Treatment of multiple myeloma with monoclonal antibodies and the dilemma of false positive M-spikes in peripheral blood

Kazunori Murata, Samuel I. McCash, Brittany Carroll, Alexander M. Lesokhin, Hani Hassoun, Nikoletta Lendvai, Neha S. Korde, Sham Mailankody, Heather J. Landau, Guenther Koehne, David J. Chung, Sergio A. Giralt, Lakshmi V. Ramanathan, Ola Landgren

Research output: Contribution to journalArticlepeer-review

32 Scopus citations

Abstract

Objectives To characterize the effect of three humanized IgG κ monoclonal antibodies (daratumumab, isatuximab, and elotuzumab) on the interpretation of results generated by protein electrophoresis, immunofixation, free light chain, and heavy/light chain assays performed on human serum. Methods Healthy volunteer serum and serum from multiple myeloma patients were supplemented with clinically relevant concentrations of each of the three monoclonal antibodies. These specimens then underwent analysis via serum protein electrophoresis, immunofixation, serum free light chain quantification, heavy/light chain quantification, total IgG, and total protein. In addition, serum specimens from patients who had undergone treatment with elotuzumab for multiple myeloma underwent similar analysis. Results Addition of the study drugs to serum from both the healthy donor as well as multiple myeloma patients resulted in a visible and quantifiable M-protein on SPEP and a visible IgGκ band by IFE. Increases were also noted in total IgG, IgGκ, and IgGκ/IgGλ-ratios. Analysis of serum from multiple myeloma patients receiving study drug showed similar findings with an additional IgGκ band and quantifiable M-protein with similar migration patterns in specimens drawn after administration. Conclusion The treatment of multiple myeloma patients with monoclonal antibodies results in a visible and quantifiable M-protein that has the potential to falsely indicate poor response to therapy.

Original languageEnglish (US)
Pages (from-to)66-71
Number of pages6
JournalClinical Biochemistry
Volume51
DOIs
StatePublished - 2018
Externally publishedYes

Keywords

  • Daratumumab
  • Electrophoresis
  • Elotuzumab
  • Immunofixation
  • Isatuximab
  • Myeloma

ASJC Scopus subject areas

  • Clinical Biochemistry

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