During the review process, the FDA evaluated TYSABRI® safety data primarily from the ongoing Phase III MS 6 A Sponsor may apply for accelerated approval of a biological product for serious or life- threatening illnesses if the drug candidate has the potential to address an unmet medical need. See 21 C.F.R. § 601.40-51; see also Am. Compl. ¶¶ 83-85. 7