To Evaluate the Safety, Tolerability, Pharmacokinetics, Pharmacodynamics, and Immunogenicity of LYNC-101 for Injection in Healthy Adult Participants

Part 1: Single Ascending Dose (SAD) Part 1 is designed to evaluate the safety, tolerability, PK, PD, immunogenicity, and cytokine profiles of a single intravenous dose of LYNC-101 for Injection in healthy adult participants. Eligible participants will be sequentially enrolled into 5 ascending dose groups: 1 mg/kg, 2.5 mg/kg, 4 mg/kg, 6 mg/kg, and 8 mg/kg. Group 1 will enroll 2 participants randomized to receive LYNC-101 for Injection or placebo. Groups 2 through 5 will each enroll 8 participants, randomized so that 6 participants receive LYNC-101 for Injection and 2 participants receive placebo. Participants will be admitted to the Phase I clinical study site on Day -1 and will receive a single intravenous infusion of LYNC-101 for Injection or placebo on Day 1. Participants will remain at the study site through Day 5 and may be discharged after completion of safety and blood sampling assessments, with investigator approval. Participants will return for follow-up assessments and blood sampling on Days 8, 11, 15, 22, 29, 36, and 43 after dosing. Sentinel dosing will be implemented in all dose groups except Group 1. In each applicable cohort, the first 2 participants will be randomized in a 1:1 ratio to receive LYNC-101 for Injection or placebo. If no significant safety concerns are identified within 72 hours after dosing in the sentinel participants, the remaining participants in the cohort will be randomized in a ratio of 5:1 to receive LYNC-101 for Injection or placebo. Dose escalation will proceed stepwise from the lowest dose level. The Safety Review Committee (SRC) will review safety, tolerability, and available PK data through Day 15 after dosing of the last participant in each cohort to determine whether escalation to the next dose level may proceed. Part 2: Multiple Ascending Dose (MAD) Part 2 is designed to evaluate the safety, tolerability, PK, PD, immunogenicity, and cytokine profiles of multiple intravenous doses of LYNC-101 for Injection in healthy adult participants. Eligible participants will be sequentially enrolled into 2 ascending dose groups, tentatively planned as 3 mg/kg and 4 mg/kg, with dose levels subject to adjustment based on results from the SAD part. Approximately 16 participants are planned in total. Each cohort will include 8 participants randomized in a 3:1 ratio to receive LYNC-101 for Injection or placebo, such that 6 participants receive LYNC-101 for Injection and 2 participants receive placebo. Participants will receive study treatment once every 21 days for a total of 3 doses on Days 1, 22, and 43. Participants will be admitted on Day -1 before each dosing period and discharged after completion of post-dose safety and blood sampling assessments, with investigator approval. The SRC will review safety, tolerability, and available PK data through Day 57 after the last dose of the last participant in each cohort to determine whether escalation to the next dose level may proceed. Based on accumulated safety, tolerability, and PK data, the Investigator and Sponsor may modify the study design, including dose levels, post-dose observation periods, timing of safety assessments, and PK/PD/immunogenicity/cytokine sampling schedules.