San Antonio—Higher prescription copayments seemed to 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, Inc.
AIs are routinely prescribed as maintenance therapy in endocrine-responsive early breast cancer and have been shown to reduce the risk of recurrence. However, studies show that 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 or more for a 3-month period were 26% to 34% more likely to stop filling their prescriptions, than those paying less than $30, Dr Hershman reported.
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 less than $30, $30 to $89.99 and $90 and above.
Median copayment for a 90-day prescription was $50 for patients under the age of 65 and $40 for those aged 65 and older. For 43% of patients, the copayment was $0 to $30.
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 than those paying less than $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 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
A study from the United Kingdom, also presented at the meeting, found high rates of discontinuation there as well, even though the drugs are provided at no charge in that health care system, suggesting the issues surrounding treatment adherence are complex.
Three quarters of the patients 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.