Namilumab – a safe and effective treatment for poor-responder patients with rheumatoid arthritis?

This study investigated if namilumab is an effective treatment for patients with rheumatoid arthritis (RA) with a poor response to other therapies. They found that namilumab improved RA symptoms and was well tolerated.

Rheumatoid arthritis (RA) is a condition caused by inflammation. This leads to painful swelling in the joints. RA is treated using drugs to reduce inflammation. There are many different types of drugs to treat RA. Methotrexate (MTX) is a drug that is usually very effective in treating RA. Tumor necrosis factor inhibitors (TNFi) are biological drugs that also reduce inflammation in RA. Over time, patients with RA may fail to respond to both MTX and/or TNFis. 

New drugs are in development for patients with RA and inadequate response (IR). One target is a granulocyte-macrophage colony-stimulating factor (GM-CSF). GM-CSF is produced at high levels in RA. It stimulates immune T cells to produce chemicals that cause inflammation. Namilumab is a monoclonal antibody that binds to GM-CSF. This stops GM-CSF functioning and reduces inflammation. It is unclear if namilumab is safe and effective in patients with an IR to MTX or TNFis. 

This study included 108 patients with RA. Patients were randomly assigned to one of 4 groups. One group received a placebo (inactive drug). The other groups received either 20, 80 or 150 mg of namilumab. This was done by an injection under the skin. The study lasted for 12 weeks. 

RA symptoms were significantly reduced by namilumab treatment. This was observed as early as 2 weeks for the 150 mg dose. This effect was similar in MTX-IR and TNF-IR patients. After 12 weeks, 44% of patients treated with the 20 mg dose, 39.1% in the 80 mg dose and 30.8% in the 150 mg dose of namilumab had a reduction in pain of more than 40%. This reduction was by 20% lower in the placebo group.

Namilumab was well tolerated by most patients. 2.3% (3/106) of patients developed anti-drug antibodies (ADAs). The rates of side effects were similar between namilumab and placebo-treated patients. These included common cold, shortness of breath, bronchitis, and headache.

The authors concluded that namilumab improved RA symptoms and was well tolerated.

This was a relatively short study. The long-term safety of namilumab requires more investigation.

If you have any concerns regarding RA treatment, please consult with your doctor.