Altria Group Inc. and Philip Morris International Inc. must halt imports and sales of their IQOS heated tobacco device, the U.S. International Trade Commission ruled Wednesday in a patent case brought by rival R.J. Reynolds Tobacco Co.

The case now moves to administrative review, which is expected to last two months; the decision must be signed by President Biden before it takes effect. PMI said it plans to appeal the ruling.

IQOS...

Altria Group Inc. and Philip Morris International Inc. must halt imports and sales of their IQOS heated tobacco device, the U.S. International Trade Commission ruled Wednesday in a patent case brought by rival R.J. Reynolds Tobacco Co.

The case now moves to administrative review, which is expected to last two months; the decision must be signed by President Biden before it takes effect. PMI said it plans to appeal the ruling.

IQOS is a cigarette alternative made by PMI and sold in the U.S. by Altria, two makers of Marlboro cigarettes. The ITC ruled that the product infringes on two patents owned by Reynolds, maker of Newport cigarettes.

Since IQOS doesn’t burn tobacco, the device doesn’t produce smoke when users inhale. It is the only inhalable tobacco product on the U.S. market cleared by the Food and Drug Administration to say in marketing materials that it exposes users to fewer harmful chemicals than cigarettes.

PMI sells the product in dozens of countries. Altria introduced IQOS in the U.S. in 2019 and until now has sold it in just a handful of states. Altria paused the rollout earlier this year because of the pending patent case.

IQOS doesn’t produce smoke when users inhale because the device doesn’t burn tobacco.

Photo: louisa gouliamaki/Agence France-Presse/Getty Images

“We are puzzled and concerned by the Commission’s decision,” a PMI spokesman said. Lawsuits based on the same patent families have been unsuccessful in European courts and the European Patent Office, he added.

Altria said it is working with PMI, a company that spun off from Altria in 2008, on contingency plans and continues to believe that Reynolds’s patents are invalid.

“Infringement of our intellectual property undermines our ability to invest and innovate and thereby reduce the health impact of our business,” said a spokeswoman for Reynolds, a subsidiary of British American Tobacco PLC. “We will therefore defend our IP robustly across the globe.”

Write to Jennifer Maloney at jennifer.maloney@wsj.com