Rare disease registries: potential applications towards impact on development of new drug treatments.

BACKGROUND: Low prevalence, lack of knowledge about the disease course, and phenotype heterogeneity hamper the development of drugs for rare diseases. Rare disease registries (RDRs) can be helpful by playing a role in understanding the course of the disease, and providing information necessary for clinical trial design, if designed and maintained properly. We describe the potential applications of a RDR and what type of information should be incorporated to support the design of clinical trials in the process of drug development, based on a broad inventory of registry experience. We evaluated two existing RDRs in more detail to check the completeness of these RDRs for trial design. RESULTS: Before and during the application for regulatory approval a RDR can improve the efficiency and quality in clinical trial design by informing the sample size calculation and expected disease course. In exceptional circumstances information from RDRs has been used as historical controls for a one-armed clinical trial, and high quality RDRs may be used for registry-based randomized controlled trials. In the post marketing phase of (conditional) drug approval a disease-specific RDR is likely to provide more relevant information than a product-specific registry. CONCLUSIONS: A RDR can be very helpful to improve the efficiency and quality of clinical trial design in several ways. To enable the applicability and optimal use of a RDR longitudinal data collection is indispensable, and specific data collection, prepared for repeated measurement, is needed. The developed checklist can help to define the appropriate variables to include. Attention should be paid to the inclusion of patient-relevant outcome measures in the RDR from the start. More research and experience is needed on the possibilities and limitations of combining RDR information with clinical trial data to maximize the availability of relevant evidence for regulatory decisions in rare diseases.

Dose increase needed in most cystic fibrosis lung transplantation patients when changing from twice- to once-daily tacrolimus oral administration.

AIM: The aim of this pharmacokinetic (PK) study was to evaluate tacrolimus (TAC) exposure in stable cystic fibrosis (CF) lung transplant (LT) recipients, converted from TAC twice daily to TAC once daily in an open-label, prospective, single-centre study. METHODS: Eligible patients were post-transplant CF patients (18-65 years) with stable lung function, on stable doses of TAC twice daily and who were candidates to switch to TAC once daily. Twelve consecutive patients were included in the study. Patients had their first PK analysis on day 1, still under the stable TAC twice-daily regimen, and were converted to TAC once daily from day 2 onwards. The doses were adjusted according to clinical judgement to achieve target levels, and a second 24-h PK period profile was obtained once the patient was on a stable dosage on the therapeutic range. RESULTS: The mean total (SD) daily dose of TAC twice daily at baseline upon enrolment was 0.17 (0.10) mg/kg/day. The mean (SD) daily dose of TAC once daily after adjustments was 0.22 (0.12) mg/kg/day. In order to achieve target C min levels with a similar AUC0-24, 82% of subjects who were converted to TAC once daily required an increase of dose, in a range of 0-66.7%, with a mean dose increase of 28%. CONCLUSIONS: Our study results indicate that the switch for conversion from TAC twice daily to TAC once daily in patients with CF may need dose adjustment in order to reach levels within the therapeutic target.