Should those who are sick or dying and have exhausted all other options be able to try drugs that haven't yet been approved? The US Food and Drug Administration (FDA) seems to think so and in December proposed a controversial scheme to help people get the drugs they need.

Hidden dangers: New rules would allow those with serious illnesses to take unapproved drugs.

The move could cause chaos, jeopardizing drug development and exposing scores of people to unsafe drugs, experts caution.

The proposal is controversial not least because it allows people to try drugs in early stages of testing—in rare circumstances, even those that have never been studied in humans. Some of these might later prove to cause nasty side effects or even death, critics note.

[Expanding access] could be a disaster for the drug approval process. Jerry Menikoff, University of Kansas

The most common way for an individual to get an experimental drug is to enroll in a clinical trial. Not everyone qualifies for these studies, however, and some participants receive a placebo rather than the drug.

The FDA has for decades allowed people dying of certain “life-threatening” diseases, such as AIDS and cancer, to try experimental drugs outside of clinical trials. But the process of applying on the grounds of 'compassionate use' is convoluted, sometimes requiring inside contacts at a company or at the FDA.

For example, the rules also allowed those with a “serious” illness, such as depression and rheumatoid arthritis, to apply for experimental drugs, but the definition of serious was buried in a separate set of regulations.

The new rules clarify those ambiguities, spelling out who is eligible for these drugs, how to request them and how much companies can charge for them. The proposal is under a 90-day review that ends in March.

“We believe these rules, when finalized, will help reach out to other populations,” says Rachel Behrman, deputy director of the FDA's office of medical policy. “We will review every request.”

As people learn more about these rules, however, the agency might find itself flooded with requests for investigational drugs for anything from depression to cancer. Drug makers, which have traditionally resisted supplying experimental drugs because of liability issues, might also succumb to the demand. The proposed rules might in part be a response to a lawsuit brought by the Virginia-based advocacy group Abigail Alliance (Nat. Med. 12, 596, 2006).

“Making this a little more accessible may cause the well-informed patients to be more demanding,” says Richard Kingham, a partner at the law firm Covington and Burling. “And history shows that if there's pressure, a company will consider supplying the drug.”

Most antidepressants work for only about half of those who take them. If companies release those drugs, it could paint a misleading picture of the drug's safety and efficacy. It could also take away incentives for individuals to enroll in clinical trials.

Expanding access to experimental drugs “could be a disaster for the drug approval process,” says Jerry Menikoff, a health law expert at the University of Kansas. “The only reason some people enroll in studies is because they need the drug.”