Cetero Research, a contract research organization recently formed in Cary through a series of acquisitions and mergers, is growing again.

Cetero said Tuesday that it had acquired Allied Research International, a CRO based in Toronto, Canada.

Financial details of the transaction were not disclosed.

Cetero offers clinical and bioanalytical research services for pharmaceutical firms.

The company was created in 2006 through mergers with PRACS Institute, Ltd. of Fargo, N.D., Gateway Medical Research of St. Louis, Mo., and Ba Research International of Houston, Texas.

The company already has some 1,400 beds and three bioanalytical labs.

Allied Research International offers 210 beds plus four environmental exposure chambers.

“Allied’s addition to the Cetero family provides unparalleled depth in our Phase I [clinical trial] capabilities, especially with the environmental exposure chambers,” said Jerry Merritt, chief executive officer of Cetero. “These cutting-edge research chambers are world-class clinical units designed and validated to produce a controlled response to allergens while monitoring the effects of the investigational drug.”