The TOTAL trial dilemma: A survey among professionals on equipoise regarding fetal therapy for severe congenital diaphragmatic hernia

Ethical reflections on organizing the first human trial of artificial womb technologies

OBJECTIVE

To investigate how to protect participants in the artificial womb technology (AWT) human trials.

METHOD

We compared randomized controlled trials and single arm trials to understand which trial design best balances the interests of science and participants. We also compared AWT trials with comparable settings to understand how to protect participants.

RESULTS

Randomized trials might fail in reaching a sizeable sample, which could pointlessly expose participants to risks. Furthermore, parents who choose to participate in the trial might expect to receive AWT. Failed expectations might distress parents and hinder the therapeutic relationship. The trial is divided into two steps. First, delivery into AWT involves two participants: the mother and the fetus. As AWT requires a C-section, the procedure cannot be carried out without the mother's consent regardless of fetal benefit. Treatment in AWT, involves one participant: the infant. As for any other invasive intervention, the AWT trial should be suspended if harmful.

CONCLUSIONS

A single arm trial could prevent some of the methodological and ethical challenges of the randomized trials. Moreover, better decisional tools should be developed to help parents decide whether to participate in the AWT trial. For example, using visual aids or showing the AWT.

In Utero Therapy for Congenital Diaphragmatic Hernia

Congenital diaphragmatic hernia is an anomaly that is often prenatally diagnosed and spans a wide spectrum of disease, with high morbidity and mortality associated with fetuses with severe defects. Congenital diaphragmatic hernia is thus an ideal target for fetal intervention. We review the literature on prenatal diagnosis, describe the history of fetal intervention for congenital diaphragmatic hernia, and discuss fetal endoscopic tracheal occlusion and the Tracheal Occlusion To Accelerate Lung growth trial results. Finally, we present preclinical studies for potential future directions.

Congenital diaphragmatic hernia

Congenital diaphragmatic hernia (CDH) is a rare birth defect characterized by incomplete closure of the diaphragm and herniation of fetal abdominal organs into the chest that results in pulmonary hypoplasia, postnatal pulmonary hypertension owing to vascular remodelling and cardiac dysfunction. The high mortality and morbidity rates associated with CDH are directly related to the severity of cardiopulmonary pathophysiology. Although the aetiology remains unknown, CDH has a polygenic origin in approximately one-third of cases. CDH is typically diagnosed with antenatal ultrasonography, which also aids in risk stratification, alongside fetal MRI and echocardiography. At specialized centres, prenatal management includes fetal endoscopic tracheal occlusion, which is a surgical intervention aimed at promoting lung growth in utero. Postnatal management focuses on cardiopulmonary stabilization and, in severe cases, can involve extracorporeal life support. Clinical practice guidelines continue to evolve owing to the rapidly changing landscape of therapeutic options, which include pulmonary hypertension management, ventilation strategies and surgical approaches. Survivors often have long-term, multisystem morbidities, including pulmonary dysfunction, gastroesophageal reflux, musculoskeletal deformities and neurodevelopmental impairment. Emerging research focuses on small RNA species as biomarkers of severity and regenerative medicine approaches to improve fetal lung development.

Challenges and Pitfalls: Performing Clinical Trials in Patients With Congenital Diaphragmatic Hernia

Congenital diaphragmatic hernia (CDH) is a rare developmental defect of the lungs and diaphragm, with substantial morbidity and mortality. Although internationally established treatment guidelines have been developed, most recommendations are still expert opinions. Trials in patients with CDH, more in particular randomized controlled trials, are rare. Only three multicenter trials in patients with CDH have been completed, which focused on fetoscopic tracheal occlusion and ventilation mode. Another four are currently recruiting, two with a focus on perinatal transition and two on the treatment of pulmonary hypertension. Herein, we discuss major challenges and pitfalls when performing a clinical trial in infants with CDH. It is essential to select the correct intervention and dose, select the appropriate population of CDH patients, and also define a relevant endpoint that allows a realistic duration and sample size. New statistical approaches might increase the feasibility of randomized controlled trials in patients with CDH. One should also timely perform the trial when there is still equipoise. But above all, awareness of policymakers for the relevance of investigator-initiated trials is essential for future clinical research in this rare disease.

