(Reuters) – GlaxoSmithKline said on Monday it had applied for U.S. approval for its experimental multiple myeloma drug that showed meaningful response in nearly a third of patients, setting up a battle against Johnson & Johnson and Genmab’s Darzalex.

New data from the treatment, belantamab mafodotin, showed 30 of 97 patients experienced a reduction in their myeloma cells at the end of a mid-stage study, DREAMM-2.

The trial was testing belantamab mafodotin, also known as GSK2857916, in patients who had received four to seven prior other treatments, including J&J and Genmab’s blockbuster drug Darzalex.

Data earlier this month showed Darzalex cut the risk of death or worsening cancer by 37% in patients with multiple myeloma, a cancer of the white blood cells. [nFWN28K0JT]

GSK has submitted a marketing application to the U.S. Food and Drug Administration (FDA) in the 2.5 mg/kg dose. If approved, belantamab mafodotin would be the first anti-B-cell maturation antigen (BCMA) agent available in the United States, the company said.

Belantamab mafodotin targets the BCMA protein in cells characteristic of multiple myeloma – an area of focus for many drugmakers.

The latest results are from the first of about 10 trials planned for belantamab mafodotin as GSK aims to soon show its benefits in earlier phases of treatment.

Axel Hoos, GSK’s oncology research and development head, said the rate of response – or the number of patients that experience a reduction in myeloma cells – should go up with every earlier cycle of treatment.

“We are pretty confident that we can actually achieve the same (response rates) if not more and eventually even beat Darzalex in some settings,” he said.

As early as next year, the British group aims to launch a trial where the drug is given to newly diagnosed multiple myeloma patients.

J&J and Genmab are expected to generate more than $4 billion in Darzalex revenues between them in 2020, according to the Refinitiv average analyst estimate.

(Reporting by Pushkala Aripaka in Bengaluru and Ludwig Burger in Frankfurt)