Table 1.
Description of protocols and study designs. Figures are numbers (percentages) unless stated otherwise
| Characteristic | Data | |
|---|---|---|
| Type of cancer (n=93 protocols): | ||
| Breast | 20 | (21.5) |
| Small cell lung | 10 | (10.8) |
| Acute myeloid leukaemia | 9 | (9.7) |
| Colorectal | 8 | (8.6) |
| Hodgkin's disease | 7 | (7.5) |
| Non-Hodgkin's lymphoma | 7 | (7.5) |
| Non-small cell lung | 4 | (4.3) |
| Multiple myeloma | 4 | (4.3) |
| Other* | 24 | (25.8) |
| Date closed (n=93 protocols): | ||
| 1981-5 | 35 | (37.6) |
| 1986-90 | 28 | (30.1) |
| 1991-5 | 30 | (32.3) |
| Reason closed (n=93 protocols): | ||
| Reached recruitment target | 86 | (92.5) |
| Interim analysis | 7† | (7.5) |
| No of arms (n=103 randomisations): | ||
| 2 | 77 | (74.8) |
| 3 | 20 | (19.4) |
| ≥4 | 6 | (5.8) |
| Type of control (n=103 randomisations): | ||
| Active | 86 | (83.5) |
| Placebo or observation‡ | 17 | (16.5) |
| Sidedness of hypothesis test used in power calculations (n=97 randomisations that provided power calculations):
| ||
| 1 | 49 | (50.5) |
| 2 | 40 | (41.2) |
| Not specified | 8 | (8.3) |
| Power (n=94 randomisations that provided a unique study power):
|
|
|
| <0.80 | 3 | (3.2) |
| 0.80-0.84 | 62 | (66.0) |
| 0.85-0.89 | 15 | (16.0) |
| ≥0.90 | 14 | (14.9) |
| Alpha error (n=97 randomisations that provided power calculations)§:
|
|
|
| ≤0.025 | 6 | (6.2) |
| 0.026-0.05 | 47 | (48.5) |
| 0.051-0.10 | 39 | (40.2) |
| >0.10 | 5 | (5.2) |
| Effect size used in power calculations (n=88 randomisations for which a planned effect size could be calculated)¶:
| ||
| ≤1.25 | 2 | (2.3) |
| 1.26-1.50 | 42 | (47.7) |
| 1.51-1.75 | 27 | (30.7) |
| 1.76-2.0 | 13 | (14.8) |
| >2.0 | 4 | (4.6) |
| Median (interquartile range) | ||
| Duration of study accrual (years) (n=93 protocols)** | 4.3 | (3.2-5.3) |
| Ratio of actual to planned accrual duration (n=93 protocols)** | 1.2 | (1.0-1.8) |
| Sample size, total (n=103 randomisations) | 299 | (204-465) |
| Sample size, per arm (n=103 randomisations) | 125 | (92-184) |
| Ratio of actual to planned sample size (n=103 randomisations) | 1.0 | (1.0-1.1) |
Includes acute lymphoblastic leukaemia (3), melanoma (3), sarcoma (3), chronic lymphocytic leukaemia (3), prostate (2), bladder (2), pancreas (1), head and neck (1), ovarian (1), germ cell (1), oesophageal (1), renal-cell (1), thyroid (1), and myelodysplastic syndrome (1).
Four of these favoured experimental arm.
Participants had received active treatment before randomisation in 15 of 17 studies with placebo/observation control.
Two sided equivalent. Where sidedness was unspecified, we assumed power calculations involved two sided alpha errors.
Indicates hazard ratios for time to event comparisons, and response rate ratios for response comparisons.
Denominator is 86 studies (94 randomisations). Excludes studies that closed early on basis of interim data.