Role of Serum Lactate Dehydrogenase (LDH) As a Prognostic Marker for Autologous Hematopoietic Stem Cell Transplantation for Multiple Myeloma.

The International Staging System (ISS), chromosomal abnormalities, and response to therapy are well recognized predictors of outcome in multiple myeloma (MM). However, the role of serum lactate dehydrogenase (LDH) as a prognostic marker for MM is not well established. Recently we showed that high LDH at diagnosis of MM is a predictor of shorter survival. Here we report the impact of the LDH level at the time of autologous hematopoietic stem cell transplantation (auto-HCT) on its outcome.

We evaluated 1,658 patients with symptomatic myeloma who underwent auto-HCT from July 1988 to December 2010 at our institution. The primary objective was to determine the impact of high LDH (>1000 IU/L) level, obtained on the start day of the preparative regimen, on progression free survival (PFS) and overall survival (OS).

Patient characteristics according to LDH level at auto-HCT are summarized in Table 1. Patients in the 2 LDH groups (>1000 or ≤ 1000) were matched for age, gender, disease status, and response to prior therapy at the time of auto-HCT. Patients with LDH >1000 IU/L had a significantly higher beta-2 microglobulin (β2m) and bone marrow plasmacytosis at the time of auto-HCT. Median times to neutrophil (10 vs. 10 days: p=0.10) and platelet engraftment (11.3 vs.12.2 days: p=0.20) were not different in the 2 groups. Also, there was no significant difference in CR, VGPR, PR or overall response rates between the 2 groups. Median follow up was 35 months (1 to 244). Median OS in patients with LDH >1000 and ≤ 1000 were 49.2 and 68.0 months, respectively (p=0.03). Median PFS in patients with LDH >1000 and ≤ 1000 were 14.4 and 24.7 months, respectively (p=0.001). On univariate analyses, >10% plasma cells in bone marrow biopsy, relapsed disease, serum β2M ≥ 3.5 at auto-HCT, presence of any chromosomal abnormality, and < PR after auto-HCT were associated with significantly shorter PFS and OS.

Having a serum LDH value of >1000 IU/L prior to auto-HCT is associated with shorter PFS and OS in patients with MM. These high risk patients may require aggressive post-transplant therapy, including consolidation, maintenance, tandem transplants or novel approaches like immunotherapy.

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