Clinical research organization PPD has hired a Pfizer (NYSE:PFE) veteran to become its new CEO.

David Simmons brings 15 years experience at the world’s largest pharmaceutical company to PPD, which is one of the largest CROs in the pharmaceutical services industry. The CEO post became vacant after PPD was taken private in a $3.9 billion acquisition by private equity firms The Caryle Group and Hellman & Friedman last year.

Former PPD CEO Ray Hill held his job for just three months. Hill started at PPD last September — just prior to the announcement of the acquisition. When the sale closed in December, the CRO’s new private equity owners did not retain him. Hill had joined PPD from IMS Health and his international experience and was expected to fit the strategy of global CROs pursuing more work in emerging markets. Simmons’ experience will help him fulfill that mission.

At Pfizer, Simmons is president and general manager emerging markets and established products, business units that represent $18.5 billion of Pfizer’s annual revenue.

Simmons’ work leading the emerging markets unit entailed overseeing 19,000 employees in 70 countries. Pfizer claims it has provided medicines to more than 5.5 billion patients in emerging markets around the world. Pfizer defines “established products” as medicines that have lost or are close to losing their exclusivity; Pfizer’s established products portfolio has more than 600 products. Before his current Pfizer post, Simmons has overseen biosimilar development, information technology and pharmaceutical operations. He has worked for Pfizer in several countries around the world.

Simmons starts at PPD on June 4. He will be based at PPD’s Wilmington, North Carolina headquarters.