Adherence to Oral Oncolytic Prescriptions

Chicago—Using a pharmacy claims database, researchers found that one third of patients who began oral oncolytic therapy between May 1, 2007, and March 31, 2009, abandoned their first prescription or delayed filling the prescription. The rate was higher than in other chronic therapeutic classes, according to the authors, who suggested the adherence findings should be taken into account when constructing health plan benefit designs. Results were presented at the ASCO meeting in a poster session titled Abandoning Oral Oncolytic Prescriptions at the Pharmacy: Patient and Health Plan Factors Influencing Adherence. The authors said that between 25% and 35% of oncology drugs are oral agents, with the percentage increasing in recent years. Because cancer patients need timely access to their medications to achieve the best results, the authors were interested in understanding patient adherence. Researchers analyzed the database and examined 10,508 patients who met the following criteria: a claim paid or reversed for capecitabine, imatinib, sorafenib, lenalidomide, sunitinib, erlotinib, temozolomide, or lapatinib; no other oncolytic claims in the previous 120 days; active prescription claims at least 120 days before and 90 days after the first fill; insured by Medicare or a commercial plan; and complete data for all variables. They defined abandonment as the reversal of a claim without a subsequent paid claim for any oral or intravenous oncolytic within the following 90 days. Of the patient population, 51.5% were ≤65 years of age, 52.8% were female, 64.3% had an annual household income ≤$75,000, 83.5% were covered by a commercial health plan, and 72.7% had cost-sharing between $0 and $100. The overall abandonment rate for oncolytics was 10%, while approximately another 25% delayed filling the prescription for up to 90 days. The higher the patient cost-sharing, the less likely they were to fill the prescription. For instance, 6.4% of patients who had a cost-sharing between $0 and $100 (n=7638) abandoned their newly initiated oral oncolytic compared with 10.7% of those with a cost-sharing between $101 and $150 (n=271), 9.3% of those with a cost-sharing between $151 and $200 (n=258), 12.2% of those with a cost-sharing between $201 and $250 (n=123), 12.0% of those with a cost-sharing between $251 and $350 (n=291), 16.0% of those with a cost-sharing between $351 and $500 (n=200), and 24.7% of those with a cost-sharing >$500 (n=1727). Compared with a cost-sharing between $0 and $100, patients in each of the higher cost-sharing groups were significantly more likely to abandon their prescriptions. In addition, compared with patients using capecitabine, patients who took imatinib, sorafenib, sunitinib, erlotinib, and lapatinib were significantly more likely to abandon their initial oral oncolytic prescriptions. The researchers also found no significant association between Medicare, commercial plans, or income level and abandonment. Compared with claims submitted in the first quarter of 2008, there was a higher likelihood of abandonment in the second, third, and fourth quarters of the year (45%, 48%, and 29%, respectively). There were a few study limitations, according to the authors. They said that patients could have accessed pharmacies outside of the sample, although they attempted to include all of the pharmacy claims data. Also, the pharmacy claims data may have included some intravenous medications. Finally, they did not have access to patients who abandoned the claim but then obtained the medication through a patient assistance program. Research funding was provided by the Community Oncology Alliance in partnership with Celgene Corp, Genentech, Millennium Pharmaceuticals, Novartis Pharmaceuticals, and Pfizer, Inc.