Amgen’s Kyprolis has beaten Janssen’s Velcade on progression-free survival in patients with relapsed or refractory multiple myeloma taking part in the Phase III Endeavor trial.

Kyprolis (carfilzomib), the first irreversible proteasome inhibitor, was approved in the European Union in November for use in combination with Celgene’s Revlimid (lenalidomide) and dexamethasone for adults with multiple myeloma who have received at least one prior therapy. Irreversibility of binding offers more sustained target enzyme inhibition, it is believed, resulting in protein build-up and cell death.

In the Endeavor study, 929 patients with relapsed multiple myeloma, and up to three prior lines of therapy, were randomised to receive Kyprolis and dexamethasone or intravenous Velcade (bortezomib)/dexamethasone. Results showed that median progression free survival was 18.7 months versus 9.4 months, respectively.

Philippe Moreau, from the University of Nantes, France, and colleagues, undertook a post hoc subgroup analysis categorising study participants into two groups according to number of prior treatment lines. Results showed in patients receiving one prior therapy disease progression or death occurred in 30.2 percent receiving Kyprolis versus 47 percent taking Velcade.

For those receiving more than two prior lines of therapy, disease progression and death occurred in 43.5 and 57.5 percent, respectively. “Carfilzomib had a favourable benefit risk profile in relapsed multiple myeloma, irrespective of prior treatment. Carfilzomib should be considered in patients who have progressed on lenalidomide maintenance,” Moreau concluded.

On the back of data from the Endeavor study, Amgen has also filed for permission in both Europe and the US to market its drug in combination with dexamethasone alone for MM patients.