5PSQ-046 Efficacy and safety of panitumumab in metastatic colorectal cancer treatment

Background The use of panitumumab in the treatment of metastatic colorectal cancer (mCRC) remains controversial because of its risk/benefit profile. Purpose The aim of this study was to investigate the efficacy and safety of panitumumab in patients with wild-type KRAS gene in the treatment of mCRC. Material and methods For this retrospective and observational study, patients diagnosed with mCRC treated with panitumumab monotherapy and in combination with chemotherapy during the period from January 2009 to March 2017 were selected. Only patients treated with panitumumab for a period longer than 12 weeks were included in the study. The following variables were recorded: age, sex, line therapy, location of the primary tumour and metastases, treatment duration and adverse events associated with panitumumab. Treatment efficacy was assessed according to Response Evaluation Criteria In Solid Tumours (RECIST) ( criteria, progression-free survival (PFS) and global survival (GS). Panitumumab safety was assessed by adverse events described in the clinical history. Results A total of 33 patients (21 males) were included, whose average age was of 72±9,42 years and the treatment duration was 6.1±3 months. Patients were treated with panitumumab monotherapy (40%), in combination with FOLFOX (30%), with FOLFIRI (18%) or with other combinations (12%). Panitumumab was used as first-line therapy in 48% of the cases. Main locations of primary tumour were: colon (36%), sigma (31%), rectum (21%), rectum-sigma (9%) and cecum (3%). Hepatic metastases were developed by 63% of the patients. According to RECIST criteria, the assessment of efficacy was: partial response (40%), progressive disease (30%), stable disease (21%) and complete response (9%). Median PFS and GS were 4.5 and 17.3 months respectively. In combination with FOLFOX, 5.3 and 17.4 months, with FOLFIRI 4.6 and 17.1 months and in monotherapy 4.5 and 17.2 months. The most frequent adverse events were dermal toxicity (97%), diarrhoea (60%), hypomagnesaemia (27%), conjunctivitis (15%) and constipation (6%). Conclusion Panitumumab monotherapy, and in combination with chemotherapy, is effective and well-tolerated in the treatment of patients with mCRC, despite the high incidence of dermal toxicity. Although the number of patients is limited, results obtained are similar to published studies. References and/or acknowledgements https://ejhp.bmj.com/content/24/Suppl_1/A99.2 No conflict of interest.