Biologic drugs as analgesics for the management of osteoarthritis

Background: Biologic drugs are novel therapeutic agents with demonstrated effectiveness in the management of a variety of chronic inflammatory disorders. Unmet needs in the treatment of chronic pain have led physicians to utilise a similar approach to patients suffering from conditions not characterised by systemic inflammation such as osteoarthritis (OA). The aim of this review is to discuss the current knowledge on the use of commonly used biologic agents (i.e. anti-tumour necrosis factor alpha (anti-TNF alpha) and anti-nerve growth factor (anti-NGF)) for the management of OA.
Methods: A narrative literature review of studies investigating the use of biologic agents for the management of osteoarthritis was conducted. We searched MEDLINE and EMBASE for English language publications. A hand-search of reference lists of relevant studies was also performed.
Results: Current evidence does not support TNF-alpha inhibition for the management of OA, although a selected subgroup of these patients with a marked inflammatory profile may benefit from this therapy. Anti-NGF therapy has been shown to reduce pain and improve function compared to placebo and non-steroidal anti-inflammatory drugs in OA but concerns remain regarding the safety of such treatment. The discrepant results observed in RCTs of biologic agents may be related to heterogeneity, small sample sizes and differences in the mode of administration of these drugs.
Conclusion: Anti-NGF therapy is efficacious for pain in patients with hip and knee OA. Despite the fact that current data suggests that anti-cytokine treatments have limited efficacy in patients with chronic osteoarthitic pain, larger and better designed studies in more selected populations are justified to determine whether such therapeutic approaches can improve outcomes in this disabling condition where our medical treatment armamentarium is relatively poor.