A potential new treatment under development for prostate cancer may
offer clinical advantages, researchers reported at the annual meeting
of the American Urological Association in Atlanta. The new therapy
uses Atrix Laboratories innovative Atrigel drug delivery system
to administer a sustained release of leuprolide (Lupron)
subcutaneously, rather than intramuscularly, for 30 to 120 days.
The intramuscular injections are often quite painful,
said Dr. Ramon Perez, director of research at the Urology Health
Center in New Port Richey, Florida. Dr. Perez is conducting clinical
studies with this new treatment. Leuprolide acetate in the
Atrigel system uses a smaller needle, and the subcutaneous delivery
is far more comfortable for the patient, he continued. My
patients who are now required to switch to the other formulations
because of Atrix study completion voice a remarkable preference to
stay on the new Atrix therapy.
Less Invasive, Less Traumatic
Of the more than 180,000 American men diagnosed with prostate cancer
annually, a large percentage tend to be older and without great
muscle mass, making intramuscular injections more difficult.
It is less traumatic and invasive to administer treatment in
these patients subcutaneously and, assuming its effectiveness is
comparable to current therapy, this is likely to make the Atrigel
formulation an important new treatment option, said Dr. Maury
Jayson, a principal investigator with the Medical and Clinical
Research Associates of Bay Shore, New York.
Dr. Perez noted that intramuscular injections have produced several
instances of bothersome tissue bleeding in patients who are also
receiving anticoagulant therapy, causing marked discomfort. With
patients on anticoagulants, we definitely prefer subcutaneous
delivery, he said. In these patients, I like the 30-day
release time because that means a smaller volume and thus a smaller needle.
The new Atrigel formulation is injected subcutaneously as a liquid.
Once administered, it solidifies and releases a predetermined
systemic dose of leuprolide continuously as it is bioabsorbed. The
sustained levels of leuprolide have been found to result in a marked
decrease in testosterone levels, which, in turn, suppresses tumor
growth in patients with hormone-responsive prostate cancer.
Atrix recently announced successful preliminary results of ongoing
phase III trials of its 30-day leuprolide formulation, and has
submitted investigational new drug applications to begin clinical
trials of Atrigel formulations releasing leuprolide for 90 and 120
days, respectively. A single injection of the bioabsorbable Atrigel
product has been shown to result in significant blood levels of the medication.
The Atrigel drug delivery technology is not only easier for
medical professionals to use and more acceptable to patients, but is
much simpler and less costly to manufacture, said David
Bethune, chairman and chief executive officer of Atrix. It
allows for the sustained release of virtually any pharmaceutical,
ranging from small molecules to complex peptides and proteins, and
over times ranging from a few days to several months.
According to the manufacturer, unlike microcapsules or microspheres,
which are usually injected intramuscularly, the subcutaneously
administered Atrigel can also be easily retrieved if treatment needs
to be discontinued. Moreover, the system can be administered with a
standard needle or syringe, and unlike many implants now used for
long-acting drug delivery, it is bioabsorbable and does not require