INEX Pharmaceuticals is developing a liposomal formulation of vincristine [Onco TCS, vincacine, VSLI, Vincristine sulfate liposomes for injection] for the treatment of relapsed aggressive non-Hodgkin's lymphoma (NHL) and other cancers. It is being developed using INEX's proprietary drug-delivery technology platform called the transmembrane carrier systems (TCS), which enables the targeted intracellular delivery of various therapeutic agents. Liposomal vincristine is expected to have certain advantages over the existing standard preparation of vincristine because the use of TCS technology enables the vincristine to circulate in the blood for longer, accumulate in the tumour, and be released over an extended period of time at the tumour site. The application of TCS technology to any agent, including vincristine, has the potential to increase the efficacy and decrease the side effects of the agent.INEX decided in 1998 to focus on gaining approval for liposomal vincristine in the treatment of relapsed aggressive NHL because no standard therapy was approved for this indication. In 1999, liposomal vincristine was granted accelerated development status by the US FDA, which enables the FDA to approve it based on the surrogate endpoint of a single clinical trial. In addition, the FDA granted liposomal vincristine fast track status in August 2000.In April 2001, INEX and Elan Corporation formed a joint venture for the development and commercialisation of liposomal vincristine, with both companies contributing assets to the venture including worldwide rights to the product and intellectual property rights. The joint venture was called IE Oncology. However, in June 2002, Elan announced that it was going to focus its business strategy on three specific areas, which would not include cancer therapies. INEX announced it had regained 100% ownership of liposomal vincristine in April 2003, by reacquiring the 19.9% equity interest held by Elan and in addition retaining a fully paid-up licence to Elan's intellectual property pertaining to liposomal vincristine. All obligations to Elan under the agreement will be met through three milestone payments totalling $8 million. Some of the milestones may be paid in shares valued at the then current market price.[1]In January 2004, INEX and Enzon Pharmaceuticals formed a strategic partnership to develop and commercialise liposomal vincristine. Under the terms of the agreement, Enzon receives the exclusive North American commercialisation rights for liposomal vincristine for all indications. INEX will receive upfront and milestone payments as well as a percentage of commercial sales. Additionally, the formation of this partnership triggered a US$3 million payment from INEX to the former joint venture partner, Elan Corporation.[2,3]Nine clinical trials of liposomal vincristine are currently being conducted, including one phase I/II trial and eight phase II trials. A phase II/III trial was completed in December 2002.In September 2003, Inex commenced a ‘rolling submission’ for liposomal vincristine by submitting the first of three major sections of the NDA to the FDA. The second major section was submitted to the FDA in December 2003. INEX expects to complete the filing with the submission of the clinical section of the NDA in the first quarter of 2004.[4,5]Dow Jones Newswires reported on 1 October 2001 that the CEO of INEX expects Onco TCS to achieve sales of between $US100 and $US400 million annually for the company. FDA approval was then predicted for late 2002 or early 2003.