The intent of this study is to evaluate the safety and tolerability of single escalating subcutaneous doses of CUG252 in healthy adult subjects.

This is a Phase Ia study of CUG252, comprising a randomized, double-blind, placebo-controlled, single ascending dose in healthy adult subjects.

For healthy subject cohorts,

Inclusion Criteria:

• Non-smoking adult healthy male and female, aged 18 to 65 years (inclusive), at the time of consent with a body mass index (BMI) between 18.0 and 32.0 kg/m2 (inclusive), at Screening.
• Healthy as determined by medical history, physical examination, vital signs, clinical laboratory safety tests, ECG, and chest X-ray

Exclusion Criteria:

• Active bacterial, viral, fungal infection or known inflammatory process, infection or antibiotic treatment
• Laboratory test results outside the local reference range and deemed clinically significant
• History of chronic medications, immunosuppressant or steroids
• History of malignant neoplasm
• History of relevant atopy
• History of hypersensitivity to biologic agents or any of the excipients in the formulation.
• Excessive xanthine consumption
• History of drug or alcohol addiction or dependence within 1 year
• Positive of a tuberculosis test or a history of tuberculosis
• Abnormal blood pressure and/or ECG parameters
• Any prescribed medications within 28 days or nonprescription drugs within 7 days
• Previously received aldesleukin or any other IL-2 derivative