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A temporary halt in PC-SPES
availability. (October 2002)
For the near future, there will be no
need to talk to patients about PC-SPES as it's manufacturer, BotanicLab,
has stopped production and all grants and studies involving PC-SPES are on
hold. The reason: contamination with DES, Indocin and Warfarin in lots
manufactured between 1996 and mid-1999. This was reported in an editorial
(fascinating reading) and article in the Journal of the National Cancer
Institute, Vol.94, September 4, 2002, 1275-1281. Contamination may have
entered at the plants in China. The usual 9 capsules of PC-SPES contained
0.5 mg of DES and 30 mg indomethacin. The study that had been in progress
by Dr. Eric Small comparing DES to PC-SPES is currently on hold. There had
been good rationale for such a study since the real question was whether
PC-SPES had something "extra" that would render it more effective than 1
mg DES. The major herbal ingredients of PC-SPES were biacalin, which
inhibits prostate cancer by apotosis and inhibits 5 alpha-reductase and
has aromatase inhibitory properties, and a lesser ingredient,
licochalocone A (a licorice flavinoid), which has Bcl-2 modulating
properties. So legitimate research issues remain, but they need to be
carried out with a better regulated product.
The question had always been whether PC-SPES was just a very much more
expensive way to give an estrogen - such as DES. (Thirty 1 mg tabs of DES
are available at Kelly Ross pharmacy for $30 - phone number: 622-3565).
Many articles report the temporary effectiveness of 1 mg DES. An
illustrative article is "Stilbesterol Effective As Salvage Therapy For
Refractory Prostate Cancer" in Br J Urol Int 2000;85:1069-1073. In this
study, 1 mg DES was combined with hydrocortisone (not required, as
reported elsewhere -editor's note). Among 29 patients, they report a
median drop of PSA of 84% (292 ng/mL to a nadir of 66 ng/mL). The nadir
occurred at 4 months and the response persisted a median of 6 months, but
some responses lasted considerably longer. Interestingly, 9 capsules of
PC-SPES reduced PSA by 54% in hormone resistant patients for a median
duration of four months. Finally, in other studies, 0.5 mg DES was used
with similar results, which links us back to the PC-SPES story.
Bottom Line: Availability of PC-SPES halted, but 1 mg DES probably has
equal effect.
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