No smoke without...

C&I Issue 15, 2009

Since the 1980s, tobacco companies have investigated and brought to market cigarettes that heat, but not burn, tobacco, or have modifi ed the tobacco blend to reduce specifi c toxic and/or carcinogenic compounds in the smoke. Cigarette smoke, which contains about 150 toxicants, causes a host of fatal health problems, including cardiovascular disease, chronic obstructive pulmonary disease, stroke and cancer. Nevertheless, at least a fi fth of people over 16 in Britain and nearly a third of 20 to 24-year-olds still smoke.

 Now, British American Tobacco (BAT) is conducting its fi rst clinical trial-type study of novel cigarettes that have been designed to produce less toxicants in their smoke, compared with conventional cigarettes. While it is only a fi rst step towards genuinely safer cigarettes, new legislation in the US could encourage further innovation in this controversial area.

 The idea behind BAT's study is to fi nd the right combination of technologies and biomarkers in the body to ultimately develop and sell less toxic cigarettes.

 BAT's prototype products comprise three different technologies (see Box), which, when measured in the lab by a smoking machine, are claimed to reduce many of the toxicants in cigarette smoke by between 50 and 90%, compared with conventional cigarettes. To test whether this is actually the case when people – not machines – smoke, the study involves switching smokers of regular cigarettes to similar strength novel cigarettes, measuring biomarkers in their saliva and urine and comparing the levels to those in smokers who weren't switched and to non-smokers. If smoking the novel cigarettes reduces the smokers' exposure to various toxicants, the levels of the excreted biomarkers should be reduced in those smoking the novel cigarettes (www.controlled-trials.com/ ISRCTN72157335).

 But can smoking be made genuinely safer? Robert West, Cancer Research UK-funded director of tobacco studies at the UCL Health Behaviour Research Centre, says: 'In my opinion the tobacco industry seem perfectly happy to market and aggressively promote addictive products that they know kill millions of people. Research into how their products might kill slightly fewer millions seems to be rather missing the point.’

 Others disagree. ‘There is a clear sense within the scientific community, beyond those that would take the “abstinence is the only good approach to smoking”, that the smoke from a cigarette, or cigarette-like product, can be made less toxic, and from that it could be argued that the negative biological impacts of smoking could be reduced,’ says consultant Roger Jenkins, a consultant and former chemist at Oak Ridge National Laboratory in the US, who has conducted research on tobacco smoke and secondhand smoke exposure for the tobacco industry and the Center for Indoor Air Research.

 ‘We have to move beyond demonising tobacco companies to making it clear that we expect them to raise the sense of urgency in developing genuinely less harmful products,’ says Mallen Baker, a consultant on corporate social responsibility. ‘Governments should either ban tobacco outright, or make it possible and even necessary that reduced harm products be developed that are accepted in the marketplace.’

 In June 2009, US president Barack Obama signed historic legislation – The Family Smoking Prevention and Tobacco Control Act – giving the US Food and Drug Administration authority to regulate tobacco products, which, like new drugs, will now have to undergo rigorous scientific review to support any health claims. ‘The US legislation is right to focus on the composition of the products. We need tobacco companies to have clear signals and incentives to innovate to produce reduced harm products,’ says Baker.

 David O' Reilly, BAT's head of public health and scientific affairs, says that the effect on innovation will depend on what the regulations are. ‘Blanket bans on additives and ingredients could stifl e innovation. Scientifically-based frameworks could help promote safer products,’ he says.

 Meanwhile, as far as it goes, BAT's study would provide very useful information concerning the utility of ‘potentially reduced exposure products’, says Jenkins. But, although such studies are an important first step, they cannot determine whether smoking a lower toxicant product would lead to a potentially improved health outcome, he points out.

 The current study builds on previous work in which four of the chemicals in tobacco smoke were correlated with biomarkers in the body: nicotine with metabolites of nicotine such as cotinine; 4-(methylnitrosamino)-1-(3- pyridyl)-1-utanone (NNK) with the biomarker 4-(methylnitrosoamino)-1-butanol (NNAL); acrolein with 3-hydroxypropyl mercapturicacid (HPMA); and pyrene with 1-hydroxypyrene (OHP). The current study, which started in April 2009, will measure these plus another 13 smoke toxicants.

 BAT has shown that it is possible to measure the corresponding biomarkers of these toxicants, but there is no evidence yet that its products will reduce people's exposure to those toxicants. Some toxicants in tobacco smoke are also found elsewhere: People can be exposed to benzene, for example, at petrol stations, or polyaromatic hydrocarbons in barbecued food, and volatile nitrosamines from cooking bacon. To control the conditions and minimise the effects of metabolism and environment on biomarker expression, the study participants – 250 smokers and 50 non-smokers – will be confined to the clinic and eat and drink similar things.

 BAT's study measures biomarkers of exposure, which help to assess the levels of toxicant inside a person. But it is biomarkers of harm that are needed to tell what biological effect those toxicants are having over time. However, there are few, if any, agreed-upon by the scientific community. Finding those is a big part of BAT's research programme, says Proctor. What BAT's study does show, however, is a more transparent model of tobaccoproduct development. While other tobacco scientists including Gerhart Scherer, and tobacco companies such as RJ Reynolds, have conducted similar studies on reduced exposure products, BAT is registering its study online and publishing results in a peer-reviewed journal. ‘The company made a commitment to openness and transparency many years ago … before the FDA legislation had even been conceived,’ says O'Reilly.

 ‘If the [US] government supports BAT’s commitment to openness, then other companies may be pressured to follow suit,’ says Baker.

 A big problem, however, is smokers' acceptance of new products. BAT's novel cigarettes contain similar amounts of nicotine as normal cigarettes but, regardless of their relative safety, smokers might not like them. The general diluter in the tobacco, for example, produces drops of glycerol in the smoke, which also dilutes the taste, says Proctor. A lack of taste could make smokers over smoke or draw harder – as was the problem with the introduction of low-tar cigarettes.

 ‘Getting consumers to give up something that they perceive to taste better even though there are much more healthy alternatives [like diet drinks, for example] is not an easy thing to do,’ says Jenkins. ‘Put simply, if the smoke does not taste good to the smoking community, they simply will not adopt the new product.’ BAT's trial results are expected in early 2010.

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