Shares of Antisoma tumbled as much as 13% earlier this week as investors reacted with alarm to news that the company has changed its strategy for its oncology drug ASA404, effectively pitting the drug against Roche and Genentech’s big boy Avastin.

In an interim management statement, the company unveiled its partner Novartis’ new plans to test ASA404 in non-small cell lung cancer patients with both squamous and non-squamous types of the disease, in a pivotal Phase III trial due to start early next year.

Originally, the trial was just going to assess the drug’s potential in the squamous form of NSCLC, but inclusion of non-squamous patients – who are currently treated with Avastin (bevacizumab) - will more than double the drug’s market potential, the firms claim.

However, according to industry reports, investors are concerned about taking on Avastin, and that it may prove difficult to convince patients taking the therapy to switch over to ASA404 for a clinical trial, which could draw out the study’s duration. Nevertheless, Antisoma predicts that, should the Phase III trial be a success, applications to market the drug for NSCLC will be filed in 2010 or 2011.

Further disappointment came in the shape of a delay to the start of a Phase II trial of AS1411 in renal cancer, which was scheduled for the first half of 2008. According to the company, it intends to complete additional preclinical and toxicology work “to identify a safe and optimal approach to repeat dosing of AS1411” before finalising its plans.

On the flip side
But there was also good news too; A randomised mid-stage study of AS1411 in acute myeloid leukaemia is on target and initial data should be reported in the first half of next year, and the company said it is planning a trial of the drug in a third cancer indication, for which is expects to announce details early next year.

Furthermore, AS1402 looks set to enter a randomised Phase II trial assessing its use in breast cancer next year, and AS1409 should enter Phase I testing before the year is out.

And despite the setbacks, the company remains confident that it is poised for a successful year ahead. “We are making significant advances across our pipeline, and expect to achieve further important milestones during 2008,” commented Glyn Edwards, Antisoma’s chief executive. “With last-reported cash of over £60 million and a strong operational base, we are well placed both to maximise the value of our existing assets and to continue the growth of our business.”