Thalidomide and Dexamethasone Is an Effective Salvage Regimen for Myeloma Patients Relapsing after Autologous Transplant.

PURPOSE: High-dose therapy followed by autologous stem cell transplantation (AT) is the standard treatment for newly diagnosed multiple myeloma patients. Which is the best treatment option for patients relapsing after AT has not been defined. To address this issues the efficacy of Thalidomide and Dexamethasone (TD), AT and Conventional Chemotherapy (CC) was evaluated.

MATERIALS AND METHODS: We retrospective analysed the outcome of 90 multiple myeloma patients, median age 61, range 34–77, who received a first salvage treatment between January 1999 and September 2003. All patients received AT at diagnosis. Relapse was defined as introduction of therapeutic modality that was different from maintenance treatment.

After a median time from diagnosis of 32 months, 43 patients were treated with TD (Thalidomide 100 mg/day associated with DEX 40 mg on days 1-4 each month), after a median time from diagnosis of 29 months, 28 patients were treated at first relapse with AT (86% single MEL100, 11% double MEL100, 4% single MEL200), and after a median time from diagnosis of 32 months, 19 patients were treated with CC (32% Doxorubicin, Cyclophosphamide, Etoposide, Cisplatinum combination chemotherapy, 26% Doxorubicin containing regimens, 26% Cyclophosphamide containing regimens, 11% other therapies).

Data were analysed when the median follow-up from the start of salvage TD was 30 months (range 4.5–45), from the start of salvage AT was 18 months (range 3.5–24) and from the start of salvage CC was 21 months (range 2–19.5).

End points of the study were response, progression free survival (PFS) from first relapse and overall survival (OS) from first relapse and from diagnosis.

RESULTS: Patients characteristics were similar among different groups. At relapse the response rate after TD was: 19% near complete remission (nCR) (absence of M-Protein detected by electrophoresis), 28% partial response (PR) (M-Protein reduction 50–99%), 35% stable disease (SD) (M-Protein reduction 0–49%) and 19% progressive disease (PD). After AT was: 11% nCR, 71% PR, 11% SD, 7% PD; and after CC was: 16% PR, 32% SD and 53% PD. Response rate was significantly lower for patients receiving salvage CC in comparison with AT and TD (p<0.001).

The median PFS from relapse was 20.3 months for TD, 9 months for AT and 4.5 months for CC (p<0.001). The OS from relapse at 50 months was 58% for TD, 13% for AT and 21% for CC (p = 0.008). The median OS from diagnosis was 116.34 months for TD, 41.3 months for AT and 59.5 months for CC (p<0.001).

The multivariate analysis indicates that TD, β2 microglobulin and age were the only independent risk factors associated with improved outcome.

CONCLUSION: In conclusion, TD improved PFS and OS in myeloma patients relapsing after autologous transplant.