Clinical application of Web Accessible Population Pharmacokinetic Service—Hemophilia (WAPPS‐Hemo): Patterns of blood sampling and patient characteristics among clinician users Journal Articles uri icon

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  • AbstractBackgroundUse of population pharmacokinetics (PopPK) to facilitate PK‐informed prophylaxis in clinical practice has gained momentum among haemophilia providers due to the accessibility of tools such as the Web Accessible Population Pharmacokinetic Service—Hemophilia (WAPPS‐Hemo) and availability of extended half‐life (EHL) factor concentrates. It is unknown how clinicians implement PopPK.AimTo investigate the evolution of PopPK use in clinical practice by comparing blood sampling strategies, patient features, and factor group between initial and recent periods of WAPPS‐Hemo availability.MethodsPK data for haemophilia A and haemophilia B patients from two time periods were extracted from the WAPPS‐Hemo database: early availability (10/2015‐09/2016) and recent use (10/2017‐09/2018). We compared patient characteristics (age, body weight, haemophilia type), product type and dose, and blood sampling times between the time frames.ResultsOver 1900 eligible infusions were submitted to WAPPS‐Hemo during the periods studied, with 85% representing FVIII concentrates. In the recent cohort, PK profiles were requested for younger patients (median age 18 vs 26 years), with increased proportional EHL FVIII use (29% vs 14% of infusions). High‐use centres generally submitted fewer blood samples per infusion than non‐high‐use centres, although the number of samples collected by non‐high‐use centres decreased significantly over time. During both periods, blood sample timing was generally consistent with ISTH recommended windows.ConclusionThe use of WAPPS‐Hemo by haemophilia providers grew by over threefold between the time periods investigated. While sampling times have included key time points proposed first by Björkman since early WAPPS‐Hemo usage, a trend towards minimizing sampling was observed.


  • McEneny‐King, Alanna
  • Yeung, Cindy HT
  • Edginton, Andrea N
  • Iorio, Alfonso
  • Croteau, Stacy E

publication date

  • January 2020