Development of a criterion for response to therapy at 6 months in multiple myeloma

Abstract: To investigate the prognostic value of therapy at 6 months on survival in multiple myeloma, to develop a new criterion assessing response to initial therapy at 6 months, and to compare it to a current criterion. The types of initial and 6‐month therapy were considered in a prognostic factor analysis in 70 patients treated in routine practice. Using the response to initial therapy defined by the clinician's decision as grouping variable in this group, a discriminant analysis identified the characteristics of responder patients. The validity of the resulting criterion was tested in another test group. Its prognostic ability was compared to the CLMTF criterion (50% M‐component reduction from baseline). The therapy at 6 months, reflecting the clinician's appraisal of response to initial therapy, predicted survival significantly. A criterion combining two variables (M‐component change and haemoglobin level at 6 months) classified 70% and 72.4% of patients correctly regarding response status in the training and test groups respectively. This criterion was shown to perform better than the CLMTF criterion in predicting survival. Conclusion: A new criterion for response to therapy at 6 months, also presented in a nomogram, combines M‐component change and haemoglobin level at 6 months.