Australian pharmacists could soon substitute a biosimilar infliximab for its reference product without prescribing physicians’ –or even patients’—knowledge. The Department of Health’s Pharmaceutical Benefits Advisory Committee has recommended adding an infliximab biosimilar to the country’s list of approved drugs as an equivalent to its reference product. Known as “a-flagging,” the move would allow pharmacists to substitute and switch between the two non-identical medications.
Prior to approval, this infliximab biosimilar underwent evaluation by Australia’s Therapeutic Goods Administration. The agency considered the biosimilar’s quality, safety and efficacy relative to the reference product, supporting approval to treat eight inflammatory conditions. Approved conditions include rheumatoid arthritis, psoriasis, ulcerative colitis, Crohn’s disease and others. As part of the biosimilar approval process, the Department of Health extrapolated indications – approving the biosimilar to treat certain diseases based not upon extensive testing but upon the drug’s resemblance to its brand-name reference product.
While some health officials hope “a”-flagging infliximab will lower treatment costs, other stakeholders worry that it weakens physicians’ ability to guide patient care. In an online statement, Medicines Australia noted that “Biosimilars can treat the same condition as the reference original biologic, but they can and do have a range of variations which may or may not have an adverse impact on patients. Biologic medicines are not generic medicines. Therefore, it is critical that a patient’s doctor is involved in any decision to move a patient from one biologic or biosimilar medicine to another and they need a strong evidence base to rely upon to make that decision.”
Slight variations in molecular structure between reference biologics and their follow-on biosimilars can sometimes trigger different responses from patients. These include immunogenic effects, which are common side effects for biological medicines. A 2015 study conducted in Ireland found that five percent of patients treated with the infliximab reference product required hospital readmission, as compared with 80 percent of patients treated with the biosimilar follow-on product. Likewise, none of the patients treated with the reference product required surgery, though 29 percent of patients treated with the infliximab biosimilar did.
In past instances, as with the 2010 consideration of a filgrastim biosimilar, the Pharmaceutical Benefits Advisory Committee has opted against “a”-flagging. The committee explained that, “The current practice of ‘a’ flagging in the Schedule of Pharmaceutical Benefits, denoting that brand substitution may be undertaken by pharmacists at the point of dispensing, will not be applied to [biosimilars] at this time.”
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