Given the high-risk nature of eritoran, most analysts had already heavily risk-adjusted their forecasts for the drug, which before Tuesday sat at $477m by 2016. Decent revenues but not fully reflective of the potential market size - Eisai had estimated peak sales of $1bn while one Barclays analyst predicted sales of over $2bn in 2021 would be possible.
Assuming further trials are required, a minimum two-year delay to launch until 2014 can be expected which would significantly reduce current estimates. With a potential value of $1.33bn, according to 'EvaluatePharmas NPV Analyzer, representing up to 13% of Eisai's market capitalization, the stock could be in for a significant fall Wednesday. The news broke after the Tokyo stock exchange closed.
Either way the potential loss of eritoran is tough to take as Eisai grapples with the recent loss of US patent protection for its biggest drug, Aricept, the gold standard therapy for Alzheimer's disease which sold nearly $4bn last year – global sales are expected to halve by 2014.
