A Phase 1 Comparative Study to Evaluate Pharmacokinetics, Immunogenicity, Safety and Tolerability of Bmab3000 and Herceptin Hylecta® After a Single 600 mg SC Injection in Healthy Male Volunteers

This is a Phase 1, randomized, double-blind, two-arm, parallel-group trial comparing the pharmacokinetics (PK), immunogenicity, safety, and tolerability of Bmab3000 (test) and Herceptin Hylecta (reference) after a single subcutaneous (s.c.) dose. A total of 150 healthy male participants (75 per arm) will be enrolled to ensure 138 evaluable subjects. Participants will be randomized in 1:1 using stratified block randomization based on baseline body weight (≥50-≤75 kg and \>75-≤100 kg). Each participant will be involved in the study for approximately four months, which includes one screening visit, a 3-night inpatient stay, and 16 scheduled outpatient follow-up visits. Participants will attend a screening visit (Day -28 to Day -1) to confirm eligibility. This will include obtaining informed consent, medical history, physical examination, vital signs, biometric measurements, ECG, echocardiogram, and blood and urine tests, as well as drug and alcohol screening. Eligible participants will be admitted to the study site on Day -1 for pre-dose assessments to confirm continued eligibility. On Day 1, participants will receive a single subcutaneous injection of either Bmab3000 or Herceptin Hylecta. During the inpatient stay (Days -1 to 3), participants will undergo continuous safety monitoring, including regular vital signs, ECGs, injection site checks, and blood sampling for pharmacokinetic, safety, and immunogenicity assessments. After discharge, participants will return for outpatient visits till Day 85 for continued safety monitoring, blood sampling for pharmacokinetic and immunogenicity analyses, and ECGs and vital sign assessments. The final visit on Day 91 will include a full physical examination, echocardiogram, ECG and blood sampling for pharmacokinetic \& immunogenicity analyses and final laboratory evaluations.