What is the recommended diagnostic workup and treatment strategy for multiple myeloma?

Recommended Diagnostic Workup and Treatment for Multiple Myeloma

For newly diagnosed multiple myeloma, start with quadruplet therapy containing daratumumab or isatuximab combined with bortezomib, lenalidomide, and dexamethasone (Dara-VRd or Isa-VRd), regardless of transplant eligibility 1.

Diagnostic Workup

Essential Laboratory Tests

• Complete blood count with differential and platelets to assess for anemia (present in 73% at diagnosis) 2
• Serum chemistry panel: creatinine (19% have acute kidney injury at presentation), albumin, corrected calcium, lactate dehydrogenase 2
• Serum protein studies: quantitative immunoglobulins, serum protein electrophoresis (SPEP), serum immunofixation electrophoresis (SIFE), and serum free light chain assay 3
• 24-hour urine collection: total protein, urine protein electrophoresis (UPEP), urine immunofixation electrophoresis (UIFE) 3
• Beta-2 microglobulin for staging 2

Bone Marrow Evaluation

• Bone marrow aspirate and biopsy with:
  • FISH testing for high-risk cytogenetics: t(4;14), del(17p), t(14;16) 2
  • Flow cytometry for plasma cell quantification 3
  • Consider single nucleotide polymorphism array or next-generation sequencing 3

Imaging Studies

Perform one of the following (79% have osteolytic bone disease at presentation) 2:

• Whole-body low-dose CT (preferred initial modality)
• Whole-body MRI without contrast
• Whole-body FDG PET/CT 3

Critical pitfall: Avoid traditional skeletal surveys—they miss early bone disease that CT/MRI/PET can detect 3.

Risk Stratification

Use the Revised International Staging System (R2-ISS) combining 2:

• Beta-2 microglobulin levels
• Albumin levels
• Lactate dehydrogenase
• High-risk FISH abnormalities: t(4;14), del(17p), t(14;16)

Stage I patients (28% at diagnosis) have 82% five-year survival, making this prognostication crucial for treatment intensity decisions 2.

Treatment Strategy

For Transplant-Eligible Patients

Induction therapy (first-line preference):

• Daratumumab-VRd (Dara-VRd) or Isatuximab-VRd (Isa-VRd) as quadruplet therapy 1, 4
• If quadruplet unavailable: VRd (bortezomib/lenalidomide/dexamethasone) 4

Consolidation:

• High-dose melphalan (200 mg/m²) followed by autologous stem cell transplantation 4
• This combination achieves median progression-free survival of 41 months versus historical 8.5 months without therapy 2

Maintenance:

• Lenalidomide maintenance until progression 4, 1
• Consider adding daratumumab, carfilzomib, and/or dexamethasone based on individual risk 1

Critical caveat: Avoid melphalan or other alkylating agents before stem cell collection—they are stem cell toxins that compromise harvest 3.

For Transplant-Ineligible Patients

First-line therapy (preferred regimens):

• Daratumumab-Rd (Dara-Rd): In the MAIA study, 30-month PFS was 70.6% versus 55.6% with Rd alone (HR 0.56, P<0.001) 4
• Daratumumab-VMP (Dara-VMP): ALCYONE study showed median PFS 36.4 versus 19.3 months (HR 0.60, P=0.0003) 4
• Isatuximab-VRd (Isa-VRd) 1

Alternative if quadruplet unavailable:

• VRd (superior to Rd: median PFS 41 vs 29 months, P=0.003) 4
• VMP or Rd alone (older standards) 4

Treatment duration: Continue until disease progression or unacceptable toxicity 4.

Special Populations

Patients >75 years or frail (30% of newly diagnosed):

• Dose-reduce standard regimens
• Consider doublet therapy (Rd or VMP) if quadruplet not tolerated 4

Renal insufficiency (present in 19%):

• Bortezomib-based regimens preferred—no dose adjustment needed 5
• Lenalidomide requires dose reduction based on creatinine clearance
• Daratumumab is safe in renal impairment 4

Key Evidence Hierarchy

The 2026 ASCO-Ontario Health guideline 1 represents the most recent high-quality recommendation, superseding the 2021 EHA-ESMO 4 and 2020 NCCN 3 guidelines. The shift to quadruplet therapy as standard of care is the most significant recent change, supported by trials showing superior outcomes with anti-CD38 monoclonal antibody addition to triplet backbones.

The 2025 EHA-EMN guidelines 6 introduce the R2-ISS staging system and emphasize minimal residual disease monitoring, though specific treatment algorithms align with the ASCO recommendations.

Important divergence: While older guidelines listed VRd as first-line for transplant-eligible patients 4, the 2026 ASCO guideline firmly establishes quadruplet therapy as the new standard 1. This reflects the maturation of data from trials adding daratumumab or isatuximab to VRd.

Monitoring During Treatment

• Response assessment every 2-3 cycles using serum/urine protein studies
• Repeat imaging if new symptoms suggest progression
• Monitor for treatment-related complications: peripheral neuropathy (bortezomib), thromboembolism (lenalidomide), infusion reactions (daratumumab)