SAN FRANCISCO, April 2, 2012 /PRNewswire/ -- Nektar Therapeutics (Nasdaq: NKTR) announced today that the first subjects were dosed last week in a Phase 1 clinical study to evaluate the pharmacokinetics and safety of NKTR-192, the company's novel short-acting mu-opioid analgesic candidate. NKTR-192 is designed to have a short-acting profile with rapid onset of pain relief for the treatment of acute pain. With a reduced rate of entry into the central nervous system (CNS) as compared to other fast-acting opioid therapies in preclinical studies, NKTR-192 has the potential to greatly reduce the euphoria that underlies opioid abuse and dependence, as well as other unwanted CNS side effects, such as sedation. The unique characteristics of NKTR-192 are engineered into its new molecular design and are not the result of formulation techniques. The single-dose Phase 1 clinical study will assess the pharmacokinetics and safety of NKTR-192 in up to 36 healthy subjects. The primary objective of the study is to assess the pharmacokinetic profile of various dosages in humans in order to design future clinical studies for the compound. This Phase 1 clinical study is being conducted in the United States at Lifetree Clinical Research. "With prescription opioid abuse at epidemic levels in the United States, new approaches are desperately needed to address this serious problem," said Robert Medve, M.D., Chief Medical Officer of Nektar Therapeutics. "NKTR-192 is a highly compelling new opioid molecule that has exceeded our 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. 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." Preclinical data for NKTR-192 was highlighted last November at the Society for Neuroscience Annual Meeting: Neuroscience 2011. Data from in vivo and in vitro studies demonstrated that NKTR-192 exhibits onset of analgesic activity within five minutes, as well as a peak effect comparable to current opioids. In preclinical models used to predict the abuse liability of compounds, NKTR-192 shows a marked reduction in self-administration of NKTR-192 as compared to reference opioids. Additionally, NKTR-192 exhibits a significantly reduced rate of entry into the CNS as compared to leading opioid agents.