Selumetinib

12.1 Mechanism of Action Selumetinib is an inhibitor of mitogen-activated protein kinase kinases 1 and 2 (MEK1/2). MEK1/2 proteins are upstream regulators of the extracellular signal-related kinase (ERK) pathway. Both MEK and ERK are critical components of the RAS-regulated RAF-MEK-ERK pathway, which is often activated in different types of cancers. In genetically modified mouse models of NF1 that generate neurofibromas that recapitulate the genotype and phenotype of human NF1, oral dosing of selumetinib inhibited ERK phosphorylation, and reduced neurofibroma numbers, volume, and proliferation.

1 INDICATIONS AND USAGE KOSELUGO is indicated for the treatment of adult and pediatric patients 1 year of age and older with neurofibromatosis type 1 (NF1) who have symptomatic, inoperable plexiform neurofibromas (PN) [see Dosage and Administration (2) ]. KOSELUGO is a kinase inhibitor indicated for the treatment of adult and pediatric patients 1 year of age and older with neurofibromatosis type 1 (NF1) who have symptomatic, inoperable plexiform neurofibromas (PN). ( 1 )

2 DOSAGE AND ADMINISTRATION • KOSELUGO capsules: The recommended dosage is 25 mg/m 2 , swallowed whole, taken orally twice daily with or without food (see Table 1) . (2.1 , 2.2 ) • KOSELUGO oral granules: The recommended dosage is equivalent to 25 mg/m 2 , sprinkled onto or mixed with soft food and taken orally twice daily (see Table 2). ( 2.1 , 2.2 ) • Moderate hepatic impairment (Child-Pugh B): The recommended dosage is 20 mg/m 2 orally twice daily (see Tables 6 and 7) . ( 2.2 , 2.4 ) • Severe hepatic impairment (Child-Pugh C): The recommended dosage has not been established. ( 2.4 , 8.6 ) • Strong or Moderate CYP3A4 Inhibitors or Fluconazole: If coadministration with strong or moderate CYP3A4 inhibitors or fluconazole cannot be avoided, reduce the dose of KOSELUGO (see Tables 8 and 9) . ( 2.5 ) 2.1 Recommended Dosage The recommended dosage of KOSELUGO capsules ( see Table 1 ) and KOSELUGO oral granules ( see Table 2 ) for adult and pediatric patients 1 year of age and older, based on body surface area, is 25 mg/m 2 orally twice daily, until disease progression or unacceptable toxicity [see Dosage and Administration (2.2)]. Table 1 Recommended Dosage: KOSELUGO Capsules Body Surface Area The recommended dosage of KOSELUGO capsules for patients with a BSA less than 0.55 m 2 has not been established. KOSELUGO Capsules 0.55 – 0.69 m 2 20 mg in the morning and 10 mg in the evening 0.70 – 0.89 m 2 20 mg twice daily 0.90 – 1.09 m 2 25 mg twice daily 1.10 – 1.29 m 2 30 mg twice daily 1.30 – 1.49 m 2 35 mg twice daily 1.50 – 1.69 m 2 40 mg twice daily 1.70 – 1.89 m 2 45 mg twice daily ≥ 1.90 m 2 50 mg twice daily Table 2 Recommended Dosage: KOSELUGO Oral Granules Body Surface Area The recommended dosage of KOSELUGO oral granules for patients with a BSA less than 0.40 m 2 has not been established. KOSELUGO Oral Granules 0.40 – 0.59 m 2 12.5 mg twice daily 0.60 – 0.69 m 2 15 mg twice daily 0.70 – 0.89 m 2 20 mg twice daily 0.90 – 1.09 m 2 25 mg twice daily 1.10 – 1.29 m 2 30 mg twice daily 1.30 – 1.49 m 2 35 mg twice daily 1.50 – 1.69 m 2 40 mg twice daily 1.70 – 1.89 m 2 45 mg twice daily ≥ 1.90 m 2 50 mg twice daily 2.2 Administration KOSELUGO is available in two dosage forms: KOSELUGO capsules and KOSELUGO oral granules. Prescribe KOSELUGO oral granules for patients who have difficulty swallowing whole capsules. KOSELUGO Capsules • Administer KOSELUGO capsules to patients who can swallow a whole capsule. • Swallow KOSELUGO capsules whole. Do not open, chew or crush KOSELUGO capsules. • KOSELUGO capsules may be administered with or without food. KOSELUGO Oral Granules Administer KOSELUGO oral granules to patients who have difficulty swallowing a whole capsule. Sprinkle KOSELUGO oral granules on or mix with a small amount (about 1 to 3 teaspoons) of smooth yogurt, or fruit puree containing the following fruits: apple, banana, pear, or strawberry and consume within 30 minutes of preparation. If not consumed within 30 minutes of preparation, discard and prepare a new dose. If a dose has been partially consumed within 30 minutes of preparation, discard the remainder of the dose and do not prepare a new dose, aim to complete dosing within 30 minutes next time. The KOSELUGO oral granules should be free-flowing. Do NOT use if the oral granules are clumped or stuck inside the capsule shell. Instruct the patient or caregiver to contact their pharmacy if this happens. Discard the empty capsule shells after use. Do NOT swallow, chew, or dissolve the capsule shells of KOSELUGO oral granules. Do NOT chew or crush the KOSELUGO oral granules. Do NOT add oral granules to liquids. Do NOT mix KOSELUGO oral granules in grapefruit or any juice, fruit puree or jam containing Seville orange. Missed Dose If a dose of KOSELUGO capsules or KOSELUGO oral granules is missed, make up that dose unless the next dose is due within 6 hours. Vomiting If vomiting occurs after taking a dose of KOSELUGO capsules or KOSELUGO oral granules, do not take an additional dose. Take the next dose at the regular scheduled time. 2.3 Dosage Modifications for Adverse Reactions The recommended dose reductions for adverse reactions for KOSELUGO capsules and KOSELUGO oral granules are provided in Tables 3 and 4, respectively. Table 3 Recommended Dose Reductions for KOSELUGO Capsules for Adverse Reactions Body Surface Area First Dose Reduction (mg/dose) Second Dose Reduction (mg/dose) Morning Evening Morning Evening 0.55 – 0.69 m 2 10 10 10 mg once daily 0.70 – 0.89 m 2 20 10 10 10 0.90 – 1.09 m 2 25 10 10 10 1.10 – 1.29 m 2 25 20 20 10 1.30 – 1.49 m 2 25 25 25 10 1.50 – 1.69 m 2 30 30 25 20 1.70 – 1.89 m 2 35 30 25 20 ≥ 1.90 m 2 35 35 25 25 Permanently discontinue KOSELUGO capsules in patients unable to tolerate two dose reductions. Table 4 Recommended Dose Reductions for KOSELUGO Oral Granules for Adverse Reactions Body Surface Area First Dose Reduction (mg/dose) Second Dose Reduction (mg/dose) Morning Evening Morning Evening 0.40 – 0.59 m 2 10 10 7.5 7.5 0.60 –

