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Abstract:
Iometopane [(123)I beta-CIT, GPI 200, RTI 55], a tropane derivative labelled with iodine-123, is a dopamine imaging agent that was under development with Guilford Pharmaceuticals (as Dopascan Injection) for the early diagnosis of Parkinson's disease. Neurochemical imaging with iometopane using conventional single photon emission computerised tomography (SPECT) provided images of the brain for the distinguished diagnosis of Parkinson's disease. The ability of iometopane to bind to the dopamine transporter on presynaptic dopaminergic nerve terminal in the striatum (caudate nucleus and putamen) has been used to differentiate the uptake of the agent by the neurons in the striatum in patients with a Parkinsonian disorder (Parkinson's disease and progressive supranuclear palsy) from patients without a Parkinsonian disorder (essential tremor and healthy controls) with high sensitivity and specificity. The diminished uptake of iometopane in the striatum on the SPECT images of patients with a Parkinsonian disorder can be applied to assess both disease trait and disease state (severity) reflected by the severity of the brain dopamine neuron loss. The rate of clinical progression of Parkinson's disease varies greatly and is currently unpredictable. Imaging with iometopane provides the opportunity to evaluate patients longitudinally from early to late disease using an objective biomarker for dopamine nerve cell degeneration. Diagnostic imaging with Dopascan Injection is thought to differentiate Parkinson's disease from other forms of tremor, eliminate tests such as MRI and CT scans, unnecessary and inappropriate medications (psychotropics), and significantly reduce the number of people remaining on Parkinson's disease medications for life, despite not having Parkinson's disease. Guilford Pharmaceuticals acquired the licence for iometopane from the Research Triangle Institute, US, and sub-licensed it to Daiichi Radioisotope Laboratories for marketing, sales and distribution in Japan, Korea and Taiwan. In July 2003, Daiichi Radioisotope Laboratories paid a milestone payment of $0.55 million to Guilford after filing an application for approval in Japan. In January 2002, Guilford signed an exclusive European development, marketing and sales and distribution agreement for iometopane with MAP Medical Technologies of Finland. Under the terms of the agreement, MAP Medical Technologies will assume responsibility for regulatory approvals, manufacturing, marketing and selling the agent in all member states of the EU and other selected markets. In return, Guilford will receive an upfront payment, milestone payments and royalties on future sales in these territories. In July 2002, MAP Medical Technologies become a subsidiary of Schering AG. In March 2002, Guilford Pharmaceuticals sublicensed iometopane to Molecular Neuroimaging LLC (MNI) of Connecticut, USA. Under the terms of the agreement, MNI will pay a royalty for each administration of iometopane, and also provide Guilford Pharmaceuticals with favourable pricing for the services (including administration of iometopane) for any clinical trials of Guilford's product candidates. This agreement will be terminated upon the US FDA's approval of the product candidate for marketing and sale in the US. Guilford has retained commercial rights to Dopascan Injection in the US. MAP Medical Technologies (Schering AG) submitted a Marketing Authorisation Application (MAA) in Finland for European approval of iometopane for the diagnosis of Parkinson's disease in April 2002. Daiichi Radioisotope Laboratories filed an application for approval of iometopane (Dopascan Injection) for the diagnosis of Parkinson's disease in Japan in July 2003. Guilford Pharmaceuticals is conducting a phase II clinical trial in 200 patients with Parkinson's disease where iometopane imaging is used to assess the effectiveness of GPI 1485, an investigational drug candidate, at baseline and at one year and two years after treatment with either GPI 1485 or placebo. The enrolment is expected to be completed in Q3 of 2003. Guint with either GPI 1485 or placebo. The enrolment is expected to be completed in Q3 of 2003. Guilford Pharmaceuticals decided not to proceed with phase III clinical trials and further development of iometopane due to its inability to contract a suitable manufacturer for the clinical and commercial supply of iometopane on acceptable conditions in the US. Guilford Pharmaceuticals obtained the patent coverage for iometopane in the US, Australia and Europe (Austria, Belgium, Switzerland, Liechtenstein, Germany, Denmark, Spain, France, the United Kingdom, Italy, Luxembourg, the Netherlands, Sweden and Greece). Separate filings were made in Finland, Norway, Japan, Canada and Korea. The manufacturing methods of Dopascan are protected by patents in the US and Europe. Dopascan is a registered trademark in the US, Canada, Europe and Asia.