TGA CTN and CTA (formerly CTX) Schemes

The CTN (Clinical Trial Notification) and CTA (Clinical Trial Approval) schemes are Australia’s two regulatory pathways, administered by the Therapeutic Goods Administration (TGA) under the Therapeutic Goods Act 1989 (Cth), for the lawful supply of an unapproved therapeutic good for use in a clinical trial. The CTA scheme was known as the CTX (Clinical Trial Exemption) scheme until the TGA renamed it in November 2020 — the rename was intended to more accurately describe what the pathway actually is (a sponsor applying for the TGA’s approval), since ‘exemption’ had misleadingly implied the product was exempt from TGA scrutiny altogether, which was never the case under this pathway. Older literature, older institutional SOPs, and some search results will still use ‘CTX’ — treat CTX and CTA as the same scheme under different names, not two different schemes.

What both schemes have in common

Both schemes exist because a therapeutic good used in a clinical trial is, almost by definition, not yet entered on the Australian Register of Therapeutic Goods (ARTG) for the use being trialled — it is either a wholly new product or an already-registered product being used outside its approved indication, dose, or route. Supplying an unapproved good in Australia is otherwise restricted, so a sponsor needs one of these two pathways before it can lawfully be provided to trial participants. Neither scheme substitutes for, or overlaps with, ethical review: every trial still requires approval from a Human Research Ethics Committee (HREC) under the NHMRC’s National Statement on Ethical Conduct in Human Research, and CTN trials additionally require the conducting institution’s own governance authorisation. The TGA’s role under CTN/CTA is narrowly about the lawful supply of the unapproved product itself, not the scientific merit or ethics of the study design.

CTN: notification, not pre-approval

Under the CTN scheme, the sponsor self-determines that the product and trial are appropriate to proceed on notification alone, obtains HREC approval for the protocol, then lodges a Clinical Trial Notification with the TGA through the TGA Business Services online CTN form and pays the CTN fee. The TGA does not evaluate the scientific data before the trial starts — notification, not affirmative TGA sign-off, is what allows the trial to proceed. The CTN scheme is the pathway used for the large majority of Australian trials, particularly those involving already-characterised products, established drug classes, or lower-risk investigational uses, where the sponsor and the reviewing HREC are positioned to make the risk judgment themselves.

CTA (formerly CTX): formal TGA evaluation before the trial starts

Under the CTA scheme, the sponsor instead submits an application for the TGA’s own evaluation and approval of the unapproved good before the trial can begin. The TGA reviews the available quality, safety, and (where relevant) efficacy data supporting the proposed trial use, and the trial cannot start until that approval is granted — on top of, not instead of, HREC approval. Sponsors typically use the CTA pathway for products with a genuinely novel mechanism, limited existing human safety data, or other characteristics that make an affirmative regulatory evaluation the more appropriate starting point than sponsor/HREC self-assessment alone.

Choosing between CTN and CTA

The decision belongs to the sponsor, guided by TGA guidance on the two schemes: it turns on the level of uncertainty around the product’s safety profile and the trial’s risk, not on trial phase alone (both early- and later-phase trials can run under either scheme depending on the product). Sponsors uncertain which pathway applies can request TGA advice before lodging. Choosing incorrectly, or lodging a CTN for a product the TGA would expect under CTA, is a compliance risk research offices and sponsors need to catch during protocol development, not after HREC approval is already in hand.

Related concepts

• HREC (Human Research Ethics Committee) — the Australian ethics-review body whose approval is required for every trial regardless of CTN/CTA pathway.
• ANZCTR — Australia and New Zealand’s public trial registry; a separate disclosure obligation from CTN/CTA, which concern lawful supply of the unapproved good, not public registration.
• ICH GCP and ICH E6(R2) — the conduct standard trials must follow once underway, independent of which TGA pathway authorised the product’s supply.
• PMDA Clinical Trial Notification (CTN) — Japan’s differently-structured notification pathway; shares the CTN name with Australia’s scheme but is a distinct national system under a different regulator and legal basis.
• Investigational New Drug (IND) — the closest US FDA analogue in function (authorising an unapproved product’s trial use), though structured very differently from either Australian scheme.

Verified directly against the Therapeutic Goods Administration’s own pages (tga.gov.au) describing the CTN scheme and the CTX-to-CTA rename, corroborated by independent secondary regulatory-affairs sources describing the current CTN/CTA distinction.