As expected, a panel of experts has recommended to US regulators that Roche’s rheumatoid arthritis drug Actemra should be given marketing approval, despite some concerns about possible liver damage.

The Arthritis Advisory Committee of the US Food and Drug Administration has voted 10-1 for approval of Actemra (tocilizumab), a novel interleukin-6 (IL-6) receptor-inhibiting monoclonal antibody, for reducing the signs and symptoms in adults with moderate to severe RA. The recommendation is based on data from five Phase III trials involving over 4,000 people, which demonstrated that Actemra – alone or in combination with methotrexate or other disease modifying anti-rheumatic drugs – significantly reduced RA signs and symptoms, regardless of previous therapy or disease severity.

Kenneth Bahrt, Roche’s global medical director for autoimmunity, said the committee's “overwhelmingly positive recommendation brings Actemra one step closer to becoming available to patients who suffer from the painful and debilitating symptoms associated with RA". The FDA, which usually follows the advice from its panellists, will make a final decision by mid-September.

Panel members were indeed impressed by the data on the whole but raised concerns about potential side effects, including liver damage. One of them, Jeffrey Siegel, clinical team leader at the FDA's Division of Anesthesia, Analgesia and Rheumatology Products, said the data suggested there was only a small problem of liver abnormalities in patients on Actemra but there is still a worry about long-term use.

In response, Roche said it will continue studying Actemra for five years, and create registries to track any problems associated with the drug, which was launched by the Swiss firm’s subsidiary Chugai in Japan in June 2005 as a therapy for Castleman's disease. In April this year, additional indications for RA, polyarticular-course juvenile idiopathic arthritis and systemic-onset JIA were also approved in Japan.

It looks like Roche has another blockbuster on its hands as Actemra provides a new option for patients who do not respond to anti-tumour necrosis factor-alpha therapies such as Abbott Laboratories’ Humira (adalimumab), Johnson & Johnson/Schering-Plough’s Remicade (infliximab) and Wyeth/Amgen’s Enbrel (etanercept). Up to a third of patients are not adequately treated with those drugs, Roche believes, and analysts have been estimating sales in the range of $2-$4 billion.