A project concept calling for the study of botanical/ drug interactions in animal models through Phase I/II clinical studies was approved by the National Center for Complementary & Alternative Medicine's advisory council at a May 8 meeting in Rockville, Md.

"Given the widespread use of so many botanical supplements, a series of prospective studies based on likely botanical/drug co-usage patterns and reported adverse events or synergistic expectations would provide the public and health professionals with the information necessary to make appropriate treatment choices," the concept document notes.

"The widespread usage of botanicals, the high probability that botanicals and pharmaceutical drugs are being used concomitantly...and the published reports of botanical/drug adverse events mean that this initiative is both timely and necessary," it continues.

The concept document refers to two reports published in the Feb. 12 Lancet showing St. John's wort affected the concentration of the HIV-1 protease inhibitor indinavir, and reduced the plasma concentration of cyclosporin, causing acute heart transplant rejection in two patients.

FDA released a public health advisory Feb. 10 warning against combining St. John's wort with the drugs (¹ Also see "St. John's Wort/HIV Protease Inhibitor Use Warnings Issued By FDA, NIH" - Pink Sheet, 14 February, 2000.). The Consumer Healthcare Products Association has since adopted an Rx drug use warning for St. John's wort supplements (² Also see "St. John's Wort, Rx Drug Use Warning Adopted By CHPA" - Pink Sheet, 8 May, 2000.).

The initiative also refers to a study showing a majority of surgical patients took herbs, vitamins, dietary supplements or homeopathic medicines within two weeks of surgery. "Since over 25 million anesthetics are administered each year in the U.S., the potential for adverse reactions or exacerbation of expected side effects of anesthesia from preoperative botanicals or other dietary supplements may be widespread," the document states.

Such interaction could include "black cohosh, which could potentiate hypertensive medications, St. John's wort, which could interact with stimulants...kava kava and valerian, which could potentiate barbiturates," among others, the concept review notes.

Potential positive interactions are mentioned as well. The initiative states "oral administration of green tea (Camellia sinensis) or its amino acid component theanine may enhance the antitumor activity of the chemotherapeutic agents doxorubicin and adriamycin" in mice, while in vitro studies show the milk thistle-derived flavonoid silybin may have "a synergistic antiproliferative effect...with cisplatin and doxyrubicin."

The advisory council agreed a request for applications soliciting five to 10 developmental grants (R21) and five to 10 investigator-initiated awards (R01) should be issued by NCCAM. Each R21 is projected to cost $360,000 over two years and the estimated cost of the R01s is $500,000 each per year for up to three years. The initiative likely will not see action for at least six months.

Two other concepts approved by the council on the condition NCCAM secures funding support from another NIH institute or center are for cooperative agreements or contracts to study chromium as a treatment for diabetes and magnesium for asthma.

The initiative on chromium notes the National Institutes of Health's Office of Dietary Supplements held a workshop on chromium and diabetes in November, which led to a review of available scientific evidence scheduled for completion this summer. The size of the NCCAM study would depend on the review's findings; the initiative suggests $2 mil. be set aside in FY 2001, with total costs estimated at $10 mil. Numerous companies market chromium picolinate in dietary supplements.

The magnesium initiative would solicit applications for a double-blind, randomized, placebo-controlled, multi-site trial to assess "whether intravenous magnesium supplementation is an effective treatment for acute asthma." The funding proposal is identical to that in the chromium initiative.

The two remaining concept documents approved were deemed the highest priorities. One would provide competitive supplements to National Cancer Institute Cancer Centers to study the efficacy and mechanisms of action of CAM therapies in treating cancer, while the other would support a "trial investigating the efficacy and safety of EDTA chelation therapy in individuals suffering from [coronary artery disease]."

NCCAM and NCI each will devote $1 mil. per year for up to three years under the cancer initiative, while the concept document on EDTA chelation therapy estimates the project would cost $3 mil., to be awarded during the next fiscal year.

Botanical/Drug Interactions To Be Studied By NCCAM

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