Quadruplet induction with extended consolidation held up at five years in high-risk myeloma, against an external control

Design

Multicentre phase 2 trial with a Bayesian design and molecularly matched external control from Myeloma XI; 5-year follow-up

Population

107 analysed patients with newly diagnosed high-risk multiple myeloma or plasma cell leukaemia vs 120 matched controls

Primary outcome

Progression-free survival, progression-free survival 2 and overall survival at 5 years

Effect

PFS HR 0.32 (95% CI 0.22 to 0.45); overall survival HR 0.43 (0.28 to 0.65)

OPTIMUM was a UK phase 2 trial in 108 patients with newly diagnosed high-risk multiple myeloma or plasma cell leukaemia, using daratumumab, cyclophosphamide, bortezomib, lenalidomide and dexamethasone induction, autologous transplant, extended consolidation and maintenance with lenalidomide and daratumumab. Its activity was compared with a molecularly matched external control group of 120 patients from the Myeloma XI trial.

After median follow-up of about 71 months, progression-free survival was not reached against 24.4 months in controls (hazard ratio 0.32, 95% CI 0.22 to 0.45) and overall survival favoured OPTIMUM (hazard ratio 0.43, 0.28 to 0.65). Progression-free survival 2 was not reached against 43.9 months (hazard ratio 0.26). The benefit was consistent across high-risk subgroups except in patients with three or more high-risk cytogenetic abnormalities, a post hoc subgroup.

The comparison with an external, earlier control cohort cannot remove differences in era, supportive care and patient selection, so hazard ratios of this size from a non-randomised comparison are likely to be overstated. The result supports risk-stratified, molecularly guided treatment but is not a replacement for randomised evidence. Daratumumab access and cost limit use in many Indian centres.

• Test for high-risk cytogenetics at diagnosis, since the strategy is built on risk stratification
• Discuss quadruplet induction with extended consolidation for transplant-eligible high-risk patients, where available
• Be cautious with patients who have three or more high-risk abnormalities, who did not share the benefit
• Monitor for infections and cytopenias during prolonged maintenance
• Consider access, cost and funding at the outset of treatment planning

Why it matters

High-risk myeloma has had poor long-term outcomes, and this shows sustained separation at five years from historical controls.

Don't overread it

An external-control comparison from a phase 2 trial is not a randomised comparison, and the hazard ratios are probably optimistic.

The statistics, in plain English

A hazard ratio of 0.32 means the rate of progression or death was about two thirds lower than in controls. Because controls came from a different trial run in a different period, some of that gap may reflect better supportive care or patient selection. The subgroup with three or more abnormalities was chosen after the data were seen, so its result is weaker evidence.

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