Thanks for the dating post, neuro. This means the wholesaler or distributor who shipped these vials to you still had 08/04 production in stock.
One poster here (a MS patient)reported seeing a 12/05 expiration date on 01/31/05, his last infusion date. This means to me (and should to anyone who accepts as fact that standard procedure in the industry is to ship the oldest product first) that the wholesaler or distributor who shipped a 12/05 vial to the infusion site for this patient had no more 11/05 vials to ship. It also means that ELN/BIIB had no more 11/05 vials as of 1/31/05.
A 12/05 expiration date means the product was produced in 09/04. Now I'm waiting for the date an end user first sees a 01/06 expiration date.
Assuming you use the same wholesaler, neuro, I'm curious to track my FIFO (first-in-first-out) theory. If the same wholsaler sends you 12/05 vials then two weeks later sends you 11/05 vials, that blows away the FIFO theory with respect to that wholesaler.
Even though tracking dates different expiration dates are seen at the end user level may not give us a perfect system of tracking consumption vs production, it will give us a rough approximation at the BIIB/ELN level.
Please, all end users, report the expiration date on the vial and the date you saw it. I will be keeping score.