Proteon Therapeutics Inc. was marked as the worst performer on the NASDAQ Composite in Tuesday’s close with a 74.75% dive to 2.50 in late trade. The Waltham-based biotech company‘s stock plummet was followed by Inovalan Holdings Inc. with a decline of 35.35% to 9.60 and aTyr Pharma Inc. which lost 23.29% to 2.800.

Meanwhile, the best performers were US Energy Corp., climbing 62.41% to 2.2900, Sunshine Heart Inc. which jumped 52.63% to settle at 0.580 and Rennova Health Inc., rising 44.70% to end the prior session at 0.164.

Missed Primary Goal

Proteon Therapeutics (PRTO) shares cratered yesterday after the firm posted top-line results from its late-stage chronic kidney disease (CKD) trial.


The pharmaceutical company reported that is first Phase 3 clinical trial called Patency-1 with its experimental drug vonapanitase, did not meet its primary goal of enhanced primary unassisted patency compared to placebo. This has caused PRTO shares plunge over 70% in premarket trading, wipingout an estimated $116 million of its market cap.

Steven Burke, M.D., the senior vice president and chief medical officer of Proteon Therapeutics, said the company is disappointed that the study had not met the said endpoint.

“However, it appears that vonapanitase had a drug effect and we are encouraged by the secondary patency and fistula use for hemodialysis findings in this trial, both of which we believe are clinically important. We plan to review the full data set from PATENCY-1 and further investigate these findings in our ongoing Phase 3 clinical trial, PATENCY-2.” Burke remarked.

The trial’s primary endpoint—the aforementioned 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, or what is commonly known as blood flow. In other words, the drug treatment was intended for patients who have surgery to create a fistula, an access in the arm needed for hemodialysis. The drug— a naturally-occurring enzyme that aids blood vessels to heal — is designed to ease the risk of failure of the fistula, which can reduce blood flow and require additional surgery.

Vonapanitase-treated patients had 17% alleviation in the risk of primary unassisted patency loss over one year, compared to the placebo. At the end of one year, 42% out of the 313 patients who received vonapanitase retained primary unassisted patency, compared to 31% of the placebo-treated patients.

Other Findings

These top-line results for the trial’s secondary endpoint also indicated that vonapanitase may improve secondary patency compared to placebo. Additionally, data from one of the trial’s three tertiary endpoints suggested that vonapanitase may improve unaided fistula use for hemodialysis. These findings have encouraged the company to continue the study.

In terms of the secondary endpoint in the same period after a year, 74% of vonapanitase-treated patients maintained secondary patency, compared to 61% of placebo-treated patients.

The unpleasant effects were fairly alike between the vonapanitase-treated patients and the placebo-treated patients. Common adverse effects were consistent with medical events experienced by CKD patients who are undergoing radiocephalic fistula surgery.


Patency-2, another Phase 3 study of vonapanitase, is ongoing. CEO Timothy Noyes stated that: “Because of the clinical importance of fistula abandonment and fistula use for hemodialysis to both patients and physicians, we plan to increase the planned enrollment of PATENCY-2 and look for other ways to use these results to guide our development efforts.”

On Tuesday, Proteon announced it still had ample financial resources, estimated about $43 million as of the end of November, to continue functioning into the third quarter of 2018.

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