Credit: CDC
When their share of prescription costs becomes too high, many patients with chronic myeloid leukemia (CML) will skip doses of imatinib or stop taking the drug entirely, new research suggests.
In a study of about 1500 patients, the median co-payment for an imatinib prescription was about $30 per fill, but the range was $0 to $4792.
Patients with higher co-payments were 70% more likely than their peers to stop taking imatinib and 42% more likely to skip doses of the drug.
Stacie B. Dusetzina, PhD, of the University of North Carolina at Chapel Hill, and her colleagues conducted this research and described the results in the Journal of Clinical Oncology.
Co-payment requirements vary
The researchers analyzed health plan claims from privately insured adults (ages 18 to 64) from 2002 to 2011. The data included 1541 CML patients beginning treatment with imatinib.
For the whole study period, the mean co-payment was $108 for a 30-day supply of imatinib. Patients in the lowest 25th percentile paid a mean of $17, and patients in the upper 75th percentile paid a mean of $53.
As expected, monthly co-payments increased over time. They averaged $55 in 2002 and $145 in 2011, with 6.4% of patients paying more than $500 a month.
Dr Dusetzina noted that the data only included patients on employer-based insurance plans, and most individuals had low out-of-pocket costs.
“We studied people who are part of large employer groups, so their insurance is probably more generous than someone who is buying insurance on a private market that does not have a lot of negotiating power,” she said.
Costs correlate with adherence
In the first 180 days of treatment, 30% of patients with higher co-payments were non-adherent to imatinib treatment, compared to 21% of patients with lower co-payments. Non-adherence was defined as having less than 80% of days with imatinib available.
Seventeen percent of patients with higher co-payments discontinued taking imatinib, compared to 10% of patients with lower co-payments. Discontinuation was defined as having a gap of more than 60 days after the exhaustion of imatinib therapy.
These data did not include patients who could not begin taking imatinib due to costs. Therefore, Dr Dusetzina said this study likely underestimates the effects of drug costs on treatment adherence.
“If you went to the pharmacy to obtain your prescription, and they said it was $5000, and you walked away because you couldn’t afford to pay, you’re not in the data,” she said. “We could only study individuals who filled at least one prescription.”
Dr Dusetzina also said these findings have implications beyond imatinib and CML. Many new treatments for rare conditions can cost insurers and patients more than $100,000 year.
“Our results are particularly relevant for specialty pharmaceutical products—those that cost over $10,000 a month,” she said.
“However, the lessons learned likely relate to any pharmaceutical product that has high out-of-pocket costs. It is important that we identify strategies to make effective but expensive medications more affordable to patients.”
