January 25, 2001
Abstracted from PR Newswire
Grants Expedited Review to Abarelix
Mass., January 25, 2001 -- Praecis Pharmaceuticals Incorporated (Nasdaq:
PRCS) today announced that the United States Food and Drug Administration
(FDA) has informed the company that the FDA has accepted and filed the
company's New Drug Application (NDA) for abarelix depot for the hormonal
treatment of prostate cancer. In addition, the FDA advised the company
that the agency has granted abarelix depot priority review, a classification
applied to a product that, if approved, would in the FDA's judgment
represent a significant improvement compared to marketed products. The
FDA's classification of this NDA as a priority review means that the
agency is committed to complete its review of the NDA within six months
of the submission, which would be June 12, 2001. During the review period,
the agency may ask for additional information that could extend its
review beyond June 12, 2001. Following
completion of its review, the FDA will inform the company whether or
not the drug is approved for marketing, and if not, what additional
steps are necessary for its approval.
|Graphic taken from T. Cook and W.P.
Sheridan. Development of GnRH Antagonists for Prostate Cancer:
New Approaches to Treatment. Oncologist; 5 (2): 162-168,
April 2000. Full text article available
here in PDF format.
Abarelix is the latest drug for suppression of testosterone
production in men with prostate cancer. Abarelix, a peptide analog of
GnRH (gonadotropin releasing hormone), acts to block receptors in the
anterior pituitary gland. Abarelix offers a theoretical advantage over
existing GnRH analogs (Lupron, Zoladex), which are agonists, ie they stimulate
production of testosterone before suppressing it. Abarelix is a pure antagonist,
and no preliminary surge of testosterone is seen in men receiving it.
Abarelix is the product of Praecis
Pharmaceuticals. After FDA approval, the product will be marketed
by Amgen. Phase III
trial data of Abarelix, which were presented at ASCO 2000, are summarized
here. The major abstract by John Trachtenberg et al is available
Graphic taken from ASCO 2000 Poster
of M. Garnick et al.
Garnick's stylized chart shows differences in testosterone
response following administration of agonist (Lupron / Zoladex) or antagonist
(Abarelix) types of GnRH analogs. While a brief, mild "surge" in testosterone
levels is initially seen when a GnRH agonist (Lupron or Zoladex) is administerered,
a castrate level is seen after 2 - 3 weeks in approximately 95% of men
treated with either an agonist or antagonist. In former times, when most
men receiving GnRH analogs had overt metastatic disease, the testosterone
surge wasassociated with a clinical disease "flare" in approximately 10%
of patients (I.
Thompson et al, J. Urol. 144:1479-80, December 1990
). However, most
men in contemporary series do not have overt metastases; disease flare
nowadays appears to be less common than in former times; and any long-term
effect of testosterone surge is unknown.