Some glycosaminoglycans in cartilage reportedly have anti-inflammatory and immune-system -stimulating properties,[57,58] Reviewed in [1,2,14,16] and it has been suggested that either they or some of their breakdown products are toxic to tumor cells. Reviewed in [2,3] Thus, the antitumor potential of cartilage may involve more than one mechanism of action.
Cartilage products are sold commercially in the United States as dietary supplements. More than 40 different brand names of shark cartilage alone are available to consumers. Reviewed in  In the United States, dietary supplements are regulated as foods, not drugs. Therefore, premarket evaluation and approval by the U.S. Food and Drug Administration (FDA) are not required unless specific disease prevention or treatment claims are made. Because manufacturers of cartilage products are not required to show evidence of anticancer or other biologic effects, Reviewed in  it is unclear whether any of these products have therapeutic potential. In addition, individual products may vary considerably from lot to lot because standard manufacturing processes do not exist, and binding agents and fillers may be added during production. Reviewed in  The FDA has not approved the use of cartilage as a treatment for people with cancer or any other medical condition. The FDA is notifying consumers of a refund program for purchasers of Lane Labs-USA, Inc.'s shark cartilage product, BeneFin. Consumers are eligible for a partial refund of the purchase price and any shipping and handling costs if this product was purchased between September 22, 1999 and July 12, 2004.
To conduct clinical drug research in the United States, researchers must file an Investigational New Drug (IND) application with the FDA. To date, IND status has been granted to at least four groups of investigators, one of which was the MDA-ID-99303 trial, that is now closed, to study cartilage as a treatment for people with cancer.[7,59] Reviewed in  Because the IND application process is confidential and because the existence of an IND can be disclosed only by the applicants, it is not known whether other applications have been made.
In animal studies, cartilage products have been administered in a variety of ways. In some studies, oral administration of either liquid or powdered forms has been used.[20,40,41,44,45,60] Reviewed in [15,48] In other studies, cartilage products have been given by injection (intravenous or intraperitoneal), applied topically, or placed in slow-release plastic pellets that were surgically implanted.[27,28,33,34,36,39,41,43,45] Reviewed in [29,47,49] Most of the latter studies investigated the effects of cartilage products on the development of blood vessels in the chorioallantoic membrane of chicken embryos, the cornea of rabbits, or the conjunctiva of mice.[27,28,33,36,39,41,43,45] Reviewed in [29,47,49]