Shares in Clavis Pharma plummeted more than 90% yesterday as investors panicked on news that Clovis Oncology called time on the development of its partnered cancer drug.

Clovis unveiled data from the LEAP (Low hENT1 and Adenocarcinoma of the Pancreas) trial in patients with metastatic pancreatic cancer, which showed no difference in overall survival between patients receiving the drug CO-101 (also known as CP-4126), and those given the chemotherapy gemcitabine.

CO-101 is a lipid-conjugated form of gemcitabine made with Clavis' proprietary Lipid Vector Technology.

It was hoped that the modified drug would benefit pancreatic cancer patients with low levels of the hENT1 protein, as this was previously believed to prevent chemotherapy from entering tumour cells.

However, the trial showed that, contrary to the results of numerous published retrospective studies, the hENT1 status of patients seemed to have no impact on survival for patients taking gemcitabine, the firm noted.

"We are obviously disappointed with these results, which are unambiguous,” said Patrick Mahaffy, president and chief executive of Clovis.

Development suspended

Consequently, the firm said it will suspend all development of CO-101, pending further evaluation of the LEAP data, focusing its resources on the three product candidates in its portfolio instead.

“The results from the LEAP study are surprising and disappointing given the evidence we have seen from previous studies reported in the literature," said Olav Hellebø, CEO of Norwegian drugmaker Clavis.

Clavis said it will continue to focus on elacytarabine and its CLAVELA Phase III study in patients with acute myeloid leukaemia, but investor confidence in the group's technology has evidently been badly shaken by the failure of CO-101.