Generic aromatase inhibitors increase breast cancer treatment adherence by 50%

Columbia University Medical CenterOct 28 2014

Although oral hormonal therapy is known to substantially reduce breast cancer recurrence in women with hormone receptor-positive tumors, about one-half of patients fail to take their medications as directed. A new study by Columbia University Medical Center (CUMC) researchers has found that the introduction of generic aromatase inhibitors (the most common type of hormone therapy), which are considerably less expensive than their brand name counterparts, increased treatment adherence by 50 percent.

The study was published today in the online issue of Journal of the National Cancer Institute.

"Our findings suggest that more effort should be made to reduce out-of-pocket costs for these potentially life-saving medications. This is especially important given the rapid increase of expensive oral cancer therapies," said study leader Dawn L. Hershman, MD, MS, associate professor of medicine at the College of Physicians and Surgeons, and associate professor of epidemiology at the Mailman School of Public Health, Columbia University Medical Center. Dr. Hershman is also leader of the Breast Cancer Program at the Herbert Irving Comprehensive Cancer Center at NewYork-Presbyterian/Columbia University Medical Center.

"We know that hormone therapy for women with hormone receptor-positive breast cancer can reduce recurrence by up to 50 percent," added Dr. Hershman."However, work by our group and others has shown that a substantial number of women discontinue treatment before the recommended five years or do not take the prescribed dose. This is increasingly important because we are starting to learn that even longer therapy—up to 10 years—may be beneficial. It's critical that we understand why people do not take their medication and what we can do to improve adherence."

In a previous study, Dr. Hershman and her colleagues found that higher co-payments for

aromatase inhibitors (AIs) significantly decreased adherence to therapy. "When AIs were released in generic form in 2010, we had a unique opportunity to study whether a reduction in overall medication cost would make a difference in adherence," she said. To find out, the researchers examined the pharmacy records of 5,511 women ages 50 or older with early stage breast cancer (requiring lumpectomy or mastectomy) who were prescribed hormonal therapy between 2007-2012. Each patient was followed for a period of 24 months.

The researchers found that women taking generic AIs were more 50 percent more likely to take the medications on schedule and 30% less likely to discontinue therapy early compared to women taking brand name AIs. Among women on brand name generics, 33 percent discontinued therapy, compared to just 16 percent on generics.

As monthly out-of-pocket co-payments increased, adherence rates decreased. Even a small increase in monthly co-payments, from less than $15 to $15 to $30, resulted in a significant decrease in adherence," said Dr. Hershman. "That might not seem like a lot money, but it can be a big expense if you multiply it over five or ten years and you have other prescriptions to pay for."

There are several factors that can contribute to medication nonadherence. "Cost is not the only reason," said Dr. Hershman. "But it can intensify other factors such as side effects. Up to 40 percent of women taking AIs experience joint stiffness. If you add a high co-payment to the mix, that's often enough to make them discontinue therapy."

Another reason for nonadherence, at least with AIs, is that patients don't see day-to-day signs that the medications are working. "In contrast, if you have hypertension and you're getting regular blood pressure checks, you can see what happens when you stop taking your medication," she said.

Dr. Hershman offered several suggestions for increasing adherence to AIs. "First, it's important for physicians to ask patients whether they are able to pay for their medications," she said. "Many patients aren't comfortable raising this issue and will just discontinue therapy. By engaging patients in conversation, we may be able to come up with a solution, perhaps by finding less expensive alternatives or by asking pharmaceutical companies to assist patients with co-payments."

Physicians also need to remind patients that AIs are effective. "Every time a patient comes for a visit is an opportunity to reinforce the importance of adhering to treatment," Dr. Hershman said.

Finally, states could pass bills requiring health insurance companies to keep co-payments for oral cancer therapies at affordable levels, a move that several legislatures are considering. "From a public policy standpoint, we want to do everything possible to ensure that patients get life-saving medications. We will save many more lives by treating early stage breast cancer with hormonal therapy than by treating metastatic disease with chemotherapy."

Because of the growing availability of costly oral biologic therapies for cancer, the problem of medication nonadherence is likely to grow even larger. The average monthly cost of brand-name and generic AIs are $380 and $150 respectively, while the average monthly cost of oral biologics ranges from $5,000 to $8,000.

Medication nonadherence is a major issue throughout the health care system, according to the researchers. One recent study estimated that the annual cost of nonadherence to all types medications is $289 billion, or 13 percent of total U.S. health expenditures.