When patients with rheumatoid arthritis (RA) don’t get relief from an anti-tumor necrosis factor (TNF) drug, they are better off switching to Orencia or rituximab rather than an anti-tumor necrosis drug, researchers say.

“The concept is to find out whether there is a better strategy than another anti-TNF,” said lead researcher Denis Choquette, from the Rheumatology Institute of Montreal, Canada.

Anti-TNF drugs are a class of drugs that treat inflammatory conditions such as RA. They include infliximab (the active ingredient in Remicade, Remsima and Inflectra), adalimumab (the active ingredient in Humira and Exemptia) and Enbrel.

These drugs are often able to reduce inflammation and stop disease progression, but one-third of patients do not find success when taking them to treat RA.

The researchers examined the “retention rate” of the two drugs. That is the length of time that patients keep taking a medication. It’s a rough measure of whether the drug is improving their symptoms and whether it is causing side effects.

In one study, the researchers compared patients who had switched to Orencia after taking a different anti-TNF for RA. They included 76 taking Orencia, 47 taking adalimumab, 47 taking Enbrel and 19 taking infliximab.

They found that the retention rate was much higher with Orencia than with the other drugs. After six years, 41.2 percent of those taking Orencia had stuck with that drug. By contrast only 15.2 percent of those taking Enbrel, and 22.7 percent of those taking infliximab had stuck with those drugs.

The same team of researchers got very similar results in a study on ritixumab  (the active ingredient in Rituxan, MabThera and Zytux).

In this study, they lumped together data on patients taking adalimumab, Enbrel and infliximab after switching from another anti-TNF drug. They compared these patients to patients taking ritixumab after switching from an anti-TNF drug.

They found that 80.1 percent of patients were still taking ritixumab six years after switching, versus only 19.1 percent of patients taking adalimumab, Enbrel or infliximab.

Similarly, 53.6 percent of patients who had tried two other biologic drugs before ritixumab stuck with it for at least six years, compared to 37.2 percent of the patients taking adalimumab, Enbrel or infliximab.

The Orencia study was funded by Bristol-Myers Squibb, the maker of Orencia. The ritixmumab study drew from a database funded by Bristol-Myers Squibb,  Abbvie, Amgen, Celgene, Janssen, Pfizer, Roche and UCB.