Primary endpoints were safety/tolerability and changes in total subjective opioid withdrawal scale (SOWS) score. Secondary endpoints included other withdrawal scales and analgesia and physiological measurements. Indicators of altered analgesia or tolerance (reduced opioid effects with repeat morphine exposure) were assessed in laboratory sessions with oxycodone administration and cold water immersion of the hand followed by objective and subjective pain endpoints.About MN-166 Clinical Development in Addiction Clinical development of MN-166 is ongoing in both methamphetamine addiction and opioid addiction. These clinical trials are conducted by some of the country's leading experts in opioid and methamphetamine addiction. A Phase 1b clinical trial of MN-166 in methamphetamine dependence is near completion at UCLA. A Phase 2 outpatient clinical trial of MN-166 in methamphetamine dependence, led by investigators at UCLA, has been funded by NIDA. In opioid addiction, a second NIDA-funded clinical trial of MN-166 in prescription opioid or heroin abusers is currently ongoing with the investigators at Columbia University and the New York State Psychiatric Institute. This ongoing Phase 2a trial involves in-unit treatment for six weeks with either placebo or 100 mg/day MN-166 and is tailored to confirm some prior endpoints and to assess the effect of MN-166 on opioid craving and self-administration behavior. About MN-166 (ibudilast) MN-166 has been marketed in Japan and Korea since 1989 to treat cerebrovascular disorders, including post-stroke complications, and bronchial asthma. MediciNova licensed MN-166 (ibudilast), from Kyorin Pharmaceutical in October 2004 for potential utility in relapsing remitting multiple sclerosis. MediciNova scientists and collaborators independently established evidence of ibudilast utility in opioid and methamphetamine addiction as well as chronic neuropathic pain. MN-166 is a first-in-class, orally bioavailable, small molecule phosphodiesterase (PDE) -4 and -10 inhibitor and a macrophage migration inhibitory factor (MIF) inhibitor that suppresses pro-inflammatory cytokines including IL-1ß, TNF-a, and IL-6, and may upregulate the anti-inflammatory cytokine IL-10 and neurotrophic factors. It attenuates the activation of brain glial cells in neurological disorders and that cellular action is thought to contribute to its therapeutic action. Accordingly, MediciNova's development efforts in progressive MS and chronic neuropathic pain are founded upon both anti-neuroinflammatory and neuroprotective actions which have been demonstrated in preclinical and clinical data.