Pfizer Japan Inc has received an approval for the manufacturing and marketing authorisation of the anti-tumour drug/kinase inhibitor Sutent capsule 12.5 mg (sunitinib malate) indicated for gastrointestinal stromal tumour (GIST) after failure of imatinib treatment due to resistance and for renal cell carcinoma (RCC) not indicated for curative resection and metastatic renal cell carcinoma.
Sutent is a new oral-dose anti-tumour drug referred to as a kinase inhibitor, and a low-molecular-weight compound capable of selectively inhibiting the tyrosine kinase receptor involved in tumour growth and vascularization. In the treatment of renal cell carcinoma, Sutent suppresses the growth primarily by inhibiting the intracellular signal transduction related to the vascular endothelial growth factor receptor (VEGFR) and the platelet derived growth factor receptor (PDGFR). It also suppresses the growth of GIST primarily by inhibiting the intracellular signal transduction related to PDGFR-a and KIT (CD117).
In a phase III clinical study involving patients with GIST resistant to imatinib (a drug previously approved for use in GIST treatment) and patients with metastatic GIST who could not tolerate imatinib, the median time to tumour progression was significantly longer in the Sutent treated group (27.3 weeks) than in the placebo group (6.4 weeks). In another phase III clinical study designed to determine a drug of first choice for the treatment of advanced RCC, patients with RCC who had received no prior drug therapy were treated either with interferon-a (IFN-a; an existing standard drug for the treatment of this disease) or Sutent. The median progression-free survival period in the Sutent treated group and IFN-a treated group were 47.3 weeks and 22.0 weeks, respectively. Furthermore, the response rate to Sutent therapy was 5 times higher than that in the IFN-a group (27.5 per cent vs 5.3 per cent). The efficacy and tolerability of this drug in Japanese patients have been demonstrated in domestic phase I and II clinical studies.
As part of the approval for the manufacturing and marketing authorization of this drug, the Japanese regulatory authority made it obligatory for Pfizer Japan to conduct a post-marketing survey, covering all patients treated with the drug, until data from a certain number of cases will be collected, in order to collect data on the safety and efficacy of the drug as soon as possible and to take necessary measures to ensure appropriate use of the drug.
Sutent was approved in January 2006 in the USA. To date, it has been approved in more than 75 countries worldwide, including several countries in Europe. The use of Sutent is recommended by the "Guidelines on Treatment of GIST and RCC" prepared by the National Comprehensive Cancer Network (NCCN), USA. In Japan, an application for approval of Sutent was filed in December 2006 with the Ministry of Health, Labour and Welfare, and it has just been approved.