Patient access to GLP-1 receptor agonists is set to become even more challenging, with exenatide (Byetta) soon to be discontinued in Australia.

The drug’s sponsor, AstraZeneca, has advised the 5 mcg and 10 mcg pre-filled pens will no longer be available from 1 December due to “discontinuation of global supply” and higher than anticipated sales.

The 5 mcg device is already out of stock with most wholesalers across Australia and will not be replenished. The 10 mcg stock is expected to be exhausted in December 2022.

As a result, regulators have advised clinicians to consider alternative therapies for patients prior to a complete exhaustion of supply.

The announcement comes as severe shortages continue to plague other GLP-1 analogues, amid a boom in off-label prescribing for weight loss.

These supply issues had in turn spurred some patients previously on semagultide (Ozempic) and dulaglutide (Trulicity) to switch to exenatide, despite the latter’s more frequent (twice daily) administration requirements.

In a letter to healthcare professionals last week, AstraZeneca stressed the discontinuation was planned some time ago, before supply issues hit the rest of the market.

The “significant increase in demand” had seen remaining supplies depleted faster than anticipated, the letter said.

“The discontinuation date… has therefore been brought forward from 31 May 2023 to 1 Dec 2022.”

“If you have any patients treated with Byetta pre-filled pens, please ensure they are transitioned to another suitable treatment option.”

Australian Diabetes Society CEO Associate Professor Sof Andrikopoulos said the timing of the move was unfortunate, although the product had been steadily losing popularity for many years before the recent surge in demand.

“This decision would have been made at a time when it wasn’t being used because there were better and more convenient drugs on the market,” he told the limbic.

“But now everything has landed at the same time, so it’s an unfortunate sequence of events.”

Asked whether the move should prompt the TGA to impose restrictions on other drugs in the class to prevent off-label prescribing in the absence of a diabetes diagnosis, Professor Andrikopoulos said it was “already too late”.

Such a move would also be problematic in the absence of safety concerns, he said.

He added: “We should see the opportunity here and the positives, in that it is a good opportunity for patients to go and see their doctors and just revisit their diabetes management plan.”

“Some good may come of that.”