A Phase II, open-label, randomised study to assess the efficacy and safety of the MEK1/2 inhibitor AZD6244 (ARRY-142886) versus capecitabine monotherapy in patients with colorectal cancer who have failed one or two prior chemotherapeutic regimens.

Objectives To assess the efficacy and safety of the MEK1/2 inhibitor AZD6244 (ARRY-142886) in patients with metastatic colorectal cancer who had failed one or two previous chemotherapeutic regimens that included oxaliplatin and/or irinotecan. Methods This was a Phase II, multicentre, open-label, randomised, two-arm, parallel-group study comparing AZD6244 with capecitabine monotherapy. Patients received either 100 mg twice daily oral AZD6244 free-base suspension every day or 1,250 mg/m2 twice daily oral capecitabine, for 2 weeks, followed by a 1-week rest period, in 3-weekly cycles. The primary endpoint was the number of patients experiencing disease progression events. Results Sixty-nine patients were randomised in the study (34 and 35 patients in the AZD6244 and capecitabine groups, respectively). Disease progression events were experienced by 28 patients (∼80%) in both the AZD6244 and capecitabine treatment groups. Median progression-free survival was 81 days and 88 days in the AZD6244 and capecitabine groups, respectively. Ten patients in the AZD6244 treatment arm had a best response of stable disease. For capecitabine, best response was a partial response in one patient, with stable disease in a further 15 patients. The most frequently observed adverse events reported with AZD6244 were acneiform dermatitis, diarrhoea, asthenia and peripheral oedema, compared with hand-foot syndrome, diarrhoea, nausea and abdominal pain with capecitabine. Conclusions AZD6244 showed similar efficacy to capecitabine in terms of the number of patients with a disease progression event and of progression-free survival. AZD6244 is currently undergoing evaluation in Phase II trials in combination with other chemotherapeutic agents.