Proteon Therapeutics Inc. announced positive results from a long-term analysis of more than three years of follow-up data from a Phase 2 study of its drug vonapanitase (formerly PRT-201). The study evaluated the safety and efficacy of vonapanitase in patients with chronic kidney disease undergoing surgical creation of an arteriovenous fistula for hemodialysis. The study,presented at National Kidney Foundation’s 2015 Spring Clinical Meetings, demonstrated prolonged primary patency of an arteriovenous fistula and a statistically significant improvement in the rate of corrective procedures over more than three years of follow-up for the 30 mcg vonapanitase dose as compared to placebo.

An analysis of the results in the subset of patients receiving a radiocephalic AVF, which was not pre-specified, showed statistically significant improvements in primary patency, secondary patency (AVF survival) and the rate of corrective procedures over more than three years of follow-up for the 30 mcg vonapanitase dose as compared to placebo.

The Phase 2 multicenter, randomized, double-blind, placebo-controlled clinical study evaluated safety and efficacy of a single application of vonapanitase delivered immediately after surgical creation of an AVF.


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Patients that received vonapanitase reported adverse events related to the AVF comparable to placebo over more than three years. These events were consistent with the medical events experienced by chronic kidney disease patients undergoing surgical creation of an AVF.

Bradley Dixon, MD, a nephrologist and Associate Professor of Medicine at the University of Iowa’s Department of Internal Medicine, presented the results in a late-breaking clinical trial session.

“These results suggest that a single treatment of vonapanitase immediately after radiocephalic AVF surgical creation may yield durable benefits for patients,” said Dixon. “A radiocephalic AVF is the preferred form of vascular access for hemodialysis patients, and the benefits of vonapanitase, if observed in pivotal Phase 3 studies, would have great clinical importance to patients and their caregivers.”

Proteon is currently enrolling patients in a Phase 3 multicenter, randomized, double-blind, placebo-controlled clinical study of vonapanitase in CKD patients undergoing surgical creation of a radiocephalic AVF for hemodialysis. The Company expects to complete enrollment by the end of 2015 and is anticipating initiating enrollment in a second Phase 3 clinical study in the second quarter of 2015. Proteon is also conducting an ongoing Phase 1 clinical study of vonapanitase in patients with symptomatic peripheral artery disease (PAD).

About vonapanitase
Vonapanitase (formerly PRT-201) is an investigational drug designed to improve arteriovenous fistula (AVF) patency, the period of time during which an AVF remains open with adequate blood flow to enable hemodialysis. Vonapanitase is applied in a single administration and is currently being studied in a Phase 3 clinical trial in patients with chronic kidney disease (CKD) undergoing surgical creation of a radiocephalic arteriovenous fistula for hemodialysis. Vonapanitase has received fast track and orphan drug designations from the U.S. Food and Drug Administration (FDA), and orphan medicinal product designation from the European Commission, for hemodialysis vascular access indications. Vonapanitase may have multiple surgical and endovascular applications in which vessel injury leads to blockages in blood vessels and reduced blood flow, and is currently being evaluated in a Phase 1 clinical trial in patients with symptomatic peripheral artery disease.