Efficacy and Safety of Maintenance Therapy Using Cetuximab in Patients with Metastatic Colorectal Cancer: Retrospective Study

Tiantian Xuan,1 Zhanmei Wang,1 Sibo Meng,1 Jiaxin Li,1 Jisheng Li,2 Fangli Cao,1,* Linli Qu1,* 1Department of Medical Oncology, Qilu Hospital (Qingdao), Cheeloo College of Medicine, Shandong University, Qingdao, Shandong, People’s Republic of China; 2Department of Medical Oncology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, Shandong, People’s Republic of China*These authors contributed equally to this workCorrespondence: Fangli Cao; Linli Qu, Department of Medical Oncology, Qilu Hospital (Qingdao), Cheeloo College of Medicine, Shandong University, 758 Hefei Road, Qingdao, Shandong, 266035, People’s Republic of China, Tel +86-18561811936 ; +86-18561811457, Email caofangliqilu@163.com; qulinli2021@163.comPurpose: Cetuximab (CET) combined with chemotherapy significantly improved the survival in RAS and RAF wild-type metastatic colorectal cancer (mCRC) patients, while clinical evidence was lacking on the use of maintenance therapy (MT). The study aimed to explore the role of maintenance therapy following Cetuximab + chemotherapy and the optimal Cetuximab-based maintenance therapy regimen.Patients and Methods: We retrospectively reviewed data on the efficacy and safety of CET-based MT in patients with mCRC who achieved disease control after induction therapy.Results: Eighty-one patients with mCRC who achieved disease control after CET + chemotherapy induction were enrolled. Overall median progression-free survival (PFS) was 10.5 (95% CI = 8.8– 12.2) months and median maintenance/observation PFS (mnPFS) was 6.0 (95% CI = 5.0– 7.0) months. Among these 81 patients, 61 patients were prescribed MT (CET alone for 21 patients and CET + chemotherapy for 40 patients). Median PFS and mnPFS in the MT group were significantly longer than those for the non-MT group. Different MT regimens did not affect PFS and mnPFS significantly. Univariate and multivariate analysis demonstrated MT, complete response/partial response during induction therapy, and absence of peritoneal metastasis to be positively associated with longer PFS and mnPFS. Treatment-related adverse events (AEs) were tolerable during MT, and AE-related deaths were not observed.Conclusion: MT with CET or CET + chemotherapy was an appropriate option following initial induction chemotherapy for patients with RAS and RAF wild-type mCRC. This strategy endowed survival benefits and a tolerable safety profile.Keywords: colorectal cancer, maintenance therapy, cetuximab, RAS and RAF wild-type, targeted therapy