Current MRD testing
These techniques require patients to undergo a bone marrow (BM) aspiration or bone marrow biopsy to collect a bone marrow sample. This can be combined with imaging techniques to detect malignant cells outside the bone marrow. BM-MRD testing estimate the myeloma tumor burden by the quantification of cell-based parameters, such as the expression of specific cell surface markers (NGF) or Ig gene rearrangements (NGS).
The result of MRD assessment is either positive, meaning that myeloma cells are detected, or negative, meaning that myeloma cells are not detected. MRD negativity indicates a very deep response to treatment. If this deep response is maintained over time, with repeat MRD testing, patients will on average, have longer periods of remission and overall survival. MRD testing may require repeat bone-marrow aspiration and/or biopsy which can negatively impact a patient’s quality of life. It can also result in false negative results due to hemodilution or extramedullary disease. MRD timepoints are therefore limited and sometimes are missing.