Amag Pharmaceuticals Inc. said Wednesday it will buy drugmaker Allos Therapeutics Inc. for stock valued at about $268 million in a deal designed to bolster their commercial portfolio and cut costs.

Amag, based in Lexington, Mass., makes Feraheme for the treatment of iron deficiency anemia in adults with chronic kidney disease. Allos, based in Westminster, Colo., produces the T-cell lymphoma treatment Folotyn.

The companies estimate that they can save between $55 million and $60 million annually by eliminating costs, most of which will be realized in the first fiscal year after the deal closes.

Costs tied to the deal should total between $35 million and $38 million.

The boards of both companies have approved the deal, which is expected to close in the fourth quarter.

Under terms of the deal, Allos stockholders will get 0.1282 shares of Amag stock for each share of Allos.

Amag shareholders will own about 61 percent of the combined company, while Allos stockholders will have 39 percent.

Amag will nominate five of the nine members of the new company’s board, and its CEO, Dr. Brian J.G. Pereira, will serve as CEO of the new company. Amag Chairman Michael Narachi will retain his role as well.

The combined company will be based in Lexington, Mass., and probably will be renamed at a later date.

Shares of Allos fell 12 cents to $1.94 in late trading while Amag shares fell $2.76, or 14.5 percent, to $16.31.