Immunomedics Updates ADC Results

Immunomedics, Inc. received encouraging results from a Phase I dose-escalation trial of its proprietary antibody-drug conjugate (ADC), labetuzumab-SN-38, or IMMU-130, in patients with metastatic colorectal cancer.

Results from 15 very advanced patients who were progressing after prior therapies, including irinotecan, were presented at the European Cancer Congress. Only five patients to date have been evaluated after completing therapy with four or more doses of the ADC, administered once every two weeks, with the rest having advancing disease that precluded further therapy. At this early stage of clinical development, IMMU-130 has produced a partial response in one patient with a duration of response of 4.7 months, or 140 days. This patient had failed multiple prior therapies, including irinotecan.

The maximum tolerated dose for the once-every-2-weeks dosing schedule has been confirmed to be below 24 mg/kg. This study has moved to a dose expansion stage to evaluate lower doses given once or twice weekly. As many as 10 clinical sites may participate in this new study. No human anti-humanized antibodies have yet been detected. Serum analysis revealed a quicker removal of the intact conjugate compared with the parent antibody, due in part to the intended release of SN-38 from the ADC.