Utilization of Biotechnological Drugs in Rare Diseases Requiring Use of Off-Label Drugs in Children in Turkey.

BACKGROUND/AIM Pediatric patients, especially with rare diseases, represents a population which has high tendency towards off-label drug use (OLDU) and needs a careful practice of pharmacotherapy than in adults. We aimed to investigate biotechnological drug use in children with rare diseases requiring OLDU. MATERIALS AND METHODS This retrospective study examined all single-diagnosed OLDU applications (n=5792) for 4992 children (<18-year) in Turkey. Applications of rare diseases were selected, and their descriptive characteristics were examined including demographic features of patients, biotechnological drug utilization status, and disease categories. The off-label status of the drugs at the end of 2020 was also examined. RESULTS In total, 77.7% (n=4501) of OLDU applications were made for rare diseases. Biotechnological drug use was higher in rare disease applications than in non-rare diseases (37.9% vs. 19.2%, respectively; p<0.0001). Canakinumab was the top applied biotechnological drug (73.2%). Compared to that in small-molecule drugs, the mean age of patients was higher in biotechnological drug-containing applications (8.1±5.3 vs 9.7±4.9, respectively; p<0.0001). Biotechnological drug use was higher in non-neoplastic rare diseases (40.3%) than in neoplastic rare diseases (26.4%), (p<0.0001). At the end of the year 2020, the approval status of the off-label indications covered in 2016 was significantly higher for rare (24.4%) vs. non-rare (5.2%, p<0.0001) diseases and for biotechnological (32.3%) vs. small-molecule (13.9%, p<0.0001) drugs. In total, 87.7% of the drugs would have to be still used in the off-label setting at the end of 2020. CONCLUSION It was seen that more than three-quarters of the pediatric OLDU applications are for rare diseases and the need for biotechnological OLDU in this group is almost 2-fold of small-molecule drug use. While further projected findings imply a higher approval tendency towards for rare diseases and biotechnological drugs, there seems to be more room for improvement for pediatric drug use.