Objective Response Rate (ORR) in the liver was a secondary endpoint of the SIRFLOX study. SIR-Spheres® Y-90 resin microspheres in combination with first line chemotherapy, versus chemotherapy alone, showed a significant increase of 9.9% in ORR in the liver and a three-fold improvement in complete response rate (CR) in the liver.1
Listen to Dr. Peter Gibbs discussing liver response rate and resection rate of SIR-Spheres Y-90 resin microspheres treated patients from the SIRFLOX Study.
Dr. Gibbs key comments and takeaways:
- Dr. Gibbs notes that the resection rate varied across SIRFLOX study sites. However, he observed that for a study population with unresectable liver disease, a resection rate of 14% was quite high. He believes this higher than normal resection rate may be a function of the study protocol, which required patients be continually reviewed and considered for liver resection.
- Liver surgeons seem to be reluctant to operate on Selective Internal Radiation Therapy (SIRT) treated patients, but Dr. Gibbs expects that surgeons will eventually learn that it is safe to operate on patients who have received SIRT. Dr. Gibbs’ policy is to not operate within six months of SIRT treatment, just in case the ongoing damage from the SIRT procedure compromises the surgery.
- Apart from a surgeon’s potential reluctance to operate, Dr. Gibbs also points out that there was a significant liver Complete Response rate (CR) of 6% among SIRFLOX patients who received SIR-Spheres Y-90 resin microspheres in combination with first line chemotherapy. In case of a CR, Dr. Gibbs would rather wait to resect these patients, as these are often durable treatment effects.
Listen to Dr. David Liu discussing liver resection rate after SIR-Spheres Y-90 resin microspheres treatment.
Dr. Liu’s key comments and takeaways:
- Dr. Liu notes that a recent large retrospective study called P4S* (The post SIR-Spheres surgery study), which discussed the safety of surgery post treatment with SIR-Spheres Y-90 resin microspheres, may help to allay surgeons’ fears of operating post SIRT in the appropriate patients.
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