A Study of F182112 in the Treatment of Patients With Relapsed or Refractory Multiple Myeloma

Inclusion Criteria: * Be diagnosed with multiple myeloma according to the IMWG 2016 criteria. * The previous treatment regimen must contain lenalidomide (lenalidomide must be used continuously for at least 2 cycles) and a proteasome inhibitor. * Participants whose previous treatment regimen contained pomalidomide or who were intolerant to pomalidomide cannot be enrolled. * Have an ECOG performance status score of 0 - 2. * Meet at least one of the following measurable disease indicators: 1. Serum M - protein ≥ 5 g/L. 2. Urine M - protein ≥ 200 mg/24 h. 3. Serum free light chain (FLC) test: Involved FLC level ≥ 100 mg/L and abnormal serum free light chain ratio (\< 0.26 or \> 1.65). Exclusion Criteria: * Patients with primary light - chain amyloidosis or plasma cell leukemia . * Patients with symptoms of central nervous system involvement of multiple myeloma. * Patients with a history of other malignancies other than multiple myeloma within 3 years before the first dose. * Patients with active mucosal or visceral bleeding. * Patients who have previously received BCMA - targeted therapy.