V. Osborne, M. Davies, D. Layton, S. Shakir

Background

Deferasirox is an oral iron chelating agent (ICA) primarily used to reduce chronic iron overload in patients (pts) receiving blood transfusions for various chronic anaemias and some non- transfusion dependant anaemias. Use in patients 2yrs+ is licensed for certain indications. An identified safety concern is increased serum creatinine (Cr) during treatment (Rx); monitoring is therefore recommended prior to and during Rx.

Objectives

To examine the utilisation and safety of deferasirox used in general practice in England.

Methods

Single exposure observational cohort study. Pts identified from dispensed prescriptions for deferasirox. Prescriptions collected Sep06-Sep14. Outcome data collected via postal questionnaires sent to prescribers ≥6mths after 1st dispensed prescription, including information on prior Cr measurements and prior use of alternative ICAs. Summary descriptive statistics calculated.

Results

Evaluable cohort=122 pts (2-17yrs=51, 41.8%); Median age=23yrs (IQR11-61); 58.2% male. Frequent reasons for prescribing (underlying conditions leading to iron overload): sickle cell anaemia (27/103 where specified,26.2%) and beta thalassaemia (BT) (26,25.2%); 53.8% BT pts had frequent blood transfusions (≥7ml/kg/mth packed red blood cells). Most pts (43/51,84.3%) were prescribed licensed doses of 10 or 20mg/kg/day at start. Rx initiated by a specialist for 100 pts (100/103,97.1%). 18 serum Cr values reported prior to Rx; 4 in excess of reference range [median value of all prior serum Cr 69μmol/L (IQR51-95)]. Events reported in these 4 pts included raised ferritin and renal function decline. In total, 91 incident events were reported, including 2 raised serum Cr after starting Rx. 45.6% pts (26/57) used an alternative ICA in the 12 months prior to Rx; 80.8% desferrioxamine.

Conclusion

These results show that deferasirox is largely being prescribed for its licensed indications in general practice in England and events reported were consistent with the known safety profile. These results contribute to post-marketing information. However, considering the small cohort size, any conclusions from this study should be put into context with results from other studies.