in which they reported that panitumumab and cetuximab pro-vide similar overall survival and toxicity profi les as would be expected in heavily pretreated patients with colorectal cancer. Their results also showed that the incidence of grade 3 or 4 hypomagnesaemia was greater in patients receiving panitumumab than in those receiving cetuximab, although the incidence of severe skin toxicities was similar in the two groups. A meta-analysis of randomised studies that included panitumumab and cetuximab in the treatment of several cancer types showed that risk of the hypo-magnesaemia to be even higher for panitumumab than for cetuximab.