Penwest Pharmaceuticals and Endo Pharmaceuticals are jointly developing an oral, controlled-release opioid analgesic oxymorphone [EN 3202] using Penwest's TIMERx proprietary drug delivery technology. The product is being developed for twice-a-day dosing in patients with moderate to severe pain. TIMERx is a controlled-release technology based on an agglomerated hydrophilic matrix, which consists of the polysaccharides locust bean gum and xanthan gum. The technology provides a full spectrum of controlled-release profiles lasting>>/=4 h. In February 2003, the US FDA has announced that it accepted the NDA for oxymorphone extended-release tablets, oxymorphone ER, for the treatment of moderate to severe pain in patients requiring continuous opioid therapy for an extended period of time. Late in 2002, the Oxymorphone formulation successfully completed a phase III clinical trial in patients with osteoarthritis pain. Another randomised, double-blind, placebo-controlled trial was completed in 127 patients with moderate to severe pain resulting from surgery in the knee. Results demonstrated that patients receiving EN 3202 treatment had significantly superior pain relief compared with placebo recipients. An immediate-release formulation of oxymorphone (EN 3203) has also been accepted by the US FDA.