Characteristics of efficacy evidence supporting approval of supplemental indications for prescription drugs in United States, 2005-14: systematic review

Abstract

Objective: To characterize the types of comparators and endpoints used in efficacy trials for approvals of supplemental indications, compared with the data supporting these drugs' originally approved indications.

Design: Systematic review.

Setting: Publicly accessible data on supplemental indications approved by the US Food and Drug Administration from 2005 to 2014.

Main outcome measures: Types of comparators (active, placebo, historical, none) and endpoints (clinical outcomes, clinical scales, surrogate) in the efficacy trials for these drugs' supplemental and original indication approvals.

Results: The cohort included 295 supplemental indications. Thirty per cent (41/136) of supplemental approvals for new indications were supported by efficacy trials with active comparators, compared with 51% (47/93) of modified use approvals and 11% (7/65) of approvals expanding the patient population (P<0.001), almost all of which related to pediatric patients (61/65; 94%). Trials using clinical outcome endpoints led to approval for 32% (44/137) of supplemental approvals for new indications, 30% (28/93) of modified indication approvals, and 22% (14/65) of expanded population approvals (P=0.29). Orphan drugs had supplemental approvals for 40 non-orphan indications, which were supported by similar proportions of trials using active comparators (28% (11/40) for non-orphan supplemental indications versus 24% (10/42) for original orphan indications; P=0.70) and clinical outcome endpoints (25% (10/40) versus 31% (13/42); P=0.55).

Conclusions: Wide variations were seen in the evidence supporting approval of supplemental indications, with the fewest active comparators and clinical outcome endpoints used in trials leading to supplemental approvals that expanded the patient population.

Fig 1 Construction of study sample

Fig 2 Supplemental indications approved by the FDA for novel therapeutic agents, 2005-14. Types of supplemental indications: new indication denotes no similar use was ever previously approved for agent (for example, drug initially approved for schizophrenia, now approved for bipolar mania); modified indication denotes agent previously approved for different aspect of same indication (for example, drug initially approved for adjunctive therapy in treatment of partial onset seizures, now indicated for use as monotherapy in this condition); expanded patient population denotes agent previously approved for same indication in different group of patients (for example, drug previously indicated for treatment of Crohn’s disease in adults, now approved for use in all patients aged 6 years and older).