Progression-Free Survival at Any Site
PFS at any site was the primary endpoint of the SIRFLOX study. The results did not show a statistically significant improvement of PFS at any site. SIR-Spheres® Y-90 resin microspheres are a liver-directed therapy and do not have an effect on metastases outside the liver.1
Progression-Free Survival in the Liver
The SIRFLOX study indicates that SIR-Spheres Y-90 resin microspheres in combination with first line chemotherapy, versus chemotherapy alone, significantly extended PFS in the liver by 7.9 months and resulted in a 31% reduction in risk of progression in the liver. PFS in the liver was a secondary endpoint in the SIRFLOX study.1
Subanalysis of patients stratified by hepatic tumor burden
The treatment effect following SIR-Spheres Y-90 resin microspheres was most evident in the patients with a greater baseline liver tumor burden (>12% of the liver having been replaced by tumor, a statistical cut-point that was pre-determined in order to identify potential predictors of Depth of Response).
In this group of more compromised patients, SIR-Spheres Y-90 resin microspheres was associated with a doubling of median PFS in the liver by competing risk analysis (27.2 vs.13.1 months; p=0.003).2
Patients who had a smaller liver tumor burden (≤12%) on study entry were more than six times as likely to experience a complete response or disappearance of all liver tumors following SIR-Spheres Y-90 resin microspheres compared to those who received only chemotherapy (11.3% vs.1.7%; p=0.003).2
bev*: bevacizumab (bevacizumab allowed at investigator’s discretion, per institutional practice)
No statistically significant improvement of PFS at any site
1. van Hazel GA et al. J Clin Oncol 2016; 34: 1723–1731.
2. Heinemann V et al. ESMO WCGIC, Annals of Oncology 2016; 27 (Suppl 2): Abs. O-014.