Effect of intravenous calcium and magnesium (IV CaMg) on oxaliplatin-induced sensory neurotoxicity (sNT) in adjuvant colon cancer: Results of the phase III placebo-controlled, double blind NCCTG trial N04C7

Carolyn Vachani, RN, MSN, AOCN
The Abramson Cancer Center of the University of Pennsylvania
Last Modified: June 4, 2008

The addition of oxaliplatin to the arsenal of therapies for GI cancers has had a profound effect on survival, but not without additional side effects. In particular, neuropathy has resulted in delays and reduction in doses and more importantly, resulted in poor quality of life for those affected. Researchers have determined that oxaliplatin-related neuropathy resembles muscle abnormalities such as mytonia and tetany, which are thought to be related to a decrease in calcium (Ca) and magnesium (Mg) levels. Small studies used Ca and Mg intravenous infusions to prevent oxaliplatin-induced neuropathy with some success. This presentation reviewed a large phase III study in which Ca and Mg infusions were used in the hopes of preventing this side effect.

The study was ultimately closed early, with 102 of a planned 300 patients being evaluated. The study was closed because another trial suggested that Ca and Mg infusions may decrease the efficacy of oxaliplatin. Participants received either Ca/Mg infusion or placebo along with standard chemotherapy. Patients were assessed using an NCI scale, a scale specific to oxaliplatin related neuropathy and a quality of life scale. The infusion group performed better on both side effect scales. Percent of participants with grade 2 or higher neuropathy on the NCI scale: 22% for Ca/Mg group versus 41% for the placebo group. On the oxaliplatin specific scale, grade 2 or higher neuropathy was seen in 28% for Ca/Mg group versus 51% for the placebo group. As for quality of life ratings, there was a trend towards improved swallowing and muscle cramps in the Ca/Mg group, but these differences were not yet statistically significant, which may be due to the smaller-than-expected sample size.

The suggestion that the addition of Ca/Mg may affect response rates by the CONCEPT study has dampened the results of this study, but there were some questions of how response was evaluated in the study. Further studies are needed to clarify this issue as this study has clearly shown that Ca/Mg infusions can provide benefit and could possibly lead to fewer dose reductions.