Background/Purpose

The treatment for Rheumatoid Arthritis (RA) is based on synthetic or biological disease-modifying drugs (DMARDs). Current guidelines recommend biologics in combination with methotrexate as this shows better control of disease progression. However several studies show that up to 30% of patients are treated with biologic monotherapy for different reasons. The aim of the study was to know the characteristics of patients receiving biologic monotherapy, including previous treatments and reasons for treatment change.

Methods

Observational, cross-sectional, retrospective and multicentric study with the participation of 38 rheumatology units in Spain. Patients were consecutively included if they were >18, with moderate to severe RA with an inadequate response or intolerance to synthetic or biologic DMARD (as recommended by the Spanish Rheumatology Society, SER), treated with biologic DMARD in monotherapy for >6 months and gave informed consent.

Collected variables included sociodemographic (age, gender), clinical (RA diagnosis date, extra-articular manifestations, DAS28, CDAI and SDAI, presence of joint damage), and treatment (prior treatments with DMARD and reasons for change).

Results

Two hundred and nine patients were included, 82.8% were women, mean (SD) age was 57.6 (13.6). Mean (SD) time since RA diagnosis was 13.5 (8.8) years. Most had RF (59.8%), 38.3% anti-CCP antibodies, 73.7% joint damage; 28.5% had extra-articular manifestations.

At study visit, 58.4% of patients were receiving tocilizumab, 18.7% etanercept, 12.4% adalimumab, and 10.5% other biologics. Mean (SD) number of tender joints was 1.9 (3.0), of swollen joints was 0.84 (2.1); mean (SD) CRP level was 4.0 (7.7), and ESR was 14.6 (13.4). Mean (SD) DAS28 score was 2.7 (1.1), CDAI index was 8.4 (6.9), and SDAI index was 8.8 (7.1), with 49.8%, 15.8%, and 20.1% of patients on in remission, respectively.

28 of the 122 patients (23.0%) receiving monotherapy with tocilizumab were on first-line treatment, while 70.4% of patients with anti-TNF on monotherapy were on first-line.

The first synthetic DMARD prescribed was methotrexate (62.3%), followed by gold salts (17.9%). Mean time (months) since first DMARD prescription was 19.5 (52.8) [mean (SD)] and 89.8 (86.4) since the first biologic use.

Patients had received a mean (SD) of 2.6 (1.4) synthetic DMARDs and 1.7 (0.9) biologics.

Just before initiating monotherapy, 45.5% of patients had received synthetic+biologic DMARD, 30.6% synthetic DMARD as monotherapy, and 23.9% another biologic as monotherapy (30.0% adalimumab and 28.0% etanercept).

The most frequent reason for treatment withdrawal before monotherapy was lack of effectiveness (61.2%), intolerance (10.5%), adverse events (10.0%), and lack of adherence (1.5%). 

Conclusion

The clinical control with biologics as monotherapy was good, with a mean DAS28 of 2.7. Patients with RA treated with biologic DMARD as monotherapy had previously received more than 2 synthetic DMARD. The withdrawal of the DMARD was mainly due to lack of effectiveness, intolerance, or adverse event. Treatment with biologics as monotherapy is a therapeutic alternative for patients who do not tolerate or cannot receive synthetic DMARD.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/use-of-biologic-therapy-as-monotherapy-in-patients-with-rheumatoid-arthritis/