PLATIPUS is an adaptive platform trial aimed at improving the health of infants born preterm (before 37 weeks' gestation). PLATIPUS will compare how different treatments and care provided to pregnant women and people at risk of preterm birth and infants born preterm affect infant health.

The main questions PLATIPUS aims to answer are:

1. What effect/s do different treatments/care provided to pregnant women and people at risk of preterm birth have on the health of their infants? (Pregnancy domains)
2. What effect/s do different treatments/care given to infants born preterm have on their health ? (Neonatal domains).

This registration record relates to the PLATIPUS Core (or 'master') protocol which provides guidance for the overall running of the trial. Additional appendices will outline the aims, questions, treatments, and activities for each separate research question (domain). Each Domain-Specific Appendix will be registered separately on ClinicalTrials.gov and will link to this record.

PLATIPUS is a multi-domain, multi-centre international adaptive platform trial and innovative approach to perinatal research.

Preterm birth (birth before 37 weeks' gestation) is a global issue. More than 15 million babies (1 in 10) are born preterm each year. Complications of preterm birth are the leading cause of death and disability among children under five years of age. These contribute to increased risk of all-cause mortality and early death from cardiovascular disease, diabetes and chronic lung disease in later life. There is no single cause of, or pathway to, preterm birth. Treatments during pregnancy aim to prevent or treat complications that can lead to preterm birth in pregnant women and people or reduce the impact of prematurity on neonatal outcomes. Treatments in the neonatal period (period shortly after birth) aim to improve survival and reduce potential morbidities in the preterm infant.

PLATIPUS will initially assess interventions given to pregnant women and people during pregnancy (Participant Group 1) and to preterm infants (Participant Group 2) in the first few days of life. Participants will be randomly allocated to all relevant domains for which they are eligible and provide consent. Using a trial-developed Ordinal Outcome Scale, the effect of pregnancy and/or neonatal interventions on neonatal outcome will be assessed at 42 weeks' post-menstrual age OR at primary hospital discharge, whichever occurs earliest. Secondary outcomes will examine the effect of interventions on individual pregnancy and/or neonatal endpoints, and may be domain-specific. All pregnancy domains will include a 'Maternal Outcome Set' to assess maternal health and intervention safety.

In contrast to conventional clinical trials, PLATIPUS has been designed to examine multiple different treatment options at once within the same platform. Both pregnant and neonatal participants will be randomly assigned to different concurrent treatment options, with an initial focus on treatments already considered as part of clinical care. As the trial advances, novel interventions may also be included. Interventions will be evaluated within domains. A domain is defined as a set of interventions that are intended for a specific health problem or specific therapeutic option.

Bayesian adaptive statistical modelling will be used to evaluate treatment efficacy at regular interim adaptive analyses of the pre-specified outcomes for each intervention in each domain. This will allow determination of the effectiveness of interventions once sufficient data has been accrued, rather than when a pre-specified sample size is reached. Adaptive analyses will compute the posterior probabilities of superiority, futility, inferiority, or equivalence for pre-specified comparisons within domains. Each of these potential conclusions will be pre-defined prior to commencing the intervention domain. Decisions about trial results (e.g., concluding superiority or equivalence) will be based on pre-specified threshold values for posterior probability.

All trial procedures are outlined in the "core" protocol described in this registration. Separate domain protocols with information specific to each intervention included in PLATIPUS will be linked to this registration at separate clinicaltrials.gov records:

Potential participants with core platform eligibility AND who meet all domain-specific inclusion criteria and none of the domain-specific exclusion criteria for at least one PLATIPUS domain, will be eligible to 'enrol' in the PLATIPUS trial and randomised to all eligible domains, for which consent has been provided.

CORE PLATFORM ELIGIBILITY - PREGNANCY DOMAINS

Inclusion Criteria: Pregnant women and people must fulfil the following inclusion criteria to be eligible to participate in PLATIPUS:

1. Pregnant and at risk of preterm birth
2. Receiving care at a participating site at the time of eligibility assessment.
3. Meets the eligibility criteria for at least one domain.

Exclusion Criteria: Pregnant women and people who meet the following criteria will be excluded from participation in this trial:

1. Circumstances where death (pregnant woman or person/fetal) is deemed to be imminent and inevitable. The treating team may however decide that providing an opportunity for the pregnant woman or person to participate would be in their and/or their fetus/infant's interest. OR
2. Inability to consent, unless a waiver of consent has been deemed appropriate at domain-level.

CORE PLATFORM ELIGIBILITY - NEONATAL DOMAINS

Inclusion Criteria: Preterm infants must fulfil the following criteria to be eligible to participate in PLATIPUS, infants must be:

1. Born preterm (<37 weeks' gestational age)
2. Receiving care at a participating site at the time of eligibility assessment.
3. Meet the eligibility criteria for at least one domain.

Exclusion Criteria: Preterm infants who meet the following criteria will be excluded from participation in this trial:

1. Circumstances where death (neonatal) is deemed to be imminent and inevitable. The treating team may however decide that providing an opportunity for the infant to participate is in the infant's interest. OR
2. Parental/guardian inability to consent, unless a waiver of consent has been deemed appropriate at domain-level.

DOMAIN-SPECIFIC ELIGIBILITY CRITERIA

Potential participants who meet core platform eligibility criteria will be assessed for eligibility to participate in trial domains available at their hospital. Domain-specific eligibility criteria are outlined in the related Domain-Specific Appendices.

Version 1, Apr-2024

Once data unblinding no longer compromises the integrity of the trial, a de-identified data set collected for the analysis of domains within PLATIPUS will be made available.

Conditions:

1. All domains in which the participant is co-enrolled are closed to recruitment* (*Where one or more domains in which a participant is co-enrolled are not yet closed to recruitment, the participant's data may be provided, without the treatment code, to prevent unblinding in unfinished domains).
2. Primary domain conclusions/analyses have been published, AND
3. The 2-year follow-up of participants within the domain/s of interest is/are complete.

Supporting materials (Core Protocol, Domain-Specific Appendices, Data Dictionaries and Domain-Specific Statistical Analysis Plans) will be available.

Contact: University of Melbourne - info@platipustrial.org.

This is estimated to be approximately six months following the completion of the two-year follow-up of domain participants.

To be determined. Access requests will be subject to review by trial subcommittees. The Trial Steering Committee will approve or disapprove requests. A Data Transfer Agreement and Authorship Agreement signed by relevant parties and evidence of ethical approval will be required.

The default position is that domains run on the PLATIPUS platform will be randomisation provided on a blinded basis. Blinding, however, may not always be feasible for some interventions and this will be specified in the related Domain-Specific protocol.