Switching Australian patients with moderate to severe inflammatory bowel disease from originator to biosimilar infliximab

In reply: We thank Lim and colleagues1 for their insightful comments regarding the use biosimilar medicines in Australia; their letter highlights some pertinent issues.

Firstly, we agree that uptake of biosimilar medications in Australia has been slower than expected owing to several factors, including those elucidated in the letter by Lim et al. Nevertheless, we remain optimistic that the publication of real‐world Australian data describing the safety, clinical effectiveness and cost savings associated with the introduction of biosimilar alternatives will spark renewed interest in the use of biosimilar medicines in Australia.2 To help facilitate greater biosimilar uptake, it is important to engage key stakeholders — namely, doctors, pharmacists, other health professionals, and patients — to ensure that each remains suitably informed and, particularly in the case of patients, included in decisions regarding the prescription of biosimilar medicines. Central to this approach is propagating the message that biosimilar medicines are safe, clinically effective, and must meet rigorous standards of safety and efficacy before their approval for clinical use in Australia.2,3,4

Secondly, we thank Lim and colleagues for highlighting key differences in the definitions of important terms such as “interchangeability” and “substitution” in the context of switching between originator and biosimilar medicines across United States and Australian jurisdictions respectively.1 This represents an important issue to be clarified, particularly in the context of the Pharmaceutical Benefits Advisory Committee’s approach to selectively “a‐flagging” biosimilar medications, which means they are deemed suitable for pharmacist‐driven substitution in the absence of documentation by the prescriber that brand substitution is not permitted.5 While this approach may facilitate more rapid uptake of biosimilar medicines in Australia, such a strategy is not without its challenges and would benefit from clear definitions and practical guidelines. It is important to note that in the absence of adequately powered studies demonstrating that multiple bidirectional switches between originator and biosimilar formulations are safe, clinically effective, and do not affect pharmacokinetic and immunogenic drug profiles,6 the term “interchangeable” does not sufficiently describe the status of biosimilars at this stage.