MAUI, HAWAII – Results of a carefully conducted real-world study of adherence to oral methotrexate in patients with RA were “kind of scary,” Arthur Kavanaugh, MD, said at the 2020 Rheumatology Winter Clinical Symposium.
“At 24 weeks, adherence was only 75%. And these were people who knew they were being monitored, so this is the best of the best. And yet less than 20% took the drug perfectly, meaning they took every dose as it was supposed to be,” noted Dr. Kavanaugh, professor of medicine at the University of California, San Diego, and RWCS program director.
“Adherence to methotrexate is really not very good. This is our cornerstone drug – methotrexate – and I think it certainly applies to other medications that we’re using,” he added.
He and his fellow panelist John J. Cush, MD, discussed the implications of this recent study, led by Kaleb Michaud, PhD, of the University of Nebraska Medical Center, Omaha.
The methotrexate adherence study included 60 patients with RA whose use of the disease-modifying antirheumatic drug (DMARD) over 24 weeks was monitored via the electronic Medication Event Monitoring System. These were motivated patients seen in routine clinical practice: They were participants in Forward, the National Databank for Rheumatic Diseases, and they understood that their use of methotrexate was being monitored.
Among the key findings: Patients on average took their weekly dose as directed for a total of 18 of the 24 weeks, although adherence decreased over time. Overall, 13% of participants missed 1 week, and 68% skipped 2 or more weeks. There was no significant difference in methotrexate adherence between biologic-naive and -experienced patients, nor between those on methotrexate monotherapy versus those on additional medication. Patient demographics and RA severity were similar between patients who missed taking their methotrexate for 2 weeks or more and those who missed fewer or no doses.
Higher Patient Global Assessment of Disease Activity scores were associated with correct dosing. So was being unemployed, having no prior conventional DMARD experience, and having less disability. A higher baseline score on the Beliefs about Medicines Questionnaire Specific-Necessity subscale, which indicates stronger belief in the necessity of the medication, were associated with greater likelihood of appropriate dosing, while lower scores were linked with more weeks of early dosing. However, the other elements of the Beliefs about Medicines Questionnaire weren’t significantly associated with adherence.
“This is a big problem. A lot of factors go into medication nonadherence. The solution has to begin with your relationship with the patient. If you want people to trust you, you’re going to have to work at that,” observed Dr. Cush, who is professor of medicine and rheumatology at Baylor University Medical Center, Dallas, and director of clinical rheumatology at the Baylor Research Institute.
Roy Fleischmann, MD, a rheumatologist and medical director of the Metroplex Clinical Research Center, Dallas, said that widespread suboptimal adherence to oral methotrexate has important implications for clinical trials. Often the placebo response rate in a randomized trial where the control group is on background methotrexate is so unexpectedly high that the potential efficacy of the active drug is masked; in such situations, it’s quite possible that patients who previously weren’t taking their methotrexate consistently start doing so when they join a closely supervised study, with a resultant inflated placebo response rate, he said.
One audience member who sees lots of medication adherence issues in his practice suggested that it might be time to become more aggressive in using intravenous infusion therapy instead of subcutaneously administered agents in patients with active RA and adherence problems.
“Maybe that’s why rituximab does so well in the clinical trials,” he said.
Dr. Cush and Dr. Kavanaugh reported receiving research funding from and/or serving as consultants to numerous pharmaceutical companies.