Sirtex Completes Enrollment in FOXFIRE and FOXFIRE Global Studies

January 29, 2015—Sirtex Medical Limited announced the completion of patient enrollment in the FOXFIRE and FOXFIRE Global studies of the addition of liver-directed radiation therapy with the company’s SIR-Spheres Y-90 resin microspheres to a current standard-of-care chemotherapy regimen in the first-line treatment of more than 560 patients recently diagnosed with inoperable metastatic colorectal cancer (mCRC).

The company notes that by previous design, the data of the large multicenter FOXFIRE and FOXFIRE Global studies will be combined with the findings of 500-patient SIRFLOX study to form a database of more than 1,000 patients. In April 2013, Sirtex announced the completion of SIRFLOX enrollment. 

The database will have sufficient statistical power to evaluate whether first-line SIR-Spheres microspheres in combination with a standard-of-care chemotherapy versus chemotherapy alone can significantly increase the overall survival of patients with colorectal cancer liver metastases. The results of this combined study are expected to be known in the first half of 2017.

In both studies, the chemotherapy regimen used is Folfox (oxaliplatin plus 5FU and
leucovorin), with or without the biologic agents bevacizumab or cetuximab (prescribed at the investigators’ discretion).

The FOXFIRE study enrolled more than 360 patients at 32 cancer centers in the United Kingdom. It was initiated in 2008 by the Oxford Oncology Clinical Trials Office in collaboration with the UK National Cancer Research Institute. The FOXFIRE Chief Investigators are Professor Ricky Sharma, MD, Consultant Clinical Oncologist at the Oxford University Hospitals NHS Trust, and Harpreet Wasan, MD, Consultant and Reader in Medical Oncologist at Imperial College Healthcare, Hammersmith Hospital in London.

In the company’s press release, Prof. Sharma commented, “Despite significant advances we have made in treating this disease with chemotherapy and biologically targeted therapies, optimizing the care for patients with colorectal cancer that has spread to the liver remains a significant challenge in oncology. For rectal cancer, the combination of radiotherapy and chemotherapy is an established standard of care. Treating the liver with the same combination of treatments has been difficult due to the sensitivity of healthy liver tissue to radiotherapy. These exciting clinical trials combine a safe form of internally administered radiotherapy with routine chemotherapy. Recruiting over 1,000 patients to these trials represents an important step forward in determining whether targeting these tumors with both treatments acting together is better than using chemotherapy on its own.”

Dr. Wasan added, “This is the reason why we needed to conduct definitive research in the early use of liver-directed radiotherapy with SIR-Spheres Y-90 resin microspheres in these patients. Completing enrolment in the FOXFIRE study is an important milestone in our work to address whether adding selective internal radiation therapy to first-line chemotherapy will provide an important gain in overall survival for patients with colorectal cancer liver metastases.”

Beginning in 2013, FOXFIRE Global enrolled more than 200 patients in a network of more than 80 centers in Australia, New Zealand, Asia Pacific, Israel, Western Europe, and the United States. The Principal Investigator of FOXFIRE Global is Professor Peter Gibbs, Associate Professor of Medical Oncology at the Royal Melbourne Hospital and Western Hospital in Melbourne, Australia.

Prof. Gibbs stated, “Completing these three studies was an enormous undertaking, but it is no less enormous than the need for more effective ways to treat colorectal cancer that has metastasized to the liver, which is the most common site of its spread and affects several hundred thousand patients worldwide each year. Obviously, we do not yet know if this combination of chemo-radiotherapy will prove successful in early treatment of mCRC, but we do know from published data that mCRC patients who no longer respond to chemotherapy have already benefitted from selective internal radiation therapy, or SIRT, as it is more widely known.”

SIR-Spheres Y-90 resin microspheres are used in interventional oncology to deliver selective internal radiation therapy (also known as radioembolization), a proven technology for inoperable liver tumors that delivers substantial, targeted doses of radiation directly to the cancer. Millions of SIR-Spheres Y-90 resin microspheres are infused via a catheter into the liver where they selectively target liver tumors with a dose of internal radiation up to 40 times higher than conventional radiotherapy while sparing the adjacent healthy liver tissue.

SIR-Spheres Y-90 resin microspheres have premarket approval from the US Food and Drug Administration and are indicated in the United States for the treatment of nonresectable metastatic liver tumors from primary colorectal cancer in combination with intrahepatic artery chemotherapy using floxuridine. 

SIR-Spheres Y-90 resin microspheres also have European CE Mark approval, as well as regulatory approvals in Australia, Argentina, Brazil, Switzerland, Turkey, and several other countries in Asia such as India, Korea, Singapore, and Hong Kong for the treatment of liver tumors that are unable to be removed through surgery, the company noted.