Prostate Cancer News:

PC SPES Contained 3 Prescription Drugs Including DES

The herbal supplement PC SPES, widely used until recently by prostate cancer patients, contained the estrogenic drug diethylstilbestrol (DES), the blood thinner warfarin and the anti-inflammatory drug indomethacin, according to a report presented at the annual meeting of the American Association for Cancer Research.

Investigators led by Dr. Milos Sovak, processor of radiology at the University of California, San Diego and Allen Seligson, PhD, senior scientist at the Biophysica Foundation in La Jolla, said they found the compounds in samples of PC SPES manufactured from 1996 through 2001.

Production of the product, made from a combination of eight Chinese herbs, has been halted since mid-December, first by the company's inability to obtain one of the herbs, and then in February by a product recall after tests by the California Health Department found that samples from shipments contained warfarin.

The FDA warned consumers at that time to stop taking the supplement because of the presence of the warfarin, a prescription drug.

While the California Health Department did not report finding DES, the researchers reported at the AACR meeting that they used a sophisticated chemical analysis technique known as HPLC to isolate each unique chemical constituent found in PC SPES.

Then under the direction of Dr. Marian Hajduch. at Palacky University in the Czech Republic, the researchers sought to characterize the biological activity of PC SPES, comparing the HPLC findings to the product's capacity to inhibit the growth of prostate cancer cells in the test tube.

The greatest degree of biological activity was found in those samples of PC SPES that contained the highest concentrations of DES.

Dr. Robert A. Nagourney, one of the researchers who took part in the study that found the chemicals, observed that DES was an effective earlier medical treatment for prostate cancer that was halted because it was associated with formation of blood clots in the legs.

PC SPES, manufactured by BotanicLab of La Brea, CA, was presented as an herbal remedy consisting of a proprietary blend of eight Chinese herbs. Sold as an over-the-counter herbal supplement, it was not subject to the FDA regulations that govern prescription drugs such as DES, indomethacin and warfarin.

Source: Prostate Cancer Week of April 14, 2002