Dr Kalff talks to ecancertv at IMW 2013 on an extended analysis of the ALLG MM6 trial that her and her colleagues carried out.
Their aims were to determine whether the significant PFS and OS advantages seen for thalidomide consolidation post ASCT at 3 yrs post randomization in the ALLG MM6 trial were durable at longer follow-up. This included comparing the overall response rate (ORR) to salvage therapy and secondary primary malignancy (SPM) incidence.
They looked at 243 newly diagnosed MM patients post single MEL200ASCT; randomly assigned to receive indefinite prednisolone (pred) maintenance (50mg alternate days) alone (CA n=125) or in combination with 12 months of thalidomide consolidation(100mg/d increased to 200mg after 2/52) (TA n=111).
PFS and OS were measured from date of randomization.
After a median follow-up of 5.4 yrs, the post randomization estimated 5 yr PFS rates were 27% and 15% (P=0.005; hazard ratio [HR], 0.16; 95% CI 0.044 to 0.582) and OS rates were 66% and 47% (P=0.007; HR 0.12; 95% CI 0.028 to 0.558) in TA and CA respectively. TA remained beneficial irrespective of pre-ASCT B2M level <4mg/L (p=0.002) and 4 (p=0.049). Patients required a minimum of 8 months of TA to gain PFS advantage (p=0.017), however only patients who completed 12 months of TA gained OS benefit (p=0.001). There was no difference in ORR to salvage therapy including thalidomide-based salvage, and no difference in SPM incidence.
The researchers found that PFS and OS advantages ascribed to thalidomide consolidation post ASCT remain highly significant at 5 years, however the full 12 months of thalidomide was required to derive OS benefit. Further recapitulating previous findings, thalidomide did not impact on ORR to salvage therapy at relapse.