Positive early-stage clinical trial results for a drug being studied as a new treatment for the rare disorder hereditary angiodema have revived the stock price for BioCryst (NASDAQ: BCRX).
A day after releasing the results and announcing plans to advance the compound into the next stage of clinical testing, stock in the Durham company traded as high as $4.72 per share. BioCryst stock closed Tuesday at $4.52, up 21.5 percent.
But let’s be clear here, it’s still early.
First, let’s take a look at the disease that BioCryst is targeting. Hereditary angiodema, or HAE, is a genetic, blood-based disease in which patients don’t have enough of a protein called a C1-inhibitor. Insufficient amounts of this protein can lead to attacks of swelling. The swelling can occur in the hands, feet, abdomen, even the face. Swelling in the face and throat are particularly dangerous. Airway constriction kills many HAE patients.
HAE is what’s referred to as an orphan disease, another way of saying it’s rare. The U.S. Hereditary Angiodema Association estimates that there are more than 6,500 HAE sufferers in the United States have this genetic disorder. While the disease is rare, HAE patients do have treatments available to them. The Food and Drug Administration has approved products that deliver C1-inhibitors intravenously.
BioCryst is taking a different approach. During the swelling and inflammation of an HAE attack, an enzyme called kallikrein is formed. BioCryst’s BCX4161 targets this enzyme. In healthy patients, the natural C1 inhibitor binds with kallikrein and inactivates it, BioCryst Chief Medical Officer William Sheridan explained during a conference call discussing the phase I results. But instead of binding to the kallikrein, the enzyme at the heart of these HAE attacks, BCX4161 binds to the targets of kallikrein, keeping the enzyme from triggering another compound called bradykinin. During HAE attacks bradykinin levels spike, leading to the dangerous swelling characteristic of the disease. There are FDA-approved products that target kallikrein and bradykinin. But these products are injectables.
BioCryst’s BCX4161 is administered as a a pill, which would make the treatment easier for patients to take themselves. That alone would give it an edge over the existing slate of HAE treatments. The company also showed test results showing its compound works better than C1 inhibitors. BioCryst tested the potency of BCX4161 using plasma samples donated by HAE patients during a period between HAE attacks. In these tests, the BioCryst compound was 15 times more potent than a C1 inhibitor.
Investors appear to be excited by the phase I results, given the rise in the company’s stock price. But again, it’s still early. BioCryst has yet to show that BCX4161 works in HAE patients. Yes, the phase I study showed that the compound was safe and well tolerated by patients. But these patients were all healthy and did not have HAE.
Evidence of BCX4161’s efficacy could come in tests of the compound in HAE patients. BioCryst plans to start a phase IIa study in HAE patients who have historically had at least one HAE attack per week. Besides further assessing the safety and tolerability of BCX4161, BioCryst aims to see what impact its compound has on the frequency of HAE attacks and the quality of life for HAE patients. The phase II studies are expected to start in the fourth quarter. The early clinical trial results so far are good and they suggest the potential of what could become a new treatment for HAE in a form that’s easier to for patients to take themselves. But it’s still a long way yet to get to FDA approval.
In other BioCryst news …
BioCryst announced that Dr. Fred E. Cohen has been elected to the company’s board of directors. Cohen is partner and managing director at TPG Biotech, the biotech investment arm of investment firm TPG. His research interests include structure based drug design, prion diseases, computational biology and heteropolymer chemistry. Cohen received his B.S. degree in Molecular Biophysics and Biochemistry from Yale University, his D.Phil. in Molecular Biophysics from Oxford on a Rhodes Scholarship; his M.D. from Stanford University and his postdoctoral training and postgraduate medical training in Internal Medicine and Endocrinology at the University of California, San Francisco. Cohen currently serves on the boards of directors for Genomic Health (NASDAQ:GHDX), Quintiles (NYSE:Q) as well as several privately-held companies.
