Desmopressin in haemophilia: The need for a standardised clinical response and individualised test regimen.

INTRODUCTION

Due to interindividual variation in desmopressin response, non-severe haemophilia A patients require desmopressin testing prior to therapeutic treatment. However, adequate response or frequency of blood sampling is not standardised in international guidelines. Consequently, various definitions and blood sampling protocols are currently applied. Interestingly, sustainability of desmopressin response is not incorporated into these definitions.

AIM

To study desmopressin response rates in a cohort of non-severe haemophilia A patients using currently accepted desmopressin response definitions. This, in order to formulate a standardised, uniform response which includes information on sustainability and to design a standardised blood sampling protocol.

METHODS

Currently used desmopressin responses in non-severe haemophilia A patients were derived from a literature search. Actual desmopressin response rates were individualised in 105 non-severe HA patients from the Erasmus University Medical Centre and classified according to current varying definitions.

RESULTS

Five response definitions were evaluated, three of which included only factor VIII (FVIII):C cut-off levels and two also incorporated FVIII:C-fold increase over baseline.

FVIII

C-fold increase showed no association with desmopressin response sustainability.

FVIII

C 1 hour after infusion (<0.30, ≥0.30-0.49, ≥0.50-0.79 and ≥0.80 IU/mL) was, however, indicative of desmopressin response after 6 hours.

CONCLUSION

We suggest standardised desmopressin response based on clinically relevant FVIII:C levels, e.g. 0.30 and 0.50 IU/mL. In addition, patients with <0.30 IU/mL FVIII:C after 1 hour (non-responder) or ≥0.80 IU/mL (sustained responder) do not require subsequent blood sampling. However, patients with ≥0.30-0.79 IU/mL FVIII:C after 1 hour should undergo blood sampling after 6 hours to additionally determine response sustainability.