Senate Democrats press Sanofi and AZ for answers as 'unprecedented' demand spurs shortage of RSV antibody Beyfortus

The shortage of Sanofi and AstraZeneca’s new respiratory syncytial virus (RSV) antibody Beyfortus continues to confound doctors and patients, with the Centers for Disease Control and Prevention (CDC) last week fast-tracking tens of thousands of extra doses into circulation to deal with a tough RSV season.

Now, several Senate Democrats are pressing the drugmakers to get to the bottom of the issue.

In a letter sent to the drugmakers Friday, Sen. Tammy Duckworth, D-Illinois, lamented that Sanofi and AZ “seem to have vastly underestimated” the amount of Beyfortus—also known nirsevimab—needed to protect young kids during this disease season.

The partners’ immunization, approved back in July, has quickly run into supply problems, with the CDC last month issuing an advisory for doctors to prioritize available Beyfortus 100-mg doses for infants at the highest risk of severe RSV.

At the time, Sanofi attributed the shortfall to “higher than anticipated demand,” which has affected supplies of the drug despite an “aggressive supply plan built to outperform past pediatric vaccine launches.”

Now, Duckworth and a group of other Senate Democrats are pressing Sanofi and AZ to provide a briefing on the current availability of Beyfortus and detail how the supply issues came to be.

Duckworth acknowledged that the first season of the antibody’s rollout carries inherent complexities and challenges. Still, inadequate supply and “onerous out-of-pocket costs” for providers has caused the drug’s launch to be “more chaotic than anticipated,” the senator wrote.

The lawmakers want to know when precisely Sanofi and AstraZeneca became aware of the shortage in North America as well as the date the companies provided voluntary notice to the FDA.

Further, they want to know what factors led to the partners’ “significant underestimation” of the demand for the product as well as any mitigating factors they've put in place to address the demand today.

Price also proved a sticking point for the senators, with Duckworth asking why Sanofi chose to charge the same amount—$495—for a five-pack of both the 50-mg and 100-mg doses.

Duckworth and the other senators, which include Ron Wyden, D-Oregon, and Elizabeth Warren, D-Massachusetts, have requested that AstraZeneca and Sanofi draft a response to their letter by Nov. 30.

Back in October, when the supply squeeze was first coming to light, Sanofi said it was working with AstraZeneca—the partner in charge of manufacturing—to accelerate additional supply of Beyfortus.

In a new statement emailed to Fierce Pharma, a Sanofi spokesperson noted the demand for Beyfortus has been “unprecedented.”

“Despite an aggressive supply plan built to outperform past pediatric immunization launches, demand for this product, in both the 50 and 100 mg doses, has been higher than anticipated,” he said, adding that Sanofi looks forward to discussing the situation with policymakers.

Sanofi explained that, together with AstraZeneca, the companies remain in close contact with the FDA and the CDC as they work to deliver doses for this RSV season.

AstraZeneca, for its part, noted in a separate statement that “demand for Beyfortus has far surpassed any previous standard.”

“Although we are on track to deliver all doses initially ordered in the US, we are committed to doing more, and we are pleased to confirm that in collaboration with the CDC and government agencies we are accelerating delivery of additional doses this calendar year,” a company spokesperson said. 

Editor's note: This story has been updated with comment from AstraZeneca.