I'm currently on Zoladex for endometriosis — what do I need to do before November?

AstraZeneca is withdrawing Zoladex (goserelin) from the Australian market on 1 November 2026. The PBAC has recommended triptorelin (Diphereline) as the PBS-listed replacement. Book a review with your GP or gynaecologist in the next few weeks to plan a transition. Both drugs are GnRH agonists — they suppress oestrogen production to reduce pain and symptoms — but the delivery differs: Zoladex is a subcutaneous implant; triptorelin is an intramuscular injection. AstraZeneca has committed to continuing supply at no cost for patients without a suitable alternative, but do not wait until November to discuss this.

Why wasn't triptorelin on the PBS for endometriosis before?

Triptorelin was already PBS-listed for prostate cancer, but that listing did not extend to endometriosis, fibroids, or breast cancer — conditions where it was already in widespread clinical use. The PBAC's decision to expand the listing now was triggered by AstraZeneca's commercial withdrawal of Zoladex, not a proactive review of women's health access. The PBAC assessed triptorelin as cost-effective when priced equivalently to Zoladex, and described unrestricted listing as consistent with evidence-based general practice.

Zoladex is leaving. Triptorelin is the PBS replacement — here's what it means.

What just happened

The Pharmaceutical Benefits Advisory Committee (PBAC) has backed an unrestricted PBS listing for triptorelin 3.75 mg injection (brand name: Diphereline), expanding its coverage to endometriosis, uterine fibroids, and hormone-sensitive breast cancer. The decision was announced on 17 August 2026, following a special July PBAC meeting convened specifically to address the issue.

The catalyst is commercial, not clinical: AstraZeneca has announced it will withdraw goserelin (Zoladex) from the Australian market on 1 November 2026. Zoladex has been a PBS-listed treatment for hormone-dependent prostate cancer and a widely-used — though not PBS-subsidised — treatment for endometriosis, fibroids, and breast cancer in women. Without this listing expansion, women relying on Zoladex for those conditions would have faced a gap with no subsidised replacement.

AstraZeneca has committed to providing Zoladex at no cost to patients without a suitable treatment alternative after November. But what counts as “suitable” needs to be established ahead of time, and the November timeline is firm.

Both-and

The good news first

PBS access matters structurally. An unrestricted listing means a GP or specialist can prescribe triptorelin without navigating an authority approval pathway, and patients pay the PBS co-payment rather than the unsubsidised cost of the drug. Before this listing, women with endometriosis or fibroids receiving Diphereline were doing so privately, through compounding, or through individual clinical justification — all pathways with higher barriers and cost.

The PBAC assessed triptorelin as cost-effective at pricing equivalent to Zoladex, and described the unrestricted listing as consistent with contemporary clinical practice and the available evidence. That framing carries real weight — it means the clinical community has long been using this drug for these conditions, and the regulatory system has now formalised what practice already knew.

For women managing endometriosis or symptomatic fibroids who could not previously access GnRH agonist therapy at a subsidised price, this is a material change. Access to treatment that suppresses ovarian hormone production — reducing pain, heavy bleeding, and fibroid size — has real quality-of-life implications, particularly in the perimenopausal years when these conditions can intensify.

What the reactive timing reveals

It is worth naming how this listing actually happened. Triptorelin and goserelin are both GnRH agonists — drugs that suppress pituitary signals to the gonads, temporarily reducing oestrogen production. The mechanism, the clinical evidence for endometriosis and fibroids, and the patient need have been unchanged for years. Goserelin was PBS-listed for prostate cancer; the women’s health indications were not.

The PBAC acted — but because a pharmaceutical company is exiting the market, not because a gap in women’s health access was identified and addressed proactively. That sequence matters. Endometriosis affects approximately one in nine Australian women of reproductive age. Those women waited for PBS access to a drug that clinical practice already used, until a commercial decision forced the committee’s hand.

This is not a criticism of the PBAC’s decision — it is the right one. It is context for how women’s health treatments access in Australia often works in practice: the evidence arrives well before the regulatory infrastructure catches up.

Triptorelin versus Zoladex: what actually differs

Both drugs produce equivalent hormonal suppression, but the delivery route is different. Goserelin (Zoladex) is implanted subcutaneously — usually in the abdominal wall — as a slow-release pellet. Triptorelin (Diphereline) is given as an intramuscular injection, typically into the gluteal muscle. Monthly formulations of both are standard for endometriosis and fibroid management.

The route change may feel different for patients who have been receiving Zoladex implants for some time. Some people have preferences. The PBAC has assessed triptorelin as an appropriate cost-minimised comparator; for most patients, the clinical outcome should be equivalent. If you have a specific concern — about injection tolerance, or previous difficulties with IM administration — that is a conversation worth having with your GP or gynaecologist before November, not in October when the supply has already changed.

A utilisation review is planned for approximately two years after the listing amendment comes into effect, which will give regulators visibility on uptake and any clinical issues that emerge at scale.

My two cents

If you are currently on Zoladex for endometriosis, fibroids, or hormone-sensitive breast cancer: book a GP or specialist review in the next few weeks. The transition to triptorelin should be clinically straightforward for most people, but November comes quickly, and planning the change in advance is simpler than scrambling after the supply disappears.

If you have endometriosis or symptomatic fibroids and have never been offered GnRH agonist therapy because of cost concerns, this listing is worth raising with your GP or gynaecologist as part of a treatment planning conversation. It is now one of the subsidised options available to you.

GnRH agonists are one part of a broader management toolkit — they don’t stand alone. The decision to use them involves weighing symptom burden against menopausal side effects (hot flushes, bone density considerations with extended use), and against what other management approaches have or haven’t worked for you. This listing expands the options available; it does not replace the clinical conversation about whether this is the right approach for your situation.

Verdict: yes — if you’re on Zoladex for endometriosis, fibroids, or breast cancer, or have been told PBS access was a barrier, this directly affects your care. Act before November.

Sources cited

PBAC backs triptorelin PBS expansion. newsGP, RACGP, 17 August 2026. https://www1.racgp.org.au/newsgp/clinical/pbac-backs-triptorelin-pbs-expansion
Pharmaceutical Benefits Scheme — PBS Australia. Australian Government. https://www.pbs.gov.au