The U.S. Food and Drug Administration has approved British drugmaker GSK's blood cancer drug, Blenrep, in one combination regimen, the company said on Thursday, clearing the way for its return to the market nearly three years after it was withdrawn.

The FDA approved Blenrep in combination with bortezomib and dexamethasone for patients with multiple myeloma whose disease has returned or stopped responding to treatment after at least one prior therapy. A second regimen pairing Blenrep with pomalidomide and dexamethasone, tested in a separate trial, was not included in the approval.

U.S.-listed shares of the company were down 4% in after-hours trading.

The split decision follows data from two late-stage trials. One study showed the approved combination cut the risk of death by 51% and tripled the time patients lived without disease progression compared to a regimen based on Johnson & Johnson’s Darzalex.

Blenrep was pulled from the market in 2022 after it failed to outperform an existing therapy in a confirmatory trial. The FDA's latest decision goes against the recommendation of an advisory panel in July, which had voted against both combinations.

GSK said the drug will be available under a simplified safety monitoring program to help doctors manage risks, especially those affecting vision.

The FDA approval is expected to boost investor confidence in GSK's forecast of more than 3 billion pounds ($4.03 billion) in peak sales for Blenrep. The drug is already approved in several countries including the UK, Japan, Canada and Switzerland.

The combinations were already cleared in the European Union in July, making the U.S. approval a later step in the drug's global rollout.

"The reality for most patients with multiple myeloma is a relentless cycle of remission and relapse," said Michael Andreini, CEO of Multiple Myeloma Research Foundation, adding that he sees the potential for Blenrep in combination to help patients achieve more quality time with their loved ones.

Multiple myeloma is the third most common blood cancer globally, with about 180,000 new cases diagnosed each year, according to GSK.