Not a lot of evidence is available to support the role of maintenance strategies after induction treatment therapies in patients with metastatic colorectal cancer. Panitumumab, a human monoclonal antibody, is known to be effective against wild-type RAS metastatic colorectal cancer. This study aims to compare the efficacy of maintenance therapy with panitumumab alone vs. maintenance therapy with panitumumab with fluorouracil-leucovorin.

This randomized, open-label phase 2 noninferiority trial included a total of 229 patients with RAS wild-type, unresectable metastatic colorectal adenocarcinoma who did not receive any previous treatment. The patients were randomly assigned in a 1:1 ratio to receive panitumumab plus fluorouracil-leucovorin (arm A) or panitumumab only (arm B). The primary outcome of the study was 10-month progression-free survival (PFS).

At a median follow-up of 18.0 months, a total of 169 disease progression or death events were reported. Arm B was found to be inferior to arm A. The 10-month PFS was 59.9% in arm A vs. 49.0% in arm B. However, arm A had a higher incidence of trade 3+ adverse events (42.2% vs. 20.3%).

The research concluded that maintenance therapy with panitumumab with fluorouracil-leucovorin was superior to panitumumab alone, but it also had greater adverse events.