Evaluation of minimal residual disease in multiple myeloma patients by fluorescent‐polymerase chain reaction: the prognostic impact of achieving molecular response

Abstract

Summary This study aimed to standardize a simple molecular method for evaluating the response to treatment in multiple myeloma (MM) patients after high dose chemotherapy. Fifty three patients enrolled in the GEM2000 protocol were studied for minimal residual disease (MRD) using both fluorescent‐polymerase chain reaction (F‐PCR) and flow cytometry. Most patients had achieved complete remission or very good response after autologous stem cell transplantation. The molecular analysis of immunoglobulin gene rearrangements at diagnosis and during the follow‐up was carried out by F‐PCR according to the Biomed‐2 protocols. F‐PCR could be used in 91% of the patients and the results were similar to flow cytometry. F‐PCR was able to identify a group of patients with a better prognosis [progression‐free survival (PFS) 67·86% in patients with negative F‐PCR vs. 28%; P = 0·001], even amongst patients who achieved a complete response with negative immunofixation (PFS 75% vs. 25%; P = 0·002). Multivariate analysis identified the F‐PCR result as the only variable to show a prognostic value when PFS was analysed. F‐PCR of DHJ and light chain rearrangements of immunoglobulin genes is a feasible method for evaluating MRD in MM patients after intensive therapy. Achieving molecular response by F‐PCR shows prognostic value.

Busulfan 12 mg/kg plus melphalan 140 mg/m2 versus melphalan 200 mg/m2 as conditioning regimens for autologous transplantation in newly diagnosed multiple myeloma patients included in the PETHEMA/GEM2000 study

“…As outlined previously, [22][23][24][25][26] the GEM2000 protocol was active from January 2000 to February 2005 (ClinicalTrials.gov: NCT00560053); patients aged less than 70 years with symptomatic, newly diagnosed MM who were candidates for HDT/SCT were included. Patients received induction therapy comprising six alternating cycles of VBMCP/VBAD chemotherapy, with peripheral blood stem cell collection after cycle 4 using granulocyte colony-stimulating factor 16-24 µg/kg daily for 5 days for priming.…”

Minimal residual disease testing after stem cell transplantation for multiple myeloma

“…38 As an alternative, ASO realtime quantitative PCR provides an accurate quantification of residual disease, thus overcoming the problem. Several reports using this technique have been published, showing effective outcome discrimination in the transplant setting 29,[39][40][41][42][43] (Table 5). …”

“…There have been multiple studies comparing these techniques (Table 6). 40,44,45 In three consecutive trials, Puig et al 46 analyzed differences in ASO-PCR and MFC in 170 patients that had achieved at least a PR following treatment. MRD negativity was defined as ⩽ 10 − 4 .…”

The current status of minimal residual disease assessment in myeloma

“…[5][6][7] Despite this level of response, studies have shown that the vast majority of patients have residual tumor cells that can be detected with a variety of sensitive techniques. [8][9][10][11] Several studies have demonstrated a consistent improvement in progression-free survival (PFS) with attainment of CR, but its impact on overall survival (OS) has been varied. 12,13 The impact of depth of response on PFS is not surprising, as that could be a mere reflection of the time taken for the clone to grow to a measurable level following a more effective eradication.…”

“…The current results, similar to a previous study, clearly demonstrate equivalent ability of the two techniques to detect residual disease, but crucial differences in terms of feasibility. 11 Two issues remain critical; the inability to obtain successful primers in up to a third of the patients, and the absolute requirement for a baseline sample hampers universal adaptation of this technique. These, along with the required expertise and the more universal access to flow cytometry in most of hematology laboratories, makes flow cytometry the method of choice today, and increasing ability to interrogate millions of cells in a short time and increasing number of markers that can be accommodated at a time will lead to increasing sensitivity, specificity and ease of use of this technique.…”