The trial of the drug called masitinib was carried out by researchers from several French hospitals. It involved 43 patients with arthritis resistant to current treatments.
Reporting their findings in BioMed Central's open access journal Arthritis Research and Therapy, the researchers have revealed that treatment with masitinib significantly reduced the severity of active arthritis.
"In choosing which interventions to use for the management of rheumatoid arthritis, it is important to recognise that treatment should aim to keep the disease in remission and not be used intermittently to manage exacerbations. We are encouraged from this study that masitinib not only appears to be effective, but that within the first 3 months of treatment the worst of its side-effects were over, possibly making it suitable for long-term treatment regimens," said Olivier Hermine, one of the researchers.
"The results of this study also help establish the critical role of mast cells in the pathogenesis of rheumatoid arthritis and demonstrate their viability as a therapeutic target. There is sufficient compelling evidence to warrant further placebo-controlled investigation," he added.
The researchers have revealed that masitinib inhibits the activity of mast cells, a component of the immune system thought to be involved in the pathogenesis of rheumatoid arthritis.
The clinical improvement described in the study was supported by laboratory evidence of reduced inflammation.
The authors found that adverse effects of the treatment were mainly mild to moderate.
Alain Moussy from AB Science, a pharmaceutical company who are developing masitinib for multiple indications in human and animal medicine, said: "This is a milestone article for us, being the first publication of masitinib in a human study."
Moussy added: "Our preclinical studies have shown that masitinib selectively targets cell receptors known to be involved in various disease processes but does not affect those associated with toxicity, particularly cardiotoxicity."