Assessment of adherence to cinacalcet by prescription refill rates in hemodialysis patients

Abstract

Secondary hyperparathyroidism is common among dialysis patients and leads to numerous complications including cardiovascular disease and renal osteodystrophy. Cinacalcet, an oral daily calcimimetic agent that sensitizes the calcium receptor to serum calcium, is approved for treatment of secondary hyperparathyroidism in dialysis patients. We identified 101 patients who received their first cinacalcet prescription between November 2004 and April 2005. All patients were participating in a Missouri state-funded pharmacy program providing free or low cost medications. We tracked the cinacalcet refill rate and refills for another control medication prescribed to each patient. The average cinacalcet refill rate over the first 12 months was 56% vs. 64% for the control medication (P=0.02). Good adherence, defined as >80% medication possession ratio over the 12 months, was 29% for cinacalcet and 33% for the control medication (P=0.68). Additionally, the refill rate for cinacalcet fell significantly over five quarterly periods from 53% in the first quarter to 37% in the 5th quarter. We conclude that dialysis patients' adherence to medications, including cinacalcet, is poor even when medications are provided at a nominal cost. Poor cinacalcet adherence would be expected to impair long-term control of SHPT. In a reimbursement system where injectable, but not oral medications, are bundled with dialysis payments there may be pressure to move patients to oral medications. The poor compliance found in this study highlights the potential adverse effects of movement toward self-administered oral therapy.

Pharmacology of AMG 416 (Velcalcetide), a Novel Peptide Agonist of the Calcium-Sensing Receptor, for the Treatment of Secondary Hyperparathyroidism in Hemodialysis Patients

“…One of the most common side effects seen with cinacalcet is elevated GI intolerability (most notably, increased incidence of nausea, vomiting, diarrhea), which can lead to patient noncompliance and discontinuation of treatment (Gincherman et al, 2010). Two possible explanations for the poor GI tolerability with cinacalcet have been suggested: high local exposure in the gut (particularly the GI lumen) and the potential of activating the CaSR located in the circumventricular regions of the brain (Mudo et al, 2009).…”

“…Cinacalcet is approved as a once-daily oral treatment of SHPT in end-stage renal disease (ESRD) hemodialysis patients, is effective at decreasing serum intact parathyroid hormone, and is associated with corresponding reductions in serum calcium, phosphorus, and the calciumphosphorus product in dialysis patients (Block et al, 2004b). Although patients receiving cinacalcet show significant improvements in PTH levels and bone and mineral metabolism, the clinical utility of cinacalcet can be limited by gastrointestinal (GI) intolerability (nausea, vomiting, and diarrhea), fixed-dose titration, cytochrome P450-mediated drug-drug interactions, and poor patient compliance (Padhi and Harris, 2009;Gincherman et al, 2010). Consequently, there is a need for an improved therapeutic agent for the treatment of SHPT.…”

Regimen Complexity and Prescription Adherence in Dialysis Patients

“…Even though therapy regimens in ESRD are increasingly burdensome [13,14] and patients are prescribed 10–12 tablets per day on average to manage their multiple comorbidities [15], few studies evaluated how regimen complexity and patients’ personal preferences for therapy impact on adherence in HD patients [4,15,16,17]. …”

Novel treatment options for secondary hyperparathyroidism in end-stage kidney disease patients on hemodialysis therapy

“…Тем не менее, особенно при выраженном ВГПТ суще-ствует проблема резистентности и к цинакальцету, также его применение ограничено такими побочными эффекта-ми, как тошнота, рвота, диарея, гипокальциемия, необхо-димостью тщательно титровать дозу и принимать препа-рат ежедневно 1-2 раза в день, что существенно снижает комплаентность пациентов и способность к длительному его приему [21,22]. Это послужило стимулом к дальней-шему поиску кальцимиметиков с возможностью решения ряда указанных проблем.…”