How does the scientific evidence on heated tobacco products (HTPs) compare with what we know about cigarette smoking? In this presentation from the GFN Science Lab, Dr. Leonie Price takes a look at multiple layers of evidence surrounding heated tobacco products — from aerosol chemistry and toxicant emissions to biomarkers of exposure, environmental exposure, and the behavior of smokers who switch to HTPs.
Transcription:
GFN Science Lab 3 — Leonie Price
2026-06-05 · 11:30-13:00 (Europe/Warsaw) · Global Forum on Nicotine 2026
Sud Patwardhan 0:00:11
Welcome to the GFN Science Lab 3. Thanks for hanging around in the conference till now. Appreciate it. I wish there were more people here. I was hoping this would be teaming with people and people overflowing, but maybe that'll happen as people start hearing about what these folks have to say. Let's just kick off with Dr. Leonie Price from PMI.
And you've got a bunch of slides to talk us through, please, Leonie. Can we have the slides, please?
Leonie Price 0:00:37
Hi, everyone. Yeah, I'm taking a bit of a liberty here because I know the format's supposed to be one GFN5 and then a bit of a discussion. But unfortunately, a few of my colleagues can't make it to present their GFN5s. So I'm going to take you on a whistle-stop tour through four of them. So bear with me because some of this is my research, some of it is not.
But I'll be just giving you a top line overview of a few of those topics. And if you're interested in any of them, I really encourage you to go and look at the full GFN5 because it gives you a bit more detail on what we're talking about.
So when we're talking about HTPs, it would be really nice as a scientist if you could substantiate that they were less harmful than smoking with one lovely study. And everyone says, oh, yes, brilliant. We agree and we believe you.
But unfortunately that's not the case and we have to attack the science and break it down into lots of different parts and address various bits and pieces of the scientific research in order to build a story of substantiation that these products are indeed less harmful than smoking.
And so you can do that right from looking at the chemistry of the aerosol that they generate, right the way through to how the products are used in populations. So that's the story I'm going to kind of try and tell a little bit today, is looking at all of those different layers through the different studies that we've been doing. So this is all new research.
Hopefully you'll find it interesting. So we had four research questions. The first one is... Do different HTPs offer similar reductions in toxicant emissions compared to cigarettes, or are there big differences between brand sticks and technologies?
And the reason we wanted to look at this is because when we talk to regulators, when we talk to the outside world, we often generalize to the category level. And we have a lot of data on our own products, but what about all the other products? Are they equally as good? Are they equally as harm reduction potential? We don't know.
So we thought we'd do a bit of a study on lots of different brands and sticks and see whether they're similar. And then the second research topic is do differences in heating technology results in difference of biomarkers exposure? So now we're moving into the human. And PMI has sort of continued the development of its heated tobacco products.
And previous generations were blade-based technology. So you take a stick, you put it into the device. The blade enters the center of the tobacco stick and heats the tobacco from the inside. They've recently moved to a more modern, cleaner way. The devices sometimes got dirty. It was tricky to clean them. So they've moved now to an induction-based system.
So there's a metal element inside this stick, and they use induction heating as you would like an induction hob in your kitchen to heat the tobacco differently. But does this shift in technology result in a different impact for the consumer? And that's where we looked at the biomarkers of exposure to certain toxicants.
And then the research question three, we looked at environmental exposure to the aerosol. So for people who are not aware, in Japan, you can use HTP devices inside in some venues, including some restaurants in designated areas.
And so we looked at the exposure to the waiting staff who work in these places to see whether they were exposed to the aerosol and what that meant for them. And finally, we wanted to have a look at what happens when smokers switch. So this is a longitudinal study over two years looking at different switching behaviours for people who have purchased ICOS.
And then we followed them up over two years to see what happened next. So just to take you back into the context of heated tobacco, why we think it's a good idea and why we're looking at this basically.
And that's to understand that obviously the harms of smoking are not necessarily from the tobacco itself per se, but the fact that you set it on fire, generate smoke and inhale that smoke, and the smoke is full of very nasty constituents that we know are very damaging to health. Heated tobacco products, on the other hand, are designed to heat the tobacco rather than burn it.
And so the aerosol that's generated from heated tobacco products is fundamentally different from this cigarette smoke. It contains many fewer chemicals and the chemicals that are there are at drastically lower levels. And the aerosol itself is chemically and physically quite different.
So it generates this liquid-based droplets of aerosol compared to the solid carbon-based particles that you find in cigarette smoke. And all of those things together lead us to absolutely know that this is going to be much less damaging to health than cigarette smoke. So first research question.
