AbbVie Inc’s experimental lung cancer drug data was not effective enough to seek a faster approval, in a setback to the company’s efforts to build its cancer drug pipeline and cut dependence on its blockbuster Humira.

The company’s shares were down 10.8 percent at $100.29 in early trading, shedding about $19 billion in market value.

AbbVie has been building a portfolio of oncology drugs to counter competitive threats to its rheumatoid arthritis treatment, Humira, which accounts for about two-thirds of its overall sales.

The company said on Thursday it would not seek accelerated approval for the drug, Rova-T, after consulting with the U.S. Food and Drug Administration based on “magnitude of effect across multiple parameters”.

“You’ve got okay response rate, no evidence that there are long-term survivors and then you have a pretty onerous side effect burden,” Leerink Partners analyst Geoffrey Porges told Reuters.

The mid-stage study tested Rova-T as a treatment for small cell lung cancer patients who failed to respond to at least two prior regimens.

Rova-T, which AbbVie acquired with its $5.8 billion purchase of Stemcentrx in 2016, is expected to generate sales of $1.2 billion in 2023, according to Thomson Reuters estimates.

“(AbbVie) needs something that is the cornerstone of the oncology franchise that they own and Rova-T was meant to be that,” Porges said. “And now that cornerstone is cracked you wonder if they don’t have to go out and find something else.”

Late-stage trials testing the drug as a treatment for patients who have either failed to respond to initial treatment or are newly diagnosed will continue, the company said.

Rova-T is a toxic chemical that is loaded onto an antibody to target a protein called DLL3 found in more than 80 percent of patients with the cancer.

The FDA’s accelerated approval program is meant for drugs that treat serious conditions based on a marker that is expected to lead to a clinical benefit.

Guggenheim Securities analyst Tony Butler said AbbVie will likely have to run a bigger trial that will cost more and will need to have a control arm.

“They wanted to do this with a relatively small number of patients and not have to run a control or a big study. That strategy is now thrown out.”

(Source: https://www.reuters.com/article/us-abbvie-study/abbvies-lung-cancer-drug-data-disappoints-shares-slump-idUSKBN1GY1R9)