Adherence to Oral Anticancer Meds Low

Adherence to oral anti-cancer medications is “suboptimal” — particulary for blood cancer patients — most commonly due to high out-of-pocket (OOP) costs, according to new research.

Ami Vyas

“Policies addressing cost and access to OAMS (oral anti-cancer medications) and health-system strategies to address barriers to the effective use of OAMs are needed to improve patient access to these vital medications,” wrote Ami Vyas, Ph.D., assistant professor of pharmacy practice at the University of Rhode Island, Kingston, in the Journal of Managed Care Specialty Pharmacy.

Vyas and her colleagues conducted a retrospective cohort study using data from Optum Clinformatics Data Mart commercial claims database for 2010-2018. They followed patients with a new pharmacy claim for an oral anti-cancer medication between July 2010 and December 2017 for six months.

They found that out just over half (51.9%) of 37,938 patients with cancer were adherent to oral anti-cancer medications. Patients with blood cancer had some of the lowest adherence rates at 49.6%, although the rates were lower still for patients with several other types of cancers, including ovarian cancer patients (44.6%), colorectal cancer (37.3%) and liver cancer (32.8%).

The highest rates of adherence by cancer type were: brain tumor (70.4%), stomach (68.8%), lung (64.7%), and breast (55.7%).

The researchers attributed low adherence to oral anti-cancer medications for blood cancer and certain other cancers to high monthly OOP expenses, race and ethnicity disparities, higher hospitalization rates, receiving Medicare low-income subsidy (LIS), and other issues.

The average monthly out-of-pocket costs among patients with blood cancer were $749 versus $106 monthly for those with prostate cancer.

“Higher OOP costs may lead to prescription abandonment,delayed initiation,or other forms of nonadherence,which may lead to poorer outcomes and avoidable health care utilization,” Vyas wrote.

In additon, due to the high cost of oral anticancer medications, hospitals may not have them on their formularies, according to Vyas.

Patients with inpatient hospitalizations during the six months following oral anticancer medications initiation — which is common among blood cancer patients — had significantly higher odds of nonadherence for all cancer types except stomach cancer.

“We are unable to determine the specific reasons why OAM (oral anti-cancer medication) nonadherence was higher among patients who were hospitalized. Lengthy inpatient stays may have delayed the time between refills; however, patients may have continued using their own medication while in the hospital,” Vyas wrote.

Among patients with lung, blood, renal, breast, liver, and ovarian cancers, those who received injection chemotherapy along with oral medications and those who had hospitalization had higher odds ofnonadherence.

Patients who received concurrent injection chemotherapy may have experienced treatment-related adverse events that disrupted adherence, according to another systematic review. “These patients may also experience disease-specific toxicities and events, age-related factors including polypharmacy, and adverse drug-drug interactions, resulting in hospitalizations,” Vyas wrote.

Among patients with blood cancers, Black and Hispanic patients had higher odds of OAM nonadherence compared with White patients (AOR=1.48; 95% CI=1.25-1.75 and AOR=1.38; 95% CI=1.13-1.68, respectively).

“Race and ethnicity were significantly associated with nonadherence in patients with blood cancer or lung cancer,” Vyas wrote.