To Evaluate the Safety of SG2918 in Patients With Relapsed/Refractory Multiple Myeloma

This is a multicenter, open-label, dose-escalation and dose-expansion Phase Ib/II clinical study of SG2918 conducted in Chinese patients with relapsed/refractory multiple myeloma.The primary objective of this study is to evaluate the safety and tolerability of SG2918 in patients with relapsed/refractory multiple myeloma.Secondary objectives include exploring the efficacy, pharmacokinetic profile, pharmacodynamics, and immunogenicity of SG2918.

Inclusion criteria

• Age ≥ 18 years and ≤ 80 years.
• Eastern Cooperative Oncology Group (ECOG) performance status score of 0-2.
• Life expectancy ≥ 3 months.
• Documented diagnosis of multiple myeloma.
• Measurable disease at screening (per IMWG criteria).
• Relevant laboratory values obtained within 7 days prior to the first dose must meet protocol-specified thresholds.
• Resolution of adverse events related to prior antineoplastic therapy to Grade ≤ 1 or baseline (CTCAE v6.0).
• Female participants of childbearing potential and male participants whose partners are of childbearing potential must use at least one acceptable method of contraception during study treatment and for at least 7 months after the last dose.
• Male participants must refrain from sperm donation from the signing of the Informed Consent Form (ICF) until at least 7 months after the last study dose.

Exclusion criteria

• Patients with primary refractory multiple myeloma.
• Presence of non-bone-related extramedullary soft tissue plasmacytoma at screening.
• known meningeal or Central Nervous System involvement of multiple myeloma, or high suspicion of unconfirmed meningeal or Central Nervous System involvement.
• History of peripheral neuropathy of Grade ≥ 2.
• Active infection requiring systemic therapy within 2 weeks prior to the first dose.
• Hypertension that was not effectively controlled by standardized antihypertensive treatment within 2 weeks prior to the first dose, as judged by the investigator
• History of hypertensive crisis or hypertensive encephalopathy.
• Poorly controlled diabetes mellitus.
• Severe cardiovascular or cerebrovascular disease within 6 months prior to the first dose.
• Active hepatitis B or hepatitis C infection.
• Known history of active tuberculosis or active syphilis.
• Known hypersensitivity to any component of the investigational product.
• history of Grade 3-4 allergic reaction or life threatening hypersensitivity to any biological product.
• Received any of the following therapies or surgeries.

• Prior treatment with LILRB4 targeted therapy; or severe adverse reaction to prior MMAE containing therapy.
• Immunotherapy, macromolecular targeted therapy, or other antineoplastic biologic therapy within 28 days prior to the first dose.
• Cytotoxic chemotherapy or small molecule therapy within 14 days prior to the first dose.
• Modernized traditional Chinese herbal medicine with approved antineoplastic indications within 7 days prior to the first dose.
• Requirement for systemic corticosteroids (equivalent to > 10 mg prednisone per day) or other immunosuppressive agents within 14 days prior to the first dose or during the study.
• Administration of any live or live attenuated vaccine within 28 days prior to the first dose.
• Administration of other vaccines (e.g., inactivated COVID-19 vaccine) within 14 days prior to the first dose.
• Immune related toxicity during prior antineoplastic immunotherapy that resulted in permanent treatment discontinuation.
• Current or previous idiopathic pulmonary fibrosis or idiopathic pneumonia;
• Current acute pulmonary disease, interstitial lung disease, or pneumonia.
• Any other malignancy diagnosed within 5 years prior to the first dose.
• Documented history of neurological or psychiatric disorder.
• Any other condition that, in the opinion of the investigator, may render the participant unsuitable for study participation.