Representatives dealing with primary-care products will feel the brunt of the cutbacks, as Glaxo, like many drug makers, is losing sales of older products to generic competitors.

Sales of Wyeth’s top medicines beat estimates; Wyeth announced a delay in its Alzheimer’s disease drug and the falling value of the British pound helped third-quarter results at Glaxo.

Amgen’s experimental bone drug reduced the risk of spinal fractures in women with osteoporosis by 68 percent in a pivotal clinical trial.

The agency said patients with a variation in an immune system gene should not be given the drug abacavir because they are at a far higher risk of a severe allergic reaction.

Sirtris, a drug company, has two drugs in clinical trials that it hopes will avert degenerative diseases of aging like diabetes, heart disease, cancer and Alzheimer’s.