Clarke will now work more closely with Frederic Sichler, co-chairman of parent Studio Canal, in international production, acquisitions and development of the international business. Clarke will still continue to oversee all activities including acquisitions.
Perkins will handle the day-to-day running of the theatrical and home entertainment businesses.
Also, Optimum has promoted John Rodden to general manager of Optimum Home Entertainment, Hugh Spearing to head of marketing for the theatrical arm, Alison Meese to acquisition manager and Ben Luxford to sales manager.
Clarke said: 'We are changing the theatrical team to prepare for a new slate which we have been working on since our acquisition by StudioCanal and my own role is developing along with the ambitions of the company.'
StudioCanal acquired Optimum in May 2006.
Forthcoming Optimum releases include Paul Haggis' In The Valley Of Elah, Woody Allen's Cassandra's Dream and Morgan Spurlock's Osama Bin Laden documentary.