6 ADVERSE REACTIONS The following clinically significant adverse reactions are described elsewhere in the labeling: • Left Ventricular Dysfunction [see Warnings and Precautions (5.1) ] • Ocular Toxicity [see Warnings and Precautions (5.2) ] • Gastrointestinal Toxicity [see Warnings and Precautions (5.3) ] • Skin Toxicity [see Warnings and Precautions (5.4) ] • Increased Creatine Phosphokinase [see Warnings and Precautions (5.5) ] Most common adverse reactions in pediatric patients (≥ 40%) are: vomiting, diarrhea, increased creatine phosphokinase, dry skin, paronychia, nausea, dermatitis acneiform, and pyrexia. ( 6.1 ) Most common adverse reactions in adult patients (≥ 40%) are rash (all), dermatitis acneiform, and diarrhea. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact AstraZeneca 1-800-236-9933 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 NF1 PN pediatric safety pool described in the WARNINGS AND PRECAUTIONS reflects exposure to KOSELUGO at the recommended dosage in 134 pediatric patients in SPRINKLE (N = 36) (NCT05309668), SPRINT Phase I (N = 24) (NCT01362803), SPRINT Phase II Stratum 1 (N = 50) [see Clinical Studies (14.1) ] , and Phase I Food Effect Study (N = 24) (NCT05101148). Among pediatric patients, the duration of KOSELUGO exposure was 12 months or longer (80%), more than 2 years (44%), or more than 3 years (37%). The most common adverse reactions in pediatric patients (≥ 40%) are vomiting, diarrhea, increased creatine phosphokinase, dry skin, paronychia, nausea, dermatitis acneiform, and pyrexia. In the KOMET adult NF1 PN study, 71 adult patients received KOSELUGO at the recommended dosage [see Clinical Studies (14.1) ] . Among adult patients, the duration of KOSELUGO exposure in the randomized period was 6 months or longer (92%), and 11 months or longer (66%). The most common adverse reactions in adult patients (≥ 40%) are rash (all), dermatitis acneiform, and diarrhea. Neurofibromatosis Type 1 (NF1) with Inoperable Plexiform Neurofibromas (PN) Pediatrics 2-18 years of Age (SPRINT Phase II Stratum 1) The safety of KOSELUGO was evaluated in SPRINT Phase II Stratum 1 [see Clinical Studies (14.1) ] . Eligible patients were 2-18 years of age with neurofibromatosis type 1 (NF1) who had inoperable plexiform neurofibromas (PN) that was causing significant morbidity. Patients were excluded for abnormal LVEF, uncontrolled hypertension (blood pressure ≥ the 95th percentile for age, height, and sex), any current or past history of RVO or RPED, intraocular pressure > 21 mmHg (or upper limit of normal adjusted by age), uncontrolled glaucoma, and inability to swallow whole capsules. Patients received KOSELUGO 25 mg/m 2 orally twice daily (N = 50). Among these patients, 88% were exposed for 12 months or longer and 66% were exposed for greater than 2 years. Serious adverse reactions occurred in 24% of patients who received KOSELUGO. Serious adverse reactions that occurred in 2 or more patients were anemia, hypoxia and diarrhea. Permanent discontinuation due to an adverse reaction occurred in 12% of patients who received KOSELUGO. Adverse reactions resulting in permanent discontinuation of KOSELUGO included increased blood creatinine, increased weight, diarrhea, paronychia, malignant peripheral nerve sheath tumor, acute kidney injury, and skin ulcer. Dosage interruptions and dose reductions due to adverse reactions occurred in 80% and 24% of patients who received KOSELUGO, respectively. Adverse reactions requiring a dosage interruption or reduction in ≥ 5% of patients were vomiting, paronychia, diarrhea, nausea, abdominal pain, rash, skin infection, influenza-like illness, pyrexia and weight gain. The most common adverse reactions (≥ 40%) were vomiting, rash (all), abdominal pain, diarrhea, nausea, dry skin, fatigue, musculoskeletal pain, pyrexia, acneiform rash, stomatitis, headache, paronychia, and pruritus. Table 10 presents the adverse reactions in SPRINT Phase II Stratum 1. Table 10 Adverse Reactions (≥ 20%) in Patients Who Received KOSELUGO in SPRINT Phase II Stratum 1 Adverse Reaction KOSELUGO (N = 50) All Grades (%) Grade ≥ 3 (%) * Gastrointestinal Vomiting 82 6 Abdominal pain Abdominal pain includes abdominal pain; abdominal pain upper 76 0 Diarrhea 70 16 Nausea 66 2 Stomatitis Stomatitis includes stomatitis; mouth ulceration 50 0 Constipation 34 0 Skin and Subcutaneous Tissue Rash (all) Rash (all) includes dermatitis acneiform; rash maculo-papular; erythema; rash pustular; rash; urticaria; exfoliative rash; rash pruritic; rash erythematous 80 6 Dry skin 60 0 Rash acneiform Rash (acneiform) includes dermatitis acneiform 50 4 Paronychia Paronychia includes paronychia; nail infection 48 6 Pruritus

