Serono said yesterday two Phase II trials of adecatumumab, a cancer drug licensed from US company Micromet, had missed their primary endpoints, but that it was not yet prepared to give up on the project.

The Swiss company, which recently agreed to be acquired by German drug and chemical group Merck KGaA, took comfort from the fact that adecatumumab (MT201) was able to delay the time to progression of disease, a secondary endpoint in the studies.

Adecatumumab is a fully human monoclonal antibody targeting tumour cells over-expressing the epithelial cell adhesion molecule (EpCAM), One trial involved patients with EpCAM-positive metastatic breast cancer, while the other was in relapsed, advanced prostate cancer.

The 109-patient breast cancer study showed that adecatumumab was most effective in increasing time-to-progression in patients whose tumours expressed high levels of EpCAM. And this is an important finding, said the trial’s principal investigator, Ahmad Awada of the Institut Jules Bordet in Belgium.

“Normally this patient population is believed to have a reduced overall survival compared to patients with low or no EpCAM expression,” he said.

Meanwhile, the prostate cancer study had been designed to measure serum levels of prostate-specific antigen (PSA), a marker for prostate cancer. While Serono’s drug did not meet its objective in reducing PSA, there was a trend towards an improvement, particularly with regard to PSA progression, said lead investigator Prof Axel Heidenreich of the University Hospital of Cologne in Germany.

Denise Anderson of Kepler Equities said the news was the latest in a “string of disappointing results for Serono from in-licensed oncology products,” including the demise of cancer vaccine CanVaxin last year, but should have no impact on the ongoing merger process with Merck.

The data were presented at the European Society of Medical Oncology (ESMO) meeting in Istanbul, Turkey.