This summary highlights information contained elsewhere in this prospectus and does not contain all the
information that you should consider in making your investment decision. You should read the entire prospectus, including our financial statements and related notes and the information set forth in
the sections titled "Risk Factors," "Special Note Regarding Forward-Looking Statements" and "Management's Discussion and Analysis of Financial Condition and Results of Operations" before deciding
whether to purchase shares of our common stock. Unless the context otherwise requires, we use the terms "Proteon," "our company," "we," "us" and "our" in this prospectus to refer to Proteon
We are a late-stage biopharmaceutical company focused on the development of novel, first-in-class pharmaceuticals to address the needs
of patients with renal and vascular disease. Our product candidate, PRT-201, is a recombinant human elastase that we are developing to reduce vascular access failure in patients with chronic kidney
disease undergoing or preparing for hemodialysis, a lifesaving treatment that cannot be conducted without a functioning vascular access. We believe the data from our completed Phase 2 trial of
PRT-201 in patients undergoing creation of an arteriovenous fistula, or AVF, support that a one-time, local application of PRT-201 during AVF surgical placement reduces AVF failure, thereby improving
patient outcomes and reducing the burden on patients and the healthcare system. We are not aware of any approved preventative treatments to reduce the failure rate of AVFs.
In May 2014, following the results from our Phase 2 trial and to fund our first Phase 3 trial, we closed on the $25.0 million first tranche of a $45.0 million
total financing. The financing was led by Abingworth, Deerfield and Pharmstandard and included investments from our existing venture investors. We initiated the first of two Phase 3 trials for
PRT-201 in radiocephalic AVFs, our initial indication, in the third quarter of 2014 and expect to initiate the second Phase 3 trial in the first half of 2015. PRT-201 has received fast track
designation which is designed to facilitate the development and expedite the review of drugs to treat serious conditions and fill an unmet medical need, from the United States Food and Drug
Administration, or FDA, and orphan drug designation in the United States and European Union, for hemodialysis vascular access indications.
retain worldwide commercial rights to PRT-201. If approved by regulatory authorities, we intend to commercialize this product in the United States ourselves with a specialty hospital
sales force, focused primarily on vascular surgeons, and intend to seek one or more collaborators to commercialize the product in additional markets. Our patents include claims covering formulations,
methods of manufacturing and uses of elastases, providing protection in the United States through mid 2029 and
the European Union through 2028, and with potential extension through 2032 in the United States and the European Union.
Established Medical Need
The need to improve vascular access outcomes is well established in the hemodialysis community. A 2014 publication estimated the total
cost of managing hemodialysis vascular access dysfunction in the United States to be approximately $2.9 billion annually. AVFs are the gold standard of vascular access for hemodialysis, as they
are associated with fewer complications and reduced rates of hospitalization. However AVFs have a greater than 50% failure rate in their first year after surgical placement, resulting in frequent
surgical or interventional procedures and a high rate of abandonment, leading to increased morbidity, mortality and costs of care.
estimate there are approximately 130,000 AVFs created in the United States annually. In an AVF procedure a surgeon transects a vein and sutures it to the side of a nearby artery,
typically in the arm. There are a limited number of potential artery-vein combinations in the arm that can be used by surgeons to create an AVF. The medical community endorses radiocephalic AVFs, in
which the cephalic vein is sutured to the radial artery in the wrist, as the optimal form of vascular access and the recommended first