Pharmacodynamics, efficacy, safety and administration of intra-articular therapies for knee osteoarthritis

ABSTRACT

Introduction: Osteoarthritis (OA) is the leading cause of disability in the elderly, usually presenting with mono-or oligo-arthritis where local drug delivery by intra-articular (IA) injection may be more effective in terms of increased bioavailability, less systemic exposure and reduced adverse events. Several intra-articular medications for symptomatic are available on the market while the new disease-modifying drugs (DMOADs) are progressing into phase 3 pipeline of drug development.

Areas covered: This narrative review covered the pharmacokinetic and pharmacodynamics of clinically available IA drugs which include corticosteroids, hyaluronic acid as well as injection techniques, efficacy, adverse effects and contraindications. In addition, the authors briefly describe the newer disease-modifying OA drugs (DMOAD) which are undergoing phase 3 pipeline of development such as Fibroblast growth factor (FGF-18) and Wnt inhibitor.

Expert opinion: This is a rapidly evolving area with both new products and new trials regularly emerging. It is also a critically important area in a disease field that lacks for safe and effective treatments, where intra-articular delivery may enhance both local efficacy and reduce systemic toxicity.

KEYWORDS:

• Corticosteroids
• hyaluronic acid
• intra-articular injection
• increased bioavailability
• less systemic exposure
• reduced adverse events

Article highlights

• Systemic use of imaging guidance for intra-articular injection is not recommended although it has a higher accuracy rate compared to palpation-guided injection. Existing evidence for the impact on clinical outcomes and cost-effectiveness by ultrasound guidance is still limited and inconsistent across the studies.

• Pharmacokinetic studies of intra-articular corticosteroid demonstrate that the half-life ranges from 3 to 15 days and maximum concentration in plasma ranges from 1 to 11 ng/mL depending on the products.

• Limited research evidence of pharmacokinetics in humans is available for Wnt inhibitor and no pharmacokinetic studies are available for Fibroblast Growth Factor-18.

• Intra-articular corticosteroid and hyaluronic acid injections produce differential onset and duration of action. Data suggest that the former provides higher pain relief in the short term (up to 1 month), equal efficacy at 3 months, and lower analgesic effects in the long term (up to 6 months) compared with the latter.

• Newer types of modified medication such as FX006 to prolong the residence time in the joints, and innovative targeted therapy such as fibroblast growth factor-18 (sprifermin) and Wnt inhibitor (SM04690) demonstrate encouraging disease-modifying effects in phase 2 trials, and are likely to proceed to phase 3 clinical trial stage.

• For the clinical trials involving hyaluronic acid, there are issues such as under-reporting of safety data and of negative results making it difficult to draw definitive conclusions.

Acknowledgments

DJ Hunter is funded by an NHMRC Practitioner Fellowship. The corresponding author had full access to all the data in the study and had final responsibility for the decision to submit for publication. This is a narrative review and the comments and editorial expressed herein represent those of the author and do not reflect those of any official scientific role or institution that the author may hold or be affiliated with.

Declaration of interest

D Hunter provides consultancy advice to Merck Serono, Eli Lilly, Pfizer and TLCBio.

The authors have no relevant affiliations or financial involvement with any organization or entity with a financial interest in or financial conflict with the subject matter or materials discussed in the manuscript. This includes employment, consultancies, honoraria, stock ownership or options, expert testimony, grants or patents received or pending, or royalties.

Reviewer disclosures

Peer reviewers on this manuscript have no relevant financial or other relationships to disclose.

Additional information

Funding

This paper was not funded