AbbVie observes that FDA, in correspondence with the Senate Health, Education, Labor, and Pensions (HELP) Committee, indicated that the Purple Book (available here ), contains the information AbbVie alleges should be included in the biosimilar labeling. See Letter from T. Kraus to L. Alexander et al., 2 (June 22, 2015). In FDA's view, the Purple Book adequately informs prescribers of each biosimilar's reference product and interchangeability determination. However, AbbVie acutely criticizes FDA for taking the position that "a material omission in the [labeling] for Zarxio. .. can be [cured] from another, non-labeling source."