Amgen Inc. announced on Sunday results from a clinical trial showing that its newly acquired drug Kyprolis is more effective in combating multiple myeloma blood cancer than a conventional treatment.

The Thousand Oaks biotech said that patients with relapsed multiple myeloma who took Kyprolis and the steroid dexamethasone lived twice as long without their disease worsening compared to patients who took Velcade, the established treatment for the cancer from Johnson & Johnson in New Brunswick, N.J.

Amgen acquired Kyprolis as part of its $10.4 purchase of Onyx Pharmaceuticals Inc. in 2013. Multiple myeloma is a cancer that forms in a plasma white blood cell, which helps fight infections. The disease does not always require treatment, depending on its severity.

Kyprolis had sales of about $330 million last year, and analysts have predicted sales of $570 million by 2016, but that number could grow if more doctors recommend the drug. Velcade had sales last year of about $3 billion.

“Demonstrating superiority over Velcade in this head-to-head trial supports our goal of ensuring continued improvement of patient outcomes and potentially establishing Kyprolis as the backbone of therapy for patients with multiple myeloma,” said Dr. Pablo Cagnoni, president of Onyx, in a statement.

Shares moved up $1.91, or more than 1 percent, to $159.63 on the Nasdaq.