84 days of successful daily observed dosing is just one example of the track record we can point to when asked about our capability of doing observed dosing in ambulatory outpatients. An example comes from a published study done in which we examined the effect of age on the half-life of a drug. The study involved both healthy young and elderly subjects (aged 18 to 40 and 65 and older, respectively). 

The drug in question was long-lived and the study involved two doses of the drug to determine whether there was a dose by age interaction. Each phase involved 22 days of treatment with each dose level to ensure that steady-state had been achieved. Good adherence with treatment was obviously critical to being able to answer the question. For this reason, subjects had to come to our clinical research unit every day for dosing and had to remain on the unit for two hours after dosing. 

We enrolled 21 and 17 healthy young and elderly subjects, respectively. We lost 3 (14 %) subjects in the young cohort because of failure to come to the unit daily and 0 subjects in the elderly cohort.

The study successfully detected that the half life of the drug was 50% longer in the healthy elderly versus young volunteers and further confirmed the relevance of that finding to the magnitude and duration of specific cytochrome P450 enzyme inhibition caused by the study drug. Those findings were of immediate relevance to safe clinical use of the drug and were made possible to a large degree by our ability to do observed dosing with a high degree of adherence and with the ability to terminate the small percentage of participants who were unable to meet the adherence required by the study.

This study was longest that we have done observed dosing in ambulatory outpatients but is one of only numerous examples we can cite for sponsors. In this case, dosing was once a day but we have also done studies in which twice a day observed dosing was required for an extended period of time and had equally high completion rates.