Evidence for the use of anti-CD20 therapeutic antibodies in immune thrombotic thrombocytopenic purpura management: a review.

Immune thrombotic thrombocytopenic purpura (iTTP) is an autoimmune thrombotic microangiopathy caused by antibody-mediated deficiency of the plasma metalloprotease ADAMTS13. Therapeutic antibodies that target antibody-producing B-cells via the CD20 surface receptor protein to prevent disease exacerbation and relapse have become part of the standard of care of patients with iTTP. However, clinical trial data regarding the use of anti-CD20 agents is limited to mostly phase II studies; no universally agreed-upon standardized protocol for the use of CD20-targeting antibodies for iTTP regarding choice of agent, dosage, or duration of treatment exists; refractoriness or lack of response to anti-CD20 antibodies can occur; and several agents and biosimilars are now available for the treatment of iTTP patients, which complicates the decision tree for clinicians caring for these patients. In this review, we explore the current landscape of anti-CD20 therapeutics used to treat iTTP, focusing on agents currently available for clinical use. We describe the pharmacokinetic and pharmacodynamic properties of CD20-targeting antibodies; available data regarding dosage and duration of treatment; anti-CD20 antibody therapy refractoriness or lack of response; and the evolving role of anti-CD20 biosimilars. This review will shed light on the state-of-the-art in CD20-targeting antibodies used to treat iTTP patients with an eye toward identifying areas in need of further study to aid in the care of patients with this rare and often devastating disease.