Abstract

Hand osteoarthritis (HOA) is the most frequent form of osteoarthritis. A subset of digital hand OA is marked by an “inflammatory” like presentation with painful interphalangeal joints, refractory to NSAIDS and analgesics.

This clinical form of OA may be associated with a so called “erosive” radiographic aspect marked by subchondral erosions of the finger joints and ankylosis. Many mediators of inflammation have been involved in the pathogenesis of osteoarthritis such as prostaglandin E2, free radicals and main cytokines (IL1B, IL6, and TNFa).

Using Doppler power ultrasonography and magnetic resonance imaging, it has been shown that synovitis is frequently associated with HOA and correlates with pain and with disease progression.

Taking all those considerations together, it appears logical to target synovitis in HOA, especially with an erosive form.

Because erosive hand OA is a polyarticular disease, the treatment is more systemic than local.

Local or oral NSAIDS are out of scope because this presentation focuses on patients with HOA non responders to analgesics and NSAIDS. So far, none of the disease modifying drugs such as methotrexate has proved its efficacy.

Regarding biologics, several strategies have been approached. The first biotherapy used in HOA was IL2 receptor plus hydroxychloroquine in a very limited number of patients. Then and more recently, anti-TNFa strategy has been tested in well done RCT, in painful hand OA: one with adalimumab over a year, one with adalimumab 40 mg with 2 sub-cutaneous injections, one using Etanercept (50 mg/week 24 weeks and then 25 mg/week the next 24 weeks). None of those anti-TNFa blockers demonstrated a structural or an analgesic effect. However in the long term trial published by Verbruggen G, the incidence of new erosive lesions was decreased in Adalimumab group compared to placebo, only in a subgroup of patient with clinically inflamed IP joints.

Using anti-IL1B strategy, a decrease in pain has been observed in 3 patients using daily subcutaneous injection of Anakinra (100mg) over 3 months ( ).

In this Eular meeting a double inhibition of IL-1 Beta and IL-1 Alpha (using a monoclonal antibody directed against both cytokine) failed to demonstrate any benefit compared to placebo injection over 26 weeks.

Finally anti-IL6 strategy has been presented in this 2017 Eular meeting in a limited number of patients (n=18) with erosive HOA. Using monthly IV perfusion, the authors showed an improvement in pain level and functional status.

Conclusion: though anti-inflammatory strategy in painful HOA is logical, no treatment so far has been able to demonstrate a beneficial effect. Further studies should contemplate either news targets, or new modalities of repeated injections and should be adapted according to the phenotype of pain.