ILD Maintenance Therapy Post-CAR-T in Ultra-High-Risk Relapsed/Refractory MM

Overview

Two patients with relapsed/refractory ultra-high-risk multiple myeloma (UHR MM) achieved durable disease control and sustained minimal residual disease (MRD) negativity using a combination of lisaftoclax, ixazomib, and dexamethasone (ILD) as maintenance therapy following BCMA CAR-T treatment. This oral regimen demonstrated safety and efficacy in maintaining long-term MRD suppression in a population with limited treatment options.

Background

Multiple myeloma (MM) remains incurable, with high-risk and ultra-high-risk (UHR) patients facing poor prognoses and limited therapeutic options, especially after relapse or refractory disease. CAR-T therapy targeting BCMA has shown promise, but no standard maintenance regimen exists post-CAR-T. Ixazomib, an oral proteasome inhibitor, and lisaftoclax, a novel selective BCL-2 inhibitor with favorable safety and binding profiles, represent promising agents for maintenance therapy. Combining these with dexamethasone may optimize MRD eradication and sustain remission in UHR MM patients.

Data Highlights

Two patients with relapsed/refractory UHR MM received ILD maintenance therapy post-BCMA CAR-T: ixazomib 4 mg on days 1, 8, and 15; lisaftoclax 400 mg on days 1–14; dexamethasone 20 mg on days 1, 8, and 15 in 28-day cycles. MRD negativity was assessed by 8-color flow cytometry (sensitivity 10−5), protein electrophoresis, and PET/CT imaging. Both patients achieved durable MRD negativity and disease control with manageable safety profiles.

Key Findings

• ILD maintenance therapy post-CAR-T achieved sustained MRD negativity in two UHR MM patients.
• Lisaftoclax demonstrated higher BCL-2 binding affinity and lower off-target effects compared to traditional inhibitors, supporting long-term oral use.
• Ixazomib, an oral proteasome inhibitor, contributed to effective maintenance with a favorable safety profile.
• The oral ILD regimen was well tolerated, with dose adjustments made for adverse events as needed.
• These cases suggest ILD may optimize MRD eradication and prolong remission in patients with limited treatment options.

Clinical Implications

The ILD combination offers a promising oral maintenance strategy to sustain MRD negativity and disease control in relapsed/refractory UHR MM patients post-CAR-T therapy. Its tolerability and efficacy support further formal evaluation in larger cohorts to establish a standard maintenance regimen for this high-risk population.

Conclusion

ILD maintenance therapy following BCMA CAR-T shows potential to improve outcomes in relapsed/refractory ultra-high-risk multiple myeloma by achieving durable MRD suppression and disease control. Further studies are warranted to validate these findings.

References

1. China Cancer Foundation 2023 -- Study supported by China Cancer Foundation (Project No.: CFC2023WJZD003)
2. IMWG 2026 -- International Myeloma Working Group Response Criteria
3. mSMART 3.0 and 2024 Chinese Guidelines -- Risk Stratification and Diagnosis of MM