Proteon Therapeutics Announces Publication of Results From Phase 3 Clinical Trial

Proteon Therapeutics Inc. recently announced the publication in the Journal of Vascular Surgery of results from its Phase 3 PATENCY-1 clinical trial of investigational vonapanitase. Top-line data from PATENCY-1 were publicly announced in December 2016. The study results suggested vonapanitase may improve both fistula use for hemodialysis and secondary patency (time to fistula abandonment), which are the co-primary endpoints in Proteon’s ongoing Phase 3 PATENCY-2 clinical trial. The PATENCY-2 clinical trial is fully enrolled and top-line data is expected in March 2019.

PATENCY-1 evaluated the safety and efficacy of a single dose of vonapanitase in patients with chronic kidney disease (CKD) undergoing surgical creation of a radiocephalic arteriovenous fistula for hemodialysis. The randomized, double-blind, placebo-controlled clinical trial enrolled 313 treated patients at 31 medical centers in the US. Patients were followed for up to 1 year.

As previously reported, PATENCY-1 did not meet its primary endpoint of improved primary unassisted patency, compared to placebo (p=0.254). However, for its pre-specified secondary endpoint, the trial showed a 34% reduction in the risk of secondary patency loss over 1 year, compared to placebo (p=0.048). Additionally, the trial showed a 45% relative increase in fistula use for hemodialysis, compared to placebo (p=0.006), which was another pre-specified endpoint.

“While a functioning arteriovenous fistula remains the gold standard for hemodialysis vascular access, failure rates remain unacceptably high, resulting in increased morbidity and mortality and higher health care costs,” said Anthony J. Bleyer, MD, Professor, Nephrology, Wake Forest Baptist Health, and lead author of the publication. “The PATENCY-1 results are promising because of the improvement in fistula use and secondary patency, two clinically meaningful endpoints for patients, their families, and their physicians. I look forward to the results of the ongoing PATENCY-2 trial, in which fistula use and secondary patency are the co-primary endpoints.”

The PATENCY-1 results were the basis for Proteon’s request to the US FDA for Breakthrough Therapy designation, which the FDA granted in May 2017 for increasing arteriovenous fistula secondary patency and use for hemodialysis. The FDA awards Breakthrough Therapy designations to expedite the development and review of investigational drugs that are intended to address a serious or life-threatening condition when preliminary clinical evidence indicates that the drug may offer a substantial improvement over available therapies on one or more clinically significant endpoints.

Based on the results of PATENCY-1, and following discussions with the FDA, Proteon amended the protocol for the PATENCY-2 trial, reordering the endpoints and establishing fistula use for hemodialysis and secondary patency as co-primary endpoints. If PATENCY-2 is successful in showing statistical significance (p≤0.05) for both of the co-primary endpoints, Proteon expects to file a Biologics License Application (BLA) with the FDA in the second half of 2019 and a Marketing Authorization Application (MAA) with the European Medicines Agency (EMA) in the first half of 2020.

In the most severe stage of chronic kidney disease (CKD), also known as kidney failure, the kidneys can no longer function to sustain life. The majority of patients with kidney failure undergo chronic hemodialysis, which requires a high-flow vascular access to repeatedly connect the patient’s bloodstream to a hemodialysis machine for this life-saving treatment. The preferred form of vascular access for hemodialysis is a radiocephalic arteriovenous fistula, created when a surgeon connects a vein to an artery in the lower arm, resulting in a substantial increase in blood flow and vein dilation.

Vonapanitase is an investigational drug intended to improve hemodialysis vascular access outcomes. Vonapanitase is applied in a single administration and is currently being studied in a Phase 3 clinical trial in patients with CKD undergoing surgical creation of a radiocephalic arteriovenous fistula for hemodialysis. Vonapanitase has received Breakthrough Therapy, Fast Track and Orphan Drug designations from the FDA, and Orphan Medicinal Product designation from the European Commission, for hemodialysis vascular access indications. In addition, vonapanitase may have other surgical and endovascular applications in diseases or conditions in which vessel injury leads to blockages in blood vessels and reduced blood flow. Proteon is currently conducting a Phase 1 clinical trial of vonapanitase in patients with peripheral artery disease (PAD).

Proteon Therapeutics is committed to improving the health of patients with kidney and vascular diseases through the development of novel, first-in-class therapeutics. Proteon’s lead product candidate, vonapanitase, is an investigational drug intended to improve hemodialysis vascular access outcomes. Proteon has completed enrollment in PATENCY-2, a Phase 3 clinical trial evaluating vonapanitase in patients with CKD undergoing surgical creation of a radiocephalic arteriovenous fistula for hemodialysis. Proteon is also evaluating vonapanitase in a Phase 1 clinical trial in patients with PAD. For more information, please www.proteontx.com.