Progenics Pharmaceuticals and Salix Pharmaceuticals have
entered into an exclusive worldwide (except Japan) agreement
by which Salix has licensed rights to Relistor® (methylnaltrexone bromide).
Methylnaltrexone subcutaneous injections are indicated
for treatment of opioid-induced constipation (OIC) in patients
with advanced illness who are receiving palliative care, when
response to laxative therapy is insufficient.
It is a peripherally acting mu-opioid receptor antagonist that
counteracts the constipating effects of opioid pain medications
in the gastrointestinal tract without affecting their ability to
This ability is conferred by a permanently charged tetravalent
nitrogen atom, which means that naltrexone cannot cross
the blood-brain barrier.
Consequently, it inhibits opioid effects throughout the body, such as itching and constipation, without affecting analgesic effects in the brain.
The methylnaltrexone license includes intellectual property
from the University of Chicago, Progenics Pharmaceuticals, and
Wyeth Pharmaceuticals, including patents and applications with
expiration dates from 2017 to 2031.
Relistor was approved in the United States in 2008, and
it is now approved for use in over 50 countries worldwide. In
2010, Relistor single-use, pre-filled syringes were approved
for EU use in the United States, Canada and the European
Union. Worldwide net sales of Relistor totaled $16m in 2010.
Commenting on the transaction, Mark R. Baker, President of
Progenics, said: “Our agreement with Salix represents the
culmination of our search for a partner with the skills, experience and passion to effectively market and develop Relistor.
With the strength of Salix’s sales force and development team behind this product, I believe that Relistor’s full potential can be achieved – to the benefit of OIC patients.”
Paul J. Maddon, Founder, Chief Executive and Chief Science
Officer at Progenics, said: “Our partnership with Salix maximises
the global development, commercialisation and market
potential of the Relistor franchise. Progenics and Salix share a
vision of expanding the use of this important therapy among the millions of patients who suffer from the debilitating side effects of opioid pain medication.”
An oral formulation of Relistor is in Phase III development to
potentially address OIC in patients with chronic, non-cancer pain.