BREAST CANCER PRIMARY PREVENTION TRIAL SHOULD INCLUDE ICI's NOLVADEX

BREAST CANCER PRIMARY PREVENTION TRIAL SHOULD INCLUDE ICI's NOLVADEX (tamoxifen), and should also examine the role of dietary fat, the board of scientific counselors of the National Cancer Institute's Division of Cancer Prevention and Control (DCPC) concurred at an Oct. 13 workshop. At the meeting, Richard Love, University of Wisconsin Clinical Cancer Center, discussed the rationale for the tamoxifen study, which he said should be conducted following completion of a feasibility study to determine the drug's side effect profile and the feasibility of recruitment. "A tamoxifen health trial in post-menopausal women should be conducted soon for two major reasons: first, because major potential benefits to women are suggested -- I emphasize suggested -- on coronary heart disease, breast cancer, and possible bone [mass preservation] from use of this hormonal agent; and secondly and critically, further demonstration of these suggested benefits will lead to use of tamoxifen in healthy women absent proof of overall benefit to their health," Love stated. The trial would be conducted over five years with a two-year accrual period, according to Love. Assuming a 50% effect in suppressing the appearance of preclinical cancer, and "making the assumption that we believe is justified that the effect would be immediate . . . it would take 16,000 women [for] such a trial." Direct and indirect costs for the study are estimated at $64 mil. In response to a question as to whether tamoxifen manufacturer ICI might be willing to pay for part of a prevention study, Love said he has met with ICI and the company is concerned about potential liability from using the drug in healthy people. Love also noted that a tamoxifen primary prevention trial may be initiated soon in Great Britain. ICI said it will "neither sponsor nor endorse" any primary prevention trials and that FDA and NCI are aware of its position. One concern ICI has regarding the study of Nolvadex as a primary prevention therapy is the criteria to be used to define high risk patients, the firm said. The company is assessing how to make that determination. The DCPC Board's recommendation follows a suggestion made at January meeting by NCI Director Samuel Broder, who said that a study of tamoxifen in women who are at risk of breast cancer should be considered ("The Pink Sheet" Feb. 6, T&G-5). He said that he "could foresee by way of long speculation" that women could be identified who do not have cancer but "have some abnormality that we might be able to correct in advance." * The workshop was called by DCPC Director Peter Greenwald to explore a research agenda for breast cancer prevention studies. Participants at the Oct. 13 workshop did not vote on any specific research proposal, but in general, expressed support for both a dietary intervention trial and a study of tamoxifen for primary prevention of breast cancer. Greenwald initiated the meeting after the National Cancer Advisory Board voted at a closed session in September not to fund the proposed Diet Fit Trial (Dietary Fat Intervention Trial). The trial is expected to be discussed again at the board's next meeting Dec. 4-5. The proposed 10-year study was to have examined the effect of a low-fat diet on the incidence of breast, ovarian, colon, and rectal cancers and cardiovascular disease. It would have involved 24,000 women and cost approximately $70 mil. The Diet Fit trial is similar to the Women's Health Trial, which was begun in 1985 to measure the incidence of breast cancer in 32,000 women on a low-fat diet. The DCPC Board of Scientific Counselors voted in January 1988 to discontinue the trial, citing in part the lack of evidence that reduction of dietary fat would lower the incidence of breast cancer.