What happened
Shares of Pfizer (PFE +0.00%) were sliding 3.1% lower as of 12:54 p.m. ET on Monday. The decline came after the big drugmaker announced that it is discontinuing the clinical development of vupanorsen. Pfizer licensed the experimental drug from Ionis Pharmaceuticals (IONS +2.02%) in November 2019. The company had been evaluating vupanorsen as a potential treatment for reducing cardiovascular risk and for severe hypertriglyceridemia.
So what
This was a significant setback for Pfizer. The company had previously hoped that vupanorsen could generate peak sales of more than $3 billion. The experimental drug was one of several pipeline candidates that Pfizer expected would help it add at least $15 billion in annual revenue.
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But the discontinuation of the drug was even worse news for Ionis. The biotech stock fell around 10% in early trading before rebounding somewhat.
Now what
Pfizer will now return development rights for vupanorsen to Ionis. It remains to be seen what Ionis will do with the program.
Although Pfizer's hopes of a blockbuster have gone up in smoke in this case, the company's business development activity could more than make up for the lost opportunity. Pfizer acquired Trillium Therapeutics last year and awaits the closing of its planned buyout of Arena Pharmaceuticals.