We looked at 12 commercially available consumables, which is the stick, in six device types by six manufacturers sourced from five countries. And we tested those using the standardized puffing regimes and looked at 54 harmful and potentially harmful constituents that come out in the aerosol.
And what we found, refreshingly and very reassuringly, that is across the board of all of these products that we tested, you get very, very similar and massive reductions in the HPHCs that we measured. And you can see here cigarette smoke is set at 100%. And across the board, you see this really consistent level.
So we're really happy to see that because we can talk about the HTP devices that are on the market. at the category level, not just our own products, and be pretty confident that we can make certain statements based on everything that's on the market, not just our own products.
Research question two, and this was looking at the differences in biomarkers of exposure between the heating technologies in PMIs products. Just a bit of a diagram of how the sticks look there. The blade would be inserted into the tobacco plug here, versus the induction heating one here, where you have this metal strip inside.
And then that can be heated using the magnetic technology. And this was a randomized control trial. So participants were randomized into either the blade heating technology, two versions of the induction heating technology, or continuing to smoke.
And what we also needed to look at was the consumption of the product over that five-day period, because what we didn't want to see was a change in biomarkers of exposure, but actually not knowing whether that was just because they consumed fewer sticks during the study period.
So we needed to make sure that the consumption was stable and that the nicotine exposure was stable so that we could make that basis. And you can see here that at the beginning, there was a couple of days where consumers adjusted to their new product there. But then after that, they reached their level and continued using the products in a quite stable way.
And the same with the nicotine exposure. Actually, they maintained their nicotine exposure really well. So we were fairly confident that we were on the right track. And then when we looked at the biomarkers of exposure, as you can see, set to cigarette smoke at 100%, again, huge reductions in the biomarkers of exposure. And this is just over five days.
So you would expect over a longer period of time with more prolonged switching that this would become even more evident. And you can see actually very little difference between the blade heating technology and the induction heating technology, which again is very reassuring for us.
And it kind of supports the evidence that we found looking at all of the different manufacturers' HTPs as well, which use a whole variety of different heating methods with resistive heating from the outside, from the inside, induction heating. And we're still seeing this really great reduction in biomarkers of exposure and also the chemicals in the aerosol.
So it's all pointing in the same direction, which is what we want to see. The third research question, we moved into the second hand or the environmental exposure to people who work in restaurants in Japan. Here's our little setup. And you can see here, this is the non-smoking area of the restaurant. And then within the restaurant, there's a heated tobacco use area.
And no food or drink is served in those areas. And then in some of the venues as well, there's even a smoking area inside the heated tobacco smoking area. So we've got quite a complicated setup. And what we did was we monitored the area itself. So we had sensors in the room, but we also put sensors on the staff themselves.
So as they were walking around, you could measure a bit about their exposure. And we looked at nicotine as the marker in the air. So just a bit about exposure levels in Japan, they take this 500 micrograms per meter cubed as their upper limit. And that's averaged over the course of an eight hour working day.
And then we have another number we're interested in, which is this X95 value. And that's basically taking the peak amount and assuming that you have that over the course of the day as a kind of worst case scenario. So we found that the airborne nicotine levels in the HTP use areas were well below 1% of the upper limit as set by the authorities.
And the personal nicotine, this is the X95 values, were classed as control class 1A, and there was nothing better than that. That's like the clear lowest level. So again, we're really happy to see those results.
And it shows that basically separating HTP use areas when no tobacco use is permitted is a really good idea, but also that separating HTP use from smokers is a really good idea as well, because you don't really want to expose your HTP users to smoke.
I think what's clear is that use of HTPs in indoor settings, if they are controlled, well ventilated and policed, should be considered okay. But, I mean, this is the next step for regulation, but we need to be able to have a sensible conversation about what those exposures mean. And this is a publication, if you want some more details, feel free to have a look.
And last but not least, what happens when smokers switch? How do adult smokers who purchased HTP change their nicotine product use over a two-year time period? We're always asked for longitudinal data in the industry. What happens? What are the patterns of use of this study? This is by no means a perfect study.
And the reason why is because our recruitment came from our user database of people who had purchased ICOS. So already we're looking at a very specific population. But imperfect doesn't mean it's not interesting. So we recruited, as I say, people who were smokers.
