An U.S. advisory panel on Thursday rejected claims by Philip Morris International that a new smokeless cigarette it hopes to sell in the United States reduces the risk and harm of smoking.

The panel, convened by the Food and Drug Administration, agreed with the company's claim that its smokeless cigarette reduces smokers’ exposure to harmful chemicals but said the company had not proved conclusively that that would result in less harm and disease.

The new technology, called IQOS, consists of a tube that gently heats up sticks of tobacco instead of burning them. By using heat instead of flame, Philip Morris claims, IQOS eliminates 90 to 95 percent of toxic compounds in cigarette smoke.

The cigarette has triggered debate and worries among health experts about whether IQOS will help or hurt public health in this country. Health advocates worry that such products could be used to attract new smokers and lure people away from quitting altogether.

IQOS represents a significant investment by Philip Morris as smoking in the United States drops to all-time lows. The company spent $3 billion to develop IQOS and other smokeless tobacco products and has begun selling them in other countries. The company’s stock was down 2.8 percent Thursday afternoon after tumbling by as much as 6 percent during the advisory panel’s meeting.

The FDA is expected to decide on two key questions in coming months: whether IQOS can be sold in the United States, and whether Philip Morris can market it as being less harmful.

If the FDA approves those health claims, IQOS would be the first tobacco product to carry the U.S. government’s stamp as a less harmful alternative to cigarettes — a potential marketing coup for Philip Morris.

But the advisory panel’s findings puts a damper on that application. FDA often follows the panel’s recommendation but does not have to.

“It was a two-edged response, recognition by the panel about the potential of the product but lack of evidence to support the health claims,” said Michael Eriksen, a former CDC official and tobacco expert at Georgia State University, who followed the hearing closely.

For the past two days, Eriksen had turned a conference room at his university into a watch party, streaming the panel’s hearings for students and faculty. Many in the public health world still don’t know what to make of IQOS and are trying to figure out whether it could change the landscape of smoking.

After the panel's vote, Philip Morris called the hearing an "open, positive dialogue." In a statement, the company said, "We are encouraged by the recognition of the risk reduction potential of IQOS that clearly emerged from the statements of the Committee members. We are confident in our ability to address the valid questions raised by the committee with the FDA as the review process for our application continues.”

Complicating Philip Morris’s attempt to get IQOS approved for the U.S. marketplace is the fact that many of America’s leading health organizations and experts remain deeply suspicious of the company.

This is the company, they have repeatedly pointed out, that makes Marlboro — the world’s best-selling cigarette — and misled the public for years about the hazards of smoking.

That skepticism and worry came through in many of the questions posed on Wednesday and Thursday by the advisory panel, which included leading public health experts and researchers.

Their key decisions hinged on the belief by many on the panel that Philip Morris hadn’t given them sufficient scientific proof that, while IQOS appears to reduce exposure to harmful chemicals contained in tobacco, it is not clear it would reduce harm to smokers over time.

Some pointed out the high cost of the new product, given the fact that smoking in America is increasingly becoming concentrated among the poor and less educated.

Others questioned whether smokers would really switch completely to using the smokeless cigarettes or simply use it in addition to regular cigarettes, which would negate the potential health benefit touted by the company. Many expressed concerns and asked for more data on the device's possible effect on youth and teenaged smoking.

In coming weeks before the FDA makes its final ruling, Philip Morris can submit amendments to its application to address some of the concerns raised.

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