Department of Pathology, Northshore Edward-Elmhurst Health Evanston, Illinois, United States
Background/Case Studies:
Background: A number of different therapeutic modalities have been tried for SARS CoV-2 infection early in the course of the disease, including monoclonal antibodies against the SARS CoV-2 spike protein. One of the products, imdevimab/casirimivab (REGEN-COV) has been used since November 2020. We report a case of severe thrombocytopenia due to this medication that was treated successfully with a course of therapeutic plasma exchange.
Conclusion: Plasma exchange should be considered when rapid removal of therapeutic monoclonal antibody is warranted due to life-threatening side effects.
Study
Design/Methods: NA
Results/Findings:
Case Report: An 84 y M was admitted to the hospital with not being able to care of himself at home. He had a history of coronary heart disease with stent placement and atrial fibrillation for which he was placed on rivaroxaban. On admission (day 1) he was mildly anemic (Hgb 11.4 g/dL; platelet count of 239/nL) and had hematuria. Admission testing was positive for SARS C0V-2 by pCR. The rivaroxaban was discontinued and a cystoscopy showed two venous bleeding sites which were treated by cauterization. On the fifth hospital day he received REGEN-COV and over the next two days his platelet count dropped from 153 to < 1 /nL. There was no evidence of hemolysis and no schistocytes were seen on the blood smear. A presumed diagnosis of drug-induced thrombocytopenia due to REGEN-COV was made and despite platelet transfusions, intravenous immunoglobulin 2 g/kg, and dexamethasone 40 mg daily, his platelet count stayed at < 1 or 1/nL for the next three days. Since REGEN-COV has a half-life of three weeks or more, plasma exchange was considered as a means of removing the monoclonal antibodies. Plasma exchange daily, one plasma volume with all plasma replacement was started on the ninth hospital day and continued for four days. The platelet count sequentially increased daily and was within the normal range (162/nL) by day 14. The hematuria cleared by day 11. The patient was treated for SARS-CoV-2 by other means and discharged on day 22. Conclusions:
Conclusion: Plasma exchange should be considered when rapid removal of therapeutic monoclonal antibody is warranted due to life-threatening side effects.
Importance of research: This illustrates the importance of plasma exchange in removal of a therapeutic protein with a long half -life that has life-threatening side effects.
