Background/Purpose:

To analyze the efficacy and identify predictors of response to tocilizumab (TCZ) in patients with rheumatoid arthritis (RA).

Methods:

A multicenter ambispective observational study in 126 patients with active RA treated with TCZ. The variables associated to achieve the therapeutic goal (remission of the disease defined as a DAS28 < 2.6) at 3 and 6 months were identified by a logistic regression model by using the backward approach. SAS 9.3 was used for the management and statistical analysis.

Results:

Patients’ demographic and clinical characteristics are shown in table 1, as well as the response rates at 3 and 6 months of treatment. TCZ was administered as the first biologic in 33 out of 126 patients, while in the remaining 93 was used after inadequate response or intolerance to > 1 biological therapies (mean 2.18 ± 1.1, range 1-6). Forty-three patients (35%) received TCZ as monotherapy. In the multivariate analysis, the predictive factors that increase the likelihood of clinical remission (DAS28-ESR < 2.6) at 3 months were baseline ESR > 30 mm/h (OR: 19.07, 95% CI: 2.7- 133.7) and the presence of extra-articular manifestations of the disease (OR: 15.5, 95% CI: 2.3- 102.3). The factors that decreased it were of haemoglobin (OR: 0.53, 95% CI: 0.32- 0.91), baseline DAS28-ESR (OR: 0.30, 95% CI: 0.15- 0.64) and the number of previous DMARDs and biological therapies used (OR: 0.42, 95% CI: 0.22- 0.78). The only significant factor that reduced the possibility of clinical remission (DAS28-ESR < 2.6) at 6 months was the baseline DAS28-ESR (OR: 0.55, 95% CI: 0.35- 0.88). No relationship was found in the decrease of the neutrophils count or in the positivity of rheumatoid factor / ACPA.

Table 1

Number of patients Age: (mean ± SD), years	126 57 ± 13
Gender: (female / male)	108 / 18
Disease duration: median (range), years	10 (1- 41)
Presence of rheumatoid factor/ ACPA	72% / 67%
Erosive disease	70%
Systemic extra-articular manifestations	33%
Number of previous DMARDs: (mean ± SD)	2.53 ± 1.4 (1-7)
Baseline DAS28-ESR: (mean ± SD)	5.5 ±1.08
Response rates at 3 and 6 months of treatment Remission by DAS28-ESR (< 2.6) Low activity by DAS28-ESR (< 3.2) Remission by SDAI  (< 3.3) Low activity by SDAI  (< 11) Good EULAR response Remission by ACR/EULAR criteria	31% / 40%                48% / 64% 25% / 31% 69% / 76% 48% / 63% 15% /16%

Conclusion:

The high inflammatory activity of the disease (measured by haemoglobin, ESR and DAS28), as well as the presence of extra-articular manifestations and the previous DMARDs and biological therapies may help in the selection of the best candidates for treatment with tocilizumab.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/predictive-factors-of-response-to-tocilizumab-in-patients-with-active-rheumatoid-arthritis/