Sebetralstat

12.1 Mechanism of Action Sebetralstat is a competitive, reversible inhibitor of plasma kallikrein. Plasma kallikrein is a serine protease that cleaves high molecular weight kininogen (HK) releasing bradykinin which increases vascular permeability through activation of bradykinin receptors causing edema. Sebetralstat inhibits the cleavage of HK and reduces production of bradykinin, thereby treating the clinical symptoms of an acute, episodic attack of HAE. Sebetralstat also inhibits the positive feedback mechanism of the kallikrein kinin system by plasma kallikrein, thereby reducing factor XIIa and additional plasma kallikrein generation.

1 INDICATIONS AND USAGE EKTERLY® is indicated for the treatment of acute attacks of hereditary angioedema (HAE) in adult and pediatric patients aged 12 years and older. EKTERLY ® is a plasma kallikrein inhibitor indicated for the treatment of acute attacks of hereditary angioedema (HAE) in adult and pediatric patients aged 12 years and older. ( 1 )

2 DOSAGE AND ADMINISTRATION Recommended Dosage : one dose of 600 mg (2 tablets) taken orally at the earliest recognition of an HAE attack. ( 2.1 ) A second dose of 600 mg (2 tablets) may be taken 3 hours after the first dose if response is inadequate, or if symptoms worsen or recur. ( 2.1 ) Maximum Recommended Dosage: 1,200 mg in any 24-hour period. ( 2.1 ) See full prescribing information for dosage modification for concomitant use with CYP3A4 inhibitors and inducers. ( 2.2 ) See full prescribing information for recommended dosage for patients with hepatic impairment. ( 2.3 ) 2.1 Recommended Dosage The recommended dosage of EKTERLY is one dose of 600 mg (two tablets) orally at the earliest recognition of an acute HAE attack. A second dose of 600 mg (two tablets) may be taken at least 3 hours after the first dose if response is inadequate, or if symptoms worsen or recur. Maximum recommended dosage is 1,200 mg (four tablets) in any 24-hour period. 2.2 Dosage Modification for CYP3A4 Inhibitors and Inducers Refer to Table 1 for dosage modification of EKTERLY when used concomitantly with CYP3A4 inhibitors and inducers. Table 1: Dosage Modification of EKTERLY for Concomitant use with CYP3A4 Inhibitors and Inducers Dosage Modification for Concomitant use of EKTERLY with CYP3A4 Inhibitors Strong CYP3A4 Inhibitors Avoid concomitant use with EKTERLY. Moderate CYP3A4 Inhibitors Reduce EKTERLY dosage to 300 mg (one tablet) orally at earliest recognition of an acute HAE attack. A second dose of 300 mg (one tablet) may be taken at least 3 hours after first dose if response is inadequate or if symptoms worsen or recur [ see Drug Interactions ( 7.1 ) and Clinical Pharmacology ( 12.3 ) ] . Weak CYP3A4 Inhibitors No dosage modification of EKTERLY [ see Dosage and Administration ( 2.1 ) ] . Dosage Modification for Concomitant use of EKTERLY with CYP3A4 Inducers Strong and Moderate CYP3A4 Inducers Avoid concomitant use with EKTERLY. Weak CYP3A4 Inducers No dosage modification of EKTERLY [ see Dosage and Administration ( 2.1 ) ] . 2.3 Recommended Dosage in Patients with Hepatic Impairment Refer to Table 2 for recommended dosage of EKTERLY in patients with hepatic impairment. Table 2: Recommended Dosage of EKTERLY in Patients with Hepatic Impairment Recommended Dosage of EKTERLY in Patients with Hepatic Impairment Severe Hepatic Impairment (Child-Pugh Class C) Avoid use of EKTERLY [ see Use in Specific Populations ( 8.6 ) and Clinical Pharmacology ( 12.3 ) ] . Moderate Hepatic Impairment (Child-Pugh Class B) Recommended dosage of EKTERLY is one dose of 300 mg (one tablet) orally at the earliest recognition of an acute HAE attack. A second dose of 300 mg (one tablet) may be taken at least 3 hours after the first dose if response is inadequate, or if symptoms worsen or recur [ see Use in Specific Populations ( 8.6 ) and Clinical Pharmacology ( 12.3 ) ] . Mild Hepatic Impairment (Child-Pugh Class A) Recommended dosage is the same as the recommended dosage in patients with normal hepatic function [ see Dosage and Administration ( 2.1 ) ] .

