In the first-line treatment of non-resectable metastatic colorectal cancer, the preliminary analysis of the SIRFLOX study results does not show a statistically significant improvement in overall progression-free survival ie, at any site. However, the study does show a statistically significant improvement in progression-free survival in the liver.
A press release from Sirtex states that the data will be submitted for peer review to the American Society of Clinical Oncology (ASCO) 2015 annual meeting (29 May– 2 June, Chicago, USA).
Based on the preliminary analysis just completed, the primary endpoint of the SIRFLOX study was not achieved. The preliminary analysis shows that adding SIR-Spheres Y-90 resin microspheres to a current first-line systemic chemotherapy regimen for the treatment of non-resectable metastatic colorectal cancer does not result in a statistically significant improvement in the overall progression-free survival. Overall progression free survival measures progression of existing tumours and/or the development of new tumours in any organ or body site.
The release adds that Sirtex is pleased that the preliminary analysis showed that SIR-Spheres Y-90 resin microspheres did result in a statistically significant improvement in progression-free survival in the liver. This secondary study endpoint is important as liver tumours are commonly the only, or dominant, site of disease in patients with metastatic colorectal cancer and are the major site of disease influencing survival. Up to 90% of these patients die of liver failure due to the local effects of the liver tumours. SIR-Spheres Y-90 resin microspheres are specifically targeted to treat liver tumours.
As previously advised (most recently on 9 October 2014), the SIRFLOX study results and preliminary analysis still require verification and validation through the process of academic peer review. Presentation at a scientific conference and/or publication in a medical journal are essential parts of this process.