JAK Inhibitors Go the Distance in RA Patients

Maureen Salamon

June 09, 2020

Patients with rheumatoid arthritis (RA) remained on therapy longer with the relatively new JAK inhibitors than with TNF inhibitors, according to the large international JAK-pot study, offering encouraging signals about the efficacy and safety of JAK inhibitors in these patients.

"We saw that efficacy with JAK inhibitors was at least as good as other current drugs on the market," said investigator Kim Lauper, MD, from the University of Geneva in Switzerland and the University of Manchester in the United Kingdom.

"We don't have datasets on JAK inhibitors over a long period of time, but we do have a lot of registers," Lauper told Medscape Medical News.

"In general, we were really happy to see no big difference in effectiveness" for these disease-modifying antirheumatic drugs (DMARDs) for patients with RA, she said.

In many countries, JAK inhibitors have only recently been approved as a treatment for RA, Lauper explained. In the past several years, baricitinib, tofacitinib, and upadacitinib have been approved by US Food and Drug Administration.

For their study, Lauper and her colleagues analyzed data from registers in 19 countries.

When JAK inhibitors became available in each country, the team assessed effectiveness by comparing how long patients remained on JAK inhibitors or on long-available biologics. Lauper presented the findings at the virtual European League Against Rheumatism (EULAR) 2020 Congress.

"In general, we know that drug retention is a measure of both effectiveness and safety," she explained.

Of the 25,521 patients in the 19 registers, 6,063 started on a JAK inhibitor during the 3-year study period, 13,879 started on a TNF inhibitor, 2,348 started on abatacept, and 3,231 started on an interleukin (IL)-6 inhibitor.

Three-quarters of patients were women (average age, 55 years), and average time since the diagnosis of RA was 10 years.

At baseline, patients taking JAK inhibitors had higher levels of C-reactive protein and disease activity than patients taking a biologic. They had also been treated previously with more traditional and biologic DMARDs.

Ineffectiveness was the most common reason for discontinuing a drug, cited by 49% of patients, followed by adverse events, cited by 21%.

The rate of discontinuation was lower for JAK inhibitors than for TNF inhibitors, after adjustment. However, the discontinuation rate for JAK inhibitors, abatacept, and IL-6 inhibitors was comparable.

The observational nature of the study was a limitation, Lauper acknowledged, explaining that "we couldn't adjust for confounding factors that were not measured."

Notably, there were large variations in JAK inhibitor retention rates in the different countries, which surprised both Lauper and Loreto Carmona, MD, PhD, from the Musculoskeletal Health Institute in Madrid.

"It's very interesting because there's not much heterogeneity with abatacept and IL inhibitors," said Carmona, who is chair of the EULAR abstract selection committee.

"It's all over the spectrum with JAK inhibitors," she told Medscape Medical News. But "what the research shows is that JAK inhibitors are maintained for longer, which means maybe the mix of efficacy, low toxicity, and adherence, on the whole, is better in JAK inhibitors."

The study was funded by Pfizer. Lauper and Carmona have disclosed no relevant financial relationships.

European League Against Rheumatism (EULAR) 2020 Congress: Abstract OP0231. Presented June 5, 2020.

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