AZ got past FluMist's efficacy woes, but now it's plagued by production problems

Sidelined by efficacy shortfalls for a couple of years running, AstraZeneca's inhaled flu vaccine FluMist got back into regulators’ good graces last year. Now, though, the company is dealing with an entirely different problem. 

For the upcoming flu season, manufacturing problems will severely limit U.S. supplies for the inhaled alternative to traditional flu shots. The company has struggled with yields in growing two of this year's flu virus strains, so it'll only be able to ship three lots of FluMist to the U.S. for the coming season, a spokeswoman told FiercePharma.

Those three lots—which comprise 758,000 doses—are one-third the number shipped last year. AZ dispatched nine lots of FluMist for the 2018-2019 season, AZ said.

And it's a major reduction from the numbers FluMist has put up in some previous years; AZ shipped 40 lots in the 2013-2014 season, 35 lots for 2014-2015, and 26 lots in 2015-2016. After that, the numbers declined significantly, with 10 lots in 2016-2017 and three lots in 2017-2018.

"The manufacturing process for the A/H1N1 and A/H3N2 strain recommendations made by the World Health Organization have demonstrated lower yields, creating constraints in bulk manufacturing," AZ's spokeswoman said.

The yield problem won't affect the quality of FluMist doses, AZ says. The company stopped taking orders when it became aware of the problem and worked with regulators, public health agencies and others to discuss its supply expectations.

The manufacturing setback comes after a different type of problem for AZ in prior years. During the 2016-2017 and 2017-2018 flu seasons, the CDC recommended against FluMist due to efficacy data from prior years, hitting AZ's sales.

The company changed its strain selection process and won renewed backing in February 2018 for last year's flu season. Still, it only distributed 2.7 million doses in the U.S. last year. 

RELATED: With CDC backing reinstated, AstraZeneca ships FluMist for the coming flu season

Other flu vaccine manufacturers Sanofi, Seqirus and GlaxoSmithKline annually distribute tens of millions of seasonal flu vaccine doses in the U.S. This year, manufacturers expect to distribute 162 million to 169 million flu vaccine doses, CDC reports. The agency doesn't expect any shortage of flu vaccine overall this season.

AstraZeneca reported $288 million in FluMist sales in 2015 before ACIP recommended against its use. The drugmaker recorded $104 million in FluMist sales in 2016, $78 million in 2017 and $110 million in 2018.