Dr. Cremolini pointed out that the separation of the survival curves at 28 months suggests that the 40% of patients with left-sided tumors who survived only up until that time point receive an equal benefit from panitumumab and bevacizumab.
In contrast, the remainder who survived for longer showed better outcomes with panitumumab.
Overall, she said, in her opinion and based on the findings from other studies, the current results support the use of panitumumab plus mFOLFOX6 as first-line therapy in patients with microsatellite stable RAS wild-type and with BRAF wild-type left-sided mCRC.
Dr. Cremolini emphasized that patients should be warned that, if they opt for doublet chemotherapy plus bevacizumab, they could face a median 3.6-month loss in overall survival, as well as poorer treatment activity.
However, patients with high microsatellite instability should receive immunotherapy up front, she added, while those with BRAF mutations should be given FOLFOX upfront plus bevacizumab, followed by encorafenib plus cetuximab in the case of progression.
Dr. Cremolini ended by noting that there has, as yet, been no prospective comparison of doublet chemotherapy plus an anti-EGFR antibody with triplet chemotherapy plus bevacizumab in this population.
The study was funded by Takeda. Dr. Yoshino has reported relationships with Bayer Yakuhin, Chugai Pharmaceutical, Merck, and MSD. Dr. Eng has reported relationships with Bayer Health, Gilead/Forty Seven, GlaxoSmithKline, Hookipa Biotech, Mirati Therapeutics, Natera, Pfizer, Elevar, Fruquitinib, Merck, and Pfizer.
A version of this article first appeared on Medscape.com.