Table 1. Frequencies and publication percentages of candidate determinants.
| N in analysis (% published) | |
|---|---|
| All trials included in the analysis | 574 (58.2%) |
| Sponsor | |
| Pharmaceutical industry | 352 (59.1%) |
| Investigator (industry (co-)funded) | 71 (52.1%) |
| Investigator (no industry funding involved) | 151 (58.9%) |
| Phase | |
| Phase 1 | 119 (34.5%) |
| Phase 2 | 130 (60.0%) |
| Phase 3 | 172 (72.7%) |
| Phase 4 | 57 (56.1%) |
| Other than phase 1–4* | 96 (60.4%) |
| Applicant | |
| Contract research organization | 214 (50.0%) |
| Investigator or company | 360 (63.1%) |
| Centers | |
| Single center | 249 (45.4%) |
| Multi center only in the Netherlands | 54 (53.7%) |
| Multi center in the Netherlands and the EU | 82 (68.3%) |
| Multi center in the Netherlands and outside the EU | 189 (72.0%) |
| Therapeutic effect expected | |
| Therapeutic effect expected† | 356 (64.6%) |
| No therapeutic effect expected | 218 (47.7%) |
| Type of trial | |
| Intervention | 517 (59.8%) |
| Invasive observational‡ | 45 (42.2%) |
| Non-invasive observational | 12 (50.0%) |
| Approval status of drug(s) in trial | |
| Unapproved drug(s) in trial | 306 (54.6%) |
| All drugs in trial approved, studied outside approved indication | 147 (65.3%) |
| All drugs in trial approved and studied within approved indication | 121 (58.7%) |
| Drug type | |
| Regular medicinal product | 549 (57.7%) |
| Special drug category involved§ | 25 (68.0%) |
| Participant category | |
| ≥18 years old and mentally capacitated | 532 (58.6%) |
| <18 years old and/or mentally incapacitated | 42 (52.4%) |
| Disease area | |
| Oncology | 113 (66.4%) |
| Other disease areas | 461 (56.2%) |
| Prospective registration|| | |
| Prospectively registered | 215 (74.9%) |
| Not (prospectively) registered | 359 (48.2%) |
| Completion | |
| Completed as planned | 472 (63.6%) |
| Terminated early | 102 (33.3%) |
*Studies not primarily intended to provide information about the drug, nor conducted within the context of a drug development program.
† Trials were regarded as therapeutic if it is reasonable to assume that participation will be of direct clinical benefit to the subject.
‡ In observational trials, the investigator does not seek to change the observed situation, but simply to describe and record it as accurately as possible. Invasive procedures concern the penetration of the skin or mucosa with the aid of instruments, X-rays or magnetic resonance, or the introduction of an instrument into the body, or psychologically invasive observational research, involving the experimental creation of an unaccustomed situation which may give rise to negative emotions in the subject.
§ Vaccine, radiopharmaceutical, somatic cell therapy, antisense oligonucleotide.
|| Prospective registration was defined as registration of the trial at www.clinicaltrials.gov or www.isrctn.com, at latest one month after IRB-approval.