GlaxoSmithKline and partner Johnson & Johnson have filed for approval in Europe of sirukumab, a rheumatoid arthritis drug that if approved will compete with Roche’s $1.5bn Actemra product.
GSK and J&J’s Janssen Biologics unit are seeking EMA approval for their drug in combination with methotrexate in patients who have failed or are intolerant to disease-modifying anti-rheumatic drugs (DMARDs), including TNF inhibitors.
They are also seeking approval of the antibody as a single-agent therapy for rheumatoid arthritis (RA) patients who cannot take methotrexate.
Like Actemra (tocilizumab), sirukumab is an interleukin (IL-6) inhibitor that is designed to interrupt the autoimmune process in RA, and has been developed as a once-monthly subcutaneous therapy delivered by pre-filled syringe or auto-injector.
Actemra is given either by intravenous injection or subcutaneous injection once a week, so GSK and J&J’s drug has an advantage in dosing frequency.
While no head-to-head studies have been conducted, sirukumab does not appear to be quite as effective as Actemra or its nearest late-stage competitor – Sanofi’s sarilumab – if response rates from phase III trials are compared. Sarilumab is dosed by subcutaneous injection every two weeks.
The EU filing for sirukumab is based on the results of the SIRROUND phase III trials programme, which suggest that around 55% patients on the antibody achieve an ACR 20 response – a 20% improvement in signs and symptoms of RA – compared to a placebo response rate of around 26%.
That was not as impressive as the 84% improvement seen in phase II testing, and also does not seem quite as impressive as sarilumab, which averaged a 56-60% improvement in phase III testing.
Sarilumab has already been submitted for approval in the US, so should have the first opportunity to take on Actemra in the important US market, as GSK and J&J are not due to file there until later this year.
Sanofi’s drug has also already been shown to be more effective than AbbVie’s Humira (adalimumab) – the top-selling TNF inhibitor – in a phase III trial, while GSK and J&J are still waiting for the results of their head-to-head trial that is due to complete this month.
Given that Actemra is due to lose patent protection in 2019, analysts at Datamonitor have suggested that in time sirukumab will be used as a back-up therapy in RA after Actemra/generic tocilizumab and sarilumab.
J&J chief executive Alex Gorsky said recently that there will be a role for sirukumab in the treatment spectrum because there is a lot of variability between patients in their response to IL-6 inhibitors. The two partners are also exploring use of the drug in additional indications, notably giant cell arteritis and asthma.