Is response-guided therapy being applied in the clinical setting? The hepatitis C example.

BACKGROUND: Response-guided therapy (RGT) is a treatment model that bases adjustments to therapeutic regimens on individualized patient physiologic response. This approach is applied to patients with chronic hepatitis C virus (HCV) infection who are treated with a triple therapy regimen of boceprevir or telaprevir in combination with pegylated interferon and ribavirin. As RGT expands in other pharmacologic regimens, including the treatment of breast cancer and acute myeloid leukemia, a measurement of how this approach is applied in clinical practice is important to determine whether the benefits of RGT are being optimized.

OBJECTIVE: To measure adherence to the RGT guidelines and to the treatment futility rules based on the drug labeling information for boceprevir and for telaprevir in the treatment of patients with chronic HCV infection.

METHODS: A retrospective observational cohort study was conducted using the large Humana research database, which includes pharmacy, medical, and laboratory claims, as well as enrollment data for more than 1.5 million fully insured commercial members, 1.9 million Medicare Advantage members, and 2.4 million Medicare Part D members from all 50 states. The study population included patients aged ≥18 years to <90 years who were fully insured with commercial or Medicare Advantage coverage. A pharmacy claim for boceprevir or telaprevir was used to identify patients receiving triple therapy for HCV infection. Medical, pharmacy, and laboratory claims were reviewed from the date of the first boceprevir or telaprevir pharmacy claim between May 2011 and February 2012 through a 32-week follow-up period, during which patients were required to have continuous health plan enrollment eligibility. This time period allowed for the occurrences of required HCV RNA laboratory monitoring and the assessment of treatment patterns. The use of RGT for boceprevir and telaprevir includes the monitoring of HCV RNA levels at routine intervals to determine how to proceed with therapy. Adherence to HCV RNA monitoring was measured as the proportion of eligible patients who had an HCV RNA assay at each of the recommended time intervals. According to futility rules, patients with greater-than-expected HCV RNA levels are deemed to be nonresponders and should discontinue therapy. Adherence to futility rules was measured as the proportion of patients who stopped therapy among all patients who had an HCV RNA result, which indicated treatment futility at each monitoring interval.

RESULTS: A total of 326 patients (65 in the boceprevir group; 261 in the telaprevir group) were eligible for the HCV RNA monitoring analysis, and 134 patients (20 receiving boceprevir and 114 receiving telaprevir) were eligible for the futility rules analysis. There were 1203 HCV RNA assays during the follow-up period. The percentage of patients who were adherent to HCV RNA monitoring during the entire treatment period was 29.2% in the boceprevir group and 32.2% in the telaprevir group. In both treatment groups, adherence to HCV RNA monitoring was highest at the first recommended time interval, followed by a downward trend in the second and third time intervals. Approximately 15% of 134 eligible patients met the futility rules for stopping therapy based on HCV RNA assay results, and 55% of those patients stopped the therapy in accordance with the treatment futility rules.

CONCLUSION: The implementation of RGT was suboptimal in this population of patients with chronic HCV infection; adherence to HCV RNA monitoring guidelines was less than 33%, and adherence to treatment futility rules was less than 50%. Managed care pharmacists should identify strategies to increase the adoption of RGT, which may, in turn, improve patient care and reduce unnecessary expenditures.