Predicting Patient Outcomes With MM Using Serum B-Cell Maturation Antigen
At the Lymphoma & Myeloma congress, James R. Berenson, MD, Medical and Scientific Director, Institute for Myeloma and Bone Cancer Research, West Hollywood, California, spoke about the use of serum B-cell maturation antigen (sBCMA) to predict outcomes in patients with multiple myeloma (MM).
“With myeloma we know that the standard tests for monitoring these patients are intact immunoglobulin (Ig) MM presence (serum and urine protein electrophoresis [SPEP]) or light chain MM presence (urine protein electrophoresis [UPEP] on 24-hour urine and serum-free light chains [SFLC]),” explained Dr Berenson, who described these tests as inaccurate and slow for detection of changes in clinical status.
Blood-based tests were criticized for a variety of reasons, including a lack of consistency in methods for interpreting results, inability to accurately assess renal failure, and measurement of unrelated Igs.
Urine tests are to be collected on a 24-hour basis, but because it is hard to determine whether there really was a 24-hour collection, this resource is generally unreliable. In addition, UPEP involves subjective determination of monoclonal protein.
Of note, the half-life of monoclonal antibodies is just a few weeks, with turnover too slow to effectively guide therapy.
Dr Berenson then went on to discuss the role of and rationale for testing with sBCMA, a solubilized form of B-cell maturation antigen that is elevated in B-cell cancers (eg, MM, chronic lymphocytic leukemia, Waldenstrom’s macroglobulinemia, and amyloidosis). sBCMA is reduced in individuals with immune deficiency syndromes, and has a short half-life (24-36 hours) that affords rapid determination of changes in clinical status.
In addition, sBCMA has a much more rapid turnover in blood than monoclonal protein levels, and are independent of renal function, unlike SFLC.
“sBCMA is elevated in patients with plasma cell dyscrasias, baseline sBCMA levels can be used to predict progression-free survival and overall survival in patients with MM,” said Dr Berenson.
“sBCMA can be used to track patients with non-secretory MM, and because sBCMA turns over more rapidly, earlier detection of changes in disease status is possible that can boost confidence in switching therapies,” he added.
Dr Berenson also noted that sBCMA can be used to predict the progression of monoclonal gammopathy of undetermined significance and smoldering multiple myeloma to active MM.—Hina Porcelli