Phase I/II trial of Arginine Butyrate and ganciclovir in Epstein-Barr virus-associated lymphoid malignancies

Abstract

7542 Background: Malignancies associated with latent Epstein-Barr virus (EBV) are resistant to nucleoside-type anti-viral agents because the viral enzyme target of these drugs, thymidine kinase (TK), is not expressed. Short-chain fatty acids, such as butyrate, induce EBV-TK expression in latently-infected B cells. In preclinical studies, we have shown that butyrate sensitizes EBV(+) lymphoblastoid cells, tumor lines and primary lymphoma cultures to apoptosis induced by ganciclovir. Methods: We conducted a Phase I/II trial of Arginine Butyrate in combination with ganciclovir in patients with refractory EBV(+) lymphoid malignancies to evaluate toxicity, pharmacokinetic parameters, and clinical responses. Fifteen patients with heavily-pretreated, refractory EBV(+) lymphoid malignancies, consisting of monoclonal refractory lymphoproliferative disease (PTLD), B cell non-Hodgkin’s lymphomas (NHL) (including one HIV-associated anaplastic B cell lymphoma), T cell NHL (including one cutaneous lymphoma), T/NK cell lymphomas, and Hodgkin disease were studied. Ganciclovir was administered twice daily and Arginine Butyrate was administered in an intra-patient dose-escalation. Arginine Butyrate was instituted at 500 mg/kg/day by continuous infusion, and escalated to 2000 mg/kg/day, as tolerated. Results: The MTD for Arginine Butyrate was established as 1000 mg/kg/day. Overall the combination was well-tolerated, with the most common toxicities being nausea and headache. Complications from rapid tumor lysis occurred in three patients, including acute hepatic necrosis in one patient. Reversible grade 3–4 somnolence or stupor occurred in three patients at Arginine Butyrate doses of greater than 1000 mg/kg/day. Ten of fifteen patients showed significant anti-tumor responses, with 5 CR and 5 PR. In certain patients who demonstrated a clinical CR, subsequent pathological analysis showed elimination of all tumor cells. Conclusions: The combination of Arginine Butyrate and ganciclovir was reasonably well-tolerated and appears to have significant biological activity in vitro and in vivo against refractory EBV(+) lymphoid malignancies. No significant financial relationships to disclose.