PRT-201 (vonapanitase) did not meet primary endpoint in Phase III trial to improve patency (openness) in radiocephalic arteriovenous fistulae.-Proteon Therapeutics

Proteon Therapeutics, Inc. announced that its first Phase III clinical trial with investigational vonapanitase, PATENCY-1, did not meet its primary endpoint of improved primary unassisted patency compared to placebo (p=0.254). However, the top-line results for the trial's secondary endpoint suggested that vonapanitase may improve secondary patency compared to placebo (p=0.048). Data from one of the trial's three tertiary endpoints also suggested vonapanitase may improve unassisted fistula use for hemodialysis (p=0.035) and any use of the fistula (unassisted or assisted) for hemodialysis (p=0.006). Adverse events reported for vonapanitase were similar to placebo.

PATENCY-1 evaluated the safety and efficacy of a single dose of vonapanitase in patients with chronic kidney disease (CKD) receiving or expecting to receive hemodialysis who underwent surgical creation of a radiocephalic arteriovenous fistula.This procedure is done to provide easier access to the vein in chronic kidney disease patients experiencing kidney failure who need chronic hemodialysis. The multicenter, randomized, double-blind, placebo-controlled clinical trial enrolled 313 patients at 31 medical centers in the United States. Patients in the trial were followed for up to one year. The trial's primary endpoint, primary unassisted patency, is the length of time from fistula surgical creation to the first occurrence of a fistula thrombosis or corrective procedure to restore or maintain patency (blood flow). In PATENCY-1, vonapanitase-treated patients had a 17% reduction in the risk of primary unassisted patency loss over one year, compared to placebo (p=0.254). At the end of one year, 42% of patients who received vonapanitase retained primary unassisted patency, compared to 31% of placebo-treated patients. PATENCY-1's secondary endpoint, secondary patency, is the length of time from surgical creation until fistula abandonment (final failure). In PATENCY-1, vonapanitase-treated patients had a 34% reduction in the risk of secondary patency loss over one year, compared to placebo (p=0.048). At the end of one year, 74% of vonapanitase-treated patients maintained secondary patency, compared to 61% of placebo-treated patients

Comment: Proteon is planning to increase the size of its second Phase III study PATENCY-2 with results expected in the second quarter of 2018.