At the recent American Association for Clinical Chemistry (AACC) annual scientific meeting in San Diego, Melissa Snyder, Ph.D., Consultant in the Division of Clinical Biochemistry and Immunology at Mayo Clinic in Rochester, Minnesota, presented the short course, “Clinical and Laboratory Aspects of Monoclonal Antibody Therapeutics.”
According to a recent recap in Clinical Laboratory News, new targeted monoclonal antibody (mAb) therapies are making good on the promises of precision medicine—until they inexplicably stop working. When that happens, clinicians turn to Dr. Snyder for a better understanding of the problem.
Dr. Snyder's lab has responded to this need with laboratory-developed tests (LDTs) for therapeutic drug monitoring (TDM) of drug concentration and antibodies against therapeutic mAbs (anti-drug antibodies, or ADAs).
“Many of the reasons that we traditionally do TDM do not apply to mAbs,” Snyder said. Most TDM of mAb therapies is for loss of response to therapy in inflammatory bowel disease, not toxicity or compliance.
According to Maria Alice Willrich, Ph.D., Consultant in the Department of Laboratory Medicine and Pathology and Dr. Snyder's colleague, the rise of mAb therapeutics has also introduced new mechanisms of assay interference.
"There are some cases when it is important to differentiate between endogenous mAb and therapeutic mAb,” Dr. Willrich said, and plasma cell dyscrasias are one of these cases. Serum protein electrophoresis and immunoelectrophoresis are gold standards in diagnosing and following treatment efficacy in patients with plasma cell dyscrasias, and they reliably detect monoclonal antibody populations.