With advancing technology bringing us new and more effective ways to treat myeloma, it makes sense that the way that we track the status of myeloma has also changed. Minimal Residual Disease (or Measurable Residual Disease, MRD) is what we call the very small amount of myeloma cells that may remain in the bone marrow even after treatment. These remaining numbers of myeloma cells may be too small to detect through traditional testing, but recent studies have shown that being able to get patients into a MRD negative status makes a substantial difference in the length of progression free survival they may experience.
In the US, there are currently two ways to test a patient for minimal residual disease, and both involve taking samples from the bone marrow.
Flow Cytometry - This method of testing was first developed in the 1950’s, and involves suspending the sample in a solution, and passing it through a cytometry machine. This machine sends the cells through a laser beam one at a time, at a rate of thousands of cells per second, and analyzes them individually.
Next Generation Sequencing (NGS) - This method of testing involves passing the sample through a machine which then looks at the sequencing of the genes. Myeloma can begin with a single mutation of a plasma cell, which then clones itself and multiplies. NGS testing has the ability to look at the individual makeup of each cell, looking for a specific genetic mutation. Because of this, NGS requires a baseline sample from a patient. Recent studies have shown NGS testing may be more sensitive and accurate in the detection of MRD.
The only currently FDA approved method of testing Minimal Residual Disease in myeloma is a NGS test developed by Adaptive Biotechnologues called clonoSeq.Learn more about clonoSEQ