There has been a mixed response to mid-stage data on Roche's closely-watched Alzheimer’s disease drug crenezumab.

Data presented at the Alzheimer’s Association International Conference (AAIC 2014) in Copenhagen showed that crenezumab did not meet its primary endpoints for cognition and activities of daily living (function). There was, however, a positive finding in a subgroup of the study population with mild AD who received the drug by intravenous (IV) infusion.

Crenezumab is an anti-beta amyloid antibody, licensed by Roche from AC Immune, that targets these protein fragments that are believed to play a central role in AD. However, it has yet to be established exactly what role beta amyloid plays in the disease and there have been failures in this area, notably with Johnson & Johnson/Pfizer’s bapineuzumab.

Jeffrey Cummings of the Cleveland Clinic, who presented the results in Copenhagen, said “we did see significant effects of the agent on patients with mild AD”, adding that “in every Alzheimer’s trial, we learn new information about the disease. These findings represent a new path to explore for future research and clinical trials”.

Carole Ho, head of early clinical development in neurology at Roche's Genentech unit, said the data was encouraging but the firm has yet to decide whether to proceed with Phase III trials. Sanford Bernstein analyst Tim Anderson issued a research note, saying that drugmakers do not put drugs into late-stage trials unless they have a 60%-70% chance of success, and crenezumab does not meet that.

However, Roche may persevere. “What drives this?” Mr Anderson wrote. “The tremendous size of commercial opportunity. As we have shown previously, a drug that successfully modifies AD progression could make Lipitor…look like a mid-sized product”.