Over one-third of patients with cancer, and around three-quarters of those with advanced disease, have chronic pain. Currently available opioid therapies do not yield sufficient relief in a substantial proportion of these patients and there is a clear need for new treatments.
Chronic, unremitting pain in deep tissues that results from cancer adversely affects a disproportionately large portion of the population. Worldwide, more than 11 million people are diagnosed with cancer each year and it has been estimated that by 2020 that figure will rise to more than 16 million people a year. The prevalence of cancer pain directly correlates with the stage of disease, with more than 70% of patients in the advanced stages of cancer reporting pain (World Health Organization, 1996). In particular, patients with breast and prostate cancer, both of which have a propensity to spread to bone, more often experience pain than patients with uterine and cervical cancer. Pain as an initial presenting symptom will occur in 20-40% of patients. Severe pain occurs in 20-35% of the cancer population and significantly impairs activities of daily living. The mean incidence of pain in a sample of 5,410 patients (across 22 studies) in various stages of cancer was 51%, whereas among 9,007 patients (across 38 studies) with advanced metastatic or a terminal phase of cancer, the mean incidence was 74% (Bonica, 1990).
Currently, opioids are the principal agents employed in the management of cancer pain, but the therapeutic benefit of their prolonged use is frequently offset by the development of undesirable effects such as constipation, sedation, respiratory depression and tolerance (Kehl et al., 2003).
Sativex is approved in Canada as an adjunctive analgesic treatment in adult patients with advanced cancer who experience moderate to severe pain during the highest tolerated dose of strong opioid therapy for persistent background pain.
Cancer pain is also the lead target indication for approval of Sativex in the US. Positive data in two Phase II trials has supported an advance into Phase III studies. This Phase III programme is being performed in conjunction with GW’s licensing partner for Sativex®in the US, Otsuka Pharmaceutical Co. Ltd. The programme, which is fully funded by Otsuka, includes two Phase III randomised placebo-controlled multi-centre multinational trials as well as a long term extension study. Each Phase III trial will include approximately 370 patients and will evaluate the efficacy and safety of Sativex versus placebo over a 5 week treatment period; they will recruit patients in Europe, North America, Latin America and Asia. The first Phase III trial site has now been initiated in Europe with the first patients recruited during December 2010.
Please click below to see the press release issued on the 23rd November 2010 regarding the Phase III trial:
Please click below to see the press release issued on the 23rd March 2010 regarding the Phase IIb trial data:
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