Cronin has quit the Omnicom agency, where she ran a healthcare team of around 60, to join the WPP firm, working alongside co-head Sherry Pudloski.
PN global healthcare practice director Michael Durand said the agency was 'keeping its options open' on a decision to replace Cronin and that senior V-Ps Kathy Lauri and Lisa Davidson had taken interim charge of Cronin's responsibilities.
News of Cronin's appointment coincided with confirmation that Pam Jenkins had quit Ogilvy to join Weber Shandwick as president of health public affairs. She is to lead WS's Washington, DC-based social marketing practice, which includes both pharmaceutical and non-profit clients.
Two weeks ago, Ogilvy unveiled its appointment of Jeannine Nolan to head its healthcare team in the UK.