Except when a few high-profile diseases are involved, medical researchers these days are having increasing difficulty attracting participants for clinical trials that fuel the development of new drugs.
The shortage is the result, in part, of the changing nature of medicine as more emphasis is put on the development of “orphan drugs” - pharmaceutical agents geared to treat rare medical diseases or conditions.
These expensive drugs are often bioengineered to treat diseases - both rare and common - in narrowly focused and specific ways for particular groups of people rather than for broad populations. In contrast, such earlier-era drugs as penicillin or Tamiflu work the same way for all sufferers of the infections or flu those drugs are designed to fight.
Federal laws and tax credits help offset the lack of marketability. Since 1983 more than 200 drugs and biological products have appeared on the market. Among recent ones is Xenazine (tetrabenazine), the first one approved in the U.S. to ease the jerky, involuntary muscle movement that accompanies Huntington’s disease.
While the huge amount of money being poured into orphan-drug research offsets the lack of human participation somewhat, the difficulty in finding appropriate subjects on which to test the drugs has resulted in manufacturing delays.
“It’s not lack of patient willingness but because many of the diseases being studied today involve smaller and more targeted populations - some for a specific [product] only shown to be needed in a smaller, more targeted subset,” said Kenneth Getz, a Tufts University School of Medicine research fellow and founder/chairman of the Center for Information and Study on Clinical Research Participation.
He also said that getting patients to learn about the trials is “a communications challenge,” especially in the cluttered Internet age.
Lisa Pacitto, director of marketing and patient services for MassResearch in Waltham, Mass., agreed, saying “it seems there are more trials out there that are waiting to be done than there are public volunteers clamoring to do it.”
Even when a drug or treatment under study is highly desirable, that doesn’t necessarily guarantee easy recruitment, Ms. Pacitto said.
“Overall, people can have a bad perception of clinical trials because of that word ‘guinea pig,’ ” she said.
Nurse Consultant Andrea Denicoff, who studies patient recruitment for the National Institutes of Health’s National Cancer Institute, said patients may want to try a new treatment but “when you get down to why they don’t do it, there are practical reasons. Either the studies aren’t near their home or their health insurance doesn’t provide coverage.”
Food and Drug Administration-regulated trials are increasingly being done outside the U.S. or Europe to save on staff labor costs and to locate a less-medicated population that is more ideal for drug testing. But this can cause more problems in getting drugs to patients.
“Clinical trials are complex and can involve more countries and regulatory agencies around the world,” Mr. Getz said.
While the FDA has approved more drugs for testing on human subjects, the actual number of new drugs reaching the public has been declining, whether from lack of FDA approval or from manufacturers deciding not to market a federally-approved drug.
Surveys done by Center for Information and Study on Clinical Research Participation showed that only 51 percent of respondents in 2008 called clinical research trials “somewhat” safe, down from a high of 55 percent in 2005.
Two million Americans participate each year in 4,000 studies, according to Mr. Getz.
When diseases such as seasonal or swine flu or medical issues surrounding a noted public personality receive media attention, researchers often have no problem attracting candidates to join clinical trials. A notable scarcity of a vaccine, as happened this year with the H1N1 flu vaccine, also drives up numbers.