Biosimilar ‘a’ flagging still a concern: GESA

Physicians should adopt a blanket process of refusing brand substitution until concerns regarding the PBAC’s ‘a’ flagging of biosimilars are addressed, says a senior gastroenterologist.

Dr Greg Moore, chair of the Australian Inflammatory Bowel Disease Association (AIBDA) and Head of the Inflammatory Bowel Diseases, Gastroenterology and Hepatology Unit at Monash University, said he believed this was the “most evidence based and patient safety focused approach” following the PBAC’s recommendation to ‘a’ flag the Inflectra and Remicade brands of infliximab on the PBS.

“Our main issue that these are not proven to be bioequivalent and there is a potential safety signal so nobody, no matter how well they are trained, knows that repeated switching is safe,” he said.

“A switch should require the knowledge and consent of both the patient and the prescribing clinician given this absence of safety data.”

While AIBDA and fellow organisations like the Gastroenterological Society of Australia (GESA) support the introduction of biosimilars, they are deeply concerned about the ‘a’ flagging.

They say it presents an unacceptable risk of brand switching and substitution when not enough is known yet about the safety or efficacy of repeated switching between biosimilars and biologic agents.

“At present, we do not have safety data about repeated switching,” he told the limbic.

“The development of antibodies to these drugs even without switching is a significant issue and the fact that they are not identical molecules may drive further antibody generation.

“It may not prove to be an issue in a few years when we have the data, but an absence of data of harm does not imply safety – just that there is currently an absence of data of either.”

Related story: Professional bodies join forces on ‘a’ flagging

Dr Moore said the simplest and most evidence-based solution was to remove the ‘a’ flagging, effectively removing the risk of multiple switching occurring without the clinician’s knowledge.

Meanwhile, he advised clinicians to discuss the issue with their local hospital or dispensing pharmacist and also with their patients.

“Tick the brand substitution not permitted box until we have better data about the safety of switching,” he said.

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