Stevenage-based pharmaceuticals giant GlaxoSmithKline has ranked first in Fortune magazine’s list of companies making a positive social or environmental impact through core business strategy.

The ‘Change the World’ list of 50 companies, in its second year, gauges impact, business results and extents of innovation to rank the firms ‘taking on society’s biggest problems – and making money doing so’.

And GSK’s work to fight HIV, malaria and infant mortality in less developed parts of the world has won it top spot.

The firm’s chief executive Sir Andrew Witty, who joined as a trainee in 1985, is set to step down next year after nine years at the helm – and, if all goes to plan, Fortune’s verdict is that ‘he’ll leave behind a company with an umatched record for balancing scientific progress, social impact and the profit motive’.

GSK posted a $16 billion profit in 2015, using a strategy of slim margins and massive volume in the developing world. India, for example, receives about 30 per cent of everything GSK makes – but accounts for less than one per cent of profits.

Mr Witty explained to Fortune that over time the business gets bigger and bigger, makes more and more profit – “and more people have access to fantastic medicines. We think that’s an entirely sustainable model.”

In March, GSK announced it would no longer file drug patents in lower-income parts of the world. It reinvests 20 per cent of profits in the least developed countries into training health workers and building medical infrastructure.

Through a partnership with NGO Save the Children it has trained locals to properly administer vaccinations and screen for conditions like malnutrition.

The firm also created the first malaria vaccine, and in June an HIV therapy unit majority-owned by GSK made an agreement with the government of Botswana in June to distribute the HIV drug Tivicay.

Also this year a Stevenage-based GSK team adapted one of its mouthwashes to create the umbilical cord infection-fighting gel Umbipro.

The gel doesn’t need refrigeration and, according to the United Nations, could save 85,000 babies per year.

GSK’s closest rivals for top spot in the Fortune list were Israeli desalination firm IDE Technologies and General Electric of the USA.

For more see beta.fortune.com/change-the-world/list.