November 2, 2005

Human Genome Sciences reported that the results of a Phase II clinical trial demonstrate that HGS-ETR1 (mapatumumab) is well-tolerated and can be administered safely in patients with advanced colorectal cancer.

The results were presented at the European Cancer Conference, being held in Paris. The trial, which was conducted in Germany, was an open-label study to evaluate the efficacy, safety and tolerability of HGS-ETR1 as monotherapy in patients with relapsed or refractory colorectal cancer. Data were presented on 38 patients with relapsed or refractory Stage IIIb, IV or recurrent colorectal cancer. Patients enrolled in the trial received up to six cycles of treatment in the absence of disease progression. HGS-ETR1 was administered as an intravenous infusion at 20 mg/kg at 14-day intervals in cycles 1 and 2, and at 10 mg/kg at 14-day intervals in cycles 3-6.

The primary objective of the study was to evaluate tumor response after every third treatment (approximately every six weeks). Safety and tolerability were assessed as secondary endpoints. Several additional indicators of disease activity also were evaluated, including time to response, duration of response, and progression-free survival. Plasma concentrations of HGS-ETR1 were determined for use in a population pharmacokinetic analysis.