They purchased ICOS for the first time, entered themselves into the user database, and from that user database, they were recruited into the study. And they were followed over the course of two years. Now, importantly, we didn't just look at their ICOS use. We looked at all of the nicotine products that they were using. So they... Because we realised that...
if they stopped using ICOS and moved to e-cigarettes, we would lose sight of what happened, and we didn't want that. So we made sure that the questions included in those surveys talked about their entire nicotine product consumption, not just ICOS. And generally, the people fell into these four groups.
They either completely substituted to smoke-free products, and I'm just going to generalize that now, not just to ICOS, but just to smoke-free products in general. They either completely substituted to smoke-free products, they dual-used with cigarettes and smoke-free products, they quit all nicotine products completely, or they reverted back to smoking.
So let's have a quick look at them. And I think this is amazing data, by the way. So what we really see, which is pretty amazing, and I know that these people were clearly motivated to switch in the first place, which is why they bought an ICOS device. So we have to take that into consideration when we're looking at this.
And you can see that reflected in these incredibly high numbers of people who switched. But the great thing is that over two years, they maintained that switching behaviour. And at the end of the two years, we had...
it's quite similar actually in Germany and Italy, around 60% of the people who purchased their IQOS device still using after two years, which I think is fantastic. And to support that, we had incredibly low levels of people who actually reverted back to smoking. So again, I think that tells a really strong story in itself.
But what I find really interesting is what's going on in the middle. So here we have on the gray line, this dual use here, which continues to decrease over time. And this complete cessation line, which is actually increasing.
And I think this is entirely supportive of the data that Adam presented yesterday, if you were in the session there with the PATH study, which show this dual use behaviour as a transition towards complete switching and eventually cessation. And I think that's what's really supported with this data.
And the fact that it's also repeated across two different, granted European markets, but two different areas as well. And we also have similar data coming out of the dual group with their ADJUST study, which also shows similar outcomes.
But not only that, we looked at the people who continued to dual use in the study for 12 months, and we found a huge reduction in the number of cigarettes that they were smoking per day. And this was stable over the course of time. So there was around a 50% to 60% reduction in the number of cigarettes they smoked every day, which in itself is really strong.
But not only that, they didn't really increase the number of units that they were using per day significantly. So their overall nicotine usage did not really increase despite the fact that they're dual-using two products. So in summary, we're nearly there. Thanks for staying with me.
We had substantial reductions in the formation of harmful chemicals compared to cigarette smoke, regardless of the heating technology and regardless of the product or brand. We had significant reductions in exposure to harmful chemicals in adult smokers, randomized HTPs, again, regardless of the heating technology.
We had very favourable workplace conditions for people even when HTP use is allowed indoors. And then over a two-year period, 60% of purchases of ICOS completely replaced cigarettes, dual use declined, and indicating again that dual use is a transitional phase towards complete switching and eventually potentially cessation for a large proportion of those users.
So I want to thank all the researchers who couldn't be here and have allowed me, trusted me, to present their data. And I'd be happy to take any questions from the audience. Thank you so much.
Sud Patwardhan 0:16:23
Leonie, thank you so much for the very comprehensive presentation. If I may request the tech team to keep the last slide on, which is the summary. So if people have any questions, they can pick on which of the four or anything else around that they want to ask. Yeah?
Ian Fearon 0:16:38
Ian Fearon, an independent consultant. About probably a couple of years ago now, along with Imperial Brands, we wrote a systematic review of behavioural studies on heated tobacco products. One thing that was quite striking in that was the amount of dual use, which is kind of contrary to what you've presented here.
I just wonder if there's some kind of regional differences and whether you have any insight in, say, Asia or other regions where dual use might be more common.
Leonie Price 0:17:07
Yeah, absolutely. It's a really good observation. And I think that actually comes down to the population that were included in the study, right? I think when you're looking at a population in general, you would expect to see higher levels of dual use as people are experimenting with different product types, with trying to find their way.
We know that this is a complicated journey for a lot of people. obviously the people recruited into our study had already made the decision to purchase the device. So already very invested in that journey. So I think that really explains a lot of the differences that we see compared to the general population.
And as I said at the beginning, it's not an ideal study setup, but we're screamed at for longitudinal data all the time. And it's so hard to have the perfect controlled study. So I think we have to really put it in that frame and be a bit modest about what we can say.
But overall, I think if we can get people on the journey and get them invested in that journey, we see great outcomes. And I think that's what we can say for sure. Thank you.
Lynne Dawkins 0:18:13
Thank you. Hi, Lynne Dawkins. I consult for dual labs through Pinney Associates. There's always this concern when people are switching over from the people themselves or from regulators about transfer of dependence. And I wondered if you'd included a dependence measure in your longitudinal study and looked at that. We didn't. OK. Next time.
