British Biotech plc and ImmunoGen Inc announced completion of the Phase I element of the PhaseI/II clinical study of BB-10901, a monoclonal antibody-based chemotherapy agent designed for the treatment of small cell lung cancer (SCLC).

The study, which is being conducted at two cancer research centers in the United States, is investigating once-weekly treatment with the agent.

Data from the Phase I portion of the study are to be presented today at an international medical conference in Frankfurt, Germany by Dr Anthony Tolcher of the Cancer Therapy and Research Center (CTRC) in San Antonio, Texas. Dr Tolcher, one of the study's Principal Investigators, will present the findings at the "Molecular Targets and Cancer Therapeutics" symposium, which has been organized jointly by the European Organization for Research and Treatment of Cancer (EORTC), the US-based National Cancer Institute (NCI) and the American Association for Cancer Research (AACR). In addition to the CTRC, patients in the Phase I study were treated at the University of Texas MD Anderson Cancer Center in Houston.

Dr Tolcher's poster presentation concludes that BB-10901 can be safely and feasibly administered for repetitive courses at doses comparable to those that produced anti-tumor activity in pre-clinical models. The Phase I study has determined the maximum tolerated dose (MTD) to be 60mg/m2 under the dosing regimen studied. At this dose level and below, toxicities were modest (in particular, no haematological toxicity was observed) and preliminary evidence of anti-tumor activity was noted.

Progression to Phase II is now being discussed with regulators in light of the findings in the Phase I portion.

A second Phase I study, to assess the safety and determine the MTD of BB-10901 when administered on a more frequent basis, is also being conducted in the United Kingdom.