Environmental Factor, March 2011, National Institute of Environmental Health Sciences
Peer review panel deliberates NTP Technical Reports
By Ernie Hood
This was the first meeting of the new NTP Special Emphasis Panel founded to peer review draft NTP Technical Reports. As shown above, the panel members had a considerable amount of material to consider as they came to their conclusions. (Photo courtesy of Steve McCaw)
Panel member Diane Birt, Ph.D., director of the Center for Research on Botanical Dietary Supplements at Iowa State University, was a primary reviewer of the Technical Reports on kava kava extract and alpha beta-thujone. (Photo courtesy of Steve McCaw)
The National Toxicology Program (NTP) convened a peer review of draft NTP Technical Reports by an external scientific panel at a meeting(https://ntp.niehs.nih.gov/?objectid=BD2CA47D-F1F6-975E-74AA99197B7CB205) Jan. 26 at NIEHS. Assessing the daylong consideration of technical report documents, NTP Deputy Program Director for Science Nigel Walker, Ph.D., said, "We were very pleased with the depth and breadth of the comments."
The gold standard in observational toxicology
The Technical Reports describe the results of two-year bioassays of nominated substances in male and female mice and rats. They reflect considerable effort on the part of NTP scientists and contractors - often involving 50-70 people and many years worth of work. Draft reports are prepared by an internal team led by NTP pathologist David Malarkey, D.V.M., Ph.D., and NTP toxicologist Michelle Hooth, Ph.D., and are reviewed by NTP scientists before they are released to the public and presented to the external peer review panel.
The conclusions reported are seen by regulatory agencies as authoritative sources in their decision-making. "Part of the NTP mission is providing information on hazardous substances to the stakeholders in the community, and to me, the Technical Reports meetings are where the rubber meets the road for that part of our mission," says Walker. "They exemplify everything NTP is about."
Review panel outcomes
At the January meeting, the panel reviewed draft NTP Technical Reports on kava kava extract, a botanical product used widely as a dietary supplement; retinoic acid/retinyl palmitate, a formulation of vitamin A widely used in cosmetic products; methyl trans-styryl ketone, a compound used as a synthetic flavoring or fragrance agent; styrene-acrylonitrile (SAN) trimer, a chemical byproduct suspected to be associated with childhood cancers; and alpha, beta-thujone, a compound found in herbal medicines, food and beverage flavorings, cosmetic products, and repellants.
The panel accepted the draft conclusions as written for methyl trans-styryl ketone and alpha, beta-thujone, but recommended changes for the conclusions for the other compounds, including changing the draft conclusion for SAN trimer from "equivocal evidence of carcinogenic activity" in male F344/N rats to a finding of "no evidence."
Due to time constraints, consideration of the draft Technical Report for senna, an herb used as a stimulant laxative, was postponed until the peer review panel in April.
(Ernie Hood is a contract writer for the NIEHS Office of Communications and Public Liaison.)