Molecularly targeted therapy for Kaposi's sarcoma in a kidney transplant patient: case report, "what worked and what did not"

BACKGROUND: Imatinib is a tyrosine-kinase inhibitor; for which there is limited information regarding its effects on AIDS Kaposi's sarcoma and none in patients with transplant-associated Kaposi's sarcoma. Sirolimus, an immunosuppressive drug used for kidney transplant, exhibits antiangiogenic activity related to impaired production of VEGF (vascular endothelial growth factor), clinical benefit has been reported in Kaposi's sarcoma associated with renal graft. CASE PRESENTATION: Here we report a case of an 80 year old male, who developed Kaposi's Sarcoma nine months after receiving a living non-related donor kidney transplant at age 74. Three years after treatment with different chemotherapeutic agents for progressive cutaneous Kaposi's Sarcoma with no visceral involvement, he was prescribed Imatinib (200 mg/day for two weeks followed by 400 mg/day) after four weeks of treatment he developed anasarca, further progression of KS and agranulocytosis. Imatinib was discontinued and there was significant clinical recovery. One year later his immunosuppressive therapy was changed to Sirolimus and regression of the Kaposi's sarcoma occurred. CONCLUSION: The lack of benefit and severe toxicity associated with the use of Imatinib in this patient should alert clinicians of potentially adverse consequence of its use in patients with transplant associated Kaposi's sarcoma. On the other hand the positive response seen in this patient to Sirolimus even after a long evolution of Kaposi's sarcoma, multiple chemotherapy regimens and extensive cutaneous disease further suggest it therapeutical utility for transplant associated Kaposi's sarcoma.