Immunomedics has reported data from Phase Ib/II study of Yttrium-90-labelled clivatuzumab tetraxetan and gemcitabine in advanced pancreatic cancer.

The data has suggested that repeated cycles of fractionated doses of clivatuzumab tetraxetan, labelled with yttrium-90 (90Y) and given in combination with gemcitabine, demonstrated therapeutic activity in pancreatic cancer patients. 100 patients with previously untreated stage III or IV pancreatic cancer were dosed with gemcitabine once a week × 4 with 90Y-clivatuzumab tetraxetan on weeks two, three and four (therapy cycle).

In Part I of this study, 38 patients were treated with 90Y-clivatuzumab tetraxetan and a low, fixed gemcitabine dose of 200mg/m² × 4 for radiosensitisation, the company said. The overall disease control rate by CT-based RECIST criteria, was 58%, including six patients (16%) with partial response (PR) and 16 patients (42%) with stable disease (SD) as best response.

In the open-label trial, the median overall survival (OS) for the 38 treated patients was 7.7 months, which compares favourably with other regimens for advanced pancreatic cancer. At the higher therapy doses (12 and 15mCi/m² of 90Y-clivatuzumab tetraxetan × 3), a median OS of eight months was noted. For the 13 patients who received repeated cycles of the combination therapy, median OS improved to 11.8 months.

52 patients were treated in part II of this study to receive three weekly 90Y doses of 12mCi/m² and gemcitabine doses of 200, 600 or 1,000mg/m² × 4. The disease control rates for 200, 600 and 1,000mg/m² groups were 72%, with 19% PR and 53% SD, 63% (0% PR) and 68% (18% PR), respectively.

Immunomedics president and CEO Cynthia Sullivan said the part II trial results continue to support the use of antibody-directed radiation therapy with 90Y-clivatuzumab tetraxetan in patients with pancreatic cancer.