Monitoring multiple myeloma by next-generation sequencing of V(D)J rearrangements from circulating myeloma cells and cell-free myeloma DNA

Abstract

Recent studies suggest that circulating tumor cells and cell-free DNA may represent powerful non-invasive tools for monitoring disease in patients with solid and hematologic malignancies. Here, we conducted a pilot study in 27 myeloma patients to explore the clonotypic V(D)J rearrangement for monitoring circulating myeloma cells and cell-free myeloma DNA. Next-generation sequencing was used to define the myeloma V(D)J rearrangement and for subsequent peripheral blood tracking after treatment initiation. Positivity for circulating myeloma cells/cell-free myeloma was associated with conventional remission status (P<0.001) and 91% of non-responders/progressors versus 41% of responders had evidence of persistent circulating myeloma cells/cell-free myeloma DNA (P<0.001). About half of the partial responders showed complete clearance of circulating myeloma cells/cell-free myeloma DNA despite persistent M-protein, suggesting that these markers are less inert than the M-protein, rely more on cell turnover and, therefore, decline more rapidly after initiation of effective treatment. Positivity for circulating myeloma cells and for cell-free myeloma DNA were associated with each other (P=0.042), but discordant in 30% of cases. This indicates that cell-free myeloma DNA may not be generated entirely by circulating myeloma cells and may reflect overall tumor burden. Prospective studies need to define the predictive potential of high-sensitivity determination of circulating myeloma cells and DNA in the monitoring of multiple myeloma.

Dynamics of tumor‐specific cfDNA in response to therapy in multiple myeloma patients

“…In both cases, positive/PNQ levels of cfDNA decreased to undetectable (negative) levels in 32.6% ( P = .004) and 47.6% ( P = .012) of concerned patients, respectively. These results confirm the high value of ASCT in treatment of MM patients demonstrated by various studies, but also indicate the ability of cfDNA to mirror patients' response. The fact that majority of positive/PNQ patients in all assessed categories, except ASCT, remained positive (Table ) is probably caused by various time to response of individual patients or possible non‐responders to therapy.…”

“…So far, several studies investigated cfDNA in MM patients, but only limited long‐term data are available. Here, we performed a long‐term comprehensive study of cfDNA dynamics, which extends previous findings about applicability of cfDNA analysis for minimally invasive testing of MM patients …”

“…Since we observed a significant increase of negative cfDNA samples in time (Table ), slower response to therapy, rather than resistance to therapy, is probably the reason why cfDNA levels remained stable in majority of patients at the time of assessment. On the other hand, a change from negative to positive cfDNA levels observed in some cases might indicate a possible non‐responder to therapy …”

Molecular detection of minimal residual disease in multiple myeloma

“…By NGS, Oberle et al () also demonstrated that despite the presence of M‐proteins, around half of patients with ≤VGPR showed absence of myeloma clonotypes in PB leucocytes or plasma cell‐free DNA, regardless of increased DNA input. In addition, this study showed that presence of myeloma clonotypes in PB leucocytes or cell‐free DNA from PB plasma correlated with the conventional response status, as myeloma clonotypes were detectable in 91% of patients with stable/progressive disease and 41% of patients with at least PR; this indicated that systemic tumour load was an important determinant for successful detection of myeloma clonotypes in PB.…”

Liquid Biopsy in Liquid Tumors

“…Therapy responder patients, evidenced a prompt clearence of the VDJ myeloma rearrangement, meanwhile it persisted in refractory patients after treatment [83].…”