
Thermo Fisher Scientific announced Thursday that it will buy PPD, a contract-research company for the pharmaceutical and biotech industries, in a deal valued at $17.4 billion, plus the assumption of about $3.5 billion in debt.
The acquisition will allow Waltham-based Thermo Scientific, a leader in laboratory equipment and services, to expand its reach in life sciences. PPD, based in North Carolina, provides services to help drug companies run clinical trials.