Australia’s Therapeutic Goods Administration (TGA) is seeking feedback on its plans to revise the guidance on companion diagnostics, providing a guide to help companies determine if companion testing is needed and introducing a concept to recognize the diagnostic evaluations carried out as part of a medicine application. The agency published the current version of its guidance on regulatory requirements for in vitro diagnostic (IVD) companion tests in October 2022.
TGA would add a new section on the medicine or biological indications that need companion diagnostic (CDx) testing. The section would include a flowchart intended to help companies determine if they need a companion diagnostic for the safe and effective use of the therapy and, if so, whether Australian standard-of-care testing could provide the required data.
The draft also introduces the concept of a “companion testing plan” to recognize the companion diagnostic “component evaluations undertaken as part of the medicine application.”
“The purpose of the plan is to provide reassurance that there is access to at least one adequate IVD for companion testing and ensure the Australian patients can be treated for that indication safely and effectively. All applications for registration of a new medicine or biological indication that require CDx testing must include a companion testing plan,” the agency wrote in the draft.
While the plan is “not meant to be a comprehensive description of all possible companion tests that are available in Australia,” it needs to identify one IVD that TGA “considers adequate.” The IVD can be the subject of a concurrent submission for authorization in Australia, in which case the applicant can cross-reference to the relevant details of the diagnostic filing.
In the absence of a concurrent application, the plan “provides a mechanism for the TGA to evaluate the performance and validity of IVDs intended for companion testing.” The agency said its proposed approach “recognizes that there may be barriers to bringing a CDx to the Australian market for local supply, and Australian samples may have to be sent for testing internationally.”
TGA would prefer to avoid that scenario but the option is open to bridge the gap to the availability of local testing. The agency will only accept the sending of samples to “appropriately accredited” overseas testing facilities if the development of onshore testing with an authorized or notified test “is infeasible or incomplete.”
Other proposed changes include the addition of four case studies. The case studies describe situations such as the development of a test to detect PD-L1 in esophageal squamous cell carcinoma to identify patients for treatment with an anti-cancer monoclonal antibody. Because the IVD is essential for the safe and effective use of the drug and not a mainstream pathology test, the applicant must apply for inclusion in the Australian Register of Therapeutic Goods. TGA describes the evidence to include in the filing.
The draft guidance is open for comment until 17 June.
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