Discussion
tumor, MM
RESIDUAL DISEASE, TUMOR
MS has been proposed as a minimally invasive complementary approach for monitoring of residual disease in MM patients [In both the STAMINA [From a clinical point of view, it is an important question if QIP-MS results can be used to guide treatment decisions. While we show a significant impact of single MS testing on PFS, we demonstrate that sequential MS testing, and combination of test results with baseline biological tumor features, could strongly improve the clinical value of this technique. For instance, there were GMMG-MM5 patients who converted from MS positivity to negativity during lenalidomide maintenance. Although this subgroup showed a trend towards an enrichment of IgG MM, the excellent PFS indicates that an extended half-life of the monoclonal protein did not solely underlie this observation. Of note, the patients were not exposed to an immunomodulatory agent prior to HDM/ASCT. Thus, this subgroup most probably reflects an explicitly lenalidomide-sensitive treatment group. In contrast, patients who converted from negative to positive MS had the worst outcome, highlighting MS as a method for early detection of emerging relapse in line with other studies [In line with recent studies using conventional CR or MRD-negativity to define the level of response [In conclusion, MS is a promising tool for monitoring treatment response. Recent data from the STAMINA trial [