Carfilzomib helped patients with relapsed multiple myeloma live twice as long before their blood cancer worsened, when compared to a regimen containing rival drug bortezomib in a planned interim analysis.

The results from a planned interim analysis showing that the Phase 3 head-to-head clinical trial ENDEAVOR evaluating carfilzomib in combination with low-dose dexamethasone versus bortezomib and low-dose dexamethasone met the primary endpoint of progression-free survival (PFS).

Patients with relapsed multiple myeloma treated with carfilzomib lived twice as long without their disease worsening, demonstrating statistically and clinically significant superiority over bortezomib (median PFS 18.7 months versus 9.4 months, HR=0.53, 95 percent CI, 0.44 – 0.65).

The carfilzomib combination demonstrated superiority over the bortezomib combination for secondary objectives of higher overall response rate and lower neuropathy events. Overall survival data are not yet mature and continue to be monitored.

Treatment discontinuation due to adverse events and on-study deaths were comparable between the two arms.

The rates of cardiac failure and renal failure for carfilzomib were comparable to those observed in the Phase 3 ASPIRE study. In ENDEAVOR, the rates for cardiac and renal failure were higher in the carfilzomib arm versus the bortezomib arm.

There was an increase in the incidence of hypertension and dyspnea in the carfilzomib arm compared to bortezomib and that observed in the ASPIRE study.

Full data will be submitted for presentation at the American Society of Clinical Oncology 2015 Annual Meeting.

"We are excited about the results with carfilzomib in the ENDEAVOR and ASPIRE studies and the potential positive impact for patients with relapsed multiple myeloma," said Robert A. Bradway, chairman and chief executive officer at Amgen.

"As new treatment options become available to patients with relapsed multiple myeloma, comparative trials, like ENDEAVOR, are becoming increasingly important to help physicians make informed decisions about the optimal care for patients," said Pablo J. Cagnoni, M.D., president, Onyx Pharmaceuticals, Inc.

"Demonstrating superiority over bortezomib in this head-to-head trial supports our goal of ensuring continued improvement of patient outcomes and potentially establishing carfilzomib as the backbone of therapy for patients with multiple myeloma."

The ENDEAVOR study is the first of two head-to-head studies for carfilzomib versus bortezomib, an established proteasome inhibitor, currently approved to treat multiple myeloma.

The randomised ENDEAVOR (RandomizEd, OpeN Label, Phase 3 Study of Carfilzomib Plus DExamethAsone Vs Bortezomib Plus DexamethasOne in Patients With Relapsed Multiple Myeloma) trial of 929 patients evaluated carfilzomib in combination with low-dose dexamethasone, versus bortezomib with low-dose dexamethasone in patients whose multiple myeloma has relapsed after at least one, but not more than three prior therapeutic regimens.

On July 20, 2012, the U.S. FDA granted accelerated approval of carfilzomib for the treatment of patients with multiple myeloma who have received at least two prior therapies including bortezomib and an immunomodulatory agent (IMiD) and have demonstrated disease progression on or within 60 days of completion of the last therapy. Approval was based on response rate.

Carfilzomib is also approved for use in Argentina, Mexico and Israel.

Source: AMGEN