Generic Breast Cancer Drugs Boost Adherence
The introduction of cheaper, generic aromatase inhibitors, used to prevent breast cancer recurrence, appears to have improved adherence, a researcher said here.
In an analysis of pharmacy claims data, adherence to hormone therapy varied depending on the copayment required, according to Dawn Hershman, MD, of Columbia University in New York City.
But the lower-priced generics had smaller copayments and adherence was greater than for brand name products, Hershman reported at the annual San Antonio Breast Cancer Symposium here.
The findings suggest that efforts should be directed toward reducing financial constraints on patients, as a matter of public health policy, Hershman argued.
Indeed, the study implies that reducing costs might improve adherence to therapy with aromatase inhibitors (AIs), commented Claudine Isaacs, MD, of Georgetown Lombardi Comprehensive Cancer Center in Washington, D.C., who was not part of the study. “The use of generic AIs was associated with a significant increase in adherence to and lowering in rate of discontinuation of AI,” she told MedPage Today by email. “We know that many women either do not initiate or discontinue their highly effective endocrine therapy,” she said. The study, she added, suggests “there are a number of encouraging ways to increase consistent use of this highly active therapy.” Hershman and colleagues looked at prescriptions for hormonal therapy, including brand name and generic aromatase inhibitors and tamoxifen, both before and after the 2010 introduction of generic aromatase inhibitors. All told, they had records for 13,522 patients, including 7,532 who never changed medications and 5,990 who switched at least once, Hershman said. Of the switchers, 72.9% changed from a brand-name aromatase inhibitor to a generic, she added. On average, the copayment cost was about $8 for a month’s supply of tamoxifen, about $9 for a generic aromatase inhibitor, and about $33 for a brand-name drug. In the pre-generic era, about 45% of patients started on tamoxifen and the remainder started on a brand-name aromatase inhibitor. After 2010, the tamoxifen proportion remained stable, at 42.6%, while the generics and brand-name aromatase inhibitors had 38.3% and 19.1% “market share” respectively. In a multivariate analysis, with the brand-name drugs as the reference, those taking generic drugs were significantly less likely to stop therapy. The hazard ratio was 0.62 and was significant at P<0.001. The likelihood of stopping tamoxifen therapy was the same as that for brand-name aromatase inhibitors, Hershman reported. The same analysis showed that the likelihood of stopping therapy rose significantly as the copayment rose from below $10 to greater than $20. A similar analysis showed that adherence to therapy - compared with the brand-name aromatase inhibitors - was greater with the generics and lower with tamoxifen. The hazard ratios were 1.37 and 0.68, respectively, and were significant at P<0.01 and P<0.001. Adherence was also lower with higher copayments and higher with greater income, Hershman said. She cautioned that the study covered only the first 2 years after the introduction of the generic drugs, there was no information on tumor characteristics, and adherence was measured by refills, not pill counts. Nonetheless, she argued, "out-of-pocket costs are independently associated with adherence and discontinuation," as are generic aromatase inhibitors. The study was supported by the Breast Cancer Research Foundation, the American Cancer Society, and the National Cancer Institute. Hershman said she had no disclosures.
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