Evaluation of the Impact of Three Different Pre-Transplant Strategies On the Outcome of Myeloma Patients Candidates to High-Dose Therapy.

This study aimed at evaluating the impact of three different pre-transplant therapies on the outcome of patients (pts) eligible for high-dose therapy.

two-hundred sixty eight newly diagnosed MM pts aged £65 years, Durie-Salmon stage III, II, or I in progression, were consecutively enrolled from 2000 to 2007 in three different protocols, with three different pre-transplant therapy: Group 1: (145 pts) 3 pulse-VAD cycles; Group 2: (67 pts) 3 pulse-VAD cycles plus 3 Thal-Dex cycles (thalidomide at the dose of 100 mg/day orally at bedtime, continuously for 3 months, oral dexamethasone at the dose of 20 mg on days 1-4 and 14-17 every 28 days); Group 3: (57pts) 4 Vel-Dex courses (Bortezomib 1.3 mg/m² i.v. on days 1, 4, 8, 11; oral Dexamethasone 40 mg on days 1-4 and 8-11 every 3 weeks). After induction all pts received two DCEP-short cycles as mobilization (oral Dexamethasone 40 mg/day on days 1-4 + Cyclophosphamide 700 mg/m²/day i.v., Etoposide 100 mg/ m²/day i.v., cisPlatin 25 mg/m²/day for 2 days) with peripheral blood stem-cell (PBSC) collection prompted by G-CSF followed by one or two transplants (Tx) with melphalan 200 mg/m² as conditioning regimen. Response was defined according to IMWG uniform criteria. Pts were considered responsive when obtaining at least a PR.

pts in the three group were similar for age, gender, Ig type, ISS stage. A significant higher percentage of Durie and Salmon stages III was found in group 3 (83% vs 68% in group 1 and 67% in group 2, p=0.0002). The median follow-up was 46 (1-150) months for group 1, 43 (1-68) months for group 2, and 29.7 (1-79) months for group 3. At the time of this analysis in the three groups 51%, 65%, 90% of transplanted pts respectively were still alive, and progression after transplant was registered in 84%, 80%, 50% respectively. Patient flow before Tx was similar (p=0.45): 19% in group 1, 27% in group 2, 23% in group 3. In group 1, 2% of pts went off-study after VAD, and 17% after mobilization phase. In group 2, patient flow was equally distributed: 7% after pulse VAD, 10% after thal-dex, 9% after DCEP. In group 3, 12% of the pts went off-study after Vel-Dex, 11% after DCEP. Table 1 summarized responses. In group 3 (Vel-Dex) response was better along all protocol phases with respect to group 1 or 2 (p<0.00001). The number of responsive pts progressively increased from 87% after Vel-Dex (CR 31%), to 96% after transplant (CR 38%). Response rates of group 1 and 2 patients were not significantly different either after induction (p=0.6), after DCEP (p=0.5), and after Tx (p=0.65). On intention to treat basis, vel-dex induction produced a better, although not significant, PFS (34.6 months vs 29 in group 1 and 26.8 in group 2, p=0.56). OS were not statistically different among the three groups, event though the different follow-up could affect the analysis (median OS 110 in group 1, 66 months in group 2, and not reached in group 3, p=0.37). In multivariate analysis PFS was improved only by the achievement of CR (p=0.001). No significant difference was observed between VGPR or PR (p=0.43).

In this study, only CR not VGPR impacts on the outcome. Vel-Dex producing a significant high CR rate after TX (38%), seems to improve survival of MM patients candidate to high-dose therapy with respect to conventional pre-transplant strategies.

Morra:Roche:.