D-Penicillamine Induced Myelotoxicity: A Unique Case

<b>Purpose:</b> A case of D-penicillamine-related myelotoxicity in a patient with Wilson's disease is reported. <b>Summary:</b> There is a paucity of literature regarding D-penicillamine (DPA) induced myelotoxicity in the setting of Wilson's disease (WD). A 22-year-old male presented with a 1-week history of bleeding gums and dizziness. Four months prior, he had been diagnosed with Wilson's disease and started on a regimen of DPA. His blood counts demonstrated profound pancytopenia. Due to concern for suspected drug-induced myelotoxicity, DPA was discontinued. Parvovirus B19, Epstein-Barr virus, cytomegalovirus, and varicella zoster virus polymerase chain reaction studies were negative and there was no evidence of hematological malignancy. Bone marrow biopsy demonstrated hypocellularity and trilineage hypoplasia with corresponding aspirate flow cytometry confirming the absence of acute leukemia. The patient was started on subcutaneous granulocyte-colony stimulating factor, provided transfusion support with packed red blood cells and platelets. Despite these measures, his blood count failed to recover, and he was discharged on eltrombopag 150 mg daily with plans for outpatient transfusion support. DPA was permanently discontinued, and he was prescribed trientine 750 mg daily. Unfortunately, his myelotoxicity remained consistent, requiring regular transfusions. He is currently undergoing evaluation for bone marrow transplant. <b>Conclusion:</b> DPA-induced myelotoxicity is a rare clinical entity. Our case demonstrates a unique clinical presentation of this phenomenon. Guidelines to mitigate the risk of and treat this toxicity remain to be determined.