Abrocitinib

12.1 Mechanism of Action CIBINQO is a Janus kinase (JAK) inhibitor. Abrocitinib reversibly inhibits JAK1 by blocking the adenosine triphosphate (ATP) binding site. In a cell-free isolated enzyme assay, abrocitinib was selective for JAK1 over JAK2 (28-fold), JAK3 (>340-fold), and tyrosine kinase (TYK) 2 (43-fold), as well as the broader kinome. The relevance of inhibition of specific JAK enzymes to therapeutic effectiveness is not currently known. Both the parent compound and the active metabolites inhibit JAK1 activity in vitro with similar levels of selectivity.

1 INDICATIONS AND USAGE CIBINQO is indicated for the treatment of adults and pediatric patients 12 years of age and older with refractory, moderate-to-severe atopic dermatitis whose disease is not adequately controlled with other systemic drug products, including biologics, or when use of those therapies is inadvisable. CIBINQO is a Janus kinase (JAK) inhibitor indicated for the treatment of adults and pediatric patients 12 years of age and older with refractory, moderate-to-severe atopic dermatitis whose disease is not adequately controlled with other systemic drug products, including biologics, or when use of those therapies is inadvisable. ( 1 ) Limitation of Use : CIBINQO is not recommended for use in combination with other JAK inhibitors, biologic immunomodulators, or with other immunosuppressants. Limitations of Use CIBINQO is not recommended for use in combination with other JAK inhibitors, biologic immunomodulators, or other immunosuppressants.

2 DOSAGE AND ADMINISTRATION • For recommended testing, evaluations, and procedures prior to CIBINQO initiation, see Full Prescribing Information. ( 2.1 ) • Recommended dosage is 100 mg orally once daily. ( 2.2 ) • 200 mg orally once daily is recommended for those patients who are not responding to 100 mg once daily. ( 2.2 ) • Moderate renal impairment: 50 mg once daily or 100 mg once daily for those patients who are not responding to 50 mg once daily. ( 2.3 ) • CYP2C19 poor metabolizer: 50 mg once daily or 100 mg once daily for those patients who are not responding to 50 mg once daily. ( 2.4 ) • For dosage modifications for certain adverse reactions, see Full Prescribing Information. ( 2.6 ) 2.1 Recommended Testing, Evaluations, and Procedures Prior to Treatment Initiation Perform the following tests and evaluations prior to CIBINQO initiation: • Tuberculosis (TB) infection evaluation – CIBINQO initiation is not recommended in patients with active TB. For patients with latent TB or those with a negative latent TB test who are at high risk for TB, start preventive therapy for latent TB prior to initiation of CIBINQO [see Warnings and Precautions (5.1) ] . • Viral hepatitis screening in accordance with clinical guidelines – CIBINQO initiation is not recommended in patients with active hepatitis B or hepatitis C [see Warnings and Precautions (5.1) ] . • A complete blood count (CBC) – CIBINQO initiation is not recommended in patients with a platelet count <150,000/mm 3 , an absolute lymphocyte count <500/mm 3 , an absolute neutrophil count <1,000/mm 3 , or a hemoglobin value <8 g/dL [see Warnings and Precautions (5.6) ] . Complete any necessary immunizations, including herpes zoster vaccinations, in agreement with current immunization guidelines prior to CIBINQO initiation [see Warnings and Precautions (5.7) ] . 2.2 Recommended Dosage The recommended dose is 100 mg once daily. If an adequate response is not achieved with CIBINQO 100 mg once daily, consider increasing the dosage to 200 mg once daily. Discontinue CIBINQO if an adequate response is not achieved with 200 mg once daily. Use the lowest efficacious dose to maintain response. CIBINQO can be used with or without topical corticosteroids. If a dose is missed, administer the dose as soon as possible unless it is less than 12 hours before the next dose, in which case skip the missed dose. Thereafter, resume dosing at the regular scheduled time. 2.3 Recommended Dosage in Patients with Renal Impairment or Hepatic Impairment Renal Impairment CIBINQO dosage recommendations for patients with renal impairment are provided in Table 1 [see Use in Specific Populations (8.6) and Clinical Pharmacology (12.3) ] . In patients with mild and moderate renal impairment, if an adequate response is not achieved with initial dose, the dose of CIBINQO can be doubled [see Dosage and Administration (2.2) ] . Table 1. Dosage Recommendations in Patients with Renal Impairment Renal Impairment Stage Estimated Glomerular Filtration (eGFR) Glomerular filtration rate was estimated by the Modification of Diet in Renal Disease (MDRD) formula. Dosage Mild 60 – 89 mL/minute CIBINQO 100 mg once daily Moderate 30 – 59 mL/minute CIBINQO 50 mg once daily Severe Severe Renal Impairment and End-Stage Renal Disease include patients on renal replacement therapy. 15 – 29 mL/minute Not recommended for use End-Stage Renal Disease (ESRD) <15 mL/minute Hepatic Impairment CIBINQO is not recommended for use in patients with severe hepatic impairment [see Use in Specific Populations (8.7) and Clinical Pharmacology (12.3) ]. 2.4 Recommended Dosage in CYP2C19 Poor Metabolizers In patients who are known or suspected to be CYP2C19 poor metabolizers, the recommended dosage of CIBINQO is 50 mg once daily [see Use in Specific Populations (8.8) and Clinical Pharmacology (12.5) ]. If an adequate response is not achieved with CIBINQO 50 mg once daily, consider increasing the dosage to 100 mg once daily. Discontinue therapy if inadequate response is seen after dosage increase to 100 mg once daily . 2.5 Dosage Modifications due to Strong Inhibitors In patients taking strong inhibitors of cytochrome P450 (CYP) 2C19 , reduce the dosage to 50 mg once daily [see Drug Interactions (7.1) and Clinical Pharmacology (12.3) ] . If an adequate response is not achieved with CIBINQO 50 mg daily, consider increasing the dosage to 100 mg once daily. Discontinue therapy if inadequate response is seen after dosage increase to 100 mg once daily. 2.6 Treatment Discontinuation due to Serious Infections or Hematologic Adverse Reactions Serious or Opportunistic Infections If a patient develops a serious or opportunistic infection, discontinue CIBINQO and control the infection. The risks and benefits of treatment with CIBINQO should be carefully considered prior to reinitiating therapy with CIBINQO [see Warnings and Precautions (5.1) ] . Hematologic Abnormalities Recommendations for CIBINQO discontinuation for laboratory abnormalities are s

