Background/Purpose: Studies have shown better response for anti-TNFs (aTNF) when they are used in combination with non-biologic DMARDs (nbDMARD), than when used as monotherapies.¹ Therefore, non-adherence to nbDMARDs prescribed in combination with aTNFs may reduce the benefit obtained with these agents.  This study examined the use of aTNF monotherapy in the real world, and adherence with nbDMARDs in patients receiving combination  aTNF+nbDMARDs.

Methods: We conducted a claims analysis of adult RA patients in a US managed care plan, initiating an aTNF (etanercept; adalimumab; infliximab; golimumab; or certolizumab pegol) between Jan 2006 and Dec 2010. aTNF initiators were classified as ‘biologic-naïve’ or ‘previously-exposed’, based on prior biologic use. Patients were followed from aTNF initiation until discontinuation of that aTNF or plan disenrollment. The proportion of patients receiving aTNF as monotherapy (i.e. never received nbDMARD during aTNF follow-up) was determined; nbDMARDs included methotrexate (MTX), leflunomide, sulfasalazine, hydroxychloroquine, cyclophosphamide, gold salts, azathioprine, cyclosporine, and d-penicillamine. In patients receiving combination therapy (i.e. received nbDMARD at any time during aTNF follow-up), adherence to nbDMARDs was defined as the percent of days that patients received any nbDMARD while they were receiving the aTNF agent. Thus, 100% adherence indicates that the patient was on some nbDMARD 100% of the time during their aTNF follow-up based on filled prescriptions. Adherence with MTX was also assessed separately.

Results: Of 7,074 biologic-naive RA patients initiating an aTNF, 27% received it as monotherapy and 73% in combination with nbDMARDs. Of 2,690 aTNF patients previously exposed to biologics, 31% received monotherapy and 69% in combination with nbDMARDs. Only 42% of patients receiving aTNF monotherapy vs. 89% of combination therapy patients had filled a nbDMARD prescription during the 6 months prior to initiating the aTNF agent. Among biologic-naïve combination therapy patients, 52% of patients adhered with nbDMARD therapy less than 80% of the time while receiving aTNFs; 32% of the patients had less than 60% adherence. Of biologic-naïve patients who received aTNF combination therapy with methotrexate, 56% had less than 80% adherence with MTX and 35% had less than 60% adherence with MTX while receiving the aTNF. Results were similar for aTNF patients previously exposed to biologics. Adherence calculated here based on claims data may be an overestimate because we do not know if patients consumed the filled prescriptions.

Conclusion: This study found that up to 31% of patients receiving an aTNF agent for RA in the real-world received it as monotherapy,and a substantial proportion of those receiving combination therapy had less than 60% adherence with nbDMARDs. Some of these patients may have sub-optimal outcomes, as suggested by evidence that RA patients receiving aTNFs in combination with nbDMARDs have better response.¹

¹ Nixon et al..Rheumatology 2007 ; 46 : 1140 – 7.

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/use-of-anti-tumor-necrosis-factor-monotherapy-and-adherence-with-non-biologic-disease-modifying-anti-rheumatic-drugs-in-combination-with-anti-tumor-necrosis-factor-therapy-among-rheumatoid-arthritis-p/