GlaxoSmithKline’s head of vaccines, Moncef Slaoui, has announced he will leave the company in June 2017 after nearly three decades at the company. Since joining GSK in 1998, Slaoui has served in a number of positions, including heading R&D operations for eight years.

As chairman of vaccines, he spearheaded the company’s integration of the businesses acquired from Novartis in the $20 billion asset swap agreed in 2014. Slaoui will leave the company in the same year as CEO Andrew Witty, who earlier this year said he would step down in 2017.