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Avodart® (Dutasteride 0.5mg): The first dual-acting 5 alpha-reductase
inhibitor for benign prostatic hyperplasia (BPH), approved by the FDA. Avodart®
reduces the 2 enzymes responsible for the conversion of testosterone to DHT –
which is a primary concern in hair loss. Where Propecia (Finasteride) only
blocks one enzyme, by blocking both Avodart's® result could be better. We can
expect to see Avodart® officially on the market as a hair loss
medication in 2006, if approved.
No word yet on Avodart® being approved for hair loss
by the FDA. Avodart®, manufactured by GlaxoSmithKline (GSK), was
approved in February, 2002 by the Food and Drug Administration (FDA), as a
supplemental new drug application for the treatment of symptomatic benign
prostatic hyperplasia (BPH) in men with an enlarged prostate. Dutasteride was
originally assigned the tentative brand (trade) name of "Duogen." The
manufacturer GSK will market this drug, indicated for the treatment of BPH,
under the name "Avodart™." The drug became available in pharmacies in December,
2002. This new medicine for these patients will improve urinary symptoms, reduce
risk of acute urinary retention (AUR), also reducing the risk of the need for
BPH-related surgery.
Hair Loss Issues
GSK is believed to have entered Phase III trials with Dutasteride for hair
loss. Their Supplemental New Drug Application for hair loss
is thought to have been submitted to the FDA sometime in 2001.
Avodart™ appears to have a much greater and longer inhibition of DHT than
Propecia (Finasteride) in the early testing phases. Is it better than Propecia,
and are its side effects greater or more serious? These are questions that are
unanswered at this time – but time will tell. It's currently approved in a 0.5
mg softgel form.
Dutasteride, a second-generation 5 alpha-reductase inhibitor, is the first
and only medicine to inhibit both the type 1 and type 2 enzymes responsible for
the conversion of testosterone to DHT (dihydrotestosterone), the primary cause
of prostate growth. Dutasteride's dual inhibition has been found to decrease
levels of DHT by 90 percent at two weeks and 93 percent at two years.
By reducing DHT levels, dutasteride reduces the size of an enlarged prostate.
This reduction in prostate volume was seen as early as one month with reductions
continuing through treatment. Shrinking the enlarged prostate is beneficial for
relieving urinary obstruction and improving urinary flow. While improving
urinary symptoms Dutasteride also reduces the risk of AUR (the sudden complete
inability to urinate), and BPH-related surgery, which are two potential
long-term serious consequences of BPH. The pivotal phase III study data were
published in this month's edition of the journal Urology.1
"With dutasteride, we now have a medicine that reduces the production of DHT
by more than 90 percent, helping to shrink the prostate," said Claus Roehrborn,
MD, a principal trial investigator and professor and chairman of the Department
of Urology at the University of Texas Southwestern Medical Center in Dallas ,
Texas . "By taking dutasteride, patients can improve urinary symptoms and reduce
their risk of suffering from acute urinary retention - where you suddenly can't
urinate at all - or needing BPH-related prostate surgery."
AvolveÒ , Sweden 's trade name for Dutasteride, was approved by the Swedish
regulatory authority (MPA) on July 24th 2002 . The MPA agreed to act as the
Reference Member State for the Mutual Recognition procedure within Europe and
GSK plans to market the drug in all major European markets once approvals are
finalized during 2003. The European trade name (Avolve) is still to be
confirmed.
Dutasteride ResultsThese Phase II study results below are required for
FDA approval. The Phase III trials for hair loss were scheduled to for March of
2003 in the US . The drug is expected to be on the market for hair
loss in 2006 if approved.
DUTASTERIDE PHASE 2 HAIR COUNTSAfter six month of treatment, the hair
counts measured in a 1 inch diameter circle increased by about ~96 hairs with
0.5mg Dutasteride, compared to about ~72 hairs with 5mg Finasteride. The hair
counts increased significantly with an increase in dosage with the biggest gain
being ~108 hairs with a dose of 2.5mg Dutasteride. So compared to 5mg
Finasteride (Proscar), 2.5 mg Dutasteride grew about 1.5 times as many hairs.
This is why there is so much excitement surround Dutasteride. However, there are
still unknown questions about increased side effects compared to Finasteride.
The Phase III study should tell much more.
Background on BPHBPH is one of the most common health problems in older
men.2 BPH often begins after age 50 and can progress and worsen as men age. More
than half of men over age 60 experience BPH,3 and by age 80, nearly 80 percent
of men have the disease.3,4 In the United States alone, 375,000 hospital stays
each year involve a diagnosis of BPH.5
BPH is a progressive disease in which the prostate gland surrounding the
urethra enlarges.6 As it grows, the prostate obstructs the urethra, the tube
through which urine flows, causing urinary difficulties. BPH symptoms interfere
with normal activities and reduce the sense of well being.7 Symptoms of BPH
vary, but the most common involve urinary problems, such as a hesitant,
interrupted weak stream; urgency and leaking or dribbling; and more frequent
urination, especially at night.5 In severe cases, the bladder and the kidney may
become damaged.5
An enlarged prostate can continue to increase in size and may in severe cases
lead to AUR and the need for BPH-related surgery.6 A 60-year-old man with a
20-year life expectancy has a 23 percent risk of developing acute urinary
retention.8 Among men 60 years or older, with prostatic enlargement and
obstructive symptoms, the 20-year probability of needing BPH-related surgery is
39 percent.9
To diagnose BPH, a physician will discuss urinary symptoms with a patient and
conduct a digital rectal exam. A physician may also use a simple blood test that
measures a protein called "prostate-specific antigen," or PSA. PSA is produced
by the prostate, and an increase in levels is associated with prostate growth.6
While PSA is primarily used as a screening tool for prostate cancer, it can also
be used to determine prostate enlargement.
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