Leonie Price 0:18:38
Yeah, absolutely. Yeah, but it's a really good question, and I think you're totally right. The dependence conversation is obviously where people want to go, the talk of addiction and what that means. I think there's this huge misperception that increased nicotine exposure means increased addiction, and addiction just simply doesn't work like that.
There is no threshold above this level of nicotine exposure, addicted, and below that, you're not. It's much more complicated and nuanced than that. And so I think we need to be really cognisant of that when we're designing our studies and to be able to maybe talk on that a little bit better. So I totally agree with you, Lynne. Thank you.
Lynne Dawkins 0:19:20
Absolutely. I mean, I think a transfer of dependence is a good thing, personally, and they need to have a certain level of dependence to be attractive. But not everyone agrees.
Leonie Price 0:19:29
Yeah. Abuse, liability, etc.
Sud Patwardhan 0:19:32
Any other question? I have one question to ask, kind of riding on the question that Lynn asked about nicotine and transfer of dependence, but also you mentioned misperceptions. And I'm just wondering, the third set of your data, which is the occupational exposure, Was there a specific reason you went for nicotine exposure and not some other biomarker?
And I'll tell you why I'm asking that. Because the moment you start saying, you know what, there was not that much nicotine exposure, it's within limits, and that data starts becoming something that you would very proudly say, look, this is actually a good thing in terms of science. The spin on that would be, ah, so they're looking at the concern is about nicotine exposure.
Do you know what I'm trying to get at? And is there any reason why you chose that and not some other BOE?
Leonie Price 0:20:14
I think measurability and the persistence in the environment makes it actually a really good one. But I totally agree with you. And I actually had an argument with the people who were doing the study on this. Because, yeah, from a perception perspective, it really doesn't necessarily help to be highlighting the exposure to nicotine in an environment.
But it is scientifically a very good marker to use. So, yes, we have to be very much aware of that. I think in this environment, everyone would understand that. But maybe outside these walls, we would have to be really careful about how we talk about that data. I think the issue that we have is more broadly around environmental exposure to SFP aerosols.
And because I think especially with evaping devices, for example, where you have big clouds and big like strong smells, people automatically assume, oh, my God, this chemical is getting into my lungs. But I think it's really important to highlight that just because you can smell something and you don't like it doesn't mean that it's necessarily damaging your health.
Like I can smell a dog poo on the floor and I know that it's that's not very nice for me and I don't like it, but it's not going to kill me. And I think that's where we have to kind of reinforce, contextualize the experience of people who are exposed to the environmental.
And let's face it, you know, if you don't want to be, you should be able to have areas indoors where you're not exposed for sure. But to contextualize that exposure in terms of what it means for health and why we shouldn't necessarily be panicking about this.
Sud Patwardhan 0:21:49
Thank you so much for the clear answer. There's two questions there. So first, perhaps, to the gentleman in the jacket here in the front. Name, affiliation?
Rasmus Pagh 0:21:58
I'm Rasmus. I'm with Extimo Consultants in France. I just had a question on this occupational exposure or sidestream. I don't think you presented it, but I was just, it's just a simple question. Did you measure, you had an area in that where you were doing sort of conventional combustibles. Did you measure them?
And what's the ratio, your exposure from conventional cigarettes towards the heated devices? Are we talking about a third less with heated tobacco or where are we in the range? Because I just remember my dad smoking in the car when I was a kid and I'm not sure, your analogy to the dog poo, I'm not sure that it wasn't harmful.
Leonie Price 0:22:44
Well, no, I think cigarettes smoke for sure, and we have data to absolutely substantiate that that is harmful to health. And that's why I think it's illegal in a lot of places now to smoke with children in the car. Some places it's illegal to smoke in cars.
Some places it's illegal to smoke with children in cars, for sure, because we do know that there are a lot of chemicals released and that this study did not look at the smoking rooms. But there are indoor air quality studies that do look at smoking rooms, and I'd take a look at those. But the difference is night and day.
Like, when we're looking at the indoor air quality measures in people who are smoking in a defined area versus HTP and e-cigarette, it's, like, 100-fold difference in exposures.
Rasmus Pagh 0:23:33
So you would be close to the exposure limits with combustible cigarettes?
Leonie Price 0:23:39
And exceeding a lot of the time, yeah.
Rasmus Pagh 0:23:41
All right.