The commercial life for Novartis’ Arzerra outside the U.S. is coming to an end.

On Monday, Novartis partner Genmab said the Swiss drugmaker would pull the chronic lymphocytic leukemia product from all ex-U.S. markets and set up compassionate use programs so that current patients can continue treatment.

The reason? "Many more drugs have become available for CLL over the last five years and ... there is a low number of patients using Arzerra outside of the U.S. market," Genmab CEO Jan van de Winkel said in a statement.

One of those drugs is Imbruvica, the Johnson & Johnson and AbbVie star that won EU approval in May 2016. Sales in Europe and elsewhere helped the drug quickly crack the blockbuster barrier; through the first nine months of 2017, it racked up $1.37 billion for Johnson & Johnson, the company said.

And more competition is on the way. Late last year, closely watched AstraZeneca prospect Calquence hit the scene with its first FDA approval, a nod for mantle cell lymphoma. But AZ is working hard to expand the product into the larger CLL market, and the European Commission has already granted the product an orphan drug designation in the disease.

Still, Novartis will pay a price for its decision to pull Arzerra. It's handing Genmab a lump sum of $50 million to make up for the potential milestones and royalties it’ll lose out on because of the switch, Genmab said.

Meanwhile, Novartis still sees plenty of potential for Arzerra, which it grabbed in its blockbuster 2015 asset swap with GlaxoSmithKline. The Basel-based pharma giant is testing the therapy in refractory non-Hodgkin’s lymphoma, and it’s investigating it as a treatment for multiple sclerosis, too.