Patterns of Care in Patients with Metastatic Renal Cell Carcinoma Among a U.S. Payer Population with Commercial or Medicare Advantage Membership.

Background: Several systemic therapies are now approved for first- and second-line treatment of metastatic renal cell carcinoma (mRCC). Although the National Comprehensive Cancer Network (NCCN) guidelines offer physicians evidence-based recommendations for therapy, there are few real-world studies to help inform the utilization of these agents in clinical practice.

Objectives: To (a) describe the patterns of use associated with systemic therapies for mRCC among Humana members in the United States diagnosed with mRCC, (b) assess consistency with the NCCN guidelines for treatment, and (c) to describe the initial first-line therapy regimen by prescriber specialty and site of care.

Methods: This was a retrospective study using Humana's claims database of commercially insured patients and patients insured by the Medicare Advantage Prescription Drug plan. The study period was from January 1, 2007, to December 31, 2013. Patients with mRCC were identified by ICD-9-CM codes 189.0/189.1 and 196.xx to 199.xx; all patients were between 18 and 89 years of age, had received systemic therapy for their disease, and were followed up for 180 days. Outcome measures included choice of initial systemic therapy, starting and ending doses, first-line treatment persistence and compliance, and choice of second-line therapy. Persistence was measured using time to discontinuation of first-line therapy and proportion of days covered (PDC; the ratio of [total days of drug available minus days of supply of last prescription] to [last prescription date minus first prescription date]). Compliance was measured using the medication possession ratio (MPR; the ratio of [total days supply minus days supply of last prescription] to [last prescription date minus first prescription date]).

Results: A total of 649 patients met all inclusion criteria; 109 were insured by commercial plans and 540 were insured by Medicare. The mean ± SD age of patients was 68.6 ± 9.4 years, and 68.6% were male; Medicare patients were older than commercial patients (71.7 ± 7.4 vs. 56.6 ± 9.1 years, respectively; P < 0.001). The most common comorbidities among the patient population were hypertension, hyperlipidemia, diabetes, and heart disease. The majority of patients (68.6%) received an oral tyrosine kinase inhibitor (TKI) as their first line of therapy: 43.9% received sunitinib, 14.0% received sorafenib, 10.0% received pazopanib, and 0.6% received axitinib. Mean ± SD time to discontinuation of first-line TKI treatment was 169.1 ± 29.5 days with sunitinib, 160.3 ± 41.1 days with pazopanib, and 160.1 ± 41.4 days with sorafenib. Other first-line therapies included inhibitors of mammalian target of rapamycin (mTOR) (19.7%) and the antivascular endothelial growth factor agent bevacizumab (9.4%). Among patients receiving mTOR inhibitors, 14.8% were started on temsirolimus and 4.9% were started on everolimus. The median starting and ending doses were the same for each drug except for sunitinib. Mean ± SD times to discontinuation of temsirolimus, everolimus, and bevacizumab were 171.8 ± 26.2, 137.0 ± 62.2, and 150.8 ± 56.0 days, respectively. Persistence on first-line regimen as measured by PDC was high (PDC ≥ 80%) for 89% of oral therapies and 77% of injectable therapies; first-line compliance was high (MPR ≥ 80%) for 77% of oral therapies and 68% of injectables. Among patients who received second-line therapy, the most common regimen was everolimus (29.2%), followed by bevacizumab (19.8%), temsirolimus (15.6%), and sunitinib (13.6%). Specialty codes obtained from the database provider identified internal medicine specialists and oncologists as the most common prescribers of TKIs and mTOR inhibitors.

Conclusions: Patterns of use were similar for each of the prescribed systemic treatments for mRCC, and the majority of patients were highly persistent and compliant with first-line therapies. Time to treatment discontinuation was slightly longer with oral agents compared with injectable drugs.