Glembatumumab vedotin is well tolerated in heavily pretreated patients with breast cancer and may be effective in some patients with glycoprotein NMB (gpNMB)-expressing breast cancer, a new study published online early in the Journal of Clinical Oncology has shown.
For the phase II study, researchers enrolled 124 patients with refractory breast cancer that overexpressed gpNMB, a negative prognostic marker.
Participants were randomly assigned 1:1 to receive glembatumumab vedotin or investigator’s choice chemotherapy.
Results showed that the overall response rate was 6% for the glembatumumab vedotin group versus 7% for the chemotherapy group.
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Unplanned analysis showed an objective response rate of 18% in the glembatumumab vedotin group versus 0% in the chemotherapy group in patients with triple-negative breast cancer (TNBC).
In those with gpNMB-overexpressing TNBC, the objective response rates were 40% and 0% in the glembatumumab and chemotherapy groups, respectively.
Preliminary findings were presented at the 36th Annual San Antonio Breast Cancer Symposium in San Antonio, Texas in 2013.