High-dose melphalan (HDM) without hematopoietic progenitor cell (HPC) support for treatment of plasma cell leukemia

Primary plasma cell leukemia (PPCL) is a rare subtype of multiple myeloma that follows a rapid clinical course and responds poorly to conventional myeloma treatment. Recently it has been shown that melphalan doses up to 140 mg/m2 without HPC support can be given safely to myeloma patients. We report our experience with the use of HDM without HPC support in 3 patients with PPCL. All patients received HDM (140 mg/m2) as a single 40-minute IV infusion. Filgrastim (6 g/kg/day) was started 24 hours after HDM and continued until absolute neutrophil count (ANC) was> 500/L. There was complete clearance of plasma cells from the bone marrow and resolution of cytogenetic abnormalities. IgG level in patient 1 and M-protein level in patients 2 and 3 decreased by> 75% before thalidomide initiation and was maintained for> 6 weeks. One patient (case 1) had extramedullary disease progression evidenced on day 130 and expired despite further treatment with VAD, arsenic trioxide, methylprednisolone, and thalidomide. Patient 2 achieved CR after receiving allogeneic stem cell transplantation from a matched sibling donor at day 137 and remains in complete remission. There was no treatment-related mortality. Treatment of PPCL with HDM without HPC support was well tolerated. It resulted in prompt hematologic recovery and produced dramatic control of an otherwise rapidly fatal process. Such treatment may be a viable option when HPC transplantation is not feasible. Table 1Patient characteristicsAge (y)/SexWBC (1000/μl)/BM Involve-mentM-protein Level (g/dl)/Ig TypePrior Rx/ResponseCount Recovery (D 0+)Thalido-mide Started (D 0+)Best Documented Response/Day (D 0+)TTP/Survival (Days)50/M60.5/100%Not available/IgGHigh-dose cortico-steroids/progres-sive disease20NAPR/120130/423+45/F54.6/100%3.54/IgGHigh-dose cortico-steroids/Progres-sive disease2030PR/30NA/557+66/F17.3/75%4.5/IgGVAD/progres-sive disease36100PR/164NA/219+TTP: time to progression, NA: not applicable, PR: partial response. Open table in a new tab TTP: time to progression, NA: not applicable, PR: partial response.