Description of the protocols for randomized controlled trials on cancer drugs conducted in Spain (1999-2003).
OBJECTIVE
To describe the characteristics of randomized controlled clinical trials (RCT) on cancer drugs conducted in Spain between 1999 and 2003 based on their protocols.


METHODS
We conducted an observational retrospective cohort study to identify the protocols of RCTs on cancer drugs authorized by the Agencia Española del Medicamento y Productos Sanitarios (AEMPS) (Spanish Agency for Medicines and Medical Devices) during 1999-2003. A descriptive analysis was completed and the association between variables based on the study setting and sponsorship were assessed.


RESULTS
We identified a total of 303 protocols, which included 176,835 potentially eligible patients. Three-quarter of the studies were internationally-based, 61.7% were phase III, and 76.2% were sponsored by pharmaceutical companies. The most frequently assessed outcomes were response rate (24.7%), overall survival (20.7%), and progression-free survival (14.5%). Of all protocols, 10.6% intended to include more than 1000 patients (mean: 2442, SD: 2724). Compared with their national counterparts, internationally-based studies were significantly larger (p<0.001) and were more likely to implement centralized randomization (p<0.001), blinding of the intervention (p<0.001), and survival as primary outcome (p<0.001). Additionally, most internationally-based studies were sponsored by pharmaceutical companies (p<0.01). In a high percentage of protocols, the available information was not explicit enough to assess the validity of each trial. Compared to other European countries, the proportion of Spanish cancer drugs protocols registered at www.clinicaltrials.gov (7%) was lower.


CONCLUSIONS
RCTs on cancer drugs conducted in Spain between 1999 and 2003 were more likely to be promoted by pharmaceutical companies rather than by non-profit national groups. The former were more often part of international studies, which generally had better methodological quality than national ones. There are some worldwide on-going initiatives that aim to increase the transparency and quality of future research.
Iberoamerican Cochrane Centre, Sant Pau Biomedical Research Institute (IIB Sant Pau), Barcelona, Spain ; CIBER Epidemiología y Salud Pública (CIBERESP), Barcelona, Spain ; Universitat Autònoma de Barcelona, Barcelona, Spain.
Xavier
X
Bonfill
Mónica
M
Ballesteros
Ignasi
I
Gich
María Antonia
MA
Serrano
Fernando
F
García López
Gerard
G
Urrútia
D000970:Antineoplastic Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D000971:Antineoplastic Combined Chemotherapy Protocols / Q000627:therapeutic use; D002985:Clinical Protocols; D006801:Humans; D009369:Neoplasms / Q000188:drug therapy*; D016032:Randomized Controlled Trials as Topic; D012189:Retrospective Studies; D013030:Spain; D016896:Treatment Outcome
D000970:Antineoplastic Agents