In a study reported at the Academy of Managed Care Pharmacy annual meeting, adalimumab was found to have the lowest incremental cost per responder (CPR) and to be cost-saving, compared with the next most cost-effective option, etanercept, among the biologics approved by the US Food and Drug Administration (FDA) for treating ankylosing spondylitis (AS).
“Taking costs into account, adalimumab was found to be the most cost-effective biologic treatment…,” Keith Betts, PhD, of the Analysis Group Inc, Boston, Massachusetts, and colleagues, noted on their poster.
Biologic therapies, specifically the tumor necrosis factor-α (TNF-α) inhibitors, confer immediate, significant, and sustained improvements for almost all clinical symptoms of AS, but there have been few head-to-head comparisons of their efficacy and costs. The current study was a CPR analysis of the FDA-approved biologics for treating active AS, based on data from 13 randomized clinical trials evaluating the drugs in their approved doses versus placebo. The drugs included adalimumab, etanercept, certolizumab, golimumab, and infliximab.
Betts and his team determined the relative probability of achieving response at week 12 according to ASAS 20 (improvement ≥20% or ≥10-unit reduction in at least 3 of 4 domains, without worsening in the fourth domain). They also determined ASAS40 response (≥40% improvement). Treatment costs were calculated based on wholesale acquisition costs. The incremental CPR was calculated by multiplying the incremental drug cost by the number needed to treat (NNT).
The investigators found no statistical differences between the biologic treatments in terms of ASAS20 response. Numerically, infliximab had the highest estimated ASAS20 (71%), followed by adalimumab (63%), etanercept (61%), golimumab (60%), and certolizumab (50%). ASAS40 response was also not statistically different between the treatments: infliximab (51%), adalimumab (49%), etanercept (41%), golimumab (39%), and certolizumab (35%).
However, the network meta-analysis for the estimated ASAS20 NNT and incremental cost per ASAS20 responder numerically favored adalimumab, whose incremental cost ($21,067) was $2924 lower than the next lowest, etanercept. The costs and NNT versus placebo per ASAS20 responder are shown in the Table.
Irrespective of costs, infliximab was found to require the lowest NNT to achieve ASAS20 or ASAS40 response, the authors noted.
“We conducted 3 sensitivity analyses to evaluate the robustness of the outcomes and found consistent results,” they indicated on the poster.
Disclosure: The study was funded by AbbVie, Inc.
Reference
Betts K, Griffith J, Mittal M, et al. Indirect treatment comparison of adalimumab, etanercept, certolizumab, golimumab, and infliximab for the treatment of ankylosing spondylitis. Poster presented at: Academy of Managed Care Pharmacy 27th Annual Meeting & Expo; April 7-10, 2015; San Diego, CA.