Medication adherence assessment: high accuracy of the new Ingestible Sensor System in kidney transplants

Abstract

Background: This open-label single-arm exploratory study evaluated the accuracy of the Ingestible Sensor System (ISS), a novel technology for directly assessing the ingestion of oral medications and treatment adherence.

Methods: ISS consists of an ingestible event marker (IEM), a microsensor that becomes activated in gastric fluid, and an adhesive personal monitor (APM) that detects IEM activation. In this study, the IEM was combined to enteric-coated mycophenolate sodium (ECMPS). Twenty stable adult kidney transplants received IEM-ECMPS for a mean of 9.2 weeks totaling 1227 cumulative days.

Results: Eight patients prematurely discontinued treatment due to ECMPS gastrointestinal symptoms (n=2), skin intolerance to APM (n=2), and insufficient system usability (n=4). Rash or erythema due to APM was reported in 7 (37%) patients, all during the first month of use. No serious or severe adverse events and no rejection episode were reported. IEM detection accuracy was 100% over 34 directly observed ingestions; Taking Adherence was 99.4% over a total of 2824 prescribed IEM-ECMPS ingestions. ISS could detect accurately the ingestion of two IEM-ECMPS capsules taken at the same time (detection rate of 99.3%, n=2376).

Conclusions: ISS is a promising new technology that provides highly reliable measurements of intake and timing of intake of drugs that are combined with the IEM.

Figures

FIGURE 1

Elements of the ingestible sensor system.

FIGURE 2

Mean timing adherence over time (periods of APM impedance

FIGURE 3

Representative example of an individual patient adherence profile and system functionality records. D, day; h, hour. *For APM activation, each dot represents an APM continuously active for 24 hr. The absence of a dot between days 42 and 49 indicates that the patient was not wearing the patch during this period. **Phone–server connection reports the longest time interval between two connections of the smartphone with the server on each day. For this patient, this time varied between 30 min and 24 hr, indicating difficulties with mobile network access. †Patch–phone connection reports the longest time interval between two connections of the APM with the smartphone on each day. This time interval varied also between 30 min and 24 hr, indicating that the smartphone was not carried permanently by the patient in proximity of the APM. However, because the data were stored on the APM, the APM data were still communicated to the smartphone and then to the server at least once a day. ‡Detection of daily medication ingestion was 100% during the entire study period. §Adherence to the prescribed time of intake fluctuated between 100%, 50% (one of the two daily intakes was not on time), and 0% (time missed for both daily intakes). ¶Dosing interval was the time between morning and evening intakes and oscillated around 12 hr, indicating the absence of major time deviation from the prescribed schedule for medication taking.