Eisai and partner Pfizer have received some very good news from regulators in the USA who have given the green light to a higher-dose version of their Alzheimer’s disease drug Aricept.

The US Food and Drug Administration has approved a new once-daily, higher-dose Aricept (donepezil) 23mg tablet for the treatment of moderate-to-severe AD. The approval is based on data from a large head-to-head study of Aricept 23mg versus the 10 mg tablet in over 1,400 patients whereby the new version demonstrated a statistically significant improvement in cognition, but not in global function, as compared to Aricept 10mg.

Eisai quoted Martin Farlow of the Indiana University School of Medicine and lead author of the study, noted that “slowing the decline of cognitive symptoms is important at all stages of AD. He pointed out that caregivers are usually the first to notice changes in cognition and they need to speak to the doctor “to re-evaluate therapeutic needs”.

The green light comes at an opportune time for Eisai, which earlier this year expected annual US sales of Aricept to fall 60% to $800 million from $2 billion between 2011 and 2013. The patent on the drug is due to expire in November 2010.

However, the Japanese drugmaker hopes that the higher dose, plus a patch formulation of donepezil, will help soften the blow, as patients may be switched to the new products before the arrival of generics.