Access Consortium: Alignment with ICMRA consensus on immunobridging for authorizing new COVID-19 vaccines

Placebo-controlled disease endpoint trial data are the gold standard for authorizing vaccines. However, for COVID-19 vaccines, it is difficult to conduct efficacy trials in some countries, as few candidates are willing and available to participate. Without established humoral and/or cellular immune parameters that correlate to clinical protection against disease, other approaches are needed to provide sufficient evidence for authorizing new COVID-19 vaccines.

The International Coalition of Medicines Regulatory Authorities (ICMRA) convened a workshop on June 24, 2021, to consider the development of COVID-19 vaccines. The ICMRA focused on immunobridging, the design and use of controlled trials (placebo or other controls) and correlates of protection.

Access Consortium members agree that well-justified and appropriately designed immunobridging studies are an acceptable approach for authorizing COVID-19 vaccines.

The Consortium provides additional considerations for cross-platform immunobridging. These include extending previous points of consideration for variant-based vaccines that was limited to currently authorized COVID-19 vaccines.

Consensus positions from the ICMRA meeting relevant to this statement include:

The Access Consortium considers that the weight of evidence from studies with authorized COVID-19 vaccines is sufficient to support using neutralizing antibody titres as a primary endpoint in cross-platform immunobridging trials.

Applicants are to provide a clear rationale regarding the:

The Consortium also recommends that applicants follow WHO standards in neutralization assays and consult with the relevant authority early on in the study process.

Applicants are also to provide the following:

Non-clinical data

As well as common non-clinical requirements for new vaccines and adjuvants, non-clinical data should include:

Clinical data

Along with a comparison of neutralizing antibody titres, clinical data should include:

Applicants are also advised to consult the following:

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