Best of 2019 - Ups and Downs with Abatacept Save

Two recent studies have examined the effect of starting abatacept upon the risk of serious hospitalized infections or cancer, showing divergent results from claims data analyses.

Chen and colleagues reported in Arthritis Care & Research on a propensity score-matched cohort study analyzing 11,248 matched RA patients starting abatacept or TNFi and followed until their first event.  The primary outcome was that of hospitalized (serious) infection.

Hospitalized infection was observed 37 SIE ABA treated patients compared to an event rate of 47 SIE in TNFi treated patients (HR 0.78; 95% CI 0.64-0.95).  Amongst all hospitalizable infections, the ABA associated risk was primarily significant for pulmonary related infections.

Thus, the initial use of ABA was associated with a 22% less risk for hospitalzed infections when compared to those who initiated a TNFi. The signficance was largely against those who initiated infliximab and was not significantly different when compared to those initiating etanercept or adalimumab.

In another study published in Rheumatology, Montastruc et al. assessed the risk of cancer when choosing abatacept or other biological DMARDs (bDMARD) as the initial biologic in treating RA. They also used a US commercial claims dataset with supplemental US Medicare data 2007 to 2014. (Citation source: https://buff.ly/2TCFg1b)

The  comparison included cohorts of 4328 ABA patients and 59,860 on other bDMARDs. The incidence rates for any cancer were:

• ABA: 4.76 per 100 per year
• bDMARDs: 3.41 per 100 per year

Abatacept had a small but significant increased risk of all cancer (aHR 1.17; 95% CI 1.06, 1.30).  These results were largely driven by a significantly increased incidence of non-melanoma skin cancer (aHR 1.20; 95% CI 1.03, 1.39).

The risk of other specific cancer sites were not significant between groups.

These findings have limitations and will need to be studied and replicated in other populations to be clinically meaningful.