Study of Efavaleukin Alfa in Healthy Chinese, Japanese, and Caucasian Participants

• Healthy male or female participants, between 18 and 55 years of age (inclusive) at the time of Screening. • Chinese, Japanese, or Caucasian participant: - Chinese participants must be of Chinese ancestry (4 grandparents and biological parents). - Japanese participants must be first- or second-generation Japanese (4 grandparents and biological parents; participant or both of their parents must have been born in Japan). - Caucasian participants are those who self-identify exclusively as such on the electronic case report form (eCRF) and also identify their biological parents as such. • In good health, determined by no clinically significant findings from medical history, physical examinations, 12-lead electrocardiogram (ECG), vital signs measurements, and clinical laboratory evaluations (congenital nonhemolytic hyperbilirubinemia [eg, suspicion of Gilbert’s syndrome based on total and direct bilirubin] is not acceptable) as assessed by the Investigator (or designee). • Body mass index between 17 and 30 kg/m^2 (inclusive) at the time of Screening.

• Evidence of scars, tattoos, or other skin lesions that may interfere with the injection site or injection site assessments. • History or evidence of clinically significant arrhythmia at Screening, including any clinically significant findings on the ECG taken at Check-in. • A QT interval corrected for heart rate using Fridericia’s method (QTcF) interval > 450 msec in male participants or > 470 msec in female participants or history/evidence of long QT syndrome, at Screening or Check-in. • PR interval > 210 msec, at Screening or Check-in. • Second- or third-degree atrioventricular (AV) block , at Screening or Check-in. • Systolic blood pressure (BP) > 140 mmHg or < 90 mmHg, or diastolic BP > 90 mmHg, or HR > 100 bpm, at Screening or Check-in. • Estimated glomerular filtration rate less than 60 mL/min/1.73 m^2 as calculated by the Modification of Diet in Renal Disease equation, at Screening. • HbA1C ≥ 7%, at Screening or Check-in. • Participants who have received live vaccines within 5 weeks prior to Screening, or plan to receive live vaccines within 105 days after administration of an investigational product. • Positive hepatitis B or hepatitis C panel (ie, positive hepatitis B surface antigen, hepatitis B core antibody or hepatitis C antibody) at Screening, or a medical history for hepatitis B or C; and/or positive human immunodeficiency virus test, at Screening. Participants whose results are compatible with prior vaccination may be included. Participants with a history of hepatitis B vaccination without a history of hepatitis B or C are allowed to participate. • Consumption of foods and beverages containing poppy seeds within 7 days prior to Check-in. • History of alcoholism or drug/chemical abuse within 1 year prior to Check-in. • Use of tobacco- or nicotine-containing products within 6 months prior to Check-in. • Positive test for illicit drugs, cotinine (tobacco or nicotine use), and/or alcohol use at Screening or Check-in. • Female participants with a positive pregnancy test at Screening or Check-in. • Participant has received a dose of an investigational drug within the past 90 days or 5 half-lives of the drug, whichever is longer, prior to Check-in. • Donation of blood from 90 days prior to Check-in, plasma from 2 weeks prior to Check-in, or platelets from 6 weeks prior to Check-in. • Participants with abnormal laboratory results for alanine aminotransferase (ALT) or aspartate aminotransferase (AST) (ie, > upper limit of normal) and total bilirubin (ie, > upper limit of normal) at Screening and Check-in.