The randomized Tracheal Occlusion To Accelerate Lung growth (TOTAL)-trials on fetal surgery for congenital diaphragmatic hernia: reanalysis using pooled data

BACKGROUND

Two randomized controlled trials compared the neonatal and infant outcomes after fetoscopic endoluminal tracheal occlusion with expectant prenatal management in fetuses with severe and moderate isolated congenital diaphragmatic hernia, respectively. Fetoscopic endoluminal tracheal occlusion was carried out at 27⁺⁰ to 29⁺⁶ weeks' gestation (referred to as "early") for severe and at 30⁺⁰ to 31⁺⁶ weeks ("late") for moderate hypoplasia. The reported absolute increase in the survival to discharge was 13% (95% confidence interval, -1 to 28; P=.059) and 25% (95% confidence interval, 6-46; P=.0091) for moderate and severe hypoplasia.

OBJECTIVE

Data from the 2 trials were pooled to study the heterogeneity of the treatment effect by observed over expected lung-to-head ratio and explore the effect of gestational age at balloon insertion.

STUDY DESIGN

Individual participant data from the 2 trials were reanalyzed. Women were assessed between 2008 and 2020 at 14 experienced fetoscopic endoluminal tracheal occlusion centers and were randomized in a 1:1 ratio to either expectant management or fetoscopic endoluminal tracheal occlusion. All received standardized postnatal management. The combined data involved 287 patients (196 with moderate hypoplasia and 91 with severe hypoplasia). The primary endpoint was survival to discharge from the neonatal intensive care unit. The secondary endpoints were survival to 6 months of age, survival to 6 months without oxygen supplementation, and gestational age at live birth. Penalized regression was used with the following covariates: intervention (fetoscopic endoluminal tracheal occlusion vs expectant), early balloon insertion (yes vs no), observed over expected lung-to-head ratio, liver herniation (yes vs no), and trial (severe vs moderate). The interaction between intervention and the observed over expected lung-to-head ratio was evaluated to study treatment effect heterogeneity.

RESULTS

For survival to discharge, the adjusted odds ratio of fetoscopic endoluminal tracheal occlusion was 1.78 (95% confidence interval, 1.05-3.01; P=.031). The additional effect of early balloon insertion was highly uncertain (adjusted odds ratio, 1.53; 95% confidence interval, 0.60-3.91; P=.370). When combining these 2 effects, the adjusted odds ratio of fetoscopic endoluminal tracheal occlusion with early balloon insertion was 2.73 (95% confidence interval, 1.15-6.49). The results for survival to 6 months and survival to 6 months without oxygen dependence were comparable. The gestational age at delivery was on average 1.7 weeks earlier (95% confidence interval, 1.1-2.3) following fetoscopic endoluminal tracheal occlusion with late insertion and 3.2 weeks earlier (95% confidence interval, 2.3-4.1) following fetoscopic endoluminal tracheal occlusion with early insertion compared with expectant management. There was no evidence that the effect of fetoscopic endoluminal tracheal occlusion depended on the observed over expected lung-to-head ratio for any of the endpoints.

CONCLUSION

This analysis suggests that fetoscopic endoluminal tracheal occlusion increases survival for both moderate and severe lung hypoplasia. The difference between the results for the Tracheal Occlusion To Accelerate Lung growth trials, when considered apart, may be because of the difference in the time point of balloon insertion. However, the effect of the time point of balloon insertion could not be robustly assessed because of a small sample size and the confounding effect of disease severity. Fetoscopic endoluminal tracheal occlusion with early balloon insertion in particular strongly increases the risk for preterm delivery.

Antenatal Management of Congenital Diaphragmatic Hernia: what's next ?

Congenital diaphragmatic hernia (CDH) can be diagnosed in the prenatal period and its severity can be measured by fetal imaging. There is now level I evidence that, in selected cases, Fetoscopic Endoluminal Tracheal Occlusion (FETO) increases survival to discharge from the neonatal unit as well as the risk for prematurity. Both effects are dependent on the time point of tracheal occlusion. FETO may also lead to iatrogenic death when done in unexperienced centres. The implementation of the findings from our clinical studies, may also vary based on local conditions. These may be different in terms of available skill set, access to fetal therapy, as well as outcome based on local neonatal management. We encourage prior benchmarking of local outcomes with optimal postnatal management, based on large enough numbers and using identical criteria as in the recent trials. We propose to work further on prenatal prediction methods, and the improvement of fetal intervention. In this manuscript, we describe a research agenda from a fetal medicine perspective. This research should be in parallel with innovation in neonatal and pediatric (surgical) management of this condition. This article is protected by copyright. All rights reserved.

How should fetal surgery for congenital diaphragmatic hernia be implemented in the post-TOTAL trial era: a discussion. Prenat Diagn 2022;42:301-309. [PMID: 35032132 DOI: 10.1002/pd.6091]

Following prenatal diagnosis of congenital diaphragmatic hernia, severity can be predicted based on the presence of associated