Amgen Investors Await More D-mab Data

Denosumab increases bone density in a phase III study, but bone fracture data will be released later this year.
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Updated from 7:40 a.m. EDT

Amgen

(AMGN) - Get Report

released more data Wednesday on its bone-drug Denosumab from a phase III, head-to-head study with

Merck's

(MRK) - Get Report

Fosamax.

While analysts seemed to find the increase in bone mineral density (BMD) compelling, the jury's still out on safety data, which showed numerical imbalances but no statistically significant increases in severe adverse events or bone fractures.

The late-stage study, involving 1,189 postmenopausal women with low BMD, compared twice-yearly subcutaneous injections of Denosumab to a weekly oral dose of Fosamax.

The data, presented Wednesday at the European Symposium on Calcified Tissues (ECTS) annual meeting, showed that Denosumab increased BMD at the total hip -- the primary endpoint in the study -- by 3.5% compared with 2.5% in the Fosamax arm. The drug also resulted in BMD at different measures: the trochanter by 4.5% vs. 3.5%; one-third radius by 1.1% vs. 0.6%; lumbar spine by 5.3% vs. 4.2%; and femoral neck by 2.2% vs. 1.6% in the Fosamax arm.

Amgen reported in January that the study met the primary and secondary endpoints and that adverse events were comparable between the two arms.

"The bone mineral density (BMD) data in total hip (primary endpoint) continued to impress with a p value of less than 0.0001 over the standard of care," wrote JP Morgan analyst Geoffrey Meacham in a note to investors. "However, there were continuing subtle safety signals around infection and neoplasm, and dmab was numerically higher than

Fosamax on fractures, albeit in an informal analysis." Meacham has a neutral rating on Amgen's stock.

The Fosamax arm had a 6.5% rate of serious adverse events, vs. 5.7% in the Denosumab arm. However, there was a slightly higher rate of serious infections in the Denosumab arm (1.5% vs. 1%) and also more fractures in the Denosumab arm (4% compared to 3.2%), but the differences weren't statistically significant.

Amgen noted on a conference call Wednesday that the study enrolled more patients in with a history of fractures at baseline in the Denosumab arm and the study wasn't structured to look at fractures.

The company said it has conducted an analysis of the adverse events across all of the Denosumab studies, and that thus far they are balanced. However, the company said that at this point there were a relatively small number of events, and data from two large trials -- the "Freedom" study in postmenopausal osteoperosis and the "HELP" study in prostate cancer -- will provide more information.

Earlier in May, Amgen said that in a different late-stage, one-year study of 500 postmenopausal women, Denosumab also resulted in more BMD gain than Fosamax.

Wall Street expects data from the more-anticipated three-year Freedom study in the second half of the year -- that placebo-controlled trial will look at the drug in terms of fracture reduction.

Amgen will also present midstage data on Denosumab in cancer patients at the upcoming American Society of Clinical Oncology meeting this weekend.

Amgen shares fell 37 cents, or 0.9%, to $42.67 in recent trading Wednesday. Merck was down 13 cents, or 0.3%, at $38.49.