Patient and Plan Characteristics Affecting Abandonment of Oral Oncolytic Prescriptions

Ten percent of patients abandon newly initiated oral oncolytics at the pharmacy. Patients facing higher cost sharing or increased concurrent prescription activity have a higher abandonment rate.
Published Online: May 20, 2011
Sonya Blesser Streeter, MPP, MPH; Lee Schwartzberg, MD; Nadia Husain, ScM; and Michael Johnsrud, PhD


This article was published as part of a special joint issue and also appears in the Journal of Oncology Practice.

Objective: To calculate the abandonment rate of oral oncolytic medications and identify factors that may affect likelihood of abandonment.


Study Design: Cross-sectional cohort study using administrative claims data.


Methods: We analyzed a nationally representative pharmacy claims database and identified 10,508 patients with Medicare and commercial insurance for whom oral oncolytic therapy was initiated between 2007 and 2009. We calculated the abandonment rate for the initial claim, in which abandonment was defined as reversal of an  adjudicated pharmacy claim without a subsequent paid claim for any oncolytic (oral or intravenous) within the ensuing 90 days. We assessed likelihood of abandonment using bivariate and multivariate logistic regression analyses including patient demographics, plan type, drug type, cost sharing, and concurrent prescription activity.


Results: The abandonment rate of newly initiated oral oncolytics was 10.0%. Unadjusted bivariate analyses found that high cost sharing, increased prescription activity, lower income, and Medicare coverage were associated with a higher abandonment rate (P <.05). In the logistic regression model, claims with cost sharing greater than $500 were 4 times more likely to be abandoned than claims with cost sharing of $100 or less (odds ratio [OR], 4.46; P <.001). Patients with 5 or more prescription claims processed within in the previous month had 50% higher likelihood of abandonment than patients with no other prescription activity (OR, 1.50; P <.001).


Conclusion: Abandonment of newly prescribed oral oncolytic therapy is not uncommon, and the likelihood increases for patients enrolled in plans with pharmacy benefit designs that require high cost sharing. Increased concurrent prescription activity was also associated with a higher abandonment rate. These factors should be taken into account when considering likely adherence to cancer therapy.


(Am J Manag Care. 2011;17(5 Spec No.):SP38-SP44)

Oral oncolytic therapy is an increasingly important aspect of cancer care, and adherence to treatment is critical to deriving benefit.


  • Our study found that 10% of patients abandoned their anticancer medicine, and another quarter had some delay in initiating another oncolytic.
  • Pharmacy plan design (cost-sharing amount) and complexity of patients’ drug therapy (prescription activity) are significant drivers of abandonment of oral oncolytic agents.
  • As the structure of Medicare Part D and commercial plans is modified and health reform initiatives evolve, policy makers and stakeholders should be aware of the impact of benefit structure on adherence and access to vital oncology therapy.
Patients diagnosed with cancer require timely access to appropriate treatments to achieve optimal outcomes. Until recently, drug therapy for patients with cancer consisted of intravenous (IV) infused treatment. Oncolytic medications that can be administered orally are a relatively new addition to cancer treatment and provide patients with the  benefits of ease of use and convenience.1 Utilization of oral oncolytics is expected to increase.2 Recent reports have suggested they account for approximately 25% of the current oncology pipeline.3

Because of costs associated with these newer oral oncolytic agents, pharmacy benefit plans may implement cost-containment mechanisms such as increased patient cost sharing through placement in higher copayment tiers. The degree to which increased cost sharing influences access to and utilization of oral oncolytics may be an important factor affecting patient adherence to prescribed cancer therapy.

Traditional adherence studies of oncology medication track patient utilization longitudinally by assessing refill rate, self-reported compliance with prescribed therapies, continuous dose observations, pill counting, and administrative claims analysis.1,4 Studies of nonadherence have found that barriers to appropriate care include cost-sharing requirements, agent toxicity, patient- and disease-related factors, social issues, and financial status.1,2,4

The purpose of our study was to assess abandonment of newly initiated oral oncolytics. Specifically, we were interested in examining patients who had been prescribed oral oncolytic therapy, submitted prescriptions for their first oral oncology medications to pharmacies, and then reversed claims after adjudication (ie, initial approval of claim). If patients did not follow up with a subsequent oncolytic agent, we noted their reversed claim as an abandoned prescription.

Our objective was to calculate reversal and abandonment rates of newly initiated oral oncolytic medications using an approach similar to those found in the literature.5-7 Building on previous research, we investigated the degree to which abandonment is affected by patient and plan characteristics, specifically cost-sharing requirements, patient income, concurrent prescription activity, and insurance type.


