Table 1.
Characteristics of completed and discontinued trials
| Clinical trial characteristics | Completed trials |
Discontinued trials |
All trials |
P |
|---|---|---|---|---|
| (n = 617), n (%) | (n = 127), n (%) | (n = 744), n (%) | ||
| Primary funding source | .01∗ | |||
| Academic institution | 213 (35) | 29 (23) | 242 (33) | |
| Industry | 404 (65) | 98 (77) | 502 (67) | |
| Intervention | .07† | |||
| Drug | 476 (77) | 110 (87) | 586 (79) | |
| Other | 54 (9) | 8 (6) | 62 (8) | |
| Behavioral | 50 (8) | 3 (2) | 53 (7) | |
| Device/procedure | 37 (6) | 6 (5) | 43 (6) | |
| Trial phase‡ | .06∗ | |||
| Phase 1 | 125 (20) | 23 (18) | 148 (20) | |
| Phase 2 | 201 (33) | 41 (32) | 242 (33) | |
| Phase 3 | 119 (19) | 38 (30) | 157 (21) | |
| Phase 4 | 61 (10) | 11 (9) | 72 (10) | |
| Unknown | 111 (18) | 14 (11) | 125 (17) | |
| Enrollment | <.0001† | |||
| <50 | 231 (37) | 64 (50) | 295 (40) | |
| 50–100 | 118 (19) | 16 (13) | 134 (18) | |
| 101–250 | 126 (20) | 16 (13) | 142 (19) | |
| >250 | 126 (20) | 30 (24) | 156 (21) | |
| Unknown | 16 (3) | 1 (1) | 17 (2) |
∗
Determined using χ2 test.
†
Determined using Fisher's exact test.
‡
Trials described as phase 1/2 (n = 19) were categorized as phase 2, and trials described as phase 2/3 (n = 15) were categorized as phase 3.