Common and rare adverse effects of biologic therapy

Dr Bhaskar Dasgupta is a consultant in rheumatology, head of the Rheumatology Department at Southend University Hospital (UK), and leading expert behind guidelines on polymyalgia rheumatica and giant cell arteritis.

Which common and rare adverse effects of biologic therapy should we consider during follow-up?

Bhaskar Dasgupta, MB BS, MD: The common adverse events with biologic therapies are mainly related to infections. We know that, irrespective of the class of drugs, most biologic agents can predispose to infections. These are common bacterial infections, but also the less common Mycobacterium tuberculosis infections and some of the opportunistic infections. So whenever we start patients on biologic agents, we make sure that they are clear of bacterial infections, tuberculosis (TB), and we also look for viral infections, such as hepatitis B, hepatitis C, as well as HIV.

There are also other side effects that you can get with biologic agents. They can have an effect on the blood count, so neutropenia is sometimes a feature of the use of some of the biologic agents, such as tocilizumab. We also monitor for the rarer side effects that these biologic agents can bring: sometimes interstitial lung disease, uveitis, and rarely reports of demyelinating disorders, which can also complicate the use of anti–tumor necrosis factor (TNF) agents. So we have to monitor quite carefully for some of these rarer sequelae of biologic agents.