Amgen's bone drug 'romo' fails to excite in male osteoporosis

Analysts remain skeptical of Amgen's ($AMGN) new osteoporosis treatment romosozumab as the Big Biotech releases new data ahead of a potential filing in the next year.

The new data for romosozumab (aka romo)--which is being co-developed by Amgen and its Belgian partner UCB--were being specifically studied in men with the age-related bone-wasting disease.

Romo--an antibody designed to block the protein sclerostin--achieved its Phase III BRIDGE study primary endpoint of increasing bone mineral density (BMD) of lumbar spine at 12 months, when compared with placebo.

It also hit its secondary endpoints of bone mineral density (BMD) increase of femoral neck and total hip at 12 months over placebo, and BMD increase of lumbar spine, femoral neck, and total hip at 6 months over placebo.

This comes a month after the company posted generally positive results for its new bone drug in its FRAME study for women--although analysts were quick to note that the drug didn't perform as well as its main late-stage rival at Radius Health ($RDS) and its treatment abaloparatide. Radius is set for an EU approval by the end of the year, and is also filing for an FDA endorsement in 2016.

But where Radius' drug is injected daily, Amgen's treatment is only once a month--giving it a big advantage when it comes to administration.

The drug is also competing to be better than Eli Lilly's blockbuster ($LLY) Forteo, which is going generic. Last year Amgen released data showing it beat Lilly's drug in a head-to-head study in women.

But worries about its marketability have been raised by analysts at Leerink Swann, who said in a note to investors that "it remains to be seen how romo data compares with Forteo for men" as no specific values for the magnitude of BMD increase was given out by Amgen in the BRIDGE study data.

The company also noted a relatively high rate of cardiovascular serious adverse event rate in the romo data, saying this could lead to a label warning--potentially limiting its usage for patients at risk.

Currently, the consensus forecast for romo is for a 2017 launch with 2020 revenue of $650 million--although Leerink has posted a much more pessimistic sales figure of $390 million--to as low as $230 million--by the end of the decade.

Amgen said that further analysis of the BRIDGE study data is "ongoing" and would be submitted to a future medical conference and for publication, although it did not say when. It also noted that it is planning to "discuss these results with global regulators," but again did not give a timeline.

This has irked Leerink, who said: "The press release stated that Amgen and partner UCB plan to discuss the data with global regulators, potentially filing in 2016. A similar comment was made following the FRAME study, which was less convincing at the time, as the data did not demonstrate an effect on hip fractures and did not compare favorably with Radius' abaloparatide."

Leerink said it estimates that a launch won't happen until midway through 2017, with sales from the drug not hitting the balance sheets of the companies until early 2018.

- read Amgen's data release

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