Kadmon Holdings, Inc. (NYSE:KDMN) ("Kadmon" or the "Company") today announced additional data from its ongoing Phase 2a clinical study demonstrating the safety of tesevatinib, the Company's oral tyrosine kinase inhibitor, for the treatment of autosomal dominant polycystic kidney disease (ADPKD). The data will be presented in a poster session on Saturday, November 19 at the American Society of Nephrology (ASN) Kidney Week 2016 in Chicago, IL. Recent findings from Kadmon's ongoing Phase 2a study in patients with ADPKD have demonstrated that tesevatinib is well tolerated and have also identified tesevatinib 50 mg once daily (QD) as the optimal dose to treat ADPKD. New data reported in the poster indicate that tesevatinib is a new member of a group of drugs known as MATE 1/2-K transporter inhibitors, such as cimetidine, which mildly increase levels of serum creatinine. Normally, an increase in serum creatinine can be used to indicate kidney damage, but in the case of MATE 1/2-K inhibitors, these serum creatinine increases occur without clinically meaningful alterations in renal function. Specifically, new data demonstrated that serum creatinine levels in tesevatinib patients increased by 10% to 14% during the first 28 days of treatment and reversed upon treatment discontinuation. Importantly, levels of cystatin C, another measure of renal function, were relatively unchanged during the same period. In vitro studies demonstrated that tesevatinib potently inhibits MATE1/2-K transporters at tesevatinib concentrations achieved with the 50 mg QD dose. Therefore, MATE inhibition by tesevatinib may explain mild serum creatinine increases associated with tesevatinib treatment. "Kadmon has identified a contradiction in PKD drug development: MATE transporters such as tesevatinib increase levels of creatinine, the standard measure of PKD drug efficacy, but without clinically relevant effects on kidney function," said James Tonra, Ph.D., Senior Vice President, Nonclinical Development at Kadmon and first author of the poster. "These findings further characterize the safety of tesevatinib while highlighting the need for alternative methods to evaluate kidney function in PKD drug development."