Kyprolis failed to improve survival in the phase 3 FOCUS trial in patients who had relapse following at least 3 prior regimens.
Amgen Inc's Kyprolis drug failed to extend survival compared to standard care in a trial involving patients with advanced multiple myeloma, a type of blood cancer that develops in the bone marrow.
Shares of Amgen were down 2.1 percent at $124.65 in after-hours trading on Wednesday.
"The negative results commercialization of this drug in earlier lines of myeloma, as well as other indications raise questions about the future development and ," Sanford Bernstein analyst Geoffrey Porges said in a research note.
He also said the findings "place Kyprolis at a significant regulatory and competitive disadvantage" to Pomalyst, a multiple myeloma drug sold by Celgene Corp.
Amgen said the 315-patient, phase III trial also showed an increase in bad kidney events for patients given Kyprolis when compared to the control group and to the risks described on the drug's current label.
Original report: http://reut.rs/1sG1LTi