7 DRUG INTERACTIONS • Strong or Moderate CYP3A4 Inhibitors or Fluconazole : Avoid coadministration of strong or moderate CYP3A4 inhibitors or fluconazole with KOSELUGO. If coadministration cannot be avoided, reduce the dose of KOSELUGO. ( 2.5 , 7.1 ) • Strong or Moderate CYP3A4 Inducers : Avoid concomitant use of strong and moderate CYP3A4 inducers. ( 7.1 ) 7.1 Effect of Other Drugs on KOSELUGO Strong or Moderate CYP3A4 Inhibitors or Fluconazole Management • Avoid concomitant use of strong or moderate CYP3A4 inhibitors or fluconazole with KOSELUGO. If coadministration with strong or moderate CYP3A4 inhibitors or fluconazole cannot be avoided, reduce KOSELUGO dosage [see Dosage and Administration (2.4) ]. Clinical Impact • Concomitant use of KOSELUGO with a strong or moderate CYP3A4 inhibitor or fluconazole increased selumetinib plasma concentrations [see Clinical Pharmacology (12.3) ] , which may increase the risk of adverse reactions. Strong or Moderate CYP3A4 Inducers Management • Avoid concomitant use of strong or moderate CYP3A4 inducers with KOSELUGO. Clinical Impact • Concomitant use of KOSELUGO with a strong or moderate CYP3A4 inducer decreased selumetinib plasma concentrations [see Clinical Pharmacology (12.3) ] , which may reduce KOSELUGO efficacy. Vitamin E Management • Supplemental vitamin E is not recommended if daily vitamin E intake (including the amount of vitamin E in KOSELUGO capsules and supplement) will exceed the recommended or safe limits. • Monitor for bleeding in patients administered a vitamin‑K antagonist or an anti‑platelet agent with KOSELUGO capsules. Increase INR monitoring, as appropriate, in patients taking a vitamin‑K antagonist [see Warnings and Precautions (5.3) ] . Clinical Impact • KOSELUGO capsules contain vitamin E and daily vitamin E intake that exceeds the recommended or safe limits may increase the risk of bleeding. An increased risk of bleeding may occur in patients taking a vitamin‑K antagonist or an anti‑platelet agent with KOSELUGO capsules.