This position paper addresses substitution relating to biosimilars and their reference products at the retail pharmacy level.

Pharmacy-mediated substitution is a framework permitting substitution of medicines at the retail pharmacy without the consent of the prescribing physician. In this paper, we outline a set of principles that can guide pharmacy-mediated substitution. While the principles are intended for the awareness of pharmacists, they can also relate to other healthcare providers, regulators, payers, and those involved in formulary and procurement decision-making.

Recommendations

Patient safety and access to medicines are critical in the context of pharmacy-mediated substitution, especially when it comes to biologic products including biosimilars. The position paper outlines the following principles:

• A structured science-based framework should be in place for the regulatory evaluation of pharmacy-mediated substitution.
• The prescribing physician should have the right to state on a prescription, “do not substitute” or “dispense as written” or some other statement that recognises no substitution must occur.
• Pharmacy-mediated substitution for biosimilars should only be granted if data is available to demonstrate that repeated switching between the reference product and the biosimilar is not associated with a higher risk than continuous treatment with the reference product. This data may come from a switching study but in some cases, it may not be necessary such as:
• the product is not for chronic use.
• the product is a less complex protein where clinical experience with the reference product and its class shows that the immunogenic potential is low.
• Pharmacy-mediated substitution should only occur for the indications for which the biosimilar can be marketed (e.g., not excluded by intellectual property rights).
• The patient should be able to use the medical device associated with the biosimilar without supervision from the prescribing physician or nurse.
• Measures to ensure traceability (the unique identification) of the biological/biosimilar medicine including batch number handed out to the patient at the pharmacy are particularly important for pharmacovigilance when implementing pharmacy-mediated substitution with biosimilars.