Healthcare giant W2O has acquired Arcus Medica, the Philadelphia-based medical and scientific communications shop.

Jim Weiss, founder/CEO of W2O, called Arcus a "trailblazer" in the field, "consistently following the data to get to the right outcome for its clients."

The deal bolsters W2O's medical and scientific team to about 40 members, of which 16 are doctoral-level experts.

Arcus co-founders Mary Seideman, Jonathan Seideman and Stan Eapen will lead the rebranded W2O arcus.

"Our partnership is genuinely symbiotic, and we look forward to working together to achieve something truly great for our dynamic clients and remarkable people," said Mary Seideman.

Delancey Street Partners advised Arcus on the deal.

W2O, which is headquartered in San Francisco, is the No. 1 healthcare company in O'Dwyer's 2018 rankings with fees of $168.1M.