Philip Morris International, the company behind Marlboro, is to spend another $100m this year developing its alternative to traditional cigarettes as a global marketing drive intensifies to convert smokers to a new generation of products. Martin King, chief financial officer, said on Thursday that extra funds would be deployed to accelerate innovation of the company’s IQOS product — a cigarette-like device that heats, rather than burns, tobacco. The plans, which come ahead of an imminent launch of IQOS in the US, are the latest sign of big tobacco ramping up investment to safeguard the industry’s future. Rival manufacturers are fighting over a share of the market for alternatives as health-conscious consumers reject traditional cigarettes at an accelerating rate. They include vaping company Juul, in which US tobacco group Altria struck a deal to take a 35 per cent stake last December for $13bn. Quarterly results on Thursday from PMI, which makes Marlboro outside the US, underlined how the company is becoming increasingly reliant on IQOS. Shares were up more than 7 per cent by late morning in New York, giving it a market capitalisation of $135bn, as better than anticipated volum...