By David Shook
In the public mind, AIDS looms as by far the most frightening sexually transmitted disease (STD). But the biotech industry is also scrambling to find drugs and vaccines to fight a host of less-lethal but more prevalent STDs -- from the closely related B and C strains of the hepatitis virus and the two forms of herpes to the most common of all, human papilloma virus, or HPV.
The human toll taken by these diseases is staggering. According to the U.S. Centers for Disease Control & Prevention (CDC) in Atlanta, 1 in 20 people will be exposed to hepatitis B at some point in their lives -- even though a vaccine is available today that can protect against it. An estimated 200,000 people in the U.S. are infected with the disease each year, and as many as 25% of them are eventually diagnosed with liver disease or liver failure.
Hepatitis C is even more alarming because there's no vaccine to prevent this newer strain. And it's a chronic infection that remains with its victims throughout their lives, destroying their liver and in many cases necessitating a transplant. About 40,000 new cases are reported in the U.S. annually -- roughly equal to the number of new HIV infections each year.
Given the scope of the threat, several companies -- including such powerhouses as Merck (MRK ) and GlaxoSmithKline (GSK ), as well as small biotech players such as Gilead Sciences (GILD ) and Vertex Pharmaceuticals (VRTX ) -- are now locked in a race to be the first to market a treatment or vaccine.
The potential payoff is huge. Analysts estimate that a vaccine for a common STD could rake in more than $1 billion a year in sales in the U.S. alone. For example, if an effective vaccine against genital herpes could be found and gain approval from the federal Food & Drug Administration, it could well end up being recommended by doctors as a preventative measure for all teenagers in the U.S.
The need is urgent: The CDC estimates that 1 in 5 adolescents and adults nationwide are infected with genital herpes. While the disease may cause no symptoms in many cases, it can be an embarrassing and extremely painful lifelong affliction. The CDC figures that exposure to HPV is even higher, with the majority of sexually active people exposed to one or more of the dozens of strains of HPV at some point in their lives.
While an HPV infection almost never poses a danger to men, it's the precursor to nearly all cases of cervical cancer in the U.S., which is often fatal and is diagnosed in more than 15,000 American women annually.
Merck is usually thought of as the leader in treating sexual diseases because of its highly effective AIDS cocktail Crixivan. It now has worldwide clinical trials on an experimental AIDS vaccine under way. But Merck also may be sitting on a powerful vaccine for HPV. The drug was developed for the prevention of genital warts (a common symptom of the virus) and cervical cancer, and is now in late-stage testing. Comprising virus-like particles derived from yeast containing no genetic material, the vaccine is a coat of viral proteins meant to foster an immune response.
Merck won't know for sure how well the vaccine works for three or four years, but the early signs are promising, says Dr. Kathrin Janssen, director of Merck's HPV vaccine program. She believes that the vaccine, if effective, would be an ideal preventative measure for every young woman. "We feel that it's a very important health concern and that you have to start early in educating adolescents about the risks -- before they cut loose, so to speak."
Glaxo could turn out to be Merck's main rival. It has an HPV vaccine that's roughly a year behind Merck's and that takes a different scientific approach. Glaxo's vaccine uses virus-like particles derived from an insect and an additional catalyst to help the immune system recognize the virus and attack it, says Dr. Moncef Slaoui, a senior vice-president for new products at Glaxo. At this point, it's too early to tell which of the two vaccines might prove most effective.
Glaxo, however, is also researching a broad range of treatments against STDs. The British drugmaker already is selling Valtrex, a modestly effective treatment for herpes. More important, Glaxo is testing a vaccine for genital herpes. In trials already completed, it helped protect women against infection but was ineffective in men. As a result, researchers have altered the dosing and trial design in an effort to see if it can protect men, too.
"We feel that this could be a very important," Slaoui says. "From a strict medical standpoint, there are other [more deadly] STDs for which vaccine development is more critical. But psychologically, genital herpes can have a profound impact on people who develop its symptoms."
MILDER SIDE EFFECTS.
Medically speaking, the most pressing need is to stop the spread of hepatitis. With few treatment options available, some patients have no choice but to wait for a liver transplant. Within months, however, the virus can begin to infect the transplanted liver, putting patients in danger of liver failure again. Adds Shlomo Dagan, chief scientific officer for XTL Biopharmaceuticals, an Israeli company that's developing new antibody therapies for hepatitis B and C: "Many people are not aware that they carry the disease. And in some carriers the symptoms may not appear for 10 to 15 years."
Vertex Pharmaceuticals may be the furthest along in hepatitis C research. Doctors now rely on powerful immunotherapy such as alpha interferon for treating the disease, but that produces almost unbearable side effects, leaving many patients too weak to go to work. Vertex is testing a new antiviral drug in combination with the current standard therapy vs. the standard therapy alone. A year or two from now, Vertex could be the first company to hit the market with a targeted therapy for hepatitis C that doesn't have harsh side effects.
For hepatitis B, Gilead Sciences has seen promising results for its experimental drug, adefovir. Gilead CEO John Martin expects to submit the drug for federal marketing approval by midyear, with the aim of having it in hospitals by 2003.
None of these diseases is getting as much money and attention as AIDS. Luckily, AIDS research has indirectly promoted progress against other STDs. With more than a dozen effective HIV drugs on the market, more resources are now available to spend on these lesser-known diseases. And in many cases, the science behind the drugs developed for HIV has helped researchers find new ways to fight the other STDs.
That's good news for the millions of people battling hepatitis, getting regular pap-smears to monitor an HPV infection, or suffering quietly from herpes. The new drugs and vaccines won't arrive a day too soon.
Shook covers biotechnology issues for BusinessWeek Online. Follow The Biotech Beat every week, only on BusinessWeek Online
Edited by Thane Peterson