Referenews

“If the court does not defer to FDA, it would undermine FDA’s authority and set a precedent for second-guessing by judges wholly unqualified to evaluate scientific data,” said Areta Kupchyk, a former FDA associate chief counsel now at Foley Hoag LLP.

The Alliance Defending Freedom, which is spearheading the abortion-pill lawsuit, and some other conservative lawyers have argued that the case would have little impact on other drug approvals because it concerns unusually flawed decision making.

Yet the litigation could provide a springboard for tougher court scrutiny of regulatory overreach broadly, said Marc Wheat, an attorney for Advancing American Freedom, former Vice President

Mike Pence’s

policy and advocacy nonprofit.

“This is the perfect issue of everything that has gone wrong with a federal agency and how dangerous they are when they do not adhere closely to the rule of law,” he said.

The FDA declined to comment about the legal implications of the case, but it said Friday evening that the abortion pill’s “approval was based on the best available science and done in accordance with the laws that govern our work.”

U.S. District Judge Matthew Kacsmaryck in Amarillo, Texas, on Friday ordered pulling the abortion pill from the market as a preliminary measure while a lawsuit challenging the drug’s approval proceeds. The order is set to go in effect after seven days.

“The Court does not second-guess FDA’s decision-making lightly. But here, FDA acquiesced on its legitimate safety concerns—in violation of its statutory duty—based on plainly unsound reasoning and studies that did not support its conclusions,” said Judge Kacsmaryk, a Trump appointee.

Just hours later, the Biden administration filed a notice of appeal. Also on Friday, a federal judge in Washington ordered the FDA not to place further restrictions on the drug in certain states—setting up a legal showdown that could end at the Supreme Court.

The FDA approved the abortion pill, called mifepristone, in 2000, more than four years after the application was filed. The agency said it based its approval on three studies testing the drug in nearly 2,500 women in total.

The FDA approved the drug through its accelerated program to impose certain restrictions on access, such as requiring patients to have a follow-up visit before they could fill a prescription.

It is now used in more than half of all abortions in the U.S., but has emerged as one of the battlegrounds in fights over abortion since the Supreme Court overturned Roe v. Wade last year.

Antiabortion groups and doctors who challenged mifepristone’s approval before Judge Kacsmaryck alleged the FDA was politically motivated, didn’t follow proper procedures and ignored problems with the scientific studies supporting the action.

The federal government countered that the FDA based its decision on scientific evidence, followed the proper procedures and found the pill safe and effective.

Under federal law, the FDA approves drugs that scientific studies find work safely. Typically, it requires companies to test prospective medicines in people, then reviews the data collected in the trials while deciding whether to approve and what instructions a drug’s label should give.

For decades, courts have deferred to the FDA’s scientific decision-making. Lawyers couldn’t recall a case in which a court has revoked an approval for a brand-name drug so long on the market. During a recent hearing on the abortion-pill lawsuit, lawyers for both sides acknowledged how unusual a reversal would be.

A court decision undoing the abortion pill’s approval has “the potential to be game changing if the judge sort of accepts that world,” said Eva Temkin, a former FDA associate chief counsel now at King & Spalding LLP.

Ms. Temkin, who is representing a doctor in a lawsuit filed in a federal court in North Carolina that seeks to roll back the state’s restrictions on mifepristone access, said courts’ intrusion could inject fresh uncertainty into a yearslong process, deterring drug development and financing.

ADF lawyer Erik Baptist said the group’s mifepristone lawsuit wasn’t seeking a rethinking of court deference to the FDA, but rather overturning a particular agency decision that, he said, “egregious and flagrantly” violated the law.

“What we’re asking the court to do is to hold the FDA accountable to follow the law. We’re not asking the court to step in FDA’s shoes and play scientific expert,” he said.

If an appeal makes it to the Supreme Court, it could provide the conservative majority led by Chief Justice

John Roberts

a chance to dial back the authority of federal agencies, a popular goal among conservatives in recent years, lawyers on both sides said.

“I can see the path in that direction,” said David Cohen, a professor at Drexel University’s law school who studies constitutional law and gender issues. “That is been one of sort of the core missions of the Roberts court—to push back on agency power.” Mr. Cohen serves on the board of a group promoting access to abortion.

Last year, the Supreme Court ruled 6-3 that the Environmental Protection Agency had overstepped when it devised climate-change rules under President Obama without Congress’s specific authorization.

The Supreme Court may use an abortion-pill appeal as “an opportunity to clip FDA’s wings and say, ‘You can only go so far,’” Ms. Kupchyk said. “This could be the ideal case for them to kill two birds with one stone.”

Write to Liz Essley Whyte at liz.whyte@wsj.com