Delegates at the European League Against Rheumatism conference in Barcelona, Spain have come away impressed by the fresh data Roche presented for its new compound Actemra, which blocks the activity of interleukin-6.

The Swiss drugmaker unveiled results from OPTION, the first rheumatoid arthritis Phase III study of Actemra (tocilizumab) outside Japan (Roche’s majority-owned partner Chugai already sells the drug there for Castleman's disease, a rare immune disorder). The data showed that patients who received tocilizumab in combination with methotrexate achieved rapid and significant improvement in their signs and symptoms of rheumatoid arthritis when compared to patients on methotrexate alone.

The 24-week study involving 623 patients with moderate to severe rheumatoid arthritis showed that four times the percentage of patients in the tocilizumab group experienced 50% improvement in disease symptoms compared to the control group (44% versus 11%), while 22% achieved a 70% improvement compared to 2% in the methotrexate-alone group. 28% of patients achieved the ultimate goal of remission in the tocilizumab group versus only 1% of patients in the control group.

Josef Smolen, lead investigator of the OPTION trial, said that the efficacy of interleukin-6 receptor inhibition in the study “confirms the critical role of IL-6 in the causal pathways of rheumatoid arthritis”. He added that “on this basis, the clinical success observed with tocilizumab, by targeting a novel pathway, is extremely encouraging as is the opportunity for rheumatoid arthritis patients to benefit from a potential new treatment option”.

The newest arthritis treatments target tumour necrosis factor, but up to 40% of patients do not get an adequate response. TNF inhibitors can also have significant side effects, including tuberculosis and increased cancer risk and while there are also concerns about Actemra, Prof Smolen said the problems caused by the drug were not major. Tocilizumab also increases cholesterol levels, but the effect is modest.

The safety and efficacy profile of Actemra is impressing analysts and Roche now plans to file the drug for regulatory approval in the USA and Europe by the end of 2007. The firm is hoping it will become a blockbuster and expand its small but impressive rheumatoid arthritis portfolio.

MabThera also impresses

Leading the latter is its cancer drug MabThera (rituximab), which was approved as a treatment for rheumatoid arthritis last year and Roche also presented impressive data on the drug at EULAR which revealed that the compound can deliver sustained benefits to patients and, most significantly, its safety profile is unchanged even after multiple treatments.

The data showed that after three courses of MabThera in patients who had an inadequate response to anti-TNF inhibitors, the number achieving a 70% improvement in symptoms rose to 25% from 11%. Remission rates also doubled whilst importantly, the safety profile of MabThera remained consistent in 1,053 patients, 13% of whom had received four courses of treatment.

Roche noted that further pooled safety data when used long-term revealed a consistent safety profile, with an unchanging rate of serious infections following subsequent courses. “These results add to the wealth of data already in existence on the drug’s safety profile with 2,438 patient-years of follow-up now collected,” the firm concluded.