Background The prevalence of off-label use is not well established. The indications for such uses have not been collected, neither has the literature that supports them.
Purpose To establish the prevalence of off-label use of certain chemotherapy drugs.
To list the off-label indications.
To analyse the references that support them.
Materials and methods A retrospective, descriptive study was conducted. Treatments with 11 antineoplastic labelled drugs were collected during 2012: alemtuzumab, azacitidine, bendamustine, bevacizumab, bortezomib, cetuximab, fotemustine, panitumumab, pemetrexed, rituximab and trastuzumab. Exclusion criteria: clinical trial treatments and oral medicines. We recorded: prescriber service, type of tumour, disease stage, line and combination treatment in an Excel database. If any of these last four variables did not match with the conditions approved by the Spanish or European regulatory agencies, it was considered off-label. In these cases, the support by the Food and Drug Administration (FDA), Micromedex Drugdex or other source, was recorded.
Results The prevalence of off-label use in the ninety-one treatments analysed was 20.9% (95% CI: 1.1–30.7%). Three prescriber services were involved: haematology 54.9%, oncology 42.9% and internal medicine 3.3%. Of this last one, all treatments were off-label, while for haematology and oncology off-label represented 22.4% and 12.8%, respectively of their totals. Off-label indications of each drug are shown in Table 1. Bevacizumab, cetuximab and panitumumab did not show any off-label treatment. Of the 19 off-label treatments, the 42.1% were FDA-approved indications, another 42.1% were cited in Micromedex and the remaining 3.3% by other literature.
Conclusions One in five of analysed treatments in 2012 were off-label. All treatments prescribed by internal medicine were off-label, all indicated for non onco-hematologic systemic diseases. In 84.2% of cases, all uses were supported by prestigious literature sources. These data show that comprehensive assessment is needed when off-label treatments are prescribed.
No conflict of interest.
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