After years of legal wrangling surrounding Teva’s Copaxone, the latest hit to the lucrative multiple sclerosis drug comes in the form of a safety-related boxed warning.

The label update, which also applies to Sandoz’s substitutable generic Glatopa, warns of the risk of a rare but serious allergic reaction, anaphylaxis, in patients who take the drug. 

In most cases, anaphylaxis symptoms appeared within one hour of injection, according to the FDA’s safety notice on Wednesday. Still, symptoms can emerge at any point during a patient’s treatment journey, even years after they first start on the medicine, according to the agency.

In the 82 cases worldwide of treatment-associated anaphylaxis that were reported to the FDA’s Adverse Event Reporting System database from December 1996 through May 2024, six patients died and 64 required hospitalizations, according to the FDA. The regulator first approved the drug in 1996.

Considering the initial symptoms of anaphylaxis can coincide with an immediate post-injection reaction, a common and temporary condition, the FDA advises patients to seek immediate medical attention if symptoms worsen or persist.

While the safety risks are a fresh concern for Copaxone, the drug has faced antitrust-related controversy lately. In October, Teva laid to rest four years of kickbacks and price-fixing allegations from the U.S. government with a $450 million settlement that will be paid over six years.

Later that month, the European Commission added to Teva’s headaches by fining the company 462.6 million euros ($503 million) for alleged “abusive conduct” that authorities said aimed to delay competition and prolong Copaxone’s exclusivity. In turn, the company pledged to appeal the judgment and fine, which it said was based on “extreme, untested, and factually unsupported” legal theories.

Copaxone generated $3.2 billion in U.S. sales at its peak in 2013, according to a 2020 congressional report. Sales are slower these days, in part due to generic competition. 

In 2023, the drug picked up $590 million in global sales (PDF). As of Teva’s November 2024 financial outlook (PDF), the company forecast around $500 million in 2024 sales for Copaxone.