Table 1.

Phase III trial closures by accrual sufficiency status

Phase III trials, n (%)
All (N = 238)Therapeutic (n = 181)Nontherapeutic (n = 57)
Sufficient accrual158 (66)121 (67)37 (65)
 Documented closure with complete accrual134 (56)101 (56)33 (58)
 Closed at interim analysis with positive results9 (4)8 (4)1 (2)
 Closed at interim analysis with negative results12 (5)10 (6)2 (3)
 Closed because of toxicity3 (1)2 (1)1 (2)
Insufficient accrual80 (34)60 (33)20 (35)
 Documented closure due to inadequate accrual rate70 (29)52 (29)17 (30)
 Closed because of external data obviating need for trial6 (3)6 (3)0
 Closed because of trial agent shortage2 (1)1 (0.5)1 (2)
 Closed because of manufacturer withdrawing support for trial agent2 (1)1 (0.5)1 (2)