P-361 Safety and Efficacy of Short Cetuximab Infusion for Patients with Metastatic Colorectal Cancer

Cetuximab is an FDA approved anti-EGFR monoclonal antibody that is given to patients with metastatic colorectal cancer (mCRC) who are KRAS and NRAS wildtype (wt). Dosing of cetuximab when given with FOLFOX or FOLFIRI chemotherapy is standard at 500mg/m2 given over 120 minutes as an infusion every 2 weeks (when q2weekly dosing is preferred). During the Covid19 pandemic, we attempted to reduce infusion times of non-chemotherapy agents with the aim of reducing cancer patient chair/visit time as per national and global recommendations. We retrospectively reviewed all patients who received cetuximab 500mg/m2 dose at a 60 minute infusion duration every 2 weeks with chemotherapy. Adverse events and infusion reactions were reported, and outcome measures including objective response rates (ORR). A total of 91 patients were included with mean age of 56 years. The majority were males (51; 56%) and had a performance status of 1 (67; 74%). De novo metastatic disease was found in 59% of patients, with liver (51%) followed by lung (20%) being the most common metastatic disease sites affected. Left sided primary tumors affected 45% of patients, followed by rectal at 37% followed by right sided primary tumors affecting 18% of patients. Adenocarcinoma was the primary pathology, and mucinous histology affecting 11% of patients. All patients had KRAS, and NRAS wildtype disease, with 3 being microsatellite unstable followed by 2 BRAF mutant, followed by 1 HER2 amplified tumors. Cetuximab was given with a variety of chemotherapy regimens, with FOLFIRI being the most common at 68%, followed by irinotecan alone at 17%, followed by FOLFOX at 9%, followed by FOLFOXIRI at 3%. All patients received cetuximab at an infusion duration of 60 minutes with dose of 500mg/m2. Median number of cycles was 11 (range 1-30). Objective response rate (ORR = CR + PR) when cetuximab was given as first-line therapy was 69% and disease control rate (DCR = CR + PR + SD) was 71%, whereas when cetuximab was given as second-line therapy and beyond (2nd to 7th line) the ORR was 21% and DCR 30%. Adverse events attributed to cetuximab were acneiform rash affecting the majority of patients at 89% (CTCAEv5 grades 1-2) followed by hypomagnesemia affecting 27% of patients (grades 1, 2, and 3). Dose reductions occurred in 9% of patients. No infusion related reactions were seen with cetuximab infusions given at 60 minutes. Short infusion duration of cetuximab at a dose of 500mg/m2 given over 60 minutes (instead of 120 minutes) was found to be safe in our cohort of patients. This led to shorter visit and chair time during the covid19 pandemic. This has the potential of saving time on chemotherapy chair, and associated healthcare costs.