DOUBLE-BLIND RANDOMIZED CLINICAL TRIAL WITH CHLOROQUINE VERSUS PLACEBO FOR MAINTENANCE OF REMISSION OF AUTOIMMUNE HEPATITIS

Autoimmune hepatitis (AIH) is a chronic disease with a progressive destruction of hepatic parenchyma, leading to cirrhosis and high mortality in the absence of specific treatment. It has been demonstrated that the treatment with corticosteroids and azathioprine provides clinical and laboratory improvement, reduction of histological inflammatory activity on liver biopsy and an increased survival. The life expectancy of correctly treated patients can approach that of age- and gender-matched controls. One of the features of AIH is the high rate of recurrence after discontinuation of treatment in patients who achieved histological remission. The chances of recurrence reach up to 50% at 6 months and 70% after one year, and the rates of sustained remission, are limited to 10 to 15% in 5 years. Thus, most patients require maintenance treatment to prevent recurrence.

Chloroquine is a drug of the group of 4-aminoquinolines, synthetic derivatives of quinine and constituent of the bark of the Cinchona tree. Chloroquine accumulates in tissues in considerable amounts. In animals, from 200 to 700 times the plasma concentration can be found in liver, spleen, kidneys and lungs. As a weak base, it accumulates intracellularly, particularly in lysosomes with a consequent increase in pH within these organelles, which could contribute to its toxicity. Lysosomal lamellar bodies are observed in tissues affected by chloroquine, such as retina and neuromuscular system. Chloroquine inhibits the absorption and the binding of mitochondrial calcium, alters the membrane permeability and the transport of enzymes to the lysosomes. Apparently there are other mechanisms to explain its anti-inflammatory action; such as the interference with the release of TNF from mononuclear phagocytes by inhibiting gene expression and the down-regulation of TNF receptors, by delaying their transport to the cellular surface. Due to these mechanisms of action, chloroquine has anti-inflammatory activities and therefore is used in diseases such as rheumatoid arthritis and systemic lupus erythematosus. In liver diseases, chloroquine was used in patients with hepatitis B with normalization of the levels of aminotransferases and of the prothrombin time during treatment and relapse after drug discontinuation. Chloroquine was also evaluated in patients with porphyria cutanea tarda and despite the clinical and biochemical improvement, liver biopsies remained unchanged after one year of treatment.

A previous pilot study was performed in our institution, and published in 2005, with chloroquine diphosphate for the maintenance treatment of AIH. In this study, 14 patients with a biochemical and histological remission were treated with chloroquine diphosphate 250 mg/day for at least 12 months or until disease recurrence, and compared with 18 historical controls, which was held in discontinuation of treatment after remission. The chance of relapse was 6.49 times higher in the historical controls when compared with patients in the group treated with chloroquine (72.2% versus 23.5%, p = 0.031). The use of chloroquine was safe in patients with liver cirrhosis without decompensation, and there were no serious adverse events within two years of use.

The most common adverse effects of chloroquine are mild and transient such as gastrointestinal symptoms, headache, dizziness, blurry vision and fatigue. The more severe reactions described are itching, cardiovascular manifestations, dyskinesias, eye injuries, neuromuscular disorders and hearing loss. Among the most feared adverse effects of chloroquine, are the eye injuries, usually associated with chronic treatment. They may consist of changes in the retina, lens, cornea and optic nerve. Usually they remain stable after drug withdrawal, if the drug is discontinued in early stages. However, the retinal damage can increase when found in advanced stages, and may progress even years after cessation of chloroquine. It is believed that the chloroquine retinopathy can be prevented or recognized in an early reversible stage with judicious use, appropriate doses and regular ophthalmologic follow-up. It is recommended that the daily dose does not exceed 250 mg of chloroquine diphosphate or 400 mg of hydroxychloroquine, and ophthalmologic evaluations are carried out every 4 to 6 months. Despite the adverse effects and toxic reactions described above, there is a consensus in most studies with chloroquine that it is a well tolerated drug, provided that the appropriate dosage guidelines and regular eye examinations are followed. With these cautions in mind, its use rarely causes serious side or irreversible effects.

The purpose of this study is to investigate whether chloroquine prevents the risk of recurrence of AIH in patients in remission after discontinuation of conventional treatment, in prospective, randomized, double-blind trial, and to evaluate the occurrence of side effects from the use of chloroquine.