Evaluating the Scientific Evidence
for Potential Reduced-Risk Tobacco Products
 

Biological Effects Assessment (BEA) Committee
Statement of Work (DRAFT)

 
  PURPOSE OF COMMITTEE
The Biological Effects Assessment Committee (BEAC) is charged with identifying and reviewing the current state of the science relating to biological methods employed in the analysis of the effects of tobacco use, highlighting currently available assays, models, and markers that can be used to draw scientific conclusions regarding reduced-risk for tobacco products. The primary focus will be on the identification of human studies that are able to provide information on the risk of cancer, cardiovascular disease, and chronic obstructive pulmonary disease. In vitro assays and animal models that support an anticipation of reduced-risk in humans will also be included in this review.

WORK PRODUCT
The results of this investigation will be presented in summary format to the Core Committee at their October 19-20, 2005 meeting, as a summary chapter in the RRRvw Core Committee report by July 2006, and as a formal report by late 2006.

AREAS OF INQUIRY

Identification of Potential Toxicants

  • What are some of the toxicants in tobacco smoke/smokeless tobacco that are generally recognized as harmful to humans?
  • What potential links do these toxicants have to the human disease endpoints being evaluated (i.e., cancer, cardiovascular disease, chronic obstructive pulmonary disease)?
  • What value, if any, do available regulatory risk values have in assessing the potential for reduced risk tobacco products?

Biological Assays
For each assay type the following information will be evaluated and provided to the Core Committee:
  Appropriate study designs for evaluating the biological effects of potential reduced-risk products;
  Appropriate study designs for evaluating the biological effects of potential reduced-risk products;
  Methodological considerations, such as the validity, relevance, reproducibility, reliability, specificity, sensitivity, and practicality of the available assays, models, and markers to assess reduced-risk potential in humans. BEA will also consider signal-to-noise ratios, adequate sample size and power, minimization of bias and differential error, and adequate and appropriate controls;
  Relative contributions that specific assays, models, and markers provide to the assessment of reduced-risk (i.e., weight-of-evidence analysis); and
  Significant research gaps that when filled will enhance future assessments of reduced-risk.
 
  In Vitro Assays
  What are the methods currently being used to assess genotoxicity and cytotoxicity?
  Experimental parameters will be evaluated, including:
    What should be tested (e.g., TPM, whole smoke)?
    What are the appropriate comparison products (e.g., Kentucky reference cigarettes, average sales-tar cigarette, ultra-low tar cigarette)?
    How should the results be presented (e.g., per TPM, per cigarette)?
  Are these assays relevant to human disease? If yes, to what disease endpoints?
  What are the benefits and drawbacks of such assays?
  What and how much do the results of such tests contribute to an overall assessment?
  What are the limits of current assays and what is required of future tests?
 
  Animal Studies
  Emphasis will be placed on the review and evaluation of animal models for cancer, cardiovascular disease, and chronic obstructive pulmonary disease. Specific questions to be addressed include:
  What animal models are currently being used to evaluate tobacco exposure?
  What information about dose-response can be inferred from the current models?
  How much observable change in biological response is significant?
  Experimental parameters will be evaluated, including:
    How are doses selected?
    How many animals need to be used?
    How should data be reported/normalized?
    What are the appropriate comparison products (e.g., Kentucky reference cigarettes, average sales-tar cigarette, ultra-low tar cigarette)?
  How are the identified animal models relevant to the development of human disease?
  How much emphasis should be placed on animal models?
  How do current protocols fail and what is required of future models?
 
  Human Studies
  Emphasis will be placed on biomarkers of harm for cancer, cardiovascular disease, and chronic obstructive pulmonary disease. Clinical and observational studies of biomarker identification and validation will be evaluated. Specific questions to be addressed include:
  What short-term biomarkers, if any, are currently used to evaluate disease state/progression? How well validated/accepted are these markers and what information has been provided for their validation? What are the uncertainties associated with each marker?
  How much reduction in a biomarker is needed to make a clinically important difference?
  What information about dose-response can be inferred from current biomarkers?
  What data are available to evaluate how rapidly a particular biomarker of harm may change on smoking reduction or cessation? Is the observed time-scale appropriate for an evaluation of the biomarker in a short-term clinical study?
  Are certain individuals more susceptible to smoking-associated diseases? What are the underlying causes of this susceptibility (e.g., genetics, gender, age, ethnicity, diet and nutrition, or other lifestyle factors)?
  Experimental parameters will be evaluated, including:
    What is the appropriate study duration and design when evaluating biomarkers of harm?
    What information is needed to appropriately characterize the study subjects (e.g., gender, profession nutrition/alcohol use, usual brand, age of initiation, duration of smoking, number of cigarettes per day)?
    What biomarkers of exposure are required to accurately evaluate the study data?
    What is the appropriate comparison product (e.g., the smoker's usual brand)?
  Can the results from short-term studies provide an accurate assessment of potential long-term effects?
  What are the limits of current biomarkers and what are necessary aspects of future development?