Congress gave final approval on Tuesday to a bill that would allow patients with serious illnesses to try unproven experimental treatments, sending the measure to President Trump, a strong supporter of the legislation.
By a vote of 250 to 169, the House passed the same “right to try” bill that was approved in August by unanimous consent in the Senate.
The bill would, in effect, allow dying patients to bypass the Food and Drug Administration and obtain an “investigational drug” with the approval of their doctors, if the drug manufacturer agrees to supply it.
On at least three occasions in the past four months, Mr. Trump has urged Congress to pass the bill.
“Patients with terminal conditions, and terminal illness, should have access to experimental treatment immediately” and “should not have to go from country to country to seek a cure,” he said in January in his State of the Union address.
In a Twitter post on Tuesday, Dr. Scott Gottlieb, the commissioner of the F.D.A., said, “When the House passes #RightToTry legislation I stand ready to implement it in a way that achieves Congress’ intent to promote access and protect patients.”
The chief sponsor of the bill, Senator Ron Johnson, Republican of Wisconsin, said that it “expands the scope of individual liberty” and provides “hope for terminally ill patients who have nowhere else to turn.”
Critics said the bill was not as innocuous as it sounded. It was opposed by many Democrats and by dozens of organizations that represent patients, including the National Organization for Rare Disorders and the lobbying arm of the American Cancer Society.
The right-to-try bill “could greatly increase the likelihood of our patients being harmed by unsafe and ineffective experimental therapies,” the health groups said in a letter to House leaders.
“We are deeply saddened,” said Ellen V. Sigal, the chairwoman of Friends of Cancer Research, an advocacy group. “This bill endangers patients and will offer them no value, just false hope.”
The main lobbies for the drug industry, the Pharmaceutical Research and Manufacturers of America and the Biotechnology Innovation Organization, said they had not taken a position on the bill.
Under the bill, a patient is eligible to receive an unapproved drug if he or she has “a life-threatening disease or condition” and has “exhausted approved treatment options and is unable to participate in a clinical trial” of the drug. Sponsors of the bill said it could help people with cancer, muscular dystrophy and Lou Gehrig’s disease, also known as amyotrophic lateral sclerosis, among other conditions.
“Why do you not want to allow these patients to exercise their right to fight for their future?” Representative Michael C. Burgess, Republican of Texas, asked opponents on the House floor.
Twenty-two Democrats joined 228 Republicans in voting for the bill. All of the no votes were cast by Democrats.
Patients will have to provide informed consent in writing before obtaining an unapproved drug under the bill. Manufacturers will have to provide the government with an annual summary of use of the drug, including “any known serious adverse events.”
Nothing in the bill requires pharmaceutical companies to provide experimental drugs to patients who request them. Drugmakers sometimes turn down requests because they have only a limited supply or because they are concerned about legal and medical risks.
To address such concerns, the legislation would shield drug companies, doctors and hospitals from some of the legal risks of providing unapproved drugs to patients. Doctors and hospitals would generally be protected unless they engaged in “reckless or willful misconduct” or “gross negligence,” or intentionally harmed a patient.
The House passed a similar bill with more protections for patients in March, but the Senate never took it up. So the House decided on Tuesday to pass the Senate bill.
Several former commissioners of the F.D.A. and some clinical experts at the agency said that the bill was unnecessary because patients with a serious illness could already obtain experimental medicines through a program known as expanded access or compassionate use.
The agency says it approves 99 percent of the requests it receives under this program, but in some cases, it recommends changes to protect patients before allowing the treatment to proceed.
Mr. Burgess said consumers had gained access in recent years to many innovative treatments. But, he said, “We continue to hear from patients with serious life-threatening conditions who remain frustrated with what they see as regulatory barriers to trying new therapies when everything else has failed them.”
Representative Frank Pallone Jr. of New Jersey, the senior Democrat on the Energy and Commerce Committee, said that reputable drug companies would not provide drugs to patients without the blessing of the F.D.A. But, he said, the bill opens the door for “a bad actor, some unscrupulous manufacturer, a fly-by-night outfit to promote something like snake oil, whether the F.D.A. approves it or not.”
Mr. Pallone said the bill’s definition of a life-threatening disease could be stretched to allow access to experimental drugs for people with manageable conditions, like severe diabetes or chronic heart failure.
Scientists would need to complete the first phase of clinical research on a drug before it could be made available under the bill. Phase 1 trials typically assess the safety and toxicity of a drug in a small number of volunteers.
The drive for right-to-try legislation was spearheaded by the Goldwater Institute, a public policy organization that advocates free markets and limited government. Starlee Coleman, a spokeswoman for the institute, said that 40 states had adopted right-to-try laws in the past four years.
“‘Right to try’ is the opposite of ‘right to die,’” Ms. Coleman said. “It is for people who are not ready to stop fighting.”