Amgen Inc. (AMGN) is hiring flexible, mobile sales representatives as it builds a primary care sales force, a strategy that may allow for a more efficient product launch ahead of the expected regulatory approval of osteoporosis treatment denosumab in mid-October.

The launch is likely to be the most important yet for the Thousand Oaks, Calif., biotech, as the drug focuses on primary care physicians in the U.S., a much wider target than its traditional specialty focus. Amgen's job is made more difficult because the company, unlike traditional pharmaceuticals, is creating the sales force from scratch.

The representatives' flexibility is key because it allows the biotech giant to balance both financial and regulatory risks ahead of the drug's approval, and lets the company adjust its strategy as the launch progresses, rather than deploying massive numbers of reps under the traditional model being abandoned by Big Pharma.

Job listings show that Amgen is hiring mobile representatives across the country, including in Texas, California and Illinois. The positions are part of a "rotational program" for 18 to 24 months in which a rep must cover required territories, with "significant travel," and then be willing to relocate to any territory within the state upon completion.

Amgen declined to comment on those job listings or any marketing plans regarding denosumab, although its executives have previously said they plan to break from traditional pharmaceutical methods in marketing the drug.

After getting a positive recommendation from a Food and Drug Administration advisory committee in August, Amgen is widely expected to get marketing approval for denosumab. The company has proposed the brand name Prolia for the drug.

Wall Street will be watching the launch closely as denosumab is key to Amgen's future growth. The osteoporosis marketplace is competitive and includes a cheap oral generic of Merck & Co. Inc.'s (MRK) Fosamax. Denosumab is given by physician injection twice a year.

Sanford Bernstein recently estimated that the post-menopausal osteoporosis market will be $4.8 billion to $4.9 billion by 2015, with denosumab grabbing a 20% market share and sales of $1.7 billion for the year. Amgen had 2008 revenue of about $15 billion.

If approved, denosumab will be the first biologic therapy - a drug made from biological, rather than chemical, processes - that will be sold to primary care physicians, aside from vaccines.

The task of building a sales force to target that market hasn't happened recently because Big Pharma already has its infrastructure in place. Those companies may hire some additional workers to launch a new drug, but the needed components for a launch are essentially in place.

Amgen must be cautious as it builds its staff because drug companies are barred from any marketing efforts before FDA approval. A highly mobile sales force, especially early in a launch, could help mitigate risk.

Christopher Wright, principal with ZS Associates, a sales and marketing consulting firm, noted that mobile reps can travel over wide areas to prepare for the launch, conducting research and setting up order fulfillment plans, without the temptation of talking about the drug to physicians.

Such a strategy also helps to balance the risk of the FDA delaying its approval decision, leaving Amgen with an expensive sales force in place.

"As the pharma industry overall is becoming much more cost conscious and compliance conscious, this is a really smart way of achieving those two things," Wright said. He noted that Amgen will likely continue to build the sales force as the launch continues.

Using mobile representatives will allow Amgen to carefully adjust its strategy as the launch proceeds, said Kevin Gorman, managing partner of Putnam Associate, a life sciences strategy consulting firm.

"Their intention is to be able to redeploy assets against opportunity," he said, and the company can refocus its efforts as patterns develop. The move is more cost effective than simply canvassing the market with reps, a strategy that many pharmaceutical companies are moving against.

"The flexible deployment theme is top of mind at many pharma companies, and Amgen has a clean slate," Wright said.

-Thomas Gryta, Dow Jones Newswires; 212-416-2169; thomas.gryta@dowjones.com