Prospective, open‐label, and observational study of cetuximab for metastatic colorectal carcinoma: The OPTIM1SE study

Abstract

AbstractAimThe OPTIM1SE study observed long‐term real‐world outcomes of cetuximab‐based infusional 5‐fluorouracil (5‐FU) regimens for first‐line treatment of metastatic colorectal cancer (mCRC) across Asia‐Pacific and Middle East regions, aiming to characterize their use, effectiveness, and safety in routine practice.MethodsOPTIM1SE was a prospective, open‐label, observational study. Patients with untreated KRAS wild‐type mCRC and distant metastases were treated per locally approved labels and monitored for 3 years via electronic medical records. The primary endpoint was the overall response rate (ORR). Secondary endpoints included safety, progression‐free survival (PFS), and overall survival (OS).ResultsFrom November 19, 2013, to June 30, 2016, 520 patients were enrolled in 51 sites. Patients were mostly male (61.2%), with a mean age of 58.5 (±12.0) years; 420 patients received leucovorin, 5‐FU, and irinotecan–based regimens and 94 received leucovorin, 5‐FU, and oxaliplatin. The most common primary tumor site was the rectum (38.8%), with liver metastases (65.0%). ORR was 45.4% (95% CI, 41.1%–49.7%), including 26 patients (5.0%) with a complete response. Median PFS was 9.9 months (95% CI, 8.2–11.0); median OS (mOS) was 30.8 months (95% CI, 27.9–33.6). Higher mOS was associated with tumors of left compared with right‐sided origin (hazard ratio, 0.69 [95% CI, 0.49–0.99]); higher ORR was also associated with liver metastases compared with all other metastases (55.4% vs. 40.2%). Adverse events were consistent with the known safety profile of cetuximab.ConclusionCetuximab‐based 5‐FU regimens were effective first‐line treatments for mCRC in routine practice, particularly in patients with left‐sided disease and liver metastases only.