Biological therapies — a new class of drug used to treat rheumatoid arthritis (RA) — do not increase the risk of recurring cancer when compared to conventional disease modifying anti-rheumatic drugs (DMARDs), according to a new study.
Researchers in the UK looked at data from nearly 19,000 RA patients between 2011 and 2013 and found 425 patients who had cancer. These patients were questioned about their treatment and whether they developed a new cancer.
The number of new cancer cases was slightly lower in patients taking biologics, compared to those taking conventional DMARDs (including methotrexate and sulfasalazine).
Biologics (such as rituximab and anti-TNF) are made from genetically engineered proteins derived from human genes. Like DMARDS, they inhibit parts of the immune system that cause inflammation, a central feature of rheumatoid arthritis.
While conventional DMARDs are slow-acting, the newer biological therapies act quickly and target individual molecules. However, there have been concerns that biologics can increase the risk of cancer recurring in patients who have previously had cancer.
“The exact relationship between biologics and cancer in patients with rheumatoid arthritis remains unclear,” said lead researcher Lucia Silva-Fernandez.
“We have seen that patients with rheumatoid arthritis and a prior malignancy selected to receive a biologic in the UK do not have an increased risk of overall cancer recurrence in comparison with biologic-naïve patients. Nevertheless, additional research on specific types of cancer needs to be conducted to further understand the links between biologics and cancer.”
Researchers also found that RA patients with a history of cancer were prescribed rituximab much earlier than anti-TNF. Rituximab is generally considered safer for these patients, because it is also used as a cancer treatment in lymphoma.
“This is extremely helpful information that we can share with patients in order to help them make evidence-based decisions when it comes to agreeing a management plan, said Dr. Chris Deighton, President of the British Society for Rheumatology.
“It is essential that we continue to monitor the safety profile of biological therapies, because some of our younger patients may be on them for literally decades. The long-term follow-up that has been conducted so far is very reassuring regarding the risk of cancer, even in patients who have previously had this disease.”
The research will be presented later this month in Liverpool at Rheumatology 2014, a conference for healthcare professionals with an interest in musculoskeletal conditions.
Rheumatoid arthritis affects about 1% of adults. It is an autoimmune disease that attacks joint tissue and causes painful, often debilitating inflammation. As the disease progresses, many RA patients become significantly disabled.