Sen McCaskill calls for inquiry into chemotherapy-supplement interactions

Senator Claire McCaskill, the ranking member of the US Senate Special Committee on Aging, is seeking clarification about potential interactions between dietary supplements and chemotherapy treatments.

The move comes in the wake of a new article in the Wall Street Journal that reported that several widely used botanicals and dietary supplements can interfere with chemotherapy and other treatments for chronic conditions.

According to the WSJ article, data supporting the interactions were presented last year at a conference of the American Medical Informatics Association by scientists from the University of Minnesota in Minneapolis, with echinacea, kava, and grape seed extract cited as problematic botanical supplements.

In response to what Sen McCaskill calls “troubling” findings, she has written to ten medical associations asking for any policies they have developed for when and how physicians assess dietary supplement use in patients prior to starting cancer treatment.

“The results from the University of Minnesota study are particularly troubling given that more than half of patients with chronic diseases or cancer use dietary supplements or herbal products,” writes Sen McCaskill. “In addition, studies have reportedly shown that as many as 70% of patients who use alternative therapies fail to inform their physicians, which increases the risk of dangerous interactions occurring for patients during the course of cancer treatment. 

“Compounding this issue is the fact that the Food and Drug Administration (FDA) lacks the authority and the regulatory procedures to ensure that dietary supplement consumers undergoing cancer treatment recognize and reduce the risk of life-threatening interactions. As I noted in recent correspondence with FDA, the current dietary supplement regulatory regime does not subject new supplement products to testing for potency, side effects, or drug interactions.

“Moreover, the lack of FDA regulations concerning standard manufacturing procedures for botanical products has led to ‘the emerging problem that manufacturers, retailers, and law enforcement officials may use differing and possibly conflicting standards,’ which increases the risk of manipulation and adulteration of botanical-based supplements. As a result of the recent findings by the University of Minnesota, I am concerned that consumers facing serious health conditions lack adequate information to protect them from dangerous interactions with products in the dietary supplement aisle.”

The ten associations contacted are: the American Medical Association, the American College of Physicians, the American Society of Clinical Oncology, the American Geriatrics Society, the American Cancer Society, the National Medical Association, the American Osteopathic Association, the Gerontological Society of America, the National Hispanic Medical Association, and the American Pharmacists Association.

“Our regulatory scheme for dietary supplements is flawed”

A new paper published in JAMA Oncology also explored the potential of dietary supplements to interfere with chemotherapy and concluded: “Current dietary supplement use and higher number of CAM [complementary and alternative medicine] modalities used […] were associated with decreased initiation of clinically indicated chemotherapy. Oncologists should consider discussing CAM with their patients during the chemotherapy decision-making process.”

“The fact is that we don’t know enough about how dietary supplements interact with cancer treatments—or with the treatment of other serious conditions,” said Sen McCaskill in a press release. “The lack of consumer protection in the dietary supplement industry has left patients facing life-threatening illnesses even more vulnerable. I can’t sit by while their health and safety is compromised just because our regulatory scheme for dietary supplements is flawed.”

McCaskill, the top-ranking Democrat on the Senate Special Committee on Aging, wrote to ten medical associations asking for any policies they have developed for when and how physicians assess dietary supplement use in patients prior to starting cancer treatment.

Sen McCaskill and supplements

Sen. McCaskill has become increasingly vocal against the presence of “fraudulent or unsafe dietary supplements” in the marketplace.

She opened an inquiry into brain health supplements last summer by sending letters to the FDA and 15 major retailers after launching an inquiry into products, regulations, and retailers in the dietary supplement industry that specifically market to seniors using claims about improving memory and treating dementia and Alzheimer’s disease.

She also called on the FDA to suspend sales of supplements containing vinpocetine and picamilon pending an investigation. When the Agency was perceived to not be acting quickly enough, Sen McCaskill wrote to the 10 retailers to ask them to voluntarily remove any picamilon supplements.

Earlier this year she requested a comprehensive list of enforcement actions taken by the Department of Justice related to the dietary supplement industry.