Dr. Kaine’s study involved 167 patients, with an average age of 49 years, who had been treated for RA on average for seven years. All patients were also taking methotrexate and low-dose oral corticosteroids during the study period.

During the first phase, all patients received abatacept injections once a week for 78 days. Patients were then randomized to continue their abatacept treatment or receive a placebo once a week for 12 weeks. When that period ended, those in the placebo group were randomized to resume abatacept injections with or without an intravenous, or IV, loading dose for an additional 12 weeks. At each point, their antibody levels and DAS28 scores – a measure of disease activity – were noted.

Dr. Kaine reports that the three-month interruption and subsequent reintroduction of abatacept injections were safe and the medication continued to be effective, independent of whether they were given an IV loading dose. That finding is consistent with reports on patients getting abatacept infusions, he adds.

“The study is pretty clear-cut in this finding – as only a small number of patients developed antibodies, and those don’t appear to be associated with side effects or loss of efficacy. And over time, antibodies tended to disappear when drug therapy was resumed,” Dr. Kaine explains. 

The article notes other key questions about drug holidays that would benefit from further study, such as how multiple interruptions affect the drug’s safety and efficacy, and how a drug holiday affects patients taking abatacept without methotrexate or corticosteroids.

Another issue is can the findings be extrapolated to the other biologics? “It is difficult to speculate” whether this response would hold true for other biologics or if it is specific to abatacept, says Dr. Kaine.

Still, the study is a first step. It “provides reassurance that if a patient is going to stop the drug, there’s not a risk of losing efficacy or becoming allergic to the drug when they resume taking it,” says John FitzGerald, MD, associate clinical professor of rheumatology with the UCLA Health System, who was not involved in the study.