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Can Hepatitis B Be A Blockbuster Bug?
BY AMY REEVES, INVESTOR'S BUSINESS DAILY
07/01/2015 08:02 AM ET
The new class of hepatitis C drugs, led by Gilead Sciences (NASDAQ:GILD) and AbbVie (NYSE:ABBV), has turned into one of the biggest success stories in biotech history. Yet hepatitis C is one of only five viruses that cause viral hepatitis. Do any of the others have such lucrative potential?
One possibility is hepatitis B, which despite the existence of a vaccine infects even more people than hep C. The World Health Organization estimates that about 240 million people worldwide are infected with hep B, and 780,000 people die of it every year, most from cirrhosis or cancer of the liver.
Various drugs are already used to treat hep B, including Gilead's own Viread and Hepsera, Bristol-Myers' (NYSE:BMY) Baraclude, GlaxoSmithKline's (NYSE:GSK) Epivir and Novartis' (NYSE:NVS) Tyzeka. Most of those are also HIV treatments, and like HIV treatments they often have to be taken for life to keep the virus suppressed. The present cure rate is only 5%.
Many companies are striving to develop better drugs to treat hep B, where the present cure rate is only 5%.
Many companies are striving to develop better drugs to treat hep B, where the present cure rate is only 5%. View Enlarged Image
This is a sharp contrast to the current hep C regimens such as Gilead's Harvoni and AbbVie's Viekira Pak, which cure patients after 12 weeks of therapy roughly 98% of the time.
Can such a treatment be developed for hep B? A slew of companies are trying, but hep B is a different, more complex virus.
"In the case of hepatitis C, there was always the belief that that disease is easier to cure, and so that was a good one to go after first," said Adam Cutler, senior vice president of corporate affairs at Tekmira Pharmaceuticals (NASDAQ:TKMR). "(With the hepatitis B virus) there's a viral reservoir — it's called cccDNA — that's particularly hard to get at. The virus also produces antigens that inhibit the immune response of the virus, and also act as a decoy for the body (when it's trying) to recognize the virus."
For that reason, Cutler says, Tekmira expects the ultimate cure will be a combination of drugs — and Tekmira is assembling as many of them as possible.
Besides its homegrown asset TKM-HBV, which is in phase one clinical testing, the company acquired seven more candidates with its buyout of OnCore Biopharma this year. The acquisition gives Tekmira the largest suite of products in the business, though all the acquired assets are in the preclinical stage. Cutler admits that at this point, it's impossible to tell which ones will work.
In fact, most drugs in development in this field are in very early stages. Few even have publicly reported trial data.
And the data that has come out hasn't been encouraging. Arrowhead Research (NASDAQ:ARWR) tanked last October when phase two data on its drug ARC-520 showed a more modest effect on antigens than Wall Street had hoped for. In May, GS-4774, a drug developed by GlobeImmune (NASDAQ:GBIM) in partnership with Gilead, failed to hit its endpoint in a phase two clinical trial.
Better results may be ahead, however, as several companies are expected to unveil data over the next 12 months. Gilead has another candidate in phase two testing: GS-9620, a toll-like receptor 7 (TLR7) agonist targeting a protein that regulates the immune response that helps the body recognize the hep B virus. There's no data on its effects on humans available yet, but the company has said that it will report on that in the second half of this year.
In the third quarter, Arrowhead plans to report on the highest-dose cohorts on ARC-520, so it might do better than the disappointing data released last fall. The reporting date, though, was pushed back from Q2, which raised investor suspicions that "they're trying different things with new cohorts to get better data," RBC Capital Markets analyst Michael Yee wrote in a May 11 research note.
Tekmira is due to report phase-one data on TKM-HBV possibly this year or early next year. "Market expectations on that are not high," Yee told IBD. "They'd like to see data in the first few cohorts that are better than Arrowhead's data. The Tekmira drug appears to be more potent, and we'll be watching for safety (issues)."
Both Arrowhead's and Tekmira's candidates use RNA interference (RNAi), which inhibits gene expression and destroys targeted RNA molecules. Multiple companies are testing it against a variety of diseases.
Another firm exploring its potential in hep B is Isis Pharmaceuticals (NASDAQ:ISIS), which is working on a hep B treatment as part of a larger collaboration on liver diseases with GlaxoSmithKline. The latter is preparing to launch a phase two trial after its drug met a safety endpoint in phase one, but so far there's no real efficacy data.
Privately held Novira Therapeutics is also expected to report phase one data this year on its candidate NVR 3-778, a different type of product called a capsid assembly inhibitor, which disrupts the virus's replication.
Other companies have programs rolling along, though reports aren't expected soon. Roche (OTCPK:RHHBY) launched a phase two study of its TLR7 agonist RG7795 in hep B patients who've already been treated with Baraclude. Roche also recently launched a phase-one trial of a new vaccine with partner Inovio Pharmaceuticals (NASDAQ:INO). Assembly Biosciences (NASDAQ:ASMB) is planning to launch a phase one trial of a drug targeting a protein in the hep B virus that has no human analogue.
Just how big can these products get?
Current hep B medicines are collectively drawing about $2 billion a year, but Yee says that's because they aren't very good. He says that the hep B market could get as big as the hep C market — if the drugs are as good as the new hep C drugs.
"Market size will be based on how good the data will be," he said. "Given the similar demographics, it's reasonable to assume the population size will be the same. The price of the drugs will be dictated by how good the drugs are. Drugs that are 25%, 50%, 75% functional cure rates would be huge breakthroughs."
Read More At Investor's Business Daily: http://news.investors.com/techno ... s.htm#ixzz3fOCwZ4zF
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发表于 2015-7-9 08:48
