David Kramer, who co-founded the agency now known as Digitas Health in 1988 and led the shop through two mergers and a recent reorganization, announced that he will leave the company at year’s end.

Assuming Kramer’s dual CEO roles at Digitas Health and its Publicis sister shop Razorfish Health will be Alexandra von Plato and Michael du Toit, who were appointed co-presidents in June as part of a larger restructuring that put Kramer at the helm of both shops.

“I realize that it is time for the next generation of leaders in our company to fulfill our worldwide ambition,” said Kramer, 66, in a statement.

The longtime agency boss, whose legacy may perhaps best be summed up as helping steer a skittish pharma industry toward online media, said he decided to slow down to pursue hobbies and increase time with family, but also expressed interest in corporate board posts or consulting.

Kramer co-founded Medical Broadcasting Company (MBC) with Linda Holliday 23 years ago. By 1997 MBC became “the first interactive agency serving the pharmaceutical sector.”

MBC was acquired by Digitas in 2006, and at the time Kramer cited the new parent’s deeper pockets as key to his agency’s ability to scale up. After Digitas was acquired by Publicis Groupe in 2007, the agency changed its name to Digitas Health and today has an expanded focus not only on building websites but also on more traditional marketing capabilities.

In July of this year, Kramer told MM&M, “Good agencies tinker all the time. They don’t hold onto sacred cows. They just keep moving.”

In other Digitas/Razorfish Health news, Publicis has moved the shops out of its VivaKi group and placed them under Publicis Health Care Group. The agencies will continue to operate as standalone brands within the group. Presidents du Toit and von Plato will report directly to PHCG president and CEO Nick Colucci.