What's the deal with drug companies stacking stock-moving announcements on top of earnings this quarter?

Celgene (NASDAQ:CELG) boosted its earnings with a little clinical trial data, Bristol-Myers Squibb (NYSE:BMY) announced the acquisition of Medarex last week, and Amgen (NASDAQ:AMGN) secured its future with a marketing partnership with GlaxoSmithKline (NYSE:GSK) yesterday afternoon.

Oh yeah, and Amgen released earnings.

Revenue came in 1% lower than the year-ago quarter, but Amgen's current offerings aren't the future of the company. With drugs starting to see generic competition in Europe and year-over-year comparisons for anemia drug Aranesp still hurt by a label change in the third quarter of last year, investors couldn't expect much growth. The one bright spot was Enbrel, which Amgen sells with Wyeth (NYSE:WYE), which increased 7% year over year after having a rough start to the year.

Adjusted earnings per share were up 13%, but much of that came from a decrease in research & development spending due to timing of milestone payments to collaborators. That's not exactly a sustainable way to grow earnings, and revenue has to start moving again to sustain long-term growth.

Fortunately, Amgen has a potential solution in its bone-strengthening drug, denosumab. The deal struck with Glaxo to market denosumab seems like a good fit. Amgen is letting Glaxo, a drugmaker with more international exposure, take care of developing countries such as China, Brazil, India, and South Korea. In places where Amgen already has a sales force, it'll cover the cancer indications and co-promote denosumab for postmenopausal osteoporosis.

Glaxo already has an agreement to market Roche's osteoporosis drug, Boniva, which, on one hand, means it has experience in the space, but, on the other hand, means Glaxo will be marketing two competing products. On the conference call, management assured investors that this isn't a problem, but we'll just have to wait and see if Amgen has gotten itself in the same predicament that Elan (NYSE:ELN) has, where Biogen Idec (NASDAQ:BIIB) markets both their joint multiple sclerosis drug, Tysabri, and Avonex, which it owns wholly.

At this point, Amgen's investors are in a waiting game for an approval of denosumab, but they won't have to wait too much longer to see its chances for success: the drug goes before an advisory panel meeting the middle of next month -- after earnings season, thankfully.

Double up on this Foolishness:

Elan is a Motley Fool Rule Breakers recommendation. The newsletter is always on the hunt for hot drug stocks and other cutting-edge picks. Click here to see all of our latest discoveries with a free 30-day trial subscription.

Fool contributor Brian Orelli, Ph.D., doesn't own shares of any company mentioned in this article. The Fool has a disclosure policy.