In the study, complete or partial responses in seven of 56 patients with metastatic melanoma showed durability ranging from four months to the longest still ongoing at over 34 months, with five of the seven responses ongoing for more than two years. These patients were treated with the investigational fully human anti-CTLA-4 antibody, MDX-010, in combination with MDX-1379, a gp100 melanoma vaccine.
The phase II clinical trial evaluated two dose regimens of MDX-010 in combination with MDX-1379. Of the 56 patients, 29 patients (cohort 1) received 3mg/kg intravenously over 90 minutes of MDX-010 and MDX-1379 every three weeks, and 27 patients (cohort 2) received an initial dose of 3mg/kg intravenously over 90 minutes of MDX-010 and MDX-1379, followed by subsequent doses of 1mg/kg of MDX-010 every three weeks.
Four of the 29 patients treated in cohort 1 experienced complete or partial responses. Two patients experienced complete responses that are ongoing at over 30 and 31 months, respectively, and two additional patients experienced partial responses, with one response lasting four months and the other ongoing at over 34 months.
In cohort 2, three of 27 patients experienced partial responses, with one partial response ongoing to six months and two partial responses ongoing at 25 and 26 months, respectively.
However, of the seven patients who experienced complete or partial responses in the phase II clinical trial, Grade III/IV events were reported in all five patients with ongoing duration of response greater than or equal to 25 months. All of the events were normalized or managed with medical treatment involving hospitalization, intravenous hydration, steroids, or other medical management.