Analysis of real world treatment compliance in a cohort of 2,395 patients with metastatic renal cell carcinoma (mRCC).

The effect of medication nonadherence on progression-free survival among patients with renal cell carcinoma

“…Each patient was assigned an overall adherence rate drawn from the full distribution of MPR as reported previously. 9 Mean MPR was 0.76 for everolimus; only 25.3% of patients had optimal adherence (MPR=1). Due to the small sample size of axitinib patients in the cited analysis, we assumed that MPRs for everolimus and axitinib were identical.…”

“…16 , 17 In the second module, we adapted adherence rates from published studies using claims data analyses. 9 In our targeted literature reviews, we were unable to identify adherence studies specific to axitinib and everolimus in RCC patients, so instead we adapted adherence rates for modeling purposes from a real-world study of adherence rates in RCC patients. In the third module, we measured exposure by modeling PK/PD: first, by matching existing models to clinical trials assuming optimal adherence, and then incorporating measures of real-world medication adherence.…”

“…The adherence rate for everolimus was reported previously and used for both everolimus and axitinib, as the latter had not been reported in the literature (Supplementary material). 9 Nonadherence was assumed to occur along 2 dimensions: taking the medication at a different time of day than prescribed or not taking the medication (Supplementary material). Failure to take the medication was measured using the MPR, defined as the total days of supply during the treatment period until the date of the last prescription divided by the total treatment period until the date of the last prescription administration claim.…”

“… 7 Adherence to oral therapies for RCC has ranged from 74% to 95% in studies using claims-based measures such as medication possession ratio (MPR) or proportion of days covered. 8 , 9 Using electronic pill counts, the share of oncology patients who took at least 80% of their prescribed doses of oral therapies for other solid tumor types ranged from 78% to 96%; 10 – 12 adherence estimates using serum samples are lower. 13 Further, healthcare providers frequently overestimate oncology patient adherence to self-administered medications.…”

“…We modeled second-line treatments in RCC that had evidence linking medication exposure to patient outcomes. Building on previously published adherence models, 9 we simulated pharmacokinetics/pharmacodynamics (PK/PD), building a model based on inputs from clinical trials, and estimated drug exposure in the real world by simulating different levels of adherence. We then used the modeled exposure to simulate progression-free survival (PFS) outcomes with second-line RCC treatment.…”