OBJECTIVES: : To estimate annual biologic cost per treated patient in rheumatoid arthritis (RA), plaque psoriasis, psoriatic arthritis, and ankylosing spondylitis using drug utilization from US managed care. METHODS: : The IMS LifeLink Health Plan Claims Database was used to identify adults (18-63 years) with a claim for etanercept, adalimumab, infliximab, abatacept, rituximab, golimumab, certolizumab, or ustekinumab between January 1, 2008 and December 31, 2010 preceded by ≥180-days of enrollment. Patients had to have a qualifying diagnosis between 180 days before and 30 days after index and be enrolled for ≥360 days post-index. The first biologic claim meeting these criteria defined the index date. Patients with pre-index Crohn’s disease, ulcerative colitis, non-Hodgkins lymphoma, or chronic lymphocytic lymphoma were excluded. Annual cost per treated patient equaled total dose for the index biologic and biologics taken after discontinuation of the index biologic multiplied by October 2012 WAC, plus number of administrations multiplied by the 2012 Medicare Physician Fee Schedule costs. RESULTS: : Of 35,525 included patients; 92.7% received etanercept (n=16,704), adalimumab (n=10,154), or infliximab (n=6,056). Most patients (63%) were female, mean age 48.9 years and treated for RA (56%). Pooled across indications, cost per treated patient for agents approved for all indications was $20,284 for etanercept, $20,010 for adalimumab, and $22,795 for infliximab.  Cost per treated patient in RA was $19,251 for etanercept, $20,387 for adalimumab, $21,585 for infliximab. The range in other agents was from $16,286 for golimumab (n=120) to $19,710 for certolizumab (n=101).  In psoriasis, cost per treated patient ranged from $20,261 for adalimumab (n=1,874), to $34,951for ustekinumab (n=116).   The costs in other groups were similar to those in RA. CONCLUSIONS: : Of agents approved for all indications, infliximab, which is infused, had higher costs than adalimumab or etanercept which are self-injected.  Although some new agents had lower costs in RA, sample size for these agents was limited.