6 ADVERSE REACTIONS The following clinically significant adverse reactions are described elsewhere in the labeling: • Serious Infections [see Warnings and Precautions (5.1) ] • Mortality [see Warnings and Precautions (5.2) ] • Malignancy and Lymphoproliferative Disorders [see Warnings and Precautions (5.3) ] • Major Adverse Cardiovascular Events [see Warnings and Precautions (5.4) ] • Thrombosis [see Warnings and Precautions (5.5) ] • Laboratory Abnormalities [see Warnings and Precautions (5.6) ] Most common adverse events (≥1% with CIBINQO 100 mg) are nasopharyngitis, nausea, headache, herpes simplex, increased blood creatine phosphokinase, dizziness, urinary tract infection, fatigue, acne, vomiting, impetigo, oropharyngeal pain, hypertension, influenza, gastroenteritis, and dermatitis contact. ( 6.1 ) Most common adverse reactions (≥1% with CIBINQO 200 mg and greater than CIBINQO 100 mg) are nausea, headache, herpes simplex, increased blood creatine kinase, dizziness, urinary tract infection, acne, vomiting, gastroenteritis, upper abdominal pain, abdominal discomfort, herpes zoster, and thrombocytopenia. ( 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. The safety of CIBINQO was evaluated in four randomized, placebo-controlled clinical trials (2 monotherapy, 1 combination therapy with topical corticosteroid, and 1 dose-ranging) and one long-term extension trial in subjects with moderate to severe atopic dermatitis (AD). A total of 1623 subjects with moderate to severe atopic dermatitis were treated with CIBINQO in these clinical trials representing 1428 patient-years of exposure. There were 634 subjects with at least 1 year of exposure to CIBINQO. In the placebo-controlled clinical trials, a total of 1198 subjects were exposed to CIBINQO with 608 subjects receiving CIBINQO 100 mg once daily and 590 subjects receiving CIBINQO 200 mg once daily for up to 16 weeks. The median age of subjects was 33.0 years, 124 subjects (8.1%) were 12 to less than 18 years old and 94 subjects (6.1%) were 65 years of age or older. The majority of subjects were White (68.7%) and male (53.9%). Adverse reactions occurring at ≥1% in any of the treated groups and at a higher rate than in the placebo group are presented in Table 3. A total of 61 (5.1%) subjects treated with CIBINQO were discontinued from the trials due to adverse reactions. The safety profile of CIBINQO in the monotherapy and the combination trial(s) were similar. Table 3. Adverse Reactions from Placebo-Controlled Trials Reported in ≥1% of CIBINQO Treated Subjects with Moderate to Severe Atopic Dermatitis and at Higher Rate than Placebo for up to 16 Weeks Weeks 0–16 CIBINQO 200 mg N=590 n (% Study size adjusted percentages ) CIBINQO 100 mg N=608 n (% ) Placebo N=342 n (% ) Nasopharyngitis 51 (8.7) 75 (12.4) 27 (7.9) Nausea 86 (14.5) 37 (6.0) 7 (2.1) Headache 46 (7.8) 36 (6.0) 12 (3.5) Herpes simplex Herpes simplex also includes oral herpes, ophthalmic herpes, herpes dermatitis, genital herpes. 25 (4.2) 20 (3.3) 6 (1.8) Increased blood creatine phosphokinase 17 (2.9) 14 (2.3) 5 (1.5) Dizziness 17 (2.9) 11 (1.8) 3 (0.9) Urinary tract infection 13 (2.2) 10 (1.7) 4 (1.2) Fatigue 8 (1.3) 10 (1.6) 2 (0.5) Acne 28 (4.7) 10 (1.6) 0 (0.0) Vomiting 19 (3.2) 9 (1.5) 3 (0.9) Impetigo 3 (0.5) 9 (1.5) 1 (0.3) Oropharyngeal pain 6 (1.0) 8 (1.4) 2 (0.6) Hypertension 5 (0.8) 7 (1.2) 2 (0.7) Influenza 6 (1.1) 7 (1.2) 0 (0.0) Gastroenteritis 8 (1.3) 7 (1.1) 2 (0.6) Dermatitis contact 3 (0.5) 6 (1.1) 1 (0.3) Abdominal pain upper 11 (1.9) 4 (0.6) 0 (0.0) Abdominal discomfort 7 (1.2) 3 (0.5) 1 (0.3) Herpes zoster 7 (1.2) 2 (0.3) 0 (0.0) Thrombocytopenia 9 (1.5) 0 (0.0) 0 (0.0) Specific Adverse Reactions Exposure adjusted incidence rates were adjusted by trial size for all the adverse reactions reported in this section. Overall Infections In the placebo-controlled trials, for up to 16 weeks, overall infections were reported in 90 subjects (126.8 per 100 patient-years) treated with placebo, 211 subjects (168.8 per 100 patient-years) treated with CIBINQO 100 mg and 204 subjects (159.5 per 100 patient-years) treated with CIBINQO 200 mg. In all 5 clinical trials, including the long-term extension trial, overall infections were reported in 427 subjects (91.8 per 100 patient-years) treated with CIBINQO 100 mg and 394 subjects (103.2 per 100 patient-years) treated with CIBINQO 200 mg. Serious Infections In the placebo-controlled trials, for up to 16 weeks, serious infections were reported in 2 subjects (2.6 per 100 patient-years) treated with placebo, 6 subjects (3.9 per 100 patient-years) treated with CIBINQO 100 mg, an

