Copays Undermining Aromatase Inhibitors? Yes, But . . .

Discontinuation complexities

Nick Mulcahy

December 14, 2010

December 14, 2010 (San Antonio, Texas) — Higher prescription copayment is associated with the early discontinuation of adjuvant aromatase inhibitors (AIs), according to American researchers who conducted a review of a prescription benefits database.

Women with out-of-pocket expenses of $90 or more for a 3-month period were 26% to 34% more likely to discontinue the drug than those paying less than $30.

About 20% to 25% of all women in the study completely stopped taking their AI over the 2-year study period.

But wait.

Another study — from the United Kingdom, where AIs are free and thus require no copays — had a similar finding about the rate of discontinuation.

About 20% to 25% of all women in that study completely stopped taking their AI over that 2-year study period.

The British study does not invalidate the American research, but is a reminder that AI discontinuation happens in all kinds of health systems, even one in which patient payment plays no part.

Both retrospective studies were presented here at the 33rd Annual San Antonio Breast Cancer Symposium.

The American study, an oral presentation made by lead author Dawn Hershman, MD, from Columbia University in New York City, garnered a lot of attention.

After the presentation, members of the audience, some of whom were sympathetic with Dr. Hershman's findings and described them as making "intuitive" sense, urged her to look at discontinuation related to AI adverse effects in conjunction with the variable of copays.

Quality-of-life adverse effects have been cited by women as a reason for discontinuing treatment. Judy Garber, MD, from Dana-Farber Cancer Institute in Boston, Massachusetts, and president elect of the American Association for Cancer Research, recently described the severity of quality-of-life adverse effects from AIs, such as hot flashes, night sweats, and sleep disturbance, as "menopause plus." More serious adverse effects include bone loss and cardiovascular events.

Unlike the American study, which purposely investigated the relation between the amount of the prescription copayment and compliance with adjuvant AI therapy, the British study simply looked at AI discontinuation and adherence, without investigating any causes.

The British investigators used the medical records of more than 5,700 women with breast cancer in the Tayside region of Scotland, whereas the American researchers used a national prescription database belonging to Medco Health Solutions to exclusively look at more than 21,000 women taking AIs.

Divergent intentions aside, both sets of authors endorse AIs and want to boost compliance.

"Breast cancer survival can be improved by improving compliance to hormonal therapy," said Dr. Hershman.

The British authors, led by Alistair Thompson, PhD, from the University of Dundee in Scotland, write in their symposium poster that, at certain levels, "low adherence" in taking AIs is "known to increase the risk of mortality."

United States and United Kingdom

The American study categorized copayment amounts as below $30.00, between $30.00 and $89.99, and $90.00 and above. The investigators also divided the women into 2 age groups — younger than 63 years and 63 years and older — to distinguish patients ever covered by Medicare.

Results showed that of the 8,110 younger women, 21.1% stopped taking the medication over the 2-year study period. Of the 14,050 older women, nearly 25% stopped taking the medication.

Dr. Hershman and colleagues found that the older women were more likely to discontinue — that is, completely stop taking the drug — than the younger women.

The older women with an out-of-pocket expense of $90 or more for a 3-month period were 34% more likely to discontinue than those paying less than $30 (hazard ratio [HR], 1.34; 95% confidence interval [CI], 1.24 - 1.46). The younger women were 26% more likely (HR, 1.26; 95% CI, 1.09 - 1.38).

"The elderly are particularly vulnerable to out-of-pocket costs," Dr. Hershman told her audience.

The authors also found that the greater the number of prescriptions, the greater the likelihood that a woman would discontinue treatment.

"Public policy efforts to control out-of-pocket expenses for hormonal therapy may improve breast cancer survival," Dr. Hershman told the symposium audience.

The British study did not divide the women into age groups and looked at women taking endocrine therapy for breast cancer. The study assessed, by year, women who discontinued treatment over their planned 5-year treatment period.

Nearly three quarters (71%) of the 5729 women in the study received tamoxifen; 21% received no adjuvant endocrine therapy. A minority of the women (8%) were started on AIs.

Of the patients followed for at least 1 year, 51 (11%) who had started on AIs discontinued their medication. At year 2, another 40 (12%) discontinued, for a total of 23% after 2 years.

The American study was funded partially by the American Cancer Society and partially by the Breast Cancer Research Foundation. The authors have disclosed no relevant financial relationships.

33rd Annual San Antonio Breast Cancer Symposium (SABCS): Abstracts S6-4 and P5-11-11. Presented December 11, 2010.


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