When Vas Narasimhan was told he was being considered for the top job at Swiss drugs giant Novartis, he thought there had been a mistake.
"It didn't seem plausible, at the time I was only 40," he says.
Vas, a US citizen, had been with the Swiss firm for 12 years, and while he was global head of drug development, he was still a long way down the pecking order.
Yet in 2018, soon after turning 41, he became chief executive of the drugs giant, which had annual revenues of more than $50bn (£41bn) that year and 125,000 employees around the world.
"I was shocked," says Vas. "At first I didn't really know what to make of it... it was never in my plan to become the CEO of a huge company.
"And then I felt exhilarated. Yes, it was scary as well but I was motivated to tackle this challenge. And then I dived right into thinking 'OK, what can we do with Novartis under new leadership?'."
While you might think that putting someone relatively young in charge of a global firm is a bit unusual - Vas' life story makes things become a lot clearer.
Born in Pittsburgh in 1976, to parents who had emigrated to the US from India, Vas had the benefit of a pretty good scientific background - his dad was a chemist, and his mother was a nuclear scientist.
At school in Pittsburgh and then near Philadelphia, he says he was "relatively shy and reserved, and very, very studious".
"I think I was probably focused on trying to fit in as well," he says. "At the schools I went to there weren't many other children of Indian origin, so I grew up always trying to figure out how to fit in."
Excelling at sciences and maths, he then did a degree in biological sciences at Chicago University. He also did a course in philosophy, which would be a significant influence on his subsequent leadership style.
Aiming to be a doctor, his next move was to Boston's Harvard School of Medicine. And if that wasn't enough of a stretch on his time, he also enrolled on a parallel degree in public health policy at the Harvard Kennedy School.
"I didn't really do much drinking at college," he says. "And I made do with just five or six hours sleep."
There was also no let up in his summer holidays, as he was always volunteering overseas; helping to fight malaria in Gambia, tackling tuberculosis in Peru and child poverty in India.
After getting his doctorate in medicine from Harvard in 2003, Vas says he thought of practicing medicine, but instead joined the World Health Organisation, where he spent a year working on its efforts to boost public health around the globe.
He then spent two years at management consultancy McKinsey, to boost his "knowledge of the business world", before joining Novartis.
As he rose through the ranks at the Swiss firm, one of his key roles was leading the firm's former vaccines division, which developed drugs to tackle influenza and meningitis. His work saw him appointed to the US National Academy of Medicine, the prestigious organisation for American healthcare leaders.
While Novartis no longer has a vaccines business, Vas - who was interviewed for this article on 10 Feb - says the industry is working as hard and as quickly as it can to develop a vaccine for coronavirus.
"It will take time though," he says. "And then any vaccine will have to go through clinical trials before production. It will take time."
When it comes to his leadership approach, Vas leans on his student interest in philosophy. He says he is particularly influenced by two books: The classic 6th Century BC Chinese text, Tao Te Ching, and Daniel Pink's 2009 work, Drive: The Surprising Truth About What Motivates Us.
He say that both have taught him that being a good leader is not about bossing people around but instead giving them more power - and making them happy.
"One thing we know about human motivation is that people feel their best when they have a sense of purpose and a sense of autonomy," he says.
In practical terms at Novartis, he says this means he has cut out unnecessary bureaucracy, and "eliminated tens of thousands of approvals, which have pushed down decision-making across the organisation".
"You would be surprised at how few emails I get these days," he adds. "I get the emails that matter, but the rest are now tackled at the appropriate level."
Barbara Obstoj-Cardwell, editor of The Pharma Letter, a website providing news and analysis on the pharmaceutical sector, says that Vas has a "charismatic presence".
"Vas Narasimhan appears to have brought plenty of energy, dynamism and ambition since taking over at Novartis - and so far, the results have largely been impressive."
Based at the firm's head office in Basel, there has never been a language barrier for Vas, because the company switched from using German to English back in the 1990s.
Married with children, he says that staff quickly got over their surprise at someone so young being appointed to the top job. And back in the US, his parents were also pleased. "They have stopped asking me when I'm going to finally become a doctor," he jokes.