If you have an ACS member number, please enter it here so we can link this account to your membership. (optional)

ACS values your privacy. By submitting your information, you are gaining access to C&EN and subscribing to our weekly newsletter. We use the information you provide to make your reading experience better, and we will never sell your data to third party members.



AstraZeneca Licenses Two Nektar Compounds

Pharmaceuticals: $125 Million deal puts spotlight on drug-polymer conjugates

by Michael McCoy
September 21, 2009

AstraZeneca is licensing two drugs from Nektar Therapeutics that are being developed to treat opioid-induced constipation. The deal is worth $125 million for Nektar, plus potential milestone payments.

More than 200 million opioid prescriptions are filled annually in the U.S., Nektar says. But because of how opioids act on receptors in the gastrointestinal tract, they trigger constipation in up to 90% of patients taking them.

The first drug is Nektar's NKTR-118, which has completed a Phase II clinical trial. It combines naloxol, a derivative of the opioid-antagonist naloxone, with a small polymer, polyethylene glycol. Naloxone has been used for years to reverse the effects of opioids, as in the case of an overdose.

NKTR-118 alleviates constipation by targeting peripheral opioid receptors, according to Nektar. Yet owing to the polymer component of the drug, its penetration across the blood-brain barrier is limited. Thus, it doesn't interfere with the opioids' analgesic effect.

Under the deal, Nektar is eligible to receive up to $235 million if certain regulatory milestones are reached and up to $375 million if the drug hits certain sales targets.

The second drug in the deal, NKTR-119, will combine NKTR-118 with select opioids. It is still in early-stage drug development.

Based in San Carlos, Calif., Nektar is a specialist in polymer conjugate technology. The firm calls itself the world leader in enabling biologic therapeutics with PEGylation technology and says it wants to extend this leadership into small-molecule therapies.

"In addition to the promise that these potential products provide to patients, this partnership validates Nektar's successful strategy to create novel, oral, small-molecule drug candidates with our advanced polymer conjugate technology platform," says Nektar CEO Howard W. Robin.


This article has been sent to the following recipient:

Chemistry matters. Join us to get the news you need.