A Study to Evaluate the Efficacy and Safety of IN-207907 Injection in Elderly Patients With Sarcopenia

Inclusion Criteria: * Subjects aged ≥ 65 years (for female subjects, those who are medically unable to become pregnant) * Subjects diagnosed with sarcopenia in accordance with the Korean Working Group on Sarcopenia (KWGS) guidelines * Subjects with a body weight of ≥ 35 kg and a body mass index (BMI) of ≥ 15 kg/m² and \< 30 kg/m² * Subjects with a nutritional status screening score of ≥ 8 as assessed by the Mini Nutritional Assessment (MNA) questionnaire Exclusion Criteria: * Subjects with a history of diseases or surgical procedures that may affect physical activity or function * Subjects with underlying muscle disorders, including myopathy or muscular atrophy * Subjects with neuromuscular or neurological disorders * Subjects with uncontrolled diabetes mellitus, severe renal impairment, uncontrolled thyroid disorders, vitamin D deficiency, severe hepatic impairment, severe cardiac disease, uncontrolled hypertension, respiratory disorders * Subjects with clinically significant findings on a 12-lead electrocardiogram (ECG) * Subjects who are positive for active hepatitis B, active hepatitis C, syphilis, or human immunodeficiency virus * Subjects with a history of malignancy within 5 years * Subjects who have received systemic immunosuppressants or immunostimulants * Subjects who have undergone treatment with plasmapheresis within 8 weeks * Subjects who have received treatment with medications prohibited in this clinical trial within 4 weeks * Subjects with hemoglobin levels \< 10 g/dL * Subjects who have undergone surgery requiring general anesthesia within 4 weeks * Subjects who are unable to walk or are physically inactive * Subjects who are participating in or planning to participate in a separate high-intensity program for increasing muscle mass or strength during the clinical trial period * Subjects with severe psychiatric disorders such as major depression, schizophrenia, alcoholism, or drug dependence * Subjects with a score of \< 24 on the Korean version of the Mini Mental State Examination (MMSE-K) * Subjects with known allergies or hypersensitivity to the investigational product or its excipients