Roche's drug, called Actemra (tocilizumab) is a humanized monoclonal antibody anti-receptor of interleukin-6 (IL-6) - a pro-inflammatory cytokine that stimulates an immune response to trauma and has been shown to play a role in multiple disease indications.
By blocking IL-6, Actemra is designed to reduce or prevent symptoms associated with autoimmunity and inflammation, when used in combination with traditional disease modifying drugs (DMARDs).
Actemra has already been available in Japan since 2005 as a therapy for a different indication, Castleman's disease, and in April 2006 approval was also filed for the additional indications of RA and systemic-onset juvenile idiopathic arthritis after it performed well in further clinical trials.
Spurred on by this, Roche is hoping to gain approval for the drug in Europe and the US, although this may not be as simple as it sounds - because of inter-ethnic genetic differences, drugs that are safe and efficacious in the Japanese population are sometimes not in Caucasian populations and vice versa.
However, positive results for the drug were revealed today from a randomised, double-blind study Phase III study called TOWARD (Tocilizumab in cOmbination With traditional DMARD therapy).
In this study, patients received either 8mg/kg Actemra intravenously every four weeks or placebo, in combination with stable anti-rheumatic therapy, including traditional DMARDs but excluding biologics. A greater proportion of patients treated with Actemra achieved a significant improvement in disease signs and symptoms at week 24, compared to those treated with DMARDs alone, said Roche.
Data from this latest TOWARD trial will be submitted for presentation at international scientific meetings later this year and in 2008, including the European Congress of Rheumatology on June 15, and a summary was posted on the conference's website last month.
TOWARD, which involved 1216 patients with moderate to severe RA across 130 sites in 18 countries, is the second of a programme of five Phase III global clinical trials running on Actemra, with the results of a further two studies expected later this year.
OPTION3, the first of this block of Phase III trials, was hailed by Roche in January as having successfully met its primary endpoint in patients who had an inadequate response to methorexate, although analysts at the time were reported to have said its outcome was still "slightly disappointing".
Actemra was developed by Japanese pharmaceutical company Chugai Pharmaceutical and Roche owns the rights to market Actemra outside Japan.
Roche is counting on its emerging portfolio of drugs targeting autoimmune diseases with rheumatoid arthritis as the first indication to be one of the most important drivers for its future growth.
RA is a progressive, systemic autoimmune disease affecting more than 21m people worldwide. It is characterized by chronic inflammation of multiple joints and fatigue as well as the possibility of osteoporosis, anaemia, and lung, skin and liver effects and causes pain, stiffness and swelling. After 10 years, less than half of sufferers can continue to work or function normally on a day to day basis.
If all goes well, Roche plans to file for regulatory approval of Actemra in the US and Europe by the end of this year and analysts have predicted that Actemra has the potential to generate between CHF775m (€470m) and CHF2bn if it reaches the market.