A new ‘smart drug’ for treating rheumatoid arthritis has received extremely positive results in two separate trials published this week in The Lancet.
Medical schools at the University of Vienna and the University of Yokohama have studied rheumatoid arthritis sufferers over a wide age range being treated with tocilizumab, a drug developed by pharmaceutical giants Roche and Chugai. Both studies found that the treatment could massively reduce the severity of the symptoms which the patients had to suffer and could do so with fewer side effects than common treatments
Rheumatoid arthritis is an autoimmune disorder which affects over 450,000 people in the UK and is far more common in women than men. The disease creates painful swellings in the joints and can even destroy the cartilage padding them, making the pain even worse. It can also lead to tiredness and other symptoms such as rashes and can increase the risk of heart disease.
These symptoms are caused by the immune system mistakenly identifying cells of the sufferer’s own body as disease microbes. It attacks these cells by flooding them with white blood cells called T-lymphocytes
The disease is usually treated with drugs called disease modifying antirheumatic drugs (DMARDs), the most common of which is called methotrexate. These drugs work by blocking the enzyme pathways needed to allow the T-lymphocytes to form and to attach to the sufferer’s cells. The major disadvantage of these treatments is that they are all extremely toxic and cannot be taken for a prolonged period of time, making them unsuitable for treating chronic sufferers.
Tocilizumab works by attacking the problem from a different angle. It blocks the synthesis of a protein called interleukin-6 which is found in high concentrations in severely inflamed joints and, by doing so, claims to reduce the severity of the condition. It is also far less toxic as it blocks a less crucial pathway.
The first study, by the University of Vienna, focussed on adult sufferers and says that the new drug, based on the structure of a human antibody, “significantly and rapidly improves the signs and symptoms of rheumatoid arthritis”.
In this trial, the drug was given to 623 patients with moderate to severe rheumatoid arthritis. A successful outcome for this study was defined as a 20% improvement in symptoms (under American College of Rheumatology criteria)
Of the 623 patients, 205 were given 8mg of tocilizumab per kg of body weight, 214 patients received 4mg per kg of body weight and 204 received a placebo. The drugs and placebo were given intravenously every four weeks, along with methotrexate, at doses of 10-25mg per week.
After 24 weeks, 59% of patients receiving the 8mg dose had shown a 20% decrease in symptoms. In those receiving 4mg, 48% recorded a response, compared with 26% in the placebo group. This, the study says, proves that tocilizumab could be “an effective agent for the treatment of patients with moderate to severe rheumatoid arthritis.”
The second study, by the University of Yokohama, focussed on juvenile arthritis sufferers aged 2-19. It found an improvement in symptoms in 91% of the patients treated and hails tocilizumab as “a step forward in the control of a disease that has previously proved to be difficult to manage”.
Both trials found adverse effects, such as gastric infections, in some subjects but, compared to the extreme side effects which traditional arthritis treatments can have, these were comparatively minor. Therefore, tocilizamub seems to represent a significant advance in the treatment of this painful and crippling disease.