6 ADVERSE REACTIONS The most common adverse reaction (incidence ≥2%) is headache. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact KalVista Pharmaceuticals, Inc. at 1-855-258-4782 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 EKTERLY is based on data from a double-blind, randomized, placebo-controlled, three-way, crossover clinical trial (KONFIDENT) [see Clinical Studies ( 14 )] . In KONFIDENT, a total of 110 patients aged 12 years and older with HAE treated 264 attacks. In the safety population, 93 patients received EKTERLY 600 mg, 86 patients received EKTERLY 300 mg, and 83 patients received placebo. While EKTERLY 300 mg was included in KONFIDENT, the safety data is based on the recommended dosage of EKTERLY 600 mg. Table 3 displays adverse reaction(s) with an incidence of ≥2% in the EKTERLY 600 mg treated patients and more common than placebo. Table 3: Adverse Reaction(s) with EKTERLY with Incidence ≥2% and More Common than Placebo in Patients with Hereditary Angioedema (KONFIDENT) a One (1) patient assigned to administer placebo actually received EKTERLY 600 mg. Safety results are presented by actual treatment received. Adverse Reaction EKTERLY 600 mg (N = 93) Placebo (N = 83) a n (%) n (%) Headache 3 (3.2) 1 (1.2)

7 DRUG INTERACTIONS Strong and Moderate CYP3A4 Inhibitors : Avoid use with strong CYP3A4 inhibitors. In patients taking moderate CYP3A4 inhibitors, take one dose of 300 mg. A second dose of 300 mg may be taken at least 3 hours after the first dose if response is inadequate, or if symptoms worsen or recur. ( 2.2 , 7.1 , 12.3 ) CYP3A4 Inducers : Avoid use with moderate or strong CYP3A4 inducers. ( 2.2 , 7.1 , 12.3 ) 7.1 Effect of Other Drugs on EKTERLY Strong CYP3A4 Inhibitors Avoid use of EKTERLY with strong CYP3A4 inhibitors [see Clinical Pharmacology ( 12.3 )] . Sebetralstat is a substrate of CYP3A4. Concomitant use of sebetralstat with a strong CYP3A4 inhibitor increases sebetralstat exposure, which may increase the risk of sebetralstat adverse reactions. Moderate and Weak CYP3A4 Inhibitors Reduce dose of EKTERLY to one dose of 300 mg (one tablet) orally at the earliest recognition of an HAE attack when used concomitantly with moderate CYP3A4 inhibitors. A second dose of 300 mg (one tablet) may be taken at least 3 hours after the first dose if response is inadequate, or if symptoms worsen or recur [see Dosage and Administration ( 2.2 ) and Clinical Pharmacology ( 12.3 )] . Sebetralstat is a substrate of CYP3A4. Concomitant use of sebetralstat with a moderate CYP3A4 inhibitor increases sebetralstat exposure, which may increase the risk of sebetralstat adverse reactions. No dose modification is recommended when EKTERLY is used concomitantly with a weak CYP3A4 inhibitor [see Dosage and Administration ( 2.1 ) and Clinical Pharmacology ( 12.3 )] . Strong and Moderate CYP3A4 Inducers Use of EKTERLY with strong or moderate CYP3A4 inducers is not recommended. Sebetralstat is a substrate of CYP3A4. Concomitant use of sebetralstat with a strong or moderate CYP3A4 inducer decreases sebetralstat exposure, which may decrease efficacy. Weak CYP3A4 Inducers No dose modification is recommended when EKTERLY is used concomitantly with weak CYP3A4 inducers [see Clinical Pharmacology ( 12.3 )] .