(Reuters Health) - When terminally ill Americans receive experimental medicines through so-called “compassionate use” programs, they typically only get these drugs after extensive tests for safety and effectiveness, a U.S. study suggests.

“This means that sufficient evidence of safety and effectiveness has been generated, ensuring that terminally ill patients are not being exposed to therapies that are unlikely to be beneficial or unsafe,” said senior study author Dr. Joseph Ross of Yale University School of Medicine in New Haven, Connecticut.

“To me, this is reassuring, and suggests that companies and the FDA are providing expanded access to experimental therapies in a responsible way that protects patients and the public health, ensuring that as many patients as possible are enrolled in clinical trials before expanded access,” Ross said by email.

This system may change under The Right to Try Act of 2017, which would let companies decide whether to give patients experimental therapies without any input from the U.S. Food and Drug Administration (FDA).

It has passed the U.S. Senate and is under consideration in the House of Representatives, and versions of the law had been enacted in 38 states as of March, researchers note in JAMA Network Open.

President Donald J. Trump also endorsed the Right to Try Act in his State of the Union Address, arguing that it will give potentially life-saving treatments to patients who have exhausted all approved therapies and don’t qualify for clinical trials.

The current study doesn’t examine the impact of Right to Try laws already enacted, but it does offer fresh evidence of how well compassionate use programs are working for patients, researchers say.

Under current federal policy, when terminally ill patients want to use drugs and devices that are too early in their development to be approved by the FDA, their doctors typically ask for the manufacturer to grant expanded access to the experimental therapy under the compassionate use program.

If the company agrees, the FDA and a review board where the physician works would also vet the request. Among other things, reviewers might assess whether the patient has exhausted other options and understands the potential risks and benefits of therapies that haven’t yet been cleared for sale.

For the study, researchers examined two decades of data on compassionate use, or expanded access, programs for 92 experimental treatments ultimately approved by the FDA. Half of these programs gave patients access to the drugs within 10 months or less of FDA approval.

Half of the compassionate use programs were for drugs to treat cancer, the study found. Another 17 percent of the programs were for metabolic, endocrine or genetic diseases; infectious disease treatment accounted for another 15 percent of programs.

Two-thirds of the programs started allowing patients to get experimental drugs just before companies formally submitted new drug applications (NDAs) to the FDA for approval, the study also found.

At that point, there’s more data available from human trials showing about the safety and effectiveness of experimental therapies, said Patricia Zettler of the Georgia State University College of Law.

This highlights a potential flaw in proposed Right to Try legislation: mainly that it might let patients get medicines earlier in the development process when less is known about safety or effectiveness, Zettler, who wasn’t involved in the study, said by email.

“Getting access to an investigational drug, after all, is not the same as being helped by it,” Zettler said.

The chances of a drug not helping a patient or causing serious harm are higher when medicines are earlier in development, said Dr. Paul Beninger of Tufts University School of Medicine in Boston. This is much more likely with Right to Try than with the current compassionate use system, he said.

“I could not in good conscience recommend Right to Try, nor can I identify a patient profile that would experience a differential benefit from Right to Try over the available expanded access mechanisms,” Beninger, who wasn’t involved in the study, said by email.

SOURCE: bit.ly/2tn73rs JAMA Network Open, online June 15, 2018.