Akorn announced FDA approval of a supplemental Biologics License Application for a unit dose preservative free Tetanus Diphtheria vaccine. Akorn expects to launch this new vaccine in the first quarter of 2008. In March 2007, Akorn announced that it had entered into an exclusive distribution agreement with Massachusetts Biologic Laboratories for Tetanus Diphtheria vaccine. Since September 2007, Akorn has been marketing a multi-dose preserved version of the Tetanus Diphtheria vaccine. This new approval will allow Akorn to effectively compete in the estimated $225 million US market.