SIR-Spheres microspheres (Sirtex) are safe and provide clinical benefit for patients with colon cancer liver metastases who have previously received liver-directed and systemic chemotherapy, according to the results of a prospective clinical study presented at the Society of Interventional Radiology (SIR) Annual Scientific Meeting (March 24–29, San Francisco, USA).
The data were presented by the interventional investigator Constantinos T Sofocleous in collaboration with Nancy Kemeny, GI medical oncologist, Memorial Sloan-Kettering Cancer Center, New York, USA.
The prospective single-center study assessed the safety, dose-limiting toxicities and the maximum tolerated dose of SIR-Spheres microspheres in a population whose cancer had progressed despite hepatic arterial and systemic chemotherapy treatments. Over the two year period, from September 2009-2011, 19 patients received SIR-Spheres microspheres in three escalating dose levels. The first group received 70%, the second group received 85%, and the third group received 100% of their specific calculated dose. Common side effects from the SIR-Spheres microspheres were mild-to-moderate (grade 1 or 2) fatigue and mild (grade 1) fever, which were self-limiting and transient. One patient experienced grade 3 nausea and pain, and two patients had elevated bilirubin levels attributed to progressive disease.
Evaluations 4-8 weeks post-treatment showed 12 patients (65%) with stable disease, while five (29.4%) saw disease progression. Median progression-free and overall survival were 6 (95% ci:3.2-9.7) and 16 (95% ci:5.8-17.6) months, respectively. All patients received further chemotherapy, 9 further HAI therapy, with 4 having a decrease in CEA.
“This study helps to confirm that we need to identify more effective treatment options for patients with colorectal liver metastases,” said Sofocleous. “These results have met our expectations regarding safety of SIR-Spheres in heavily pre-treated patients with good liver functions.”
Based on these findings, researchers concluded it is safe to administer the entire dose of SIR-Spheres microspheres in patients with colon cancer metastases who progressed despite prior pump and systemic chemotherapy.