"Medical Food" Available for Management of Osteoarthritis

Paula Moyer, MA

February 21, 2006

Feb. 21, 2006 — Flavocoxid ( Limbrel) is the first "medical food" for the management of osteoarthritis. The hope is that this new product, which is less selective for cyclooxygenase 1 and 2 (COX-1 and COX-2), will be safer and associated with reduced gastrointestinal bleeding and other adverse effects seen with nonsteroidal anti-inflammatory drugs (NSAIDs) and COX-2 inhibitors.

Medical foods are not classified as either drugs or nutritional supplements in the United States. Rather, medical foods are their own category and subject to their own regulatory requirements as stipulated by the US Food and Drug Administration (FDA). According to the FDA, a medical food is "a food which is formulated to be consumed or administered enterally under the supervision of a physician and which is intended for the specific dietary management of a disease or condition for which distinctive nutritional requirements, based on recognized scientific principles, are established by medical evaluation." Medical foods are regulated by the Center for Food Safety and Applied Nutrition (CFSAN), an office within the Food Division of the FDA. ( www.cfsan.fda.gov ).

Medical foods are available only by prescription, and they can only be indicated for the management of a specific disease. Flavocoxid is a medical food indicated to manage the metabolic aspects of osteoarthritis. Flavocoxid "is only indicated for the management of [osteoarthritis] and not for pain," Bruce P. Burnett, PhD, told Medscape. He is director of medical education and scientific affairs at Primus Pharmaceuticals, which manufactures Limbrel. "But the argument can be made as you control inflammation you bring down the pain associated with [it]."

The ingredients of a medical food must be generally recognized as safe. Therefore, medical foods do not have to go through the same premarket approval process as new drugs, although the manufacturers are expected to demonstrate efficacy to support their claims.

To do so, the manufacturer of flavocoxid conducted 2 studies: one was a safety study involving 80 patients and the other was a randomized, placebo-controlled trial in which one group of patients received celecoxib ( Celebrex). In the safety study, in which the treatment dose of flavocoxid was 250 mg twice daily, the adverse effect profile was comparable to that for placebo. In the randomized trial, the group receiving flavocoxid had better WOMAC scores at 90 days than those receiving celecoxib, according to Dr. Burnett.

Three clinical trials involving 600 additional patients are currently underway, and more than 25,000 patients are being monitored in postmarketing surveillance, Dr. Burnett said. "We have an adverse event rate of 0.11%," he added, noting that none of the adverse events were serious.

Medical foods have several regulatory restrictions that further differentiate them from either drugs or supplements. Therefore, manufacturers of medical foods are accountable to the FDA and must comply with regulations that pertain to labeling, product claims, and manufacturing. These requirements ensure that the medical food meets the specific and distinctive nutritional requirements of a particular disease or abnormal condition, according to Primus.

"A medical food is prescribed by a physician when a patient has special nutrient needs in order to manage a disease or health condition, and the patient is under the physician's ongoing care," according to literature supplied by Primus. "The label must clearly state that the product is intended to be used to manage a specific medical disorder or condition."

For example, phenylketonuria is managed with foods formulated to be free of phenylalanine. Other examples include hospital parenteral feeding; amino acid products for burn victims; vitamin B12, B6, and folate products for patients with hyperhomocysteinemia; and prenatal vitamins.

Medical foods are not meant to be used by the general public and they are not typically available in stores or supermarkets. The category does not include foods that are to be included within a healthy diet intended to decrease the risk of disease, such as reduced-fat foods or low-sodium foods. The nutrients found in medical foods cannot be obtained by a simple dietary change. Weight loss products are also not considered medical foods.

Flavocoxid manages the production of arachidonic acid metabolites and provides efficacy by inhibiting both COX-1 and COX-2 as well as 5-lipoxygenase (5-LOX), all of which play a role in osteoarthritis. Therefore, "[flavocoxid] is a new type of anti-inflammatory, characterized by dual inhibition," Dr. Burnett said. "It inhibits the COX enzymes equally to presumably reduce systemic side effects, as well as 5-LOX to avoid 'shunting' of arachidonic acid metabolism down this other important pathway involved in gastrointestinal bleeding or ulcers, and renal problems, concerns for both traditional NSAIDs and COX-2 inhibitors, which are less of a concern with flavocoxid due to its unique mechanism of action."

"Flavocoxid is a good alternative to NSAIDs and COX-2 inhibitors ," David A. McLain, MD, chief of rheumatology at Brookwood Medical Center in Birmingham, Alabama, told Medscape. "We don't have to be concerned about it interacting with warfarin, unlike with other products, and we can use it in people with ulcers or heart conditions." Dr. McLain was not involved in the development of flavocoxid and has no financial ties to the company.

In his practice, he has prescribed flavocoxid often for patients with osteoarthritis. "We've had a good response with flavocoxid," he said.

However, one limitation, Dr. McLain said, is coverage by insurance companies. Some will not cover medical foods. But he expressed hope that, as physicians become more comfortable with flavocoxid use and patients express satisfaction with its results, those insurance companies will feel more comfortable with its use and begin to reimburse for it. Currently, flavocoxid is reimbursed by approximately 75% of all managed care organizations, according to Dr. Burnett.

Prescribing for a medical food is very much like writing any other prescription, Dr. Burnett said. "The patient takes the [prescription] to a local pharmacy and they fill it just like they would other prescription medications," he said. "All the drug wholesalers carry [flavocoxid]. If the pharmacy doesn't have it, it can be obtained overnight from these organizations." He noted that flavocoxid cannot be substituted with any other product because there is no other dual inhibitor on the market.

Reviewed by Gary D. Vogin, MD

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