The role of biosimilar immunomodulatory drugs

The originator brand of a biological disease-modifying antirheumatic drug (bDMARD) is known as the biological reference drug. Other brands of the bDMARD are known as ‘biosimilars’. Because bDMARDs are produced in biological systems and have complex molecular structures, there are inherently minor variations between drug molecules, even between batches of the same drug. For a biosimilar product to be registered, it must have been shown to have similar efficacy, safety and physiochemical, biological and immunological characteristics to the biological reference drug.

Although switching brands is considered safe and does not compromise efficacy, there are limited data to determine whether multiple changes are appropriate. It is the consensus view of the Rheumatology Expert Group that both the drug and its brand name should be specified on the prescription to avoid unintended changes between products. Patients should also be counselled that biosimilars are considered to be equally effective as the originator; however, once a product has been started it should preferably be continued, with few exceptions.