Background/Purpose: Biologics used for rheumatoid arthritis (RA) and ankylosing spondylitis (AS), including tumor necrosis factor blockers, are a key area of focus for Veterans Affairs (VA) Pharmacy Benefits Programs. This study describes treatment patterns with etanercept (ETN), adalimumab (ADA), and infliximab (IFX) in US veterans with RA or AS during the first year of treatment.

Methods: National VA pharmacy, administrative, and clinical databases were used for this analysis. Eligibility criteria included ≥1 claim for ETN, ADA, or IFX from Jan 1, 2008 to Dec 31, 2011 preceded by at least 180 days of enrollment in the VA. The first drug and date that met this criterion was the index drug and date. Patients had to be ≥ 18 years of age on their index date; have ≥360 days of enrollment following their index date; and have ≥1 claim with an ICD-9-CM diagnosis of RA or AS prior to or within 30-days after their index date. Patients with a diagnosis of psoriatic arthritis, psoriasis, juvenile idiopathic arthritis, Crohn’s disease, ulcerative colitis, non-Hodgkin’s lymphoma, or chronic lymphocytic lymphoma, prior to or within 30-days of their index date; a claim for their index biologic prior to their index date; who used a biologic prior to its receiving approval for that condition; or who had implausible dosing (≥200% of the maximum labeled dose) were excluded.

Treatment patterns were classified based on whether or not patients were persistent on their index agent for the 360 days after their index date. Non-persistence was defined as a ≥45 day gap in days of supply on their index agent or a claim for a non-index biologic. Non-persistent patients were further categorized based on the first observed event after non-persistence: switching, a claim for a biologic other than their index biologic; restarting, another claim for their index biologic after the ≥45 day gap, or discontinued no subsequent claims for any biologic following the gap.

Results: ETN, ADA, and IFX were the index biologic for 2,109, 2,035, and 263 veterans with RA and 286, 422, and 46 veterans with AS. Approximately half of all patients with RA were persistent on therapy for the entire year; 49.3% of ETN, 51.4% of ADA, and 52.5% of IFX. Persistence in AS was lower (ETN, 42.0% and ADA, 40.0%), but higher with INF, 56.4%. In both RA and AS, switching rates were numerically higher in IFX users (RA: 18.6%; AS: 15.2%) compared with ETN (RA: 11.8%, AS: 10.1%) and ADA (RA: 10.3%, AS: 12.8%). Restarting was more common with ETN and ADA than INF in both RA and AS. Discontinuation rates were similar (11.9-14.0%) across agents in both RA and AS.

Conclusion: Overall, persistence during the first year of therapy for RA and AS was relatively low, 40.0-56.5%. Gaps in therapy occurred in 26.5-34.6% of patients taking self-injected agents, but only 15.5-16.3% of patients taking INF. More work is needed to understand the reasons for non-persistence in this population.

 

Diseases and Treatment Patterns		Etanercept		Adalimumab		Infliximab
		%	95% CI	%	95% CI	%	95% CI
RA	All	N=2,109		N=2,035		N=263
	Persistent	49.3%	47.2-51.4%	51.4%	49.2-53.6%	52.5%	46.4-58.5%
	Non-Persistent	50.7%	48.6-52.8%	48.6%	46.4-50.8%	47.5%	41.5-53.6%
	Discontinued   Biologic Therapy	12.0%	10.7-13.4%	11.9%	10.5-13.3%	12.5%	8.5-16.6%
	Restart After   a ≥ 45 day gap	26.9%	25.0-28.8%	26.4%	24.5-28.3%	16.3%	11.9-20.8%
	Switch Biologic   Therapy	11.8%	10.4-13.1%	10.3%	9.0-11.6%	18.6%	13.9-23.3%
AS	All	286		N=422		N=46
	Persistent	42.0%	36.2-47.7%	40.0%	35.4-44.7%	56.5%	42.2-70.8%
	Non-Persistent	58.0%	52.3-63.8%	60.0%	55.3-64.6%	43.5%	29.2-57.8%
	Discontinued   Biologic Therapy	13.3%	9.4-17.2%	14.0%	10.7-17.3%	13.0%	3.3-22.8%
	Restart After   a ≥ 45 day gap	34.6%	29.1-40.1%	33.2%	28.7-37.7%	15.2%	4.8-25.6%
	Switch Biologic   Therapy	10.1%	6.6-13.6%	12.8%	9.6-16.0%	15.2%	4.8-25.6%

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ACR Meeting Abstracts - https://acrabstracts.org/abstract/treatment-patterns-of-biologics-used-in-rheumatoid-arthritis-and-ankylosing-spondylitis-in-the-us-veterans-population/