GlaxoSmithKline has filed an application in Europe seeking approval to market its investigational human anti-interleukin (IL)-6 monoclonal antibody sirukumab for the treatment of rheumatoid arthritis (RA).

The application requests permission to market the drug in combination with methotrexate, in patients with moderately to severely active RA who have failed or are intolerant to conventional or biologic disease-modifying antirheumatic drugs (DMARDs) and as a monotherapy in these patients for whom treatment with methotrexate is inappropriate.

Sirukumab, which is being co-developed for RA as part of a collaboration with Janssen Biologics, is an investigational human monoclonal IgG1 kappa antibody that selectively binds with high affinity to the IL-6 cytokine, a naturally occurring protein playing a key role in autoimmune conditions.

The company intends to market a subcutaneous formulation of sirukumab in two presentations - a single-dose prefilled syringe and a single-dose autoinjector. According to GSK, the data to support the filing are based on a comprehensive Phase III clinical development programme involving more than 3,000 patients.

"We have worked with our partner Janssen to develop a robust regulatory package to support the use of sirukumab in adult patients who, despite the use of conventional and biologic therapies, still suffer from moderately to severely active rheumatoid arthritis," said Paul-Peter Tak, GSK's chief immunology officer and senior vice president R&D Pipeline.

"We believe sirukumab, if approved, will provide these patients with a once every four week subcutaneous treatment option."

Janssen and GSK formed a co-development and co-commercialisation pact for sirukumab in RA back in 2011. The agreement allows both companies the option to investigate the drug for other indications beyond RA; GSK is also testing sirukumab in a Phase III trial involving patients with Giant Cell Arteritis, and is planning a Phase II trial in asthma.

A regulatory submission in the US for the drug in the RA indication is also expected by the end of the year.