A Study to Assess Bioavailability and Pharmacokinetics of CAT- 354

An Open-Label, Parallel-Group, Bioavailability Study to Assess the Pharmacokinetics of CAT-354 Following Subcutaneous and Intravenous Administration

To compare bioavailability and pharmacokinetics of CAT-354 following subcutaneous administration compared with intravenous administration.

To compare the bioavailability and pharmacokinetics of CAT-354 following subcutaneous administration of 150 milligram (mg) and 300 mg compared with 150 mg given intravenously.

Inclusion Criteria:

• Signed and dated written informed consent is obtained prior to any study related procedure taking place
• Males, aged 19-55 years
• No significant abnormality on clinical examination or medical history (excluding atopic skin signs, symptoms and history)
• A normal 12-lead electrocardiogram (ECG) (no clinically significant abnormalities)
• Clinical chemistry, hematology and urinalysis results within the laboratory reference ranges or deemed not clinically significant by the Investigator
• A negative screen for drugs of abuse and alcohol
• Body mass index (BMI) between 18-30 kilogram per square meter (kg/m^2), inclusive
• No other clinically significant abnormality on history and clinical examination
• Able to comply with the requirements of the protocol.

Exclusion Criteria:

• Any active concomitant disease including psychological disorders
• History of medication that might carry over effects into study
• Previously received monoclonal antibody, or a similar related protein, that might sensitize subjects to CAT-354
• Participation in another investigational medicinal product study within 3 months of the start of this study or 5 half-lives of the previously administered investigational medicinal product (IMP), whichever is the longer except methodological studies in which no IMP was given
• Any acute illness in the 2 weeks before Day 0 (Visit 2)
• Any blood donation or significant loss of blood within 56 days of study initiation or plasma donation within 7 days of study initiation
• Subject is a participating Investigator, sub-Investigator, study coordinator, or employee of a participating Investigator, or is a first degree relative of the aforementioned
• Any factor which, in the opinion of the Investigator, would jeopardize the evaluation or safety or be associated with poor adherence to the protocol
• The subject's primary care physician recommends the subject should not take part in the study
• Subjects with immunodeficiency disorders
• Subjects who have a positive test for, or have been treated for hepatitis B, hepatitis C or human immunodeficiency virus (HIV).