Hydroxychloroquine as a Steroid-sparing Agent in Extrapulmonary Sarcoidosis

Sarcoidosis is a systemic granulomatous disease of unknown aetiology, mainly affecting the lungs and lymphatics. It affects people worldwide (incidence, 4.7-64/100000; prevalence, 1-36/100000/year). Although it is most often a benign acute or subacute condition, sarcoidosis may progress to a disabling chronic disease in 25% of the cases, with severe complications in about 5%, such as lung fibrosis, cardiac or neurosarcoidosis, defacing lupus pernio or blindness due to uveitis.

When indicated, corticosteroids (CS) are the mainstay of treatment. Due to the kinetics of granuloma resolution, the usual and quite 'dogmatic' duration of treatment is said to be one year, following four classical steps. The long-term use of CS is hindered by cumulative toxicity and efforts have to be made to taper them, as quickly as possible, to the lowest effective dose. A recent report mentioned 39% of the CS-treated patients requiring a steroid-sparing agent. Chloroquine (CQ) and hydroxychloroquine (HCQ) are anti-malarial drugs that have been used since the 1960's as steroidsparing agents on the basis of a landmark study by Siltzbach reporting their efficacy in 43 patients with skin and intrathoracic sarcoidosis. Subsequently, two small randomized controlled trials have shown significant and prolonged improvement on pulmonary symptoms. Only small case series/reports have shown CQ/HCQ efficacy on extra-pulmonary sarcoidosis with response rates ranging from 67 to 100%. Nevertheless, CQ/HCQ are daily used for skin, bone, and joint sarcoidosis, as well as hypercalcemia. Nowadays, HCQ is preferred over CQ because of a lower incidence of gastrointestinal and ocular adverse reactions, which can be minimized by close attention to the dosage and regular retinal examination. Its profile of safety is well-known since it has long been employed to treat systemic lupus erythematous or rheumatoid arthritis. Its action is thought to rely on its ability to accumulate in lysosomes of phagocytic cells, to affect antigen presentation and reduce pro-inflammatory cytokines. The investigator hypothesize that HCQ may be an efficacious add-on therapy for extra-pulmonary sarcoidosis leading to a significant steroid-sparing effect.