7 DRUG INTERACTIONS • Strong inhibitors of CYP2C19: The recommended dosage is 50 mg once daily or 100 mg once daily for those patients who are not responding to 50 mg once daily. ( 2.5 , 7.1 ) • Moderate to strong inhibitors of both CYP2C19 and CYP2C9, or strong CYP2C19 or CYP2C9 inducers: Avoid concomitant use. ( 7.1 ) • P-gp substrate where small concentration changes may lead to serious or life-threatening toxicities: Monitor or titrate dosage of P-gp substrate. ( 7.2 ) 7.1 Effects of Other Drugs on CIBINQO Table 4 includes drugs with clinically significant drug interactions affecting CIBINQO. Table 4. Clinically Significant Drug Interactions Affecting CIBINQO Strong CYP2C19 Inhibitors Clinical Impact Coadministration of CIBINQO with strong CYP2C19 inhibitors increases the combined exposure of abrocitinib and its two active metabolites, M1 and M2 which may increase the adverse reactions of CIBINQO [see Clinical Pharmacology (12.3) ]. Intervention Dosage reduction of CIBINQO is recommended when coadministered with strong CYP2C19 inhibitors [see Dosage and Administration (2.5) ]. Moderate to Strong Inhibitors of both CYP2C19 and CYP2C9 Clinical Impact Coadministration of CIBINQO with drugs that are moderate to strong inhibitors of both CYP2C19 and CYP2C9 increases the exposure of abrocitinib and its two active metabolites, M1 and M2 which may increase the adverse reactions of CIBINQO [ Clinical Pharmacology (12.3) ]. Intervention Avoid concomitant use of CIBINQO with drugs that are moderate to strong inhibitors of both CYP2C19 and CYP2C9 . Strong CYP2C19 or CYP2C9 Inducers Clinical Impact Coadministration of CIBINQO with strong CYP2C19 or CYP2C9 inducers decreases the combined exposure of abrocitinib and its two active metabolites, M1 and M2, which may result in loss of or reduced clinical response [see Clinical Pharmacology (12.3) ] . Intervention Avoid concomitant use of CIBINQO with strong CYP2C19 or CYP2C9 inducers. 7.2 Effects of CIBINQO on Other Drugs Table 5 includes clinically significant drug interactions affecting other drugs. Table 5. Clinically Significant Interactions Affecting Other Drugs P-gp Substrate Where Small Concentration Changes May Lead to Serious or Life-threatening Toxicities Clinical Impact Coadministration of CIBINQO with P-gp substrate increases plasma concentrations of P-gp substrates and may result in potential adverse reactions of the P-gp substrate where small concentration changes may lead to serious or life-threatening toxicities (e.g., digoxin) [see Clinical Pharmacology (12.3) ] . Intervention Monitor appropriately or dose titrate P-gp substrate where small concentration changes may lead to serious or life-threatening toxicities when coadministered with CIBINQO . Antiplatelet Therapy Drugs Clinical Impact Coadministration of CIBINQO with antiplatelet therapy drugs may increase the risk of bleeding with thrombocytopenia [see Warnings and Precautions (5.5) and Clinical Pharmacology (12.2) ]. Intervention Antiplatelet drugs, except for low-dose aspirin (≤81 mg daily), during the first 3 months of treatment are contraindicated with CIBINQO [see Contraindications (4) ] .