Background/Purpose:

The incidence of adverse events (AE) among rheumatology medication users has not been well documented in real-world disease registry datasets in the US.  We  quantified the incidence of AEs of interest among rheumatoid arthritis (RA) patients treated with adalimumab in the Corrona RA registry.

Methods:

Adult RA patients from the US Corrona RA registry who initiated treatment with adalimumab between 1/1/2008 and 6/1/2017 and had at least one follow-up visit were included. AE of interest included serious infections, malignancy (excluding non-melanoma skin cancer), hospitalized congestive heart failure (CHF) and all-cause mortality.

The incidence of patients experiencing at least one new event of that type was calculated. Person-time at risk was estimated from time of drug initiation to either the occurrence of first event or 90 days after discontinuation of adalimumab (serious infections and hospitalized CHF) or last Corrona visit (censored). All time post adalimumab initiation regardless of discontinuation was considered for both malignancy and mortality. Incidence rates (IR) per 100 person-years were calculated with 95% confidence intervals assuming a Poisson distribution.

Results:

There were 2798 adalimumab initiators available for analysis with mean age of 54.5 years, 77% were female, and mean duration of disease was 8.3 years. Nearly half (48%) were biologic naïve at the time of adalimumab initiation. Prednisone use of ≥10mg occurred in 9% of patients at the time of adalimumab initiation and the majority of the patients (74%) used adalimumab for 3 years or less.

The IR per 100 person years for serious infections, CHF requiring hospitalization, malignancy excluding non-melanoma skin cancers, and all-cause mortality were 1.86 (1.50, 2.31), 0.15 (0.07, 0.31), 0.64 (0.50, 0.84), 0.33 (0.24, 0.48), respectively. The incidence of events by duration of adalimumab exposure categories (≤1 year, >1-3 years,>3-5 years, > 5 years) are provided in the Table. Serious infection was higher in the first year of therapy (3.44 [95% CI 2.45-4.84) and other AEs did not vary by duration of exposure.

Conclusion:

The IR of serious infection, CHF, malignancy and mortality in this prospective real-world registry are reassuring as they appear consistent with adalimumab RA clinical trial data and other observational registry data.^1-4

Table.  Incidence of events by subgroups of overall exposure to adalimumab

*Serious Infections included infections that led to hospitalization or IV antibiotics. **Malignancy excluded NMSC.

References:

1.       Burmester GR, et al. Long-term safety of adalimumab (Humira) in adult patients from global clinical trials across multiple indications. Presented at the Am Coll of Rheum Annual Meeting, 2017, San Diego, CA.

2.       Rutherford, AI, et al. Ann Rheum Dis. 2018;77:905-10.

3.       Mercer LK, et al. Ann Rheum Dis. 2015;74:1087-93.

4.       Simard JF, et al. Arth Rheumatism. 2012;64:3502-10.