Table 1. Time to Initiation of Confirmatory Studies for Products Granted Accelerated FDA Approval From 2009 to 2019^a.

	No. (%)b			P value
	All product-indication pairs	Cancer product–indication pairs	Noncancer products
Confirmatory studies underway at time of accelerated approvalc
Yes	92 (71.88)	79 (78.22)	13 (48.15)	.008
No	26 (20.31)	16 (15.84)	10 (37.04)
Unable to identify	10 (7.81)	6 (5.94)	4 (14.81)
Time to start of confirmatory study, median (IQR), yd	1.41 (1.10-2.04)	1.20 (0.63-1.45)	2.11 (2.00-2.47)	.02

Abbreviation: FDA, US Food and Drug Administration.

^a Instances were excluded if postmarketing requirements solely evaluated a drug’s safety, products were duplicates (eg, approvals were for different product formulations or expanded patient populations), or manufacturers were released from postmarketing requirements (eg, due to safety or submitting other confirmatory studies for a product’s conversion).

^b Seventy-two drugs (55 cancer, 17 noncancer) with 103 indications (86 cancer; 17 noncancer) were granted accelerated approval from 2009 to 2019.

^c χ² Tests were used to compare the confirmatory studies underway at the time of accelerated approval for cancer product–indication pairs and noncancer products. If multiple confirmatory studies were being conducted for a postmarketing requirement, then we selected the earliest confirmatory study.

^d Time from accelerated approval to start of the confirmatory study was calculated for the postmarketing requirements that were not underway at the time of accelerated approval. Mood median tests were used to compare median time to start confirmatory studies between cancer product–indication pairs and noncancer products.