I read with concern your March 6 editorial “A path forward for experimental treatment,’’ which supports federal “right to try’’ legislation now pending in Congress.

This legislation would unnecessarily put patients at risk and undermine the important and effective Food and Drug Administration program already in place through which seriously ill patients can access experimental treatments. Contrary to what you suggested, the FDA recently has streamlined the expanded-access program and grants more than 99 percent of requests that it receives. Bypassing this system would weaken the FDA’s essential role in ensuring patient safety, facilitating drug development, and preserving the integrity of clinical trials.

Your editorial did not mention that the pending legislation also would reduce liability for providers of unproven treatments, limiting the ability of patients to seek redress for harm.

I am deeply concerned that this effort would embolden unscrupulous actors to sell unproven and scientifically dubious therapies to patients who, under this new legislation, would have no legal recourse. Patients are far more likely to be victimized by snake oil salesmen than they would be to benefit from effective new therapies that have not yet been approved by the FDA. For this reason, 38 different patient-advocacy groups, including the International Society for Stem Cell Research, oppose this legislation.

Unproven therapies being marketed as stem cell treatments have blinded and paralyzed patients. As a stem cell scientist, I am concerned that this legislation would cause long-term harm to this nascent field and expose patients to unnecessary risk and potential harm.

Dr. George Q. Daley

Boston

The writer is past president of the International Society for Stem Cell Research and is currently dean of Harvard Medical School.