The role of tocilizumab in the treatment of post-transfusion hyperhaemolysis

Hyperhaemolysis syndrome (HHS) is a serious complication of transfusion mostly reported in patients with sickle cell disease. HHS is characterised by the destruction of both donor and autologous red blood cells. Tocilizumab is a recombinant humanised monoclonal antibody that inhibits the binding of interleukin-6 and has been used in the treatment of severe/critical coronavirus disease 2019 infection but also some cases of HHS. We describe two further cases of HHS successfully treated with tocilizumab and propose a decision aid for when to consider this treatment.

Serial prophylactic exchange blood transfusion in pregnant women with sickle cell disease (TAPS-2): statistical and qualitative analysis plan for a randomised controlled feasibility trial

BACKGROUND

There are significant knowledge gaps regarding the effectiveness of serial prophylactic exchange blood transfusion (SPEBT) for pregnant women with sickle cell disease (SCD). The protocol for the randomised feasibility trial assessing SPEBT versus usual care in women with SCD (TAPS2 trial) has previously been published. This publication outlines the statistical and qualitative analysis plan for the study.

METHODS AND DESIGN

TAPS2 is a randomised two-arm phase 2 feasibility trial with a nested qualitative study and health economic evaluation. Up to 50 pregnant women with SCD and a singleton pregnancy will be recruited and individually randomised to either SPEBT approximately every 6-10 weeks until delivery (intervention arm) or to usual care (control arm). Information will be collected on a range of feasibility and clinical outcomes.

RESULTS

Due to the impact of COVID-19 on study recruitment, the initial study period of 24 months was extended to 48 months. Other protocol updates designed to mitigate the impact of COVID-19-related disruption included allowing for remote consent and conducting all qualitative interviews by telephone. The primary outcome for the trial is the overall recruitment rate. The number of women screened, eligible, consented, randomised and withdrawn will be summarised as a CONSORT flow diagram. Differences in clinical outcomes will additionally be presented as an initial assessment of efficacy and to inform sample size calculations for a future definitive trial. Qualitative interviews with trial participants and clinicians will be analysed using reflexive thematic analysis; data from interviews with participants who declined to participate in the trial will be extracted and incorporated into summary tables to report key findings. The health economic analysis plan is not covered by this update.

CONCLUSION

The publication of this analysis plan is designed to aid transparency and to reduce the potential for reporting bias.

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).

Serial prophylactic exchange blood transfusion in pregnant women with sickle cell disease (TAPS-2): study protocol for a randomised controlled feasibility trial

BACKGROUND

Pregnancies in women with sickle cell disease (SCD) are associated with a higher risk of sickle and pregnancy complications. Limited options exist for treating SCD during pregnancy. Serial prophylactic exchange blood transfusion (SPEBT) has been shown to be effective in treating SCD outside pregnancy, but evidence is lacking regarding its use during pregnancy. The aim of this study is to assess the feasibility and acceptability of conducting a future phase 3 randomised controlled trial (RCT) to establish the clinical and cost effectiveness of SPEBT in pregnant women with SCD.

METHODS

The study is an individually randomised, two-arm, feasibility trial with embedded qualitative and health economic studies. Fifty women, 18 years of age and older, with SCD and a singleton pregnancy at ≤ 18 weeks' gestation will be recruited from six hospitals in England. Randomisation will be conducted using a secure online database and minimised by centre, SCD genotype and maternal age. Women allocated to the intervention arm will receive SPEBT commencing at ≤ 18 weeks' gestation, performed using automated erythrocytapheresis every 6-10 weeks until the end of pregnancy, aiming to maintain HbS% or combined HbS/HbC% below 30%. Women in the standard care arm will only receive transfusion when clinically indicated. The primary outcome will be the recruitment rate. Additional endpoints include reasons for refusal to participate, attrition rate, protocol adherence, and maternal and neonatal outcomes. Women will be monitored throughout pregnancy to assess maternal, sickle, and foetal complications. Detailed information about adverse events (including hospital admission) and birth outcomes will be extracted from medical records and via interview at 6 weeks postpartum. An embedded qualitative study will consist of interviews with (a) 15-25 trial participants to assess experiences and acceptability, (b) 5-15 women who decline to participate to identify barriers to recruitment and (c) 15-20 clinical staff to explore fidelity and acceptability. A health economic study will inform a future cost effectiveness and cost-utility analysis.

DISCUSSION

This feasibility study aims to rigorously evaluate SPEBT as a treatment for SCD in pregnancy and its impact on maternal and infant outcomes.

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).

Predicting high blood pressure in pregnancy: a multivariate approach

OBJECTIVE

To identify predictors of pregnancy-induced hypertension and pre-eclampsia in 212 nulliparous women before 20 weeks' gestation and at approximately 28 weeks' gestation.

STUDY DESIGN

A randomized, prospective study in a teaching hospital. We performed standardized measurements of systolic and diastolic arterial blood pressures, body mass index, urinary calcium:creatinine ratio and components of the renin-angiotensin system, including platelet angiotensin II binding site density. Attending clinicians were blinded to the results. Outcome was assessed by one observer at the end of pregnancy. Discriminant function analysis was used to identify significant predictors.

RESULTS

Fifty-five women had transient, presumed 'white-coat', systolic hypertension at the time of first pregnancy visit; they were twice as likely to develop pregnancy-induced hypertension and pre-eclampsia and five times more likely to deliver prematurely. Body mass index, platelet angiotensin II binding site density and urinary calcium:creatinine ratio measured before 20 weeks gestation were also significant predictors. At 28 weeks of pregnancy, measurements of the blood pressure were significant predictors (reflecting the near clinical expression of the disease), together with the plasma angiotensinogen concentration.

CONCLUSIONS

A single systolic blood pressure reading of 140 mmHg or more before 20 weeks' gestation indicates a higher than normal risk of pregnancy-induced hypertension and pre-eclampsia and premature delivery. Discriminator biochemical variables were also identified at this time, which might allow the more rational use of prophylactic measures.