Nektar Therapeutics has dosed the first subjects in a Phase 1 clinical study of its NKTR-192 drug, designed for the treatment of moderate to severe acute pain.

NKTR-192 is a short-acting mu-opioid analgesic candidate developed using the company’s polymer conjugation technology to slow drug entry into the central nervous system (CNS).

The single-dose Phase 1 clinical study is conducted at Lifetree Clinical Research, US, with the aim to evaluate the pharmacokinetics and safety of NKTR-192 in up to 36 healthy subjects.

The primary objective of the trial is to determine the pharmacokinetic profile of various dosages in humans in order to design future clinical studies for the compound.

In pre-clinical studies, NKTR-192 has shown the ability to reduce the euphoria that underlies opioid abuse and dependence, as well as other unwanted CNS side effects, such as sedation.

Previous in vivo and in vitro studies reported that NKTR-192 showed onset of analgesic activity within five minutes, as well as a peak effect comparable to current opioids.

Nektar Therapeutics chief medical officer Robert Medve said NKTR-192 is a compelling new opioid molecule that has exceeded the company’s expectations in multiple preclinical studies.

"The drug candidate demonstrated a fast onset of analgesia, while at the same time showing greatly reduced abuse liability and sedation as compared to standard short-acting opioids," Medve added.

"NKTR-192 is an excellent addition to Nektar’s pain portfolio, and we look forward to evaluating this new mu-opioid analgesic molecule in the clinic."

The company has also completed Phase 1 clinical development of its drug NKTR-181, a long-acting mu-opioid analgesic for the treatment of chronic pain conditions, demonstrating sustained and dose-dependent analgesic responses. Nektar Therapeutics plans to advance NKTR-181 into Phase 2 clinical development in chronic pain patients this year.