As a child, John Tsai used to take apart his older brother’s toys to see how they were made. This curiosity propelled him into a career first as an electrical engineer, and then on to medical school and into drug development. Last year he joined Novartis as head of global drug development and Chief Medical Officer, after nearly 20 years at Pfizer, Bristol-Myers Squibb and Amgen. At Novartis he is now overseeing, amongst other things, the company’s embrace of advanced therapies — including its gene therapy Zolgensma for spinal muscular atrophy. He spoke with Asher Mullard about applying an engineering mindset to drug development, the opportunities for operational efficiencies in clinical science and the future of advanced therapies at Novartis.