He is working alongside head of brand comms Jeni Wilson in a role that aims to 'further develop awareness' of Sanofi-Aventis brands.
Sanofi-Aventis, formed from last year's merger of Aventis with Sanofi-Synthelabo, is behind brands including heart-disease drugs Plavix and Lovenox, plus pre-launch anti-obesity drug Acomplia.
Keown was a senior account director at Packer Forbes, where he worked on accounts including the International Herpes Alliance and Lilly/Boehringer Ingelheim's anti-depressant Cymbalta.
He joined the agency in May 2002 as senior account manager. He previously worked at Shire Health London for five years.
During his time at Shire Health he had a five-month secondment to Merck Sharp & Dohme's external affairs department in 2002.
Sanofi-Aventis brought in former Alliance Pharmacy comms manager Stuart Lawton-Davies as head of internal comms last month (PRWeek, 23 September).