Hormone Therapy Adherence in Early-Stage Breast Cancer

How change from a brand name to generic aromatase inhibitors affects therapy discontinuation

Non-adherence to hormonal therapy is common. A group of USA researchers investigated the change in adherence after the introduction of generic aromatase inhibitors in 2010. Discontinuation and non-adherence were higher among patients with early breast cancer who were taking brand name aromatase inhibitors vs. generic aromatase inhibitors, according to a study published on 27 October, 2014 in the Journal of the National Cancer Institute.

Aromatase inhibitor use has been shown to reduce the risk of breast cancer recurrence. However, studies reported only 40%-60% of breast cancer patients finish their recommended 5-year course of aromatase inhibitor therapy. To evaluate how the introduction of generic aromatase inhibitors in 2010 may change adherence, Dr Dawn Hershman from the Department of Medicine and Herbert Irving Comprehensive Cancer Center, College of Physicians and Surgeons, and the Department of Epidemiology at Columbia University in New York and colleagues analysed pharmacy and claims data from women older than 50 years on brand name aromatase inhibitors (2815), generic aromatase inhibitors (1411) or who switched from brand name to generic (1285). Clinical, demographic, and financial variables were evaluated. Adherence was defined as a medication possession ratio 80% or greater.

Higher copayments are associated with discontinuation of aromatase inhibitors

The median 30-day copayment for brand name aromatase inhibitors was higher compared to generic aromatase inhibitors (33.30 vs. 9.04 USD, respectively). The authors reported that women who took a generic aromatase inhibitor were less likely to discontinue its use and adherence was positively associated with generic drug use as compared to brand name aromatase inhibitors. Discontinuation was also associated with a higher copayment of 15-30 USD per month.
Higher prescription copayment amount was associated with non-adherence and discontinuation of aromatase inhibitors. After controlling for copayment, discontinuation was higher and adherence was lower with brand aromatase inhibitors. The authors concluded: “Because non-adherence is associated with worse survival, efforts should be directed towards reducing out-of-pocket costs for these life-saving medications.”


Hershman DL, Tsui J, Meyer J, et al. The Change From Brand-Name to Generic Aromatase Inhibitors and Hormone Therapy Adherence for Early-Stage Breast Cancer. JNCI 2014; 106 (11): dju319 doi: 10.1093/jnci/dju319