NKTR-118 Shows Substantial Oral Bioavailability and Extended Half-Life in Phase 1 Clinical Data Presented at American Pain Socie...( SAN CARLOS Calif. May 7 /- New Ph...),Health

SAN CARLOS, Calif., May 7 /PRNewswire-FirstCall/ -- New Phase 1 clinical trial results for NKTR-118 (oral PEG-naloxol) were presented by Nektar Therapeutics (Nasdaq: NKTR) this week at the Annual Meeting of the American Pain Society (APS) in Tampa, Florida. In this multiple-dose Phase 1 study, oral NKTR-118 was shown to have substantial oral bioavailability with rapid absorption and an extended half-life that is up to ten times the known half-life of unPEGylated naloxone.

NKTR-118 is Nektar's proprietary peripheral opioid antagonist candidate currently in a Phase 2 trial in patients with opioid-induced bowel dysfunction (OBD), including opioid-induced constipation. Nektar's advanced small molecule PEGylation technology has been shown to reduce NKTR-118's penetration across the blood-brain barrier, an important potential advance for this and many other potential therapies.

"For the first time, it has now been shown that Nektar's proprietary PEGylation technology can be used to enhance oral bioavailability for a small molecule drug," said Timothy A. Riley, Ph.D., Vice President of PEGylation Research at Nektar. "In addition, this PEGylated drug exhibited an exceptionally long half-life of eleven hours, enabling a once-daily dosing regimen for NKTR-118 as an oral therapy."

NKTR-118 was also shown to be safe and generally well-tolerated at doses up to 250 mg twice daily, with no serious or severe adverse events. The pharmacokinetics of NKTR-118 were dose-proportional and the observed terminal half-life of the drug was approximately eleven hours, independent of dose. This compares to a known half-life of between 45 and 100 minutes for naloxone.(1) At all dose levels, NKTR-118 was rapidly absorbed after oral administration,
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