Medication Adherence, Health Care Utilization, and Costs Among Patients Initiating Oral Oncolytics for Multiple Myeloma or Chronic Lymphocytic Leukemia/Small Lymphocytic Lymphoma

BACKGROUND: Oral oncolytic therapies have improved survival in hematologic cancers, such as chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL) and multiple myeloma (MM), which are now being managed like chronic conditions. However, compared with other cancers, there is a lack of studies assessing adherence, health care resource utilization, and costs in patients with these cancers. OBJECTIVE: To assess factors associated with adherence to oral oncolytic therapies, health care utilization, and costs in patients with CLL/SLL or MM. METHODS: A retrospective database study was conducted using the IBM MarketScan Commercial Claims and Medicare Supplement databases. Adults (aged ≥ 18 years) diagnosed with and prescribed an oral oncolytic for CLL/SLL (ibrutinib or idelalisib) or MM (thalidomide, lenalidomide, or pomalidomide) between 2013 and 2016 and with continuous eligibility 6 months before and 12 months after oral oncolytic initiation were identified. Adherence to oral oncolytics was measured using the proportion of days covered (PDC) metric. Multiple linear regression and multivariable logistic regression were used to identify adherence predictors. Count models assessed the relationship between adherence and resource utilization, and generalized linear models assessed the relationship between adherence and health care costs. RESULTS: A total of 701 and 2,385 patients were identified with CLL/SLL or MM, respectively. Mean PDC (SD) for CLL/SLL and MM patients was 75.3 (22.5) and 57.6 (26.5), respectively. For CLL/SLL patients, those aged ≥ 65 years (beta [B] = −4.00) had lower medication use. Among MM patients, multiple predictors of higher medication use emerged: aged ≥ 65 years (B = 3.44), higher than average outpatient resource utilization (B = 3.53), insurance plan other than preferred provider organization (PPO; B = −2.58), previous cancer therapy (B = −2.81), higher number of concurrent unique therapeutic classes (B = −0.35), and higher comorbidity burden (B = −2.55). Patients with CLL/SLL and enrolled in plans other than a PPO were more likely to be adherent (OR = 1.41, 95% CI = 1.01-1.98), whereas patients who were aged ≥ 65 years, were residents of the southern United States, and had visited the emergency department in the baseline period were less likely to be adherent. For MM patients, those aged ≥ 65 years (OR = 1.68, 95% CI = 1.38-2.04) and with higher than average outpatient services utilization (OR = 1.24, 95% CI = 1.01-1.52) were more likely to be adherent, whereas those enrolled in plans other than a PPO, previously treated with cancer therapy, and with higher comorbidity burden were less likely to be adherent. In both cohorts, adherent patients had significantly lower odds of health care utilization and incurred lower medical costs, but higher prescription costs, following oncolytic initiation; however, total costs were not significantly lower in those adherent. CONCLUSIONS: Factors were identified that influenced adherence at the patient, treatment, and health system levels. These factors can be used to identify patients requiring interventions for improving medication-taking behavior and associated health care burden.