Sandeep Dhanda, Deborah Layton, Vicki Osborne, Saad Shakir

Background

A UK PASS examined the safety and use of deferasirox prescribed in primary care in England. Deferasirox is an oral iron chelating agent indicated for treating chronic iron overload from repeated blood transfusions in patients (pts) with beta thalassaemia major and chelation therapy in other non-transfusion-dependent thalassaemias. Whilst dosing recommendations for elderly pts (≥65 yrs) are the same as for younger age groups (2 yrs+), research has shown higher frequency of adverse reactions in the former. Closer monitoring for adverse events is recommended for this pt subgroup.

Objectives

A supplementary analysis to examine the utilisation and safety of deferasirox in pts aged ≥65 yrs.

Methods

An observational cohort study. Pts identified from dispensed prescriptions (Rx) of deferasirox Sept 06-Sept 14. Outcome data collected from prescribing general practitioners via questionnaires sent ≥6 months after 1st dispensed Rx. Summary descriptive statistics calculated; % denominator ≥65 yr subgroup, unless specified.

Results

Evaluable cohort=122 pts (median age 23 yrs (IQR 11-61)). Twenty-seven pts aged ≥65 yrs (22.1% cohort); 17 male (63.0%). Starting dose specified for 12 pts ≥65 yrs (44.4%); 8 initiated on 10mg/kg/day and 4 pts on 20mg/kg/day. Frequent reasons for prescribing include myelodysplastic syndrome (n=13), iron overload (n=3) and aplastic anaemia (n=2). Majority of pts had treatment initiated by a specialist (n=22, 81.5%). Serum creatinine (SCr) was reported for 6 pts ≥65 yrs (22.2%) prior to starting; 3 were > reference range (female >90 μmol/L; male >110 μmol/L). SCr was also reported for 6 pts after starting treatment, exceeding the reference in 3 female pts (66-75 yrs, SCr 96-116µmol/L; baseline (bl) unknown) and 1 male pt (78 yrs, SCr 137 µmol/L; bl unknown). There was also an additional report of an increased SCr in a 74 yr old female pt without prior renal disease (SCr 135μmol/L; bl SCr 69μmol/L). A positive de-challenge was observed and the event was reported as a suspected adverse reaction to deferasirox.

Conclusion

These results show that deferasirox is being prescribed in older adults in England, with limited evidence of systematic monitoring in this pt subgroup. Despite recommendations for at least once monthly monitoring, missing data on renal measurements both prior to starting and during treatment were observed, in addition to events of raised SCr. Considering the small cohort of older adults, results should be put into context with other research evidence.