519P - Cetuximab plus capecitabine versus cetuximab as maintenance treatment in Chinese patients with RAS/BRAF wild type metastatic colorectal cancer (mCRC): A phase III, multicenter, open-label, randomized study (C-CLASSIC study)

Background

Cetuximab and capecitabine are both standard first-line treatment options for RAS/BRAF wt mCRC patients. However, no phase III clinical trial data are currently available for the combination of cetuximab and capecitabine as maintenance treatment. Here we present the data of 80 Chinese RAS/BRAF wt mCRC patients in the C-CLASSIC study.

Methods

RAS/BRAF wt mCRC patients who achieved disease control after first-line induction therapy with 9 cycles of FOLFOX plus cetuximab were randomized (1:1) to receive maintenance treatment with cetuximab + capecitabine (Arm A) and cetuximab alone (Arm B) . The primary endpoint was maintenance progression free survival (mPFS), and secondary endpoints included overall survival (OS), quality of life (QoL) and safety. This study was terminated early due to the speed of enrollment.

Results

By December 31, 2023, 80 patients were randomized to Arms A (n=42) and B (n=38). Primary tumors were left-sided in 74 patients (92.5%), and 81.3% of patients achieved PR or CR after induction treatment. After a median follow-up of 14.0 m, mPFS were 7.3 m (95% CI 5.32-11.24) and 5.3 m (95% CI 3.02-7.46) in Arms A and B, respectively [HR 0.61 (95% CI 0.365-1.011)]; median OS were 30.5 m (95% CI 19.09-NA) and 22.5 m (95% CI 13.01-NA), respectively [HR 0.58 (95% CI 0.271-1.242)].The QoL did not deteriorate further in either treatment group versus baseline. Grade ≥3 TRAEs were detected in 36.6% and 13.2% of Arms A and B, respectively.

Conclusions

Maintenance therapy with cetuximab + capecitabine showed a trend of improved efficacy compared with cetuximab in RAS/BRAF wt patients.

Clinical trial identification

NCT04262635.

Editorial acknowledgement

Legal entity responsible for the study

R. Xu.

Funding

This study was funded by Merck Serono, Beijing, China, an affiliate of Merck KGaA; Natural Science Foundation of Guangdong Province (No.2019A1515011786); The National Natural Science Foundation of China (82172711); The National Natural Science Foundation of China (82321003, 81930065, 82173128).

Disclosure

All authors have declared no conflicts of interest.