(Bloomberg) -- Stockpiles of Pfizer Inc.’s Paxlovid in Europe and the UK worth $2.2 billion are set to expire by the end of next month as demand for the Covid-19 treatment plummets.

The outdated supply includes $1.1 billion worth of doses that had already expired as of November, according to the London-based analytics firm Airfinity Ltd. The UK has seen the biggest chunk go to waste with an estimated 1 million past-date courses at a cost of some $700 million, Airfinity said in a report. 

Soaring death counts near the height of the pandemic spurred governments to invest heavily in Paxlovid, still the most effective treatment for Covid. As vaccination and infections have conferred widespread immunity, serious cases have become less common, curtailing use of the drug. 

Countries “had a difficult challenge of estimating demand at a critical stage in the pandemic,” Airfinity life-science analyst Marco Gallotta said in the report. “This doesn’t necessarily mean that higher uptake wasn’t desirable and could have saved lives and hospitalizations, but the reduction in testing reduced demand.”

Many countries still require that patients test positive for Covid before they can receive the drug, Airfinity said.

Pfizer said it has worked with governments to extend the shelf life of doses to minimize the number of treatments that go unused. 

“Expiry and destruction of doses can be an unavoidable consequence of a pandemic situation, a natural result of manufacturers and governments collectively aiming to address the public health crisis at speed with the overarching objective of protecting their populations in an ever-changing environment,” the company said.

The unused doses are another sign of receding public concern about the pandemic, and of Pfizer’s need for new products like the cancer drugs gained in its $43 billion deal for Seagen. Falling sales of the antiviral were among the driving forces for the company to cut its 2023 sales guidance while issuing a stock-deflating forecast for this year.

The drugmaker agreed last year to take back 7.9 million courses of Paxlovid that were set to expire soon in exchange for a credit for future supplies. Pfizer is now working to sell the drug directly to US health providers via commercial channels. 

“This is just another indicator of sluggish demand and potentially weak uptake despite the private shift in the US,” Bloomberg Intelligence analyst Max Nisen said in an email. It’s “likely one of the reasons they put out 2024 guidance so far behind consensus.”

The company’s shares surged as much as 5.2% Tuesday, the most since mid-October. Pharma stocks gained as investors looked for safe havens from a drop in tech shares, Nisen said.

(Updates with Pfizer comment in sixth paragraph, analyst comment in final.)

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