Evaluation of the kinetics of the bone marrow tumor load in the course of sequential high-dose therapy assessed by quantitative PCR as a predictive parameter in patients with multiple myeloma

Abstract

Summary:The aim of this investigation was to examine the possible clinical significance of the kinetics of bone marrow (BM) tumor load during the course of sequential high-dose therapy (HDT) as assessed by quantitative PCR in patients with multiple myeloma. In 20 patients with multiple myeloma (MM) treated with two consecutive cycles of HDT followed by autologous peripheral blood stem cell transplantation (PBSCT), clonotypic cells in the peripheral blood (PB) and BM were quantitated by PCR using allele-specific oligonucleotides (ASO) prior to the first, immediately prior to the second, and after the second HDT. The median proportion of clonotypic cells in the BM was 1.27% before the first HDT (range, 0.03-70%), 0.17% after the first (range, 0.001-22%), and 0.05% after the second HDT (range, 0.00009-1.44%). The median number of circulating clonotypic cells was 65/ml (range, 0.9-10842) prior to HDT, 2.7/ml (range, 0-315) after the first, and 3.5/ml PB (range, 0.7-97) after the second HDT. While the median BM tumor load decreased during the first (P = 0.03) and second (P = 0.044) HDT cycles, only the first cycle resulted in a reduction of clonotypic cells in the PB (P = 0.00078 and P = 1.0, respectively). In seven patients, the BM tumor load did not decrease below the initial level after one or two cycles of HDT. All of these patients developed progressive disease ( Multiple myeloma (MM) is a B cell malignancy characterized by a monoclonal expansion of plasma cells. Highdose therapy (HDT) followed by transplantation of autologous bone marrow (BM) or peripheral blood stem cells (PBSCT) results in five times higher complete response (CR) rates and prolonged overall survival compared to conventional treatment for patients with MM.

Molecular monitoring of the tumor load predicts progressive disease in patients with multiple myeloma after high-dose therapy with autologous peripheral blood stem cell transplantation

“…2,3 This makes it necessary to quantificate the tumor load using elaborate methods in order to establish patterns in the kinetics of the tumor burden. The importance of such continued measurement of the tumor cells has been demonstrated recently by Cremer et al 4 who provided evidence for a prognostic value of a determination of the tumor load in the course of sequential HDT.…”

“…The sensitivity of the ASO primers was tested for four patients (A, I, L, N), and the detection of a single copy of the target DNA in a background of DNA from 330 000 polyclonal cells was demonstrated. 4 Clinical parameters of PD PD was defined by an increase of the M-component of the serum of at least 25% up from the time of remission after HDT in 10 patients and in one patient (N) by reappearance of the Bence-Jones protein in urine by immunofixation. One patient (A) was diagnosed with an extramedullary plasmacytoma.…”

Report of the European Myeloma Network on multiparametric flow cytometry in multiple myeloma and related disorders

“…Allele-specific oligonucleotide (ASO) PCR is highly sensitive but can be costly, time-consuming and can have limited applicability. 38,[54][55][56][57][58][59][60][61] It is possible to detect neoplastic plasma cells by flow cytometry above the clinically relevant threshold of 0.01% 38,57 and this is more informative than conventional assessment. 39,40,62 Flow cytometry for residual disease detection is applicable to almost all patients, more sensitive than paraprotein or light chain assessment, and considerably cheaper than PCR analysis.…”

Hematopoietic stem cell mobilization with intravenous melphalan and G-CSF in patients with chemoresponsive multiple myeloma: report of a phase II trial

“…18,[28][29][30] Representative samples were obtained from each SCC without manipulation. To estimate the percent of clonotypic cells, limiting-dilution PCR with patient-specific CDR1/CDR3 primers was performed 18,[28][29][30][31][32][33][34] with DNA from 2 Â 10 5 cells per SCC serially log-diluted (ie 10-fold) with buffy-coat DNA (limiting-dilution PCR). Specimens giving all negative results were assessed by RT-PCR, whereas specimens giving positive results underwent limiting-dilution PCR.…”