Safety, Efficacy of Biosimilar Switching Not Established, Though Information Gap Narrows

What should practicing healthcare providers (HCPs) in rheumatology, gastroenterology, and dermatology be aware of before prescribing biosimilars for reference biologic therapeutics infliximab (Remicade), etanercept (Enbrel), adalimumab (Humira), and rituximab (Rituxan, MabThera)? Several proposed biosimilars of these reference biologics are in development, and 6 compounds have been approved by either the European Medicines Agency (EMA) or the FDA, but because there exists a variable level of good-quality evidence available regarding switching from reference drugs to their biosimilars, HCPs need guidance.

A new analysis by Robert Moots, BSc, MB BS, PhD, FRCP, Professor of Rheumatology at the University of Liverpool, Institute of Ageing and Chronic Disease, Liverpool, United Kingdom, and colleagues examined the efficacy, safety, and antigenicity of biosimilars, both marketed and proposed. The researchers concluded that, although efficacy and safety data generally showed no differences between patients who switched treatments versus those who did not, and no differences were seen pre- and post-switch, at this time, switching from reference biologics to biosimilars should remain a case-by-case clinical decision made by physician and patient. The researchers said that the safety of switching to biosimilars has not yet been fully demonstrated in terms of long-term efficacy, safety, and immunogenicity. Their study was published online June 16, 2017, in Current Rheumatology Reports.

The analysis is based on 53 switching studies in the medical literature found in PubMed, the Web of Knowledge, the International Clinical Trials Registry Platform, and selected congresses. Infliximab publications covered CT-P13, SB2, infliximab NK, and unspecified infliximab biosimilars; etanercept publications covered SB4 and GP2015; adalimumab publications covered ABP 501 and SB5; and rituximab publications covered CT-P10. Immunogenicity data were provided in only 51% of studies. The analysis covered studies including PLANETRA, PLANETAS, DANBIO, BIO-SWITCH, NOR-SWITCH, SIMILAR, CONNECT-IBD, SECURE (infliximab), BIO-SPAN, EGALITY, EQUIRA, RApsody (etanercept), and ASSIST-RT (rituximab).

The authors note that the FDA is alone among regulatory bodies in requiring a single transition evaluation to demonstrate that a biosimilar can be switched with a reference product, along with a study with 3 reference-to-biosimilar switches to demonstrate interchangeability. This factor has created a lack of switching studies in the literature, potentially negatively impacting the HCP’s ability to offer optimum treatment, the authors state.

They conclude that the decision to switch patients from a reference product to its biosimilar should be made on a case-by-case basis depending upon underlying disease, patient characteristics and comorbidities, the type of reference drug, and patient willingness to switch. The authors also recommended that switching data from one biologic molecule not be used to inform switching decisions between other biologic and biosimilar treatments, and that automatic substitution not take place at the pharmacy level, as the decision should remain in the hands of the treating clinician. They state that patients should be followed closely post-switch to monitor for adverse events, and that data should be made available for national registries that report into large pharmacovigilance databases.

Finally, the authors said that “as the information gap is filled, particularly with data derived from appropriately designed switching clinical trials and real-world experience, we believe treatment practice will adapt.”