U.S. Food and Drug Administration (FDA) officials reported on the progress of the Agency's continued assessment of bisphenol A (BPA) in FDA-regulated products during a February 24, 2009 Science Board Advisory Committee meeting. At the meeting, Mitchell Cheeseman, Ph.D., Deputy Director of FDA's Office of Food Additive Safety, stressed that reassessing the safety of a regulated food-contact material was a multi-step process, and that for any food additive or food-contact substance, a safety decision is made at a single point in time, and that these decisions should be, and are, reassessed as more relevant data become available. He indicated that the Agency is following through on the Committee's recommendations to refine the exposure assessment and to re-consider some of the toxicology studies that were previously determined inadequate for quantitative assessment.
By way of background, FDA issued its "Draft Assessment of Bisphenol A for use in Food Contact Applications" on August 14, 2008 for review by a Subcommittee of the Science Board Advisory Committee. The Subcommittee met on September 16, 2008 to discuss the draft report and ask questions of experts in the field. (For more information, please see a PackagingLaw.com article on the September 16 meeting.) A summary of the Subcommittee's response was released on October 29, 2008, and, during a meeting of the Science Board Advisory Committee on October 31, 2008, the Subcommittee voted unanimously to transmit the response to FDA with no changes. FDA issued a response to the Subcommittee's recommendations on December 3, 2008 in which the Agency included its plans for future work to evaluate the safety of BPA.
Reconsideration of Toxicology Studies
In its response, the Subcommittee suggested that FDA should provide a clearer explanation of the criteria used to determine which studies were included in its BPA assessment. More specifically, the Subcommittee said that while most of the studies FDA excluded are not amenable to the construction of a dose-response relationship resulting in a quantitative assessment, they are scientifically sound and should be used in a safety assessment in which the totality of the available data are considered. The Subcommittee recommended that the Agency consider the studies that were considered "adequate" and of "high utility" by the National Toxicology Program's (NTP) Center for the Evaluation of Risks to Human Reproduction (CERHR) in its report on BPA, released in September 2008.
During the February 24 meeting, Dr. Cheeseman reported that FDA is reviewing alternatives to evaluating the results of toxicology studies on BPA. In response to the Subcommittee's recommendation that the Agency consider all of the toxicology studies on BPA that were deemed relevant by CERHR, Dr. Cheeseman stated that the Agency is reevaluating these studies for "highlighted endpoints with clearer evaluation criteria." FDA has also finalized some testing protocols for additional studies on BPA to evaluate the potential carcinogenicity and chronic toxicity of BPA.
Exposure to BPA Reevaluated
FDA is working to improve its exposure assessment for BPA by generating more data to be included in the infant formula BPA concentration database. Responding to the Subcommittee's recommendation that the Agency do a more thorough exposure assessment using a larger, more geographically representative sample set and use intake distributions for different locations and age groups, Dr. Cheeseman explained that FDA developed a refined exposure assessment by using data from its own testing of canned infant formula, as well as data from the Environmental Working Group and Health Canada on levels of BPA in infant formula to generate the BPA exposure distribution. The Agency also used data from USDA's Continuing Survey of Food Intakes by Individuals 1994-96, 98 for the infant formula consumption distribution. By applying Monte Carlo modeling to these data, it estimated mean and 90th percentile exposures of BPA to infants of 0.4 µg/kg bw/d and 0.8 µg/kg bw/d, which are significantly lower than the exposures published in the Agency's draft report.
FDA is also reexamining its assumptions in estimating infant exposure to BPA through the use of polycarbonate baby bottles. Dr. Cheeseman stated that while BPA exposure from baby bottles and can coatings were evaluated together, the can coatings in contact with infant formula did seem to contribute more to the overall infant exposure to BPA than the polycarbonate baby bottles. In addition to the efforts made to refine the exposure estimate to BPA through food consumption, Dr. Cheeseman noted that the Agency is working with the regulated industry to find ways to minimize BPA residuals in and migration from packaging materials, and to investigate BPA alternatives, where appropriate.
Industry Observations
A representative of the American Chemistry Council's Polycarbonate/BPA Global Group, Steven Hentges, Ph.D., reported that members of the group are sponsoring research on BPA, and will be issuing a report on a toxicological study in late 2009. He also pointed out that almost all polycarbonate baby bottles have been replaced with alternative plastics or glass. Dr. Hentges was one of seven members of the public who spoke at the meeting.
At a January 30, 2009 meeting between FDA and industry trade associations that are stake holders in the regulatory future of BPA, John Rost, representing the North American Metal Packaging Alliance, Inc. (NAMPA), discussed challenges with replacing BPA in can coatings. He estimated that it could take as long as ten years to develop, gain regulatory approval, conduct product trials, and determine customer qualifications for a new BPA-free can coating. As an alternative, NAMPA is conducting studies to determine if BPA residual levels can be reduced, while maintaining the integrity of the coating and ensuring the safety of food.
FDA's Science Board Advisory Committee will meet again in the second quarter of 2009, at which time the Agency will provide another update on its progress on BPA.