Cetuximab-induced hypomagnesemia in patients with colorectal cancer.
BACKGROUND
Cetuximab treatment has been associated with severe hypomagnesemia, but the predisposing factors and management of this toxicity have been poorly characterized.


METHODS
The charts of 114 patients with colorectal cancer treated with cetuximab were reviewed. Forty-eight evaluable patients had normal magnesium levels before initiation of cetuximab and >or=1 repeat magnesium level during cetuximab treatment. The incidence, grade, and management of hypomagnesemia were described in the evaluable population.


RESULTS
Among the evaluable population, 13 patients developed grade 3/4 hypomagnesemia (27%). The incidence of grade 3/4 hypomagnesemia was 6%, 23%, and 47% in patients receiving < 3 months, 3-6 months, and > 6 months of cetuximab therapy, respectively. Grade 3/4 hypomagnesemia was refractory to oral supplementation and required daily to 3-times-weekly intravenous magnesium sulfate supplementation at 6-10 g per dose. Recovery or amelioration in hypomagnesemia occurred approximately 4 weeks after cetuximab discontinuation.


CONCLUSIONS
Severe hypomagnesemia is a frequent side effect of cetuximab therapy. Treatment of hypomagnesemia requires frequent intravenous magnesium supplementation and can be associated with significant patient inconvenience and an increased risk of venous access-related complications. Intermittent cetuximab schedules need to be investigated in order to reduce the frequency and severity of hypomagnesemia.
Fakih
Marwan G
MG
Department of Medicine, Roswell Park Cancer Institute, Buffalo, NY 14263, USA. marwan.fakih@roswellpark.org
Wilding
Gregory
G
Lombardo
Jeffrey
J
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000911:Antibodies, Monoclonal / Q000009:adverse effects*; D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents / Q000009:adverse effects*; D000068818:Cetuximab; D015179:Colorectal Neoplasms / Q000188:drug therapy*; D005260:Female; D006801:Humans; D006996:Hypocalcemia / Q000139:chemically induced; D007008:Hypokalemia / Q000139:chemically induced; D008274:Magnesium / Q000008:administration & dosage / Q000097:blood*; D008297:Male; D008875:Middle Aged; D012189:Retrospective Studies
D000911:Antibodies, Monoclonal; D061067:Antibodies, Monoclonal, Humanized; D000970:Antineoplastic Agents; D008274:Magnesium; D000068818:Cetuximab