Depth of Response – Concept
The Depth of Response (DpR) concept, a new methodology, aims to relate the degree of observed tumour shrinkage to post-progression survival. DpR is measured by tracking the percentage of tumour shrinkage at its lowest point, or nadir, compared with baseline.1 DpR has been shown to correlate with overall survival (OS) and post-progression survival in earlier mCRC studies.2
Adapted from Heinemann V et al. ESMO WCGIC, Ann Oncol 2016; 27 (Suppl 2): Abs. O-014.
Depth of Response in the Liver
In SIRFLOX, the addition of SIR-Spheres® Y-90 resin microspheres in combination with first line chemotherapy significantly increased hepatic DpR.3
The treatment effect following SIR-Spheres Y-90 resin microspheres was most evident in patients with a greater baseline liver tumour burden (>12% of the liver having been replaced by tumour, a statistical cut-point that was pre-determined in order to identify potential predictors of DpR). This group of more compromised patients, representing over half the patients in SIRFLOX, experienced a statistically significant, 20% greater DpR (77.5% vs. 57.2%; p=0.003) compared to those treated with chemotherapy alone.3 Additionally, patients who received SIR-Spheres Y-90 resin microspheres demonstrated an increase of over 100 days in Time to Nadir.
bev*: bevacizumab (bevacizumab allowed at investigator’s discretion, per institutional practice)
No statistically significant improvement of PFS at any site
1. Mansmann UR et al. J Clin Oncol 2013; 31 (Suppl): Abs 3630.
2. Heinemann V et al. Eur J Cancer 2015; 51: 1927–1936.
3. Heinemann V et al. ESMO WCGIC, Annals of Oncology 2016; 27 (Suppl 2): Abs. O-014.