FDA Steps Up Action on Drug Advertising and Targets Amvuttra
The U.S. Food and Drug Administration (FDA) is increasing enforcement against pharmaceutical advertising, with a growing number of cease-and-desist and warning letters targeting what it sees as misleading promotional claims.
The latest example involves Alnylam Pharmaceuticals, which received a cease-and-desist letter concerning alleged false or misleading information on its website for the drug Amvuttra. In its letter dated April 23, the FDA gave the company 15 days to respond and explain how they will correct their conduct, setting a deadline of May 14. Amvuttra is a drug that treats the rare heart disease known as transthyretin-mediated amyloidosis (“ATTR-CM”).
At issue are statements that Amvuttra is “[p]roven to help people with ATTR-CM live longer,” that “[p]eople lived longer with continued treatment,” and “[t]he risk of death was lower over 3 ½ years with AMVUTTRA.” The FDA determined that these claims, and others on Amvuttra’s website, create a “misleading impression” of Amvuttra’s efficacy.
The warning letter to Alnylam is part of a broader push that began in September 2025, when the FDA signalled that it would step-up its oversight of direct-to-consumer pharmaceutical advertising. At the time, FDA officials said they planned to issue around 100 cease-and-desist notices and thousands of warning letters targeting non-compliant promotions.
Recent enforcement extends beyond traditional advertising into the digital space. The FDA recently sent warning letters to dozens of telehealth companies marketing compounded versions of popular weight-loss.
Notably, this is not the first time Alnylam has found itself in the FDA’s crosshairs. In fact, in October 2025, the FDA raised concerns that a television ad from Alnylam, which depicted patients travelling and taking part in activities such as whale-watching and attending sporting events, presented an overly optimistic view of patients’ lives while downplaying the seriousness of the condition being treated. The ad was ultimately pulled by the company as it reviewed the agency’s feedback.
Cease-and-desist letters are part of the FDA’s oversight of prescription drug promotion. They can require companies to stop or revise materials that are found to be non-compliant and typically call for a prompt response outlining corrective actions.
The FDA’s more active approach indicates that it is taking an increasingly hands-on approach to regulating how drugmakers present information, particularly on company websites and other digital platforms where messaging reaches patients directly.
In that regard, how Alnylam Pharmaceuticals responds will be closely monitored by the industry. Its reply, due by mid-May, will not only indicate how it will change its marketing going forward, but also serve as a test of how effectively the FDA’s tougher stance is shaping industry behavior.