San Antonio, TX—Higher prescription copayments contribute to early discontinuation of aromatase inhibitors (AIs) for breast cancer, according to a study presented at the annual San Antonio Breast Cancer Symposium.
“Noncompliance is a problem, even among patients with pharmaceutical plans,” said Dawn Hershman, MD, of Columbia University, who led the study based on a claims database from Medco Health Solutions.
AIs are routinely prescribed as maintenance therapy in endocrineresponsive early breast cancer and have been shown to reduce the risk of recurrence. However, at least one third of women may stop taking them, partially because of side effects.
The study suggested that having to pay more for the drug may be another reason. Women with out-of-pocket expenses of ≥$90 for a 3-month period were 26% to 34% more likely to stop filling their prescriptions than those paying <$30.
Dr Hershman and colleagues combed the Medco database of approximately 12 million subscribers to select 21,160 women diagnosed with early breast cancer in 2007 and 2008 who filled at least 2 mail-order prescriptions for an AI. Copayments were stratified as <$30, $30 to $89.99, and ≥$90.
Median copayment for a 90-day prescription was $50 for patients aged <65 years and $40 for those aged ≥65 years.
Approximately 21% of the younger women and 25% of the older women completely stopped taking their AI over the 2-year study period. Older women with copayments of $90 or more over 3 months were 34% more likely to discontinue their AI therapy than those paying >$30. Younger women were 26% more likely to stop.
In addition, the more prescriptions a patient needed, the more likely she was to discontinue AI therapy. Prescriptions provided by a primary care physician rather than an oncologist were also less likely to be filled.
“Out-of-pocket costs influence both nonadherence and nonpersistence with AI treatment, and the elderly are particularly vulnerable to this,” Dr Hershman noted. “Public policy efforts to control out-of-pocket expenses for hormonal therapy may improve breast cancer survival.”
In British Study, One Quarter Discontinue “Free” Drug
In a study from the United Kingdom, also presented at the meeting, investigators found high rates of discontinuation there as well, al though the drugs are provided at no charge in that healthcare system, suggesting the issues surrounding treatment adherence are complex.
Of the patients, 75% were treated with tamoxifen, and just 8% started on AIs. Nevertheless, 23% of patients had discontinued this drug at 2 years.
“We found similar levels of noncompliance when payment was not an issue,” said Alistair Thompson, PhD, from the University of Dundee in Scotland.