HP-001 Plus Dexamethasone for Relapsed/Refractory Multiple Myeloma With Extramedullary Disease

Inclusion criteria

• Age ≥18 years at the time of signing informed consent; male or female.
• ECOG performance status of 0-2.
• Diagnosis of multiple myeloma according to IMWG criteria, with relapsed/refractory disease after at least 1 prior systemic treatment regimen; disease progression or failure to achieve a response after the most recent line of therapy; and extramedullary disease confirmed by imaging, defined as at least 1 soft-tissue extramedullary lesion ≥2 cm, at least 1 paramedullary lesion ≥5 cm, or >2 lesions.
• With or without measurable hematologic disease at screening. Measurable disease, if present, is defined as serum M-protein ≥1.0 g/dL, urine M-protein ≥200 mg/24 hours, or serum free light chain ≥10 mg/dL with an abnormal free light chain ratio.
• Adequate organ function, including ANC ≥1.0 × 10⁹/L, hemoglobin ≥60 g/L, platelet count ≥50 × 10⁹/L, creatinine clearance ≥30 mL/min, total bilirubin ≤2 × ULN (≤3 × ULN for Gilbert syndrome), AST and ALT ≤2.5 × ULN, and INR or aPTT ≤1.5 × ULN.
• Willing and able to comply with study procedures and follow-up.

Exclusion criteria

• Smoldering multiple myeloma, monoclonal gammopathy of undetermined significance, Waldenström macroglobulinemia, POEMS syndrome, amyloidosis, or primary/secondary plasma cell leukemia.
• Central nervous system involvement or clinical evidence of meningeal involvement.
• Severe or uncontrolled cardiovascular disease, including unstable angina, symptomatic congestive heart failure, myocardial infarction within 6 months before enrollment, severe uncontrolled arrhythmia, or other cardiovascular/cerebrovascular conditions considered unsuitable by the investigator.
• Major surgery within 4 weeks before the first dose or planned major surgery during the study.
• Active infection, including HIV infection, active hepatitis B (HBV-DNA positive), active hepatitis C (HCV-RNA positive), active or latent syphilis, active tuberculosis, or other active infections considered unsuitable by the investigator.
• Concurrent malignancy or other serious concomitant disease that may compromise participant safety or completion of the study.
• Pregnant or breastfeeding women.
• History of severe allergy or hypersensitivity to any component of the study treatment.
• Any other condition that, in the investigator's judgment, makes the participant unsuitable for enrollment.