Serial MRD Assessments as a Surrogate for Long Term PFS | Frits van Rhee, MD | IMS 2023

My name is Frits Van Rie. I work at the myeloma center at the University of Arkansas for medical sciences and we've been interested in detecting small numbers of myeloma cells in the bone mirrors of patients who are by standard criteria incomplete remission. This is called looking for minimal residual disease. So these are small amounts of myeloma in the marrow and we look at the significance of detecting these. So we've been doing this testing systematically since 2013 on all our patients and we've done a study of over 1700 patients looking at approximately 20,000 tests and try to identify the meaning of the presence of the small number of myeloma cells in the bone mirror that is called a positive MRD test or positive minimal residual disease test. Now the bad news is that we found that patients who have negative MRD test persistently, serially on at least three occasions in the first five years after transplant, have a very low risk of relapse on long-term follow-up. So if you belong amongst a group of patients who do have serial negative MRD tests then it's extremely unlikely that you are at risk of relapse of the myeloma. Conversely on the other hand there are patients who are persistently MRD positive and they are at increased risk of relapse. It is not a guarantee that they are going to relapse but they do have an increased risk. Now to illustrate that some positive MRD do not necessarily mean that you're going to relapse. We also found that there are some patients who have intermittently positive and negative MRD tests and they have also a reduced risk of relapse compared to the group who are always MRD positive. So it's very important to interpret these tests with some caution. There is a lot of emphasis in the myeloma community on achieving negative MRD tests and that's indeed very important when there's serial negative. On the other hand the house is not on fire so to speak if you do have an occasion positive MRD test. So there are still patients who have very good outcome despite having some positive MRD tests. So overall this is a very large study which hopefully helps people to interpret the meaning of their MRD tests.