Hot On The Hepatitis Trail
Zina Moukheiber, 10.27.03, 11:00 AM ET
NEW YORK - On Tuesday, Idenix Pharmaceuticals will be presenting phase 2 clinical data on a promising drug for hepatitis B at the American Association for the Study of Liver Diseases. The drug, telbivudine, is already in final trials; if all goes well, Idenix Chief Executive Jean-Pierre Sommadossi hopes to file for U.S. regulatory approval by the end of 2005.
The privately owned Cambridge, Mass.-based company has already won the backing of pharmaceutical star Novartis (nyse: NVS - news - people ). Last March, the Swiss company shelled out $255 million for 50% of Idenix, in a deal that could amount to more than $1 billion including milestones. "When we looked at the data, it became obvious that [Idenix] had the best drugs," says Jean-Jacques Garaud, head of Novartis' clinical research and development. Idenix hopes to deliver a one-two punch with another hepatitis B drug it has in mid-stage trials by combining it with telbivudine. Earlier this year, it also entered clinical trials for a hepatitis C drug.
The hepatitis B virus afflicts 350 million people worldwide, placing them at risk of developing liver cancer. It spreads through sexual contact, dirty needles from drug use and tainted blood.
Yet there are only two drugs on the market that target hepatitis B: Epivir from GlaxoSmithKline (nyse: GSK - news - people ) and Hepsera from Gilead (nasdaq: GILD - news - people ). Epivir is also a treatment for HIV. Hepsera was originally developed as a HIV drug, but a U.S. regulatory advisory panel rejected it in 1999, and Gilead reformulated it as a hepatitis B drug last year.
Before 1998, French viral expert Sommadossi had labored mostly on the sidelines, advising pharmaceutical companies on their antiviral drug development as a pharmacology professor at the University of Alabama in Birmingham. He had a hand in developing Bristol-Myers Squibb's (nyse: BMY - news - people ) HIV drugs Videx and Zerit, which helped establish the company's HIV franchise, as well as Glaxo's Epivir.
Five years ago, Sommadossi decided to strike out on his own and grab a piece of an underserved, but fast-growing antiviral market. (Total sales will amount to $10.6 billion this year and could approach $14 billion in three years, according to market research firm Business Communications.) He raised a total of $69 million in venture capital.
Regarded as the gold standard, Epivir had been approved in 1998 to treat hepatitis B. As with HIV, Epivir stopped hepatitis B from spreading by blocking reverse transcriptase, the enzyme that replicates the virus in a host cell. Although the two viruses shared some similarities, which Epivir capitalized on, they were essentially different. Epivir succumbed to the hepatitis B virus pretty quickly, with 30% of patients developing resistance. "Resistance is a reflection of the drug's lack of potency," says Sommadossi. He sought to develop a drug that specifically targeted hepatitis B. "It was the only way to increase potency," he says, and hopefully lessen resistance.
To jump-start his efforts, he first licensed an HIV drug from Emory University already in mid-stage trials. Sommadossi soon got a taste of the roller-coaster nature of biotech. The drug proved disappointing, and Sommadossi pulled the plug on it in 1999. But he couldn't let down his venture backers, who had already shelled out $25 million. "Failure was not an option," he says.
Enter telbivudine, developed by the Université de Montpellier in France. The drug stops hepatitis B from replicating its DNA by targeting an enzyme more specific to that virus.
In a preliminary head-to-head comparison with Epivir, patients on telbivudine experienced a median reduction of a millionfold in their viral load, compared to a 50,000-fold drop for those on Epivir. Sommadossi says that, so far, fewer than 5% of patients on telbivudine have developed resistance. Don't expect any me-too drugs here.
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