In long-awaited guidance released Friday (March 23), FDA laid out a two-part test on how the agency will determine whether there is a clinical need for 503B compounders to make drugs with bulk substances, rather than FDA-approved drugs. FDA will consider a number of factors that go beyond whether using an FDA-approved drug as a base would cause complications for patients, including the physical and chemical structure of the substance and its history of use. In a document accompanying the...