Background: MDX-060 is a fully human anti-CD30 IgG1k monoclonal antibody that induces Fc-receptor mediated killing of CD30 expressing cell lines and inhibits the growth of CD30-expressing tumor cells in a murine xenograft model. We previously reported data from the first 31 patients in a Phase I/II open-label, dose escalation study of MDX-060 in patients with relapsed or refractory CD30+ lymphomas. The purpose of the study is to determine the safety and tolerability profile of the drug, and to preliminarily evaluate efficacy. We now update the findings of this study, including reporting the results of a new higher dose cohort.

Methods: In the Phase I portion of the study, MDX-060 was administered intravenously at dose levels of 0.1, 1, 5, or 10 mg/kg weekly for 4 weeks to cohorts of 3–6 patients. In the Phase II portion of the study additional patients were administered MDX-060 intravenously at 10 (n=10) or 15 (n=17) mg/kg weekly for 4 weeks. Responses were assessed at month 2.

Results: To date, MDX-060 has been administered to 48 patients; 40 with Hodgkin’s disease (HD), 6 with anaplastic large cell lymphoma (ALCL) and 2 with other CD30 positive lymphomas. MDX-060 has been well tolerated, and a maximum tolerated dose has not been identified. There were 2 drug-related serious adverse events, 1 patient in the 1 mg/kg dosing cohort had Grade 3 elevated liver transaminase, and 1 patient in the 15 mg/kg cohort had Grade 3 pneumonia/Grade 4 ARDS. Objective clinical responses have been observed in 5 patients. Two patients had complete responses; 1 patient with ALCL in the 1 mg/kg cohort lasting 100 days, and 1 patient with HD in the 15 mg/kg cohort lasting 117 days. Retreatment of the ALCL patient with MDX-060 resulted in a second complete response. Three patients had partial responses; 1 patient with HD in the 5 mg/kg cohort lasting 92 days, and 1 patient with HD in the 15 mg/kg cohort, which is continuing at 176 days. In addition, 1 patient with ALCL in the 15 mg/kg cohort had a partial response. Stable disease was observed in 17 patients following MDX-060 administration with a median duration of 132 days (range:15–387 days). Baseline soluble CD30 levels in the plasma were evaluated, but did not appear to correlate with clinical outcome.

Conclusions: Preliminary evidence indicates MDX-060 to be well tolerated in heavily pre-treated patients with CD30+ lymphomas, with minimal toxicity, and with clinical activity observed at 1 mg/kg, 5 mg/kg and 15 mg/kg. Additional patients are being accrued at 1 mg/kg and 5 mg/kg to more accurately assess efficacy at these dose levels.

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