In a nutshell
This study compared the ability of two drugs, ganitumab and conatumumab, to treat patients with metastatic colorectal cancer when added to chemotherapy.
Some background
Cancer cells express various structures on their surface (called receptors) that may stimulate growth and help avoid destruction by the immune system. Drugs that target these structures are often utilized as cancer treatments in addition to chemotherapy. Conatumumab targets the death receptor (DR), which when activated cause cells to destroy themselves. Ganitumab target the insulin-like growth factor receptor (IGF1R), which normally stimulates cancer cells to grow more rapidly.
Many colorectal cancer cells have genetic mutations in the KRAS gene. This mutation sometimes provides the cancer with resistance to certain treatments. Only patients with KRAS gene mutations were involved in this study.
Methods & findings
Researchers recruited 155 patients with metastatic colorectal cancer (a cancer that has spread to other organs) and KRAS mutations. All patients were treated with chemotherapy (FOLFIRI combination chemotherapy). In addition to chemotherapy, 51 patients received conatumumab, 52 patients received ganitumab, and 52 patients received a placebo. 14% of the patients in the conatumumab group showed response to treatment, compared to 8% the ganitumab group and only 2% in the placebo group. Time until disease progression (called progression free survival, or PFS) was approximately two months longer in the conatumumab group compared to patients treated with ganitumab or a placebo. However, overall survival did not differ between the three treatment groups. In addition, patients treated with conatumumab reported more adverse side effects.
The bottom line
Conatumumab treatment in addition to chemotherapy showed a mild increase in progression free survival compared to ganitumab or a placebo. However, this did not translate into a benefit in overall survival.
The fine print
The statistical significance of the results shown in this trial was borderline. This means that there is some likelihood (a 14.7% chance) of the result occurring by chance alone. Further studies with a larger number of patients are needed to determine whether conatumumab treatment is truly beneficial.
What’s next?
Consult with your physician regarding conatumumab as addition to chemotherapy in the treatment of metastatic colorectal cancer.
Published By :
Annals of oncology
Date :
Jul 01, 2013
