Eliminating the need for sequential confirmation of response in multiple myeloma

Disease response and progression assessment in multiple myeloma is based on various measurements of monoclonal protein (serum and urine protein electrophoresis, serum free light chain, and/or quantitative immunoglobulins). Currently, the International Myeloma Working Group consensus response criteria require 2 sequential assessments of any 1 marker made at any time before confirmation of disease progression and the institution of any new therapy. However, this can be cumbersome in clinical trials. Herein, we hypothesized that if 2 markers meet the progression criteria simultaneously, a repeat of either will not be necessary for confirmation. We retrospectively studied all sequential patients with myeloma enrolled in clinical trials at Mayo Clinic. We identified 583 episodes of confirmed progression in our study. Among the 583 progression episodes, nearly 70% (sensitivity of the simultaneous criteria) met the 2 simultaneous variable criteria at the first testing, indicating progression. Conversely, among 413 patients who met progression criteria by 2 simultaneous values, 98% (specificity of the simultaneous criteria) of patients subsequently had confirmed progression by sequential values. In summary, for patients with 2 disease burden markers meeting the simultaneous progression criteria, sequential assessment of either 1 for confirmation may not be necessary to determine disease progression.