We acquired administrative claims data from the Wolters Kluwer Dynamic Claims Lifecycle Database, a source of nationally representative pharmacy utilization data, for 20,607 patients for whom at least 1 pharmacy claim was adjudicated for 1 of the oral oncolytic agents included in our study between January 1, 2007, and June 30,2009. The data set included pharmacy claims and demographic data for all patients as well as medical claims for a subpopulation of patients. We studied patients using capecitabine, imatinib, sorafenib, lenalidomide, sunitinib, erlotinib, temozolomide, and lapatinib. These agents represented widely available oral oncolytic agents at the time of our analyses. We then identified a subset of adjudicated oral oncolytic claims between May 1, 2007, and March 31, 2009 (defined as the index period) to determine if a patient had newly initiated therapy with a study drug. For each claim, we looked back 120 days in the patient’s claim history from first adjudication of an oral oncolytic claim during the index period to exclude patients with previous oral or IV oncolytic treatment. To confirm that the data set included prescription data for each patient both before and  after the newly initiated oral oncolytic, we restricted the sample to those patients who had at least 1 claim for any type of medication at least 120 or more days before and at least 90 days or more after the first oral oncolytic claim, a methodology employed to assess patient eligibility during the observation period.8,9

To calculate the portion of newly initiated oral oncolytics that were ultimately abandoned, we defined adjudication status of the oral oncolytic as paid, reversed with follow-up, or abandoned. Patients with claims defined as reversed with follow-up had a successfully paid IV or oral oncolytic claim within 90 days after submission date of the reversed newly initiated oncolytic. Patients with claims defined as abandoned had reversed the newly initiated oncolytic but did not have a paid oncolytic claim within 90 days of submission date of the reversed claim.

We required the sample to include only patients insured by a non-Medicare commercial or Medicare plan, including prescription drug plans and Medicare Advantage Prescription Drug plans. We also restricted the sample to claims with complete patient- and claim-level data for all variables utilized in the regression model.

To conduct bivariate and multivariate analyses, we identified patient-level characteristics such as age (<40, 41 to 65, 66 to 80, or >81 years), sex, and geographic region (Northeast, South, Midwest, or West). A variable for annual patient income was included in the data set and categorized as less than $40,000, between $40,000 and $75,000, or more than $75,000. Cost-sharing amounts were collected for each paid and reversed claim and were grouped into the following categories: $0 to $100, $101 to $150, $151 to $200, $201 to $250, $251 to $350, $351 to $500, or more than $500. We also created a variable to measure concurrent prescription activity for each patient based on the number of claims processed within 30 days before the submission date of the newly initiated oral oncolytic. The prescription activity variable was defined as follows: no claims, 1 claim, 2 to 3 claims, 4 to 5 claims, or more than 5 claims. Variables were created to control for the specific oral oncolytic agent that the patient was prescribed.

χ2 analyses were conducted to compare abandonment rates across the independent variables previously described. A logistic regression model was constructed using abandonment status (0 = no, 1 = yes) within 90 days after the initially adjudicated oral oncolytic claim as the dependent variable. Covariates included all independent variables described to identify significant predictor variables (P <.05). Odds ratios and 95% confidence intervals [CIs] were calculated for all predictors in the model using selected references for comparison.


Of the initial 20,607 patients in the data set, we identified 10,508 patients who met the final inclusion criteria for our study. Sixty-seven percent of the claims were adjudicated and paid for by the patient and/or pharmacy benefit plan, whereas 33% of claims were reversed. Of the total number of reversed claims, 23% of patients followed up with another oncolytic agent within 90 days. The remaining 10% of patients had no follow-up and thus abandoned the oral oncolytic agent. A sensitivity test to extend the follow-up window from 90 to 120 days did not significantly affect the portion of claims defined as abandoned.

Table 1 provides demographics and plan characteristics for patients included in our study. Approximately half of the patients in our sample were younger than 65 years. Patients were slightly more likely to be female, more likely to have an income between $40,000 and $75,000, and most commonly from the South. Most patients were insured by a commercial plan.

Bivariate analyses comparing the combination of paid claims and reversed claims with follow-up versus abandoned claims indicated significant differences across age groups and rate of abandonment. Thirteen percent of patients older than 80 years abandoned their first oral oncolytic compared with 10% of patients 40 years or younger (P <.05). Insurance status was also a significant variable, with abandonment rates of 16% for Medicare claims versus 9% for commercial insurance claims (P <.05).

Lower annual household income was associated with higher abandonment rates. Patients with incomes of less than $40,000 per year had an abandonment rate of 11%, decreasing to 10% for incomes between $40,000 and $75,000 and 9% for incomes above $75,000 (P <.05).

Twenty-three percent of patients submitted more than 5 claims for nononcolytic medications within the previous month of initiating the oral oncolytic, whereas 29% of patients had no concurrent prescription activity. Prescription activity was significantly associated with increased abandonment rates. Patients with more than 5 claims in the previous month had an abandonment rate of 12% compared with 9% for patients with no claims in the previous month (P <.05).

Seventy-three percent of newly initiated oncolytics had a cost-sharing amount of $100 or less, although 16% required an out-of-pocket cost of more than $500. For reference, median cost-sharing amount in the sample for all patients was $30. The abandonment rate increased with cost-sharing amount. Claims with cost sharing above $500 had the highest abandonment rate (25%) compared with an abandonment rate of 6% for claims with cost sharing of $100 or less (P <.05).

Among the 8 oral oncolytics in our study, capecitabine accounted for more than one-third of the sample. Imatinib, lenalidomide, erlotinib, and temozolomide were also commonly used medications. The unadjusted abandonment rate for each oral oncolytic agent varied greatly.

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