Evaluation of MTX-463 Administered Subcutaneously in Healthy Adult Males

Inclusion Criteria: * Males aged 18 to 60 years, inclusive * Able to understand the study and provide signed, written informed consent * Able to read and understand the language of the informed consent form and other study-related materials * Willing and able to complete all protocol-required study visits and procedures * Male participants with female partners of childbearing potential must use condoms during the treatment and until 125 days after the dose of study drug. Exclusion Criteria: * Any history of clinically significant lung disease as determined by the Investigator * Any other concurrent active medical condition determined clinically significant by the Investigator * Any current skin conditions or rashes that involve the planned area of injection * Body mass index (BMI) \>30 kg/m2 * Use of any systemic immunosuppressant medications, medications to treat diabetes, antipsychotics, anticoagulants, or other medications within 90 days of Screening * Cancer or a history of cancer or lymphoproliferative disorder within 5 years of Screening * Current infection with hepatitis B, hepatitis C, or human immunodeficiency virus (HIV) * Planning to contribute to pregnancy during the study and up to 125 days after the participant's dose of study drug * History of severe depression, psychosis, or suicidal ideation, as determined by the Investigator, within 5 years of Screening * Any clinically significant disease or laboratory abnormality detected at Screening that might interfere with a participant's ability to complete the study, on-study evaluations, or participant safety * Known allergy to MTX-463 or any of its excipients, or a history of a prior allergic reaction to a monoclonal antibody therapeutic