Background
Phase III 2×2 factorial RCT. 560 patients aged ≥60 years with newly diagnosed mantle cell lymphoma (MCL) requiring treatment. Conducted by the European MCL Network. Two-step randomization: (1) induction: R-CHOP vs R-FC; (2) in responders: rituximab maintenance vs interferon-α. The trial established the standard of care for elderly MCL and the benefit of rituximab maintenance after R-CHOP induction.
Interventions and follow up
Arm A: R-CHOP: rituximab 375 mg/m² D1 + cyclophosphamide 750 mg/m² D1 + doxorubicin 50 mg/m² D1 + vincristine 1.4 mg/m² D1 + prednisone 100 mg/d D1–5 × 8 cycles (q21d); then rituximab maintenance 375 mg/m² q8wk (in responders, until progression) or interferon-α 3 MIU 3×/wk (in responders)
Arm B: R-FC: rituximab 375 mg/m² D1 + fludarabine 25 mg/m²/d D1–3 + cyclophosphamide 200 mg/m²/d D1–3 × 6 cycles (q28d); then rituximab maintenance or interferon-α (in responders; 2nd randomization same as Arm A)
Primary endpoint: ORR (induction phase); PFS (maintenance phase)
Median follow-up: 37 months
Arm B: R-FC: rituximab 375 mg/m² D1 + fludarabine 25 mg/m²/d D1–3 + cyclophosphamide 200 mg/m²/d D1–3 × 6 cycles (q28d); then rituximab maintenance or interferon-α (in responders; 2nd randomization same as Arm A)
Primary endpoint: ORR (induction phase); PFS (maintenance phase)
Median follow-up: 37 months
Results
Induction ORR (R-CHOP vs R-FC): 86% vs 78%, P=.0083
4-year OS (R-CHOP+R-maint vs R-CHOP+IFN): 87% vs 63%, P=.005
4-year PFS (R-CHOP+R-maint vs R-CHOP+IFN): 58% vs 29%, P<.001
R-FC induction: Inferior ORR and higher toxicity; R-FC+R-maint OS 47% at 4y
4-year OS (R-CHOP+R-maint vs R-CHOP+IFN): 87% vs 63%, P=.005
4-year PFS (R-CHOP+R-maint vs R-CHOP+IFN): 58% vs 29%, P<.001
R-FC induction: Inferior ORR and higher toxicity; R-FC+R-maint OS 47% at 4y
Adverse events
Induction (grade ≥3, R-FC vs R-CHOP): neutropenia 74% vs 42%, infections 18% vs 7%; treatment-related mortality 7% (R-FC) vs 3% (R-CHOP); cardiac events 3% (R-CHOP)
Maintenance (grade ≥3 infections): 3% (rituximab) vs 9% (interferon-α); rituximab maintenance otherwise well tolerated
Maintenance (grade ≥3 infections): 3% (rituximab) vs 9% (interferon-α); rituximab maintenance otherwise well tolerated
Conclusions
R-CHOP induction followed by rituximab maintenance significantly improved PFS and OS compared with all other arms in elderly MCL. R-FC was inferior due to higher toxicity and worse survival. Rituximab maintenance after R-CHOP became the standard first-line regimen for older MCL patients not eligible for autologous transplantation.
Key Limitations
The 2×2 factorial design assumed induction and maintenance effects were independent, which may not hold for R-FC (highly immunosuppressive induction precluded effective rituximab maintenance). The IFN-α comparator for maintenance is outdated and no longer used clinically. No molecular risk stratification (Ki-67, blastoid histology, MIPI score) was incorporated, limiting subgroup guidance. BTKi-based combinations (ibrutinib, acalabrutinib) are now being tested in frontline elderly MCL and may supersede R-CHOP+R-maint.
Clinical Context
R-CHOP followed by rituximab maintenance became the ESMO guideline-recommended standard for elderly MCL patients (≥65–70y or transplant-ineligible). Younger, fit patients typically receive intensive induction (R-DHAP or R-CHOP alternating) followed by HDT-ASCT per the MCL Younger trial. BTKi combinations (SHINE: ibrutinib + BR; WINDOW-1: ibrutinib + rituximab induction) have since been investigated in elderly MCL. This trial remains a key historical reference establishing maintenance rituximab in MCL.