Tougher Bugs, Few New Drugs
Dearth of New Antibiotics Threatens Public Health
By Roxanne Nelson
Special to The Washington Post
Tuesday, March 30, 2004; Page HE01
It was 1969 and the battle against germs, it seemed, had been all but won. An impressive array of vaccines and antibiotics were rapidly turning deadly diseases such as smallpox, rheumatic fever, diphtheria and polio into distant memories. The growing armamentarium of powerful drugs appeared capable of besting any bacterial infection that dared cross its path. That year, then-Surgeon General William H. Stewart confidently testified before Congress that "it was time to close the book on infectious disease."
Unfortunately, his pronouncement proved a bit premature.
Three and a half decades later, infectious disease remains the leading cause of death worldwide, and ranks among the top 10 causes in the United States. Some 30-odd new diseases have emerged over the past 20 years -- including AIDS, SARS and Ebola. And old scourges once thought to be under control, such as tuberculosis, syphilis and gonorrhea, are reemerging with a vengeance.
Meanwhile, the once-robust pipeline of new antibiotics is running dry. Some large pharmaceutical companies are either sharply curtailing their antibacterial research and development programs or pulling out of the market altogether.
In 2002, out of 89 new drugs that appeared on the market, none were antibacterials; last year the count was two. "The pharmaceutical companies are basically our only source of new drugs, and they are downsizing their antibiotic programs," explained John Bartlett, chairman of the Antimicrobial Availability Task Force of the Infectious Disease Society of America (IDSA) and professor and chief of the Division of Infectious Diseases at the Johns Hopkins School of Medicine. "It takes $900 million to bring a drug to market, and they are finding it difficult to recoup their cost."
Generally speaking, it costs no more to develop an antibiotic than any other drug.
But for the most part, antibiotic therapy is short-lived, given for one to two weeks and then discontinued. In contrast, drugs used to treat chronic conditions such as hypertension or AIDS are often used for the duration of a patient's life. That makes these drugs' return on investment much greater.
Another disincentive for manufacturers: bacteria's ability to develop resistance to drugs that once killed them. New agents designed to tackle highly resistant bugs don't reap much profit, either, said Steve Projan, director of antibacterial research at Wyeth Pharmaceuticals, because they are meant to be used only after standard treatment has failed.
"The wide availability of cheap, generic antibiotics also makes the market less appealing," said Projan. "And anti-infective drugs are frequently subject to aggressive price controls, notably outside of the U.S."
A Stubborn Disease
Antimicrobials are still the second most commonly prescribed class of drugs in the United States, behind cardiovascular drugs, and are heavily used in hospitals. And despite their short period of usage, some of them have also proved quite lucrative for their manufacturers. For example, Zithromax (azithromycin), a broad-spectrum antibiotic (meaning, it can target many kinds of bugs) earned Pfizer $1.5 billion in sales in 2001. Augmentin (amoxicillin/clavulanate potassium), commonly used against ear infections, brought in more than $2 billion for GlaxoSmithKline .
Still, their success stories are regarded as exceptions, not sufficient to prompt a revival of antibiotic development.
Drug makers' limited resources "weigh heavily in the decision of what products to develop and what goes onto the back burner," said Alan Goldhammer, associate vice president for domestic regulatory affairs at the Pharmaceutical Research and Manufacturers of America (PhRMA). Antimicrobials, he said, "fall at the lower end of the scale, in part because they're not used to treat chronic diseases."
According to the World Health Organization (WHO), more than 150 antimicrobial agents now exist to combat infectious diseases. That may sound like a large arsenal -- but not to experts worried about the spread of antimicrobial-resistant bacteria.
"Resistance is increasing across the board," said Donald Poretz an infectious diseases specialist based in Annandale. "It's increasing in incremental amounts, but it is growing."
© 2004 The Washington Post Company