Sirtex Reports Preliminary SIRFLOX Study Results
March 17, 2015—Sirtex Medical Limited reported the preliminary results of its SIRFLOX clinical study of the company’s SIR-Spheres Y-90 resin microspheres in the first-line treatment of nonresectable metastatic colorectal cancer (mCRC).
According to the company, the SIRFLOX study is an international, multicenter, randomized controlled study that enrolled over 500 patients with mCRC that had spread to either the liver alone or the liver plus a limited number of sites outside the liver, including lymph nodes and the lungs. The study was conducted in more than 100 hospitals across Australia, Europe, Israel, New Zealand, and the United States.
In the study, patients were randomized to a current first-line systemic chemotherapy regimen using FOLFOX (folinic acid, 5-fluorouracil, and oxaliplatin) with the option to receive bevacizumab (Avastin, Genentech Inc.) or the same chemotherapy with the addition of a single administration of SIR-Spheres Y-90 resin microspheres.
Sirtex advised that 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 nonresectable mCRC does not result in a statistically significant improvement in the overall progression-free survival (PFS). Overall PFS measures progression of existing tumors and/or the development of new tumors in any organ or body site, noted the company.
However, the preliminary analysis showed that SIR-Spheres Y-90 resin microspheres did result in a statistically significant improvement in PFS in the liver. This secondary study endpoint is important because liver tumors are commonly the only, or dominant, site of disease in patients with mCRC and are the major site of disease influencing survival. Up to 90% of mCRC patients die of liver failure due to the local effects of the liver tumors. SIR-Spheres Y-90 resin microspheres are specifically targeted to treat liver tumors.
The company noted that the SIRFLOX study results and preliminary analysis still require verification and validation through the academic peer review process, including presentation at a scientific conference and/or publication in a medical journal. The final results and related detailed analysis of the SIRFLOX study will be submitted to the American Society of Clinical Oncology annual meeting, which will be held in Chicago, Illinois, on May 29–June 2, 2015.