medwireNews: Patients with rheumatoid arthritis (RA) have better outcomes when treated with rituximab or tocilizumab than abatacept or tumor necrosis factor (TNF) inhibitors, suggest the results from two real-world studies.
The first study – by Jacques-Eric Gottenberg, from Strasbourg University Hospital in France, and co-authors – used data from three French registries on 3162 RA patients who received one of three non-TNF inhibitors, either rituximab, tocilizumab, or abatacept, between September 2005 and August 2013.
In a propensity-weighted analysis in which treatment failure was defined as death, initiation of a new biologic or combination of conventional DMARDs, or a noticeable increase in oral corticosteroid dose (>10 mg/day from baseline), 68.6% of the rituximab-treated patients and 63.4% of those given tocilizumab remained on treatment without failure at the 2-year mark, compared with 39.3% of abatacept-treated patients.
Furthermore, the average duration of survival without drug failure, which was based on the restricted mean survival times, was longer for rituximab and tocilizumab than abatacept, at a respective 19.8 and 19.1 months versus 15.6 months.
By contrast, there was no appreciable difference between the drugs with regard to the adverse event profile; the mean durations of survival without serious adverse events were 22.1, 22.3, and 21.8 months for rituximab, tocilizumab, and abatacept, respectively.
“Therefore, the observed higher drug retention rate of rituximab and tocilizumab compared with abatacept is related to greater effectiveness rather than a better safety profile,” say Gottenberg et al in The BMJ.
They stress, however, that the study population had “longstanding and refractory rheumatoid arthritis,” with a median disease duration ranging from 10 to 12 years in the weighted population and prior treatment with a median of two TNF inhibitors, and therefore, these results may not be relevant for “biologic agent naïve patients with shorter disease duration.”
For the second study, Thomas Frisell (Karolinska University Hospital, Stockholm, Sweden) and fellow ARTIS Study Group investigators drew on the Swedish Rheumatology Register records of 2010–2016 to identify 9333 patients who initiated treatment with tocilizumab, rituximab, abatacept, or a TNF inhibitor as their first biologic DMARD, and 3941 who switched from a TNF inhibitor as their first biologic agent.
They found that the likelihood of remaining on and responding to treatment was greater for patients commencing biologic treatment with a non-TNF inhibitor than a TNF inhibitor. For instance, 88.3% of 938 patients given rituximab, 76.2% of 317 tocilizumab-treated patients, and 75.9% of 376 abatacept-treated patients were continuing treatment at the 1-year timepoint versus 69.4% of 7702 taking TNF inhibitors.
And the rates of a EULAR good response at the same timepoint were 28.6%, 50.9%, and 31.9% in the rituximab, tocilizumab, and abatacept groups, respectively, compared with 24.9% in the TNF inhibitor group.
For the group that switched after prior treatment with a TNF inhibitor, switching to rituximab or tocilizumab, but not abatacept, was associated with better drug retention and outcomes than receiving another TNF inhibitor, report the researchers in Rheumatology.
For instance, at 1 year, 80.5% of the 528 patients who switched to rituximab and 70.3% of the 457 who switched to tocilizumab remained on treatment, as did 65.4% of the 408 who switched to abatacept and 59.2% of the 2548 who switched to a different TNF inhibitor. The rates of a EULAR good response were 24.8% and 34.1% versus 13.1% and 11.6%, respectively.
These findings “suggest an equal, or even superior, effectiveness” of non-TNF inhibitor biologic DMARDs over TNF inhibitors, say Frisell et al, but they caution that “[t]his should be weighed against other existing evidence on their relative effectiveness and, not analysed in this study, evidence on the safety and cost-effectiveness of individual [biologic] DMARDs.”
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