On Assignment Inc. (NASD: ASGN) yesterday reported its purchase of Valesta, a European provider of specialized staffing in clinical research, for euro12.8 million (US$17.6 million) with a three-year earn-out possibility of up to euro5.2 million.

The company said the acquisition expands its presence internationally and enhances its services within the life sciences sector. On Assignment said the acquisition may boost earnings by an additional $7.1 million over three years. On Assignment reported 2010 revenue of $438.1 million.

Valesta is based in Mechelen, Belgium, and also has branch offices in Spain and The Netherlands.

On Assignment plans to use cash and its senior credit facility to finance the deal, which is expected to close Monday.

"Valesta will not only enhance our service offering in a very attractive end market within life sciences, but it will also expand our international footprint," said On Assignment President and CEO Peter Dameris. "The founders of Valesta will continue to lead and operate Valesta after the closing."