Second autologous stem cell transplantation as salvage therapy in patients with relapsed multiple myeloma: Improved outcomes in patients with longer disease free interval after first autologous stem cell transplantation
Background: Single autologous stem cell transplant (ASCT) is considered the standard of care for younger multiple myeloma (MM) patients (pts). However, it is not curative and virtually all patients will ultimately relapse. The role of a second ASCT as salvage therapy is unclear. Methods: Retrospective review of all MM pts who received a second ASCT as salvage therapy at Princess Margaret Hospital. Results: Between March 1992 and September 2005, 40 MM pts received a second ASCT for relapsed MM at our institution. Median age was 58 years (range 39–69) at second transplant. Twenty-one pts were male. Immunoglobulin subtype included IgG (25), IgA (9), light chain (3), nonsecretory (2), and IgM(1). Median initial albumin was 42g/l (27–49). In 20 patients in whom cytogenetic studies were available, 3 were positive for the 13q deletion. Transplant conditioning regimen for first transplant was melphalan (MEL) + TBI ± etoposide (E) in 6, MEL alone in 27, and other regimens in 7 pts. Second ASCT conditioning consisted of MEL + TBI ± E in 2, MEL alone in 37 and BU + CY in 1. Median CD34 counts were 10.96 × 106/L and 4.85 × 106/L for first and second ASCT, respectively. The median time from diagnosis to first transplant was 9 months (2–74). The median time to relapse after the first transplant was 29 months (6–85), with a median interval between transplants of 39 months (6–99). The median time to progression after the second transplant was 14 months (5–56). One transplant-related death occurred. At median follow-up after second ASCT of 19 months (1–74), 29 (73%) pts are alive. Nineteen (48% of all pts) are free of disease progression. The median progression-free survival (PFS) was 18 months and median overall survival (OS) was 41 months after second ASCT. Long term progression-free status based on the progression-free interval after first transplant is summarized in (Table1). Conclusions: (1) Second ASCT is a feasible and safe salvage therapy in relapsed MM patients; (2) second ASCT is effective in providing median progression-free survival of 18 months and median overall survival of 41 months after second ASCT; (3) the longer the disease free interval after first ASCT the more effective second ASCT is at extending both progression-free survival and overall survival.
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