Prophylactic exchange-transfusion in sickle cell disease pregnancy: TAPS2 feasibility randomized controlled trial

• Exchange-transfusion is used for sickle cell disease complications, but there is inadequate evidence of its safety and benefit in pregnancy

• The TAPS2 trial shows the feasibility of conducting a definitive trial of prophylactic exchange-transfusion in sickle cell disease pregnancy

Serial prophylactic exchange blood transfusion (SPEBT) is increasingly used in pregnant women with sickle cell disease (SCD), despite a lack of robust evidence. TAPS2 (Transfusion Antenatally in Pregnant Women with Sickle Cell Disease) study assessed the feasibility and acceptability of conducting a definitive randomized controlled trial of SPEBT (intervention) versus standard care (control) in pregnant women with SCD. Women ≥18 years with SCD, between 6+0 and 18+0 weeks of singleton gestation, were randomized 1:1 to control or intervention every 6-10 weeks throughout pregnancy in seven hospitals in England. The main outcomes evaluated were recruitment rate (primary outcome), acceptability, and retention. Secondary outcomes were safety, maternal and infant clinical outcomes. 194 women were screened over 42 months (extended due to the pandemic), 88 were eligible, and 35 (39.8%) consented to participate. Eighteen participants were randomized to intervention and 17 to control. Follow-up data were collected on all participants. Twelve patients in the intervention group received at least one SPEBT, of these, 11 received  3. The remaining patient was withdrawn from SPEBT due to transfusion reaction. Sixteen control participants required at least one transfusion. There were no statistically significant differences in terms of maternal, infant, or postnatal outcomes. A trend towards a lower incidence of vaso-occlusive crisis, preterm delivery and improved birthweight was observed in the intervention group. Despite the pandemic, this study achieved satisfactory recruitment and retention, confirming its acceptability to participants. TAPS2 demonstrates that it is feasible to perform a definitive international trial of SPEBT in pregnant women with SCD. Trial registration: NIH registry (www.clinicaltrials.gov), registration number NCT03975894 (registered 05/06/19); ISRCTN (www.isrctn.com), registration number ISRCTN52684446 (retrospectively registered 02/08/19). TAPS2 trial Protocol: available at https://rdcu.be/drlwc