The FDA admits there are "serious" concerns on the safety of the injection, and that there is a need for long term safety data. From the BLA approval letter: POSTMARKETING REQUIREMENTS UNDER SECTION 505(o) Section 505(o) of the Federal Food, Drug, and Cosmetic Act (FDCA) authorizes FDA to require holders of approved drug and biological product applications to conduct postmarketing studies and clinical trials for certain purposes, if FDA makes certain findings required by the statute (section 505(o)(3)(A), 21 U.S.C. 355(o)(3)(A)). We have determined that an analysis of spontaneous postmarketing adverse events reported under section 505(k)(1) of the FDCA will...