Clinical Development of Biologics Approved by the US Food and Drug Administration, 2003-2016

Biological therapies are increasingly common in the United States. Although their clinical development may deviate significantly from the classic paradigm used for small molecule drugs, there has been little systematic analysis of these programs. We describe the development programs and factors associated with approval in the first review cycle for biologics approved by the US Food and Drug Administration’s Center for Drug Evaluation and Research (FDA CDER) between 2003 and 2016.

We conducted a retrospective analysis of publicly available approval packages including clinical pharmacology/biopharmaceutics, medical and summary reviews, and approval letters for biologics approved by FDA CDER. We evaluated characteristics of the development program (eg, use of expedited pathways, clinical pharmacology studies, number and type of pivotal trials) and the prevalence and correlates of first cycle approval, a key indicator of successful product development.

We assessed 81 development programs for 75 unique therapies. Most programs (67%) made use of at least 1 expedited designation and about half (49%) were designated as orphan products. The clinical pharmacology programs were highly variable and one in four (25%) did not include an ascending dose study, where the tolerability of the therapeutic is typically determined before pivotal trials. Since 2003, an increasing proportion of biologics have been approved on first cycle approval and with fewer than 2 pivotal clinical trials (P < .001 for trend). Of the approximately three-fourths (76%) of products that were approved on the first review cycle, the likelihood of such approval was greater among development programs that performed an ascending dose study (84% vs 55%, P = .01) or held an End of Phase 2 meeting (85% vs 57%, P = .01).

Considerable regulatory flexibility, with respect to the number of pivotal trials and data supporting dosing, coincides with a growing number of biologics approved on an annual basis.