Tocilizumab Provides Significant Clinical Benefit In Rheumatoid Arthritis Patients

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Main Category: Arthritis / Rheumatology
Article Date: 15 Jun 2007 - 8:00 PDT

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The investigational compound tocilizumab (ActemraTM) significantly reduces disease activity in patients with moderate to severe rheumatoid arthritis (RA) who have an inadequate response to methotrexate, researchers announced at the European League Against Rheumatism (EULAR) 2007.

Josef Smolen, MD, chairman of the rheumatology department at the Medical University of Vienna, reported findings in 623 patients who had been randomized to receive tocilizumab 8 mg/kg, tocilizumab 4 mg/kg, or placebo, administered by intravenous infusion every four weeks. Tocilizumab is a novel monoclonal antibody targeting interleukin (IL)-6 signaling.

All patients enrolled in the study had moderate to severe active RA despite long- term metrotrexate treatment.

Participants in the trial continued to receive concomitant oral or parenteral methotrexate at their pre-study dose of 10 to 25 mg weekly throughout the trial and stopped all other disease-modifying anti-rheumatic drugs upon entry into the study.

The primary endpoint was the proportion of patients achieving American College of Rheumatology (ACR) 20 response at 24 weeks.

Results of the phase III tOcilizumab Pivotal Trial in methotrexate Inadequate respONders (OPTION) trial showed that 58.5% of patients in the 8 mg/kg group and 47.9% in the 4 mg/kg group achieved ACR20 responses at week 24 compared with 26.5% in the placebo group.

Also, 22% who received tocilizumab 8 mg/kg achieved ACR70, and 43.9% achieved ACR50. Only 2% of the placebo cohort achieved ACR70, and 10.8% achieved ACR50.

The analysis also showed a decrease in the Disease Activity Score in 28 joints (DAS28) starting the second week. At 24 weeks, the mean DAS28 score was reduced by 3.43 in the 8 mg/kg tocilizumab group, 2.63 in the 4 mg/kg tocilizumab group, and 1.55 in the placebo group.

Both doses of tocilizumab were generally well tolerated, and there was a similar rate of adverse events in the three study groups. The incidence of infections was slightly higher than with placebo but no incidence of tuberculosis was observed.

"Overall, the results show that tocilizumab in combination with methotrexate provides rapid and significant improvements in the signs and symptoms of RA," Dr. Smolen said.

He added that the high efficacy of Il-6 receptor inhibition with tocilizumab confirms the critical role of Il-6 in the pathophysiology of RA.

By Jill Stein
Jillstein03@cs.com
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