Shares in Ark Therapeutics Group have soared on promising data from a preliminary analysis of a late-stage trial of its gene-based brain cancer drug Cerepro.

A Phase III study of Cerepro (adenovirus-mediated Herpes simplex virus-thymidine kinase gene) for the treatment of operable primary malignant glioma demonstrates that the treatment “resulted in significant improvements in median survival on the primary endpoint (survival) compared with various control groups”, Ark said.

In the trial, 236 patients were randomised to either standard care [surgery and radiotherapy or surgery and radiotherapy followed by Schering-Plough’s Temodar (temozolomide)], plus Cerepro or standard care alone. The group given Cerepro and temozolomide showed an improvement of 68% in median survival time compared with standard care surgery and radiotherapy controls (350 days versus 208).

On the secondary endpoints, which include magnetic resonance imaging-based progression, all-cause mortality, safety and quality of life, the effects of Cerepro have yet to be established, Ark said, with around 45% of patients still alive. “Data from a further time point analysis are needed to fully elucidate this,” the firm added, and an updated analysis will be conducted in January next year.

David Eckland, R&D director at Ark, said the data is “in keeping with our experience and expectation of the product and we now have further evidence to show Cerepro has an anti-cancer effect”. He added that the next step is to complete the full analysis and meet with “our European Medicines Agency rapporteur to determine the way forward.”

Nigel Parker, the company’s chief executive, noted that Cerepro “is the first gene therapy product to successfully reach its primary endpoint in a major Phase III trial”. He acknowledged that “with a number of patients in the trial still to report an event, there is a substantial amount of further information to come” but claimed that Ark’s adenoviral delivery technology “has the potential to deliver a new era of gene-based therapies for acute and chronic human disease”.

Investors shared his enthusiasm and Ark shares ended the day up almost 69% to over 80 pence. However the firm’s rating was reduced to 'hold' from 'buy' by analysts at Landsbanki who described the data as mixed. The broker said it believes the EMEA will want the complete data set for making any recommendations.