Making an investment in the cannabis industry may be too risky of a move for Philip Morris International Inc. (PM) to make at this time, according to the head of the company, CEO André Calantzopoulos.

The announcement from Calantzopoulos comes a month after tobacco company Altria Group invested $2.4 billion in Canadian cannabis producer Cronos with the option to invest an additional $1.4 million over four years, taking its stake in the company to 55 percent.

Calantzopoulos told the Financial Times that there was insufficient scientific data on the long-term effects of cannabis. “We need better scientific understanding of [cannabis],” he said. “We need to remember that we are operating in an international environment with different [policy] approaches.”

Philip Morris has said it is looking into the development of smoke-free products to add to its portfolio in the future. Calantzopoulos told the Financial Times that Philip Morris was more focused on getting global regulators to open up to the idea of smoke-free tobacco products than cannabis at this time.

Philip Morris is currently developing the IQOS, a smoke-free product that heats tobacco versus burning it. Calantzopoulos said that smokeless nicotine products should be promoted as a replacement to cigarettes, claiming that they are less harmful.

“We don’t want to normalize nicotine use but we want to replace the delivery method,” Calantzopoulos told the news outlet.

While Philip Morris has declined to invest in cannabis at this time, companies such as Corona and Anheuser-Busch InBev have both made investments with marijuana companies to research and develop cannabis-infused drinks.