Inclusion Criteria:

• Aged ≥ 18 years with newly diagnosed symptomatic multiple myeloma who have not received any prior anti-myeloma therapy.
• Confirmed positive circulating abnormal plasma cells (CPCs) in peripheral blood via flow cytometry (CPCs ≥ 0.07%).
• Deemed ineligible for autologous hematopoietic stem cell transplantation due to advanced age, poor physical performance, or underlying comorbidities precluding transplant tolerance.
• Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 3.
• Estimated life expectancy of at least 6 months.
• Adequate baseline function of major vital organs to tolerate treatment; no absolute contraindications on complete blood count, liver and renal function, cardiac enzymes or coagulation profile.
• Voluntarily participate in this study, provide written informed consent, and be available for regular follow-up visits.

Exclusion Criteria:

• Diagnosis of primary plasma cell leukemia, solitary plasmacytoma, smoldering multiple myeloma or secondary multiple myeloma.

  • Prior exposure to any anti-myeloma agents, radiotherapy, or stem cell transplantation.
  • Concurrent other malignant tumors (except for in situ carcinoma cured for more than 5 years).
  • Severe active infection, active autoimmune disease, or severe cardiovascular and cerebrovascular diseases (NYHA class III-IV heart failure, recent myocardial infarction or cerebral infarction).
  • Known hypersensitivity to isatuximab, bortezomib, lenalidomide, dexamethasone, or any excipients of the study drugs.
  • Pregnant or breastfeeding females.
  • Unwilling or unable to complete follow-up, or patients with incomplete clinical data.