Harvey Berger, the co-founder and longtime former CEO of Ariad Pharmaceuticals, is taking something of a victory lap after the Cambridge biotech was acquired by Japanese drug giant Takeda for $5.2 billion on Monday.

Berger retired at the end of 2015 following an intense proxy battle waged by Alex Denner, the head of hedge fund Sarissa Capital. It is widely believed that Denner urged Berger out because of the co-founder’s hesitance to sell the company. Denner, now the chairman of the board at Ariad…