The FDA, already coping with a setback over how it regulates off-label promotion of drugs, is now facing another legal challenge.

One month after a judge ruled in favor of Amarin’s claims to legally market some off-label uses of its fish-oil pill, Vascepa, Pacira Pharmaceuticals sued the agency over a dispute about the label for its post-surgical non-opioid painkiller, Exparel.

Pacira filed the complaint Tuesday in the US District Court for the Southern District of New York, where hhe Amarin case was also filed. The cases, along with the so-called Caronia case, relate to the FDA’s restrictions on off-label marketing of drugs.  

Pacira’s case focuses on the FDA’s interpretation of the approved label for Exparel. The FDA in 2011 had approved the drug as a treatment for post-surgical pain but later said the company can only market Exparel as a post-surgical pain treatment for patients undergoing the two types of surgeries that were used in the clinical trials. It had issued awarning letter to Pacira in 2014 telling the company to stop marketing the drug as a post-surgical pain treatment for other types of surgeries.

“Recognizing that it did not have a statutory or regulatory basis to narrow Exparel’s label, FDA attempted to do so through its speech-restricting regulatory regime,” the complaint said.

The FDA declined to comment on litigation.  

Meanwhile, Amarin, which successfully sued the FDA for the right to legally promote some off-label uses of its prescription fish-oil pill Vascepa, has already started marketing those uses to physicians.

Vascepa’s website for healthcare providers now has a prestitial ad that tells site visitors about additional data for physicians about prescribing the drug to patients with high triglyceride levels and provides a link to an online brochure detailing the new information.

The brochure includes a disclaimer that said, “Amarin may now disclose additional truthful, non-misleading information not included in the Vaspeca (icosapent ethyl) prescribing Information to healthcare professionals.”

A spokesperson said Amarin had no comment about its marketing plans at the time.  

The FDA in 2013 approved Vascepa as a treatment for patients with severely high triglyceride levels, which exceed 500 milligrams per deciliter. Amarin had filed a lawsuit against the FDA earlier this year seeking approval to market the drug to patients with a less severe form of hypertriglyceridemia—patients with triglyceride levels between 200 milligrams per deciliter and 499 milligrams per deciliter—and accusing the regulator of suppressing its First Amendment rights.

The court ruled in Amarin’s favor in early August in a decision that is expected to have wide-reaching implications for pharmaceutical marketing practices. Although the Amarin ruling doesn’t broadly allow drugmakers to market off-label information about their products, even if it is truthful and misleading, it does create a pathway that other companies can follow to reach a similar legal decision in the same legal jurisdiction.