Clinical Scorecard: Pre-Treatment Strategies Prior to CAR-T Administration for Multiple Myeloma: Insights from the CMWP and CTIWP of the EBMT

At a Glance

Key Highlights

• Bridging therapy is used in >85% of MM patients awaiting CAR-T, with proteasome inhibitors and immunomodulatory drugs as most common agents.
• Bridging regimens are highly individualized, driven by prior therapy, refractory status, and disease burden, with limited protocol standardization.
• Concerns exist regarding bispecific antibody wash-out timing, T-cell fitness preservation, and logistical challenges including manufacturing delays.

Guideline-Based Recommendations

Diagnosis

• Assess prior therapy and refractory patterns to guide bridging regimen selection.
• Use serum free light chains and M-protein levels predominantly for disease monitoring during bridging.
• Employ imaging (PET/CT or MRI) and clinical symptom assessment to evaluate disease status.

Management

• Initiate bridging therapy promptly within one week after apheresis, typically lasting 1–2 months.
• Select bridging regimens based on prior treatments, disease burden, and extramedullary involvement.
• Use proteasome inhibitors, immunomodulatory drugs, chemotherapy, monoclonal antibodies, bispecific antibodies, or radiation as bridging options.
• Avoid bendamustine pre-apheresis; exercise caution with bispecific antibodies and apply short wash-out periods (2–4 weeks) before apheresis.
• Proceed to CAR-T infusion even after progression on bridging therapy in most cases.

Monitoring & Follow-up

• Monitor serum markers (free light chains, M-protein) frequently during bridging.
• Use imaging modalities regularly to assess response.
• Evaluate clinical symptoms and consider bone marrow assessment selectively.
• Make treatment decisions based on serum marker reductions, progression signals, toxicity, and imaging improvements.

Risks

• Potential lymphocyte exhaustion and toxicity from bridging regimens, especially bispecific antibodies.
• Interference with CAR-T target antigens by prior BCMA-targeting agents.
• Logistical delays related to apheresis and manufacturing processes.
• Limited evidence and lack of standardized protocols increase uncertainty in regimen selection and timing.

Patient & Prescribing Data

Multiple Myeloma patients undergoing bridging therapy prior to CAR-T infusion

Bridging therapy is widely used (>85% of patients) with proteasome inhibitors and IMiDs most common; bispecific antibodies are favored by experienced centers for superior efficacy but require careful wash-out management.

Clinical Best Practices

• Prioritize prior therapy history and refractory status when selecting bridging regimens.
• Initiate bridging therapy promptly after apheresis to maintain disease control.
• Use short wash-out periods for bispecific antibodies before apheresis to minimize impact on T-cell fitness.
• Continue to CAR-T infusion despite progression on bridging therapy unless toxicity or timing concerns arise.
• Monitor disease status with serum markers and imaging to guide treatment adjustments.
• Avoid bendamustine before apheresis due to contraindications.
• Advocate for standardized protocols and further research to optimize bridging strategies.

References

• EBMT Guidelines and Survey Data