Platelet transfusion study identifies a change that could improve outcomes for some premature babies

Fewer platelet transfusions will prevent death or major bleeding in 7 out of 100 premature neonates with severe thrombocytopenia

A paper is published today (2nd November 2018) in the New England Journal of Medicine titled, A Randomised Trial of Neonatal Platelet Transfusion Thresholds. This paper describes the final results of the PlaNet-2 / MATISSE clinical study which looked at giving platelet transfusions to premature babies.

The study found that lowering the threshold and giving fewer platelet transfusions is better and will prevent death or major bleeding in 7 out of 100 premature new born babies with low platelet counts (severe thrombocytopenia). This result was unexpected by many in the study group.

Platelets are the cells that help the blood to clot. They are often given to babies with low platelet counts and no signs of bleeding, to try to prevent bleeding (so-called prophylactic platelet transfusions). However, doctors did not know the correct platelet count at which they should start giving transfusions to these babies.

In the international PlaNeT-2 / MATISSE study, premature babies with a platelet count below 100 x109 per litre (normal platelet counts are above 150) were identified on the neonatal units, and the parents then counselled and consented about the trial. Babies were allocated by chance (or randomised) when their platelet count fell below 50, into one of two groups:

One group of babies received a platelet transfusion as their platelet count dropped below 50 (high threshold study arm)

The other group received a platelet transfusion but only whenever their platelet count dropped below 25 (low threshold study arm)

The study was carried out over a 6-year period and involved 43 paediatric or neonatal units in the UK, Ireland and the Netherlands. A total of 660 premature babies with low platelet counts (severe thrombocytopenia) took part in the study, making it the largest such study to date.

Unexpectedly, they found that giving more platelet transfusions to babies at the higher platelet count (the high threshold study arm) was associated with a worse outcome (mortality and major bleeding in the next 28 days), compared with only transfusing babies whose count had dropped lower (low threshold study arm).

Dr Anna Curley, co-chief investigator for the study and consultant neonatologist in the Neonatal Intensive Care Unit at the National Maternity Hospital, Dublin, Ireland said: “Research is essential if we are to provide the best possible evidence-based care and improve outcomes for premature babies. I am very proud to have been part of the PlaNet-2 study, where the results will help improve how we treat babies with low platelets.

“This study was only possible because of the funding we received, the hard working clinical and research staff who took part and most importantly the parents who allowed their babies to take part in our study.

“I would like to thank the clinicians and families involved in the study and let them know that their efforts will make a real difference to the care of babies worldwide.”

Professor Simon Stanworth, co-chief investigator and researcher at the Radcliffe Department of Medicine at Oxford University said: “Studies like this are only possible with the huge support and dedication of parents and staff across many hospitals and in NHS Blood and Transplant, and with help from many colleagues in the Netherlands and Ireland.”

Professor Stanworth, who is also a consultant haematologist at John Radcliffe Hospital in Oxford and NHS Blood and Transplant added: “The findings have major implications for how neonatologists use platelet transfusions for sick premature babies with low platelets. We need to remember that platelet transfusions are biological products, and they do have risks.

“This study also raises questions about using prophylactic platelet transfusions routinely in other patient groups with very low platelets”.

Doctor Andrew Cox, consultant neonatologist at East Lancashire Hospitals NHS Trust, said: “We really appreciate the selflessness of parents who agree to enrol their unwell babies into clinical trials such as the PlaNet -2 trial. This trial has a clear outcome which will improve the care of sick premature babies in units across the country and overseas.

“We often see premature babies in our unit with low platelets, and the result of the PlaNet-2 trial will guide us in managing these babies more safely and effectively.

“Babies and their families beyond those who so generously took part in the trial will benefit, and it is likely that more premature babies will survive because of them.

“This is a wonderful legacy, for which all those who care for sick babies should be thankful.”

The study was funded by NHS Blood and Transplant (NHSBT), Sanquin Research, Amsterdam in the Netherlands and Addenbrooke’s Charitable Trust Neonatal Breath of Life Fund. It was supported by the NHSBT Clinical Trials Unit and was adopted on the NIHR portfolio of clinical trials.

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Notes to editors

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