 (21%) 95 (19%) Upper respiratory tract infection Upper respiratory tract infection is composed of several similar terms including viral upper respiratory tract infection. 101 (21%) 97 (20%) Headache 76 (16%) 63 (13%) Oropharyngeal pain 69 (14%) 60 (12%) Influenza 52 (11%) 26 (5%) Fatigue 51 (11%) 46 (9%) ALT increased 38 (8%) 29 (6%) Rash 37 (8%) 22 (4%) AST increased 33 (7%) 27 (5%) Sinus congestion 32 (7%) 15 (3%) Adverse events that occurred in ≥5% of ELX/TEZ/IVA-treated patients at a similar or higher incidence than the ALYFTREK-treated patients included: infective pulmonary exacerbation of CF, COVID-19, diarrhea, abdominal pain, pyrexia, nasal congestion, increased sputum, increased blood creatinine phosphokinase, rhinorrhea, hemoptysis, nausea, back pain, arthralgia, constipation, sinusitis, dyspnea, and vomiting. Liver Function Test Elevations The incidence of adverse reactions of transaminase elevations was 9% in ALYFTREK-treated patients and 7.1% in ELX/TEZ/IVA-treated patients in Trials 1 and 2. In these trials, 1.5% of ALYFTREK-treated patients and 0.6% of ELX/TEZ/IVA-treated patients discontinued treatment for elevated transaminase

7 DRUG INTERACTIONS Strong or moderate CYP3A inducers : Concomitant use with ALYFTREK is not recommended. ( 5.5 , 7.1 ) Strong or moderate CYP3A inhibitors : Reduce ALYFTREK dosage with concomitant use. Avoid food or drink containing grapefruit. ( 2.3 , 5.6 , 7.1 ) 7.1 Effect of Other Drugs and Grapefruit on ALYFTREK Strong or Moderate CYP3A Inducers Concomitant use of ALYFTREK with strong or moderate CYP3A inducers is not recommended. Vanzacaftor, tezacaftor, and deutivacaftor are substrates of CYP3A. Concomitant use of ALYFTREK with a strong or moderate CYP3A inducer decreases vanzacaftor, tezacaftor, and deutivacaftor exposure [see Clinical Pharmacology (12.3) ] which may reduce ALYFTREK effectiveness [see Warnings and Precautions (5.5) ] . Strong or Moderate CYP3A Inhibitors Reduce the ALYFTREK dosage when used concomitantly with a strong or moderate CYP3A inhibitor [see Dosage and Administration (2.3) ] . Vanzacaftor, tezacaftor, and deutivacaftor are CYP3A substrates. Concomitant use with a strong CYP3A inhibitor increases vanzacaftor, tezacaftor, and deutivacaftor exposure [see Clinical Pharmacology (12.3) ] , which may increase the risk of ALYFTREK adverse reactions [see Warnings and Precautions (5.6) ]. Concomitant use with a moderate CYP3A inhibitor is predicted to increase vanzacaftor, tezacaftor, and deutivacaftor exposure [see Clinical Pharmacology (12.3) ] , which may increase the risk of ALYFTREK adverse reactions [see Warnings and Precautions (5.6) ]. Grapefruit Food or drink containing grapefruit should be avoided during treatment with ALYFTREK. Concomitant use of ALYFTREK with grapefruit juice which contains one or more components that moderately inhibit CYP3A may increase exposure of vanzacaftor, tezacaftor and deutivacaftor. 7.2 Effect of ALYFTREK on Other Drugs P-glycoprotein (P-gp) Substrates Unless otherwise recommended in the P-gp substrate Prescribing Information, monitor more frequently for adverse reactions with concomitant use of ALYFTREK with P-gp substrates where minimal concentration changes may lead to serious adverse reactions related to P-gp substrates. Tezacaftor and deutivacaftor (components of ALYFTREK) are P-gp inhibitors. Administration of tezacaftor/ivacaftor increases exposure of P-gp substrates [see Clinical Pharmacology (12.3) ] , which may increase the risk of adverse reactions related to these substrates. Breast Cancer Resistance Protein (BCRP) Substrates Unless otherwise recommended in BCRP substrate Prescribing Information, monitor more frequently for adverse reactions with concomitant use of ALYFTREK with BCRP substrate where minimal concentrations may lead to serious adverse reactions related to BCRP substrates. Vanzacaftor (VNZ) and deutivacaftor (D-IVA) (components of ALYFTREK) are inhibitors of BCRP in vitro. Concomitant use of ALYFTREK with BCRP substrates may increase exposure of these substrates; however, this has not been studied clinically [see Clinical Pharmacology (12.3) ]. CYP2C9 Substrates Use caution when ALYFTREK is used concomitantly with CYP2C9 substrates. Monitor the international normalized ratio (INR) more frequently with concomitant use of ALYFTREK with warfarin. This recommendation is based upon a mechanistic understanding of deutivacaftor pharmacokinetics (it is an inhibitor of CYP2C9 in vitro) [see Clinical Pharmacology (12.3) ] . Concomitant use of ALYFTREK with CYP2C9 substrates may increase exposure of these substrates; however, this has not been studied clinically. 7.3 Drugs with No Clinically Significant Interactions with ALYFTREK Ciprofloxacin No clinically relevant effect on the exposure of tezacaftor was observed when tezacaftor/ivacaftor was used concomitantly with ciprofloxacin [see Clinical Pharmacology (12.3) ] . Hormonal Contraceptives No clinically significant differences in the pharmacokinetics of ethinyl estradiol/norethindrone containing hormonal contraceptives were observed when used concomitantly with tezacaftor in combination with ivacaftor and ivacaftor alone [see Clinical Pharmacology (12.3) ] . No clinically significant differences in the pharmacokinetics of ethinyl estradiol/norethindrone containing hormonal contraceptives are expected when used in combination with ALYFTREK based upon a mechanistic understanding of vanzacaftor, tezacaftor, and deutivacaftor pharmacokinetics [see Clinical Pharmacology (12.3) ] ; however, this has not been studied clinically. A role for hormonal contraceptives contributing to rash cannot be excluded [see Adverse Reactions (6.1) ] . For patients with CF taking hormonal contraceptives who develop rash, consider interrupting ALYFTREK and hormonal contraceptives. Following the resolution of rash, consider resuming ALYFTREK without the hormonal contraceptives. If rash does not recur, resumption of hormonal contraceptives can be considered.