Phase II study of the oral selective inhibitor of nuclear export (SINE) KPT-335 (verdinexor) in dogs with lymphoma

Abbey R. Sadowski, Heather L. Gardner, Antonella Borgatti, Heather Wilson, David M. Vail, Joshua Lachowicz, Christina Manley, Avenelle Turner, Mary K. Klein, Angharad Waite, Alexandra Sahora, Cheryl A. London

Chemotherapeutic options for the treatment of canine lymphoma have not changed in several decades necessitating the identification of new therapeutics to improve patient outcome. KPT-335 (verdinexor) is a novel orally bioavailable selective inhibitor of nuclear export (SINE) that exhibited anti-tumor activity against non-Hodgkin lymphoma in a prior phase I study. The objective of this phase II study was to expand upon the initial findings and assess the activity and safety in a larger population of dogs with lymphoma. Fifty-eight dogs with naïve or progressive B-cell and T-cell lymphoma were enrolled in this clinical trial. KPT-335 was administered orally in one of three dosing groups, based on the previously established biologically active dose of 1.5 mg/kg three times weekly. Treatment with single-agent, orally administered KPT-335 resulted in an objective response rate (ORR) of 37%, of which dogs with T-cell lymphoma had an ORR of 71%. KPT-335 was well tolerated in all dose groups with grade 1-2 anorexia being the most common adverse event. Anorexia was responsive to symptomatic and supportive medications, including prednisone. These data demonstrate that KPT-335 has biologic activity in canine lymphoma, and support continued evaluation of SINE compounds such as KPT-335 in combination with standard chemotherapeutics in canine lymphoma.