With the future of a commonly used abortion medication on its way to the Supreme Court, the pharmaceutical industry has escalated its warnings: If court orders to limit or undo the Food and Drug Administration's approval of mifepristone are allowed to stand, industry executives and law experts say, the effects could reach far beyond abortion.

The lawsuit, filed last November by a coalition of anti-abortion groups and doctors, takes aim at nearly every step of the FDA's regulatory process — including its original approval of mifepristone for use up to seven weeks of pregnancy in 2000, along with the agency's later decisions to expand approval to 10 weeks of pregnancy and allow the drug to be dispensed by mail.

Those FDA decisions are now in jeopardy, prompting concern among pharmaceutical companies about the ability of judges and lawsuits to knock long-standing drugs off the market.

Earlier this week, an open letter signed by more than 500 pharmaceutical executives and researchers declared that a decision to side with the conservative groups in curtailing access to mifepristone would result in "uncertainty for the entire biopharma industry." Among the signatories were Dr. Albert Bourla, the CEO of Pfizer, and executives from industry giants Bayer and Merck.

On Wednesday, before the appeals court ruled to limit access to the drug, the Pharmaceutical Research and Manufacturers of America, a leading industry group, called the lower court's decision "alarming."

"PhRMA has serious concerns with any court substituting its opinion for the FDA's expert approval decision-making," wrote Jim C. Stansel, the group's executive vice president and general counsel.

Pharmaceutical execs file an amicus brief urging the appeals court to preserve FDA approval

As the lawsuit was being considered in the lower court, PhRMA and other industry representatives had largely stayed on the sidelines, declining to file amicus briefs outlining the industry's concerns even as other major medical groups, like the American Medical Association, weighed in.

That changed after U.S. District Judge Matthew Kacsmaryk issued a preliminary injunction on Friday that sided with the anti-abortion groups and overturned the FDA's decisions about mifepristone. His decision was immediately appealed by the Department of Justice.

With the case then before the 5th Circuit Court of Appeals, a group of pharmaceutical executives and companies filed an amicus brief urging the appellate court to block the preliminary injunction and allow the FDA's approval of mifepristone to remain in place.

Otherwise, they wrote, "the district court's lawless opinion will empower any plaintiff to grind drug approvals to a halt, disrupting patients' access to critical medicines. That outcome would chill crucial research and development, undermine the viability of investments in this important sector, and wreak havoc on drug development and approval generally, causing widespread harm to patients, providers, and the entire pharmaceutical industry."

Industry representatives argued that the court's decision could force companies to run larger and more detailed clinical trials — which could make those trials more expensive — along with making it difficult or expensive to expand the use of drugs after their original trials, which is currently common. Some FDA programs for the development of treatments for "serious" or "life-threatening" conditions could become more difficult to qualify for, they suggested.

Late Wednesday night, the 5th Circuit dialed back the original preliminary injunction, saying that it was too late to challenge the FDA's 23-year-old original approval of mifepristone.

But the appeals court also left intact much of Kacsmaryk's original ruling, including its undoing of the FDA's later decisions on mifepristone to expand access to 10 weeks of pregnancy and allow the drug to be dispensed by mail.

"Defendants have not shown that plaintiffs are unlikely to succeed on the merits of their timely challenges," the three-judge panel wrote. The injunction is set to take effect this weekend, barring an emergency intervention by the Supreme Court.

The industry says the FDA should make the decisions, not judges

Ultimately, it may be the threat of a single judge's ability to vacate an FDA approval that has most galvanized the industry, said Ameet Sarpatwari, the assistant director of the program on regulation, therapeutics and law at Harvard Medical School.

"Industry members are wondering, well, if a judge can do that, what else can't a judge, perhaps with an ax to grind, do?" he said in an interview with NPR's Morning Edition before the appeals court ruled.

Bringing new drugs to market is already expensive and time-consuming. To research and develop a new medical product can cost hundreds of millions of dollars and years of clinical trials.

Add to that the risk of litigation — and the possibility that an FDA approval could be revoked in part or in whole at any time by a judge — then companies may decide it's not worth the risk of financial loss to invest in drugs that could be seen as politically controversial, like gender-affirming medical care, contraception or drugs that protect against sexually transmitted disease.

Take vaccines as an example, said Allison Whelan, a law professor at Georgia State University. "This is essentially saying, 'Here is a way that you could stop these vaccines that you disagree with,' not for safety and efficacy reasons, but for other reasons," she said.

Left unchecked, such litigation could even become a competitive tool, Whelan said. A rival manufacturer could keep a competitor's product off the market "simply by disagreeing with the FDA's decisions about a drug and then hauling them to court to tie it up in litigation," she said.

The Supreme Court has not yet indicated if it will intervene. Even if it does, a decision could take months to issue.

Beyond their public statements, Harvard's Sarpatwari said he expected the pharmaceutical industry to be aggressive in lobbying Congress and taking other measures to preserve the FDA approval process. "I think that all cards are on the table in terms of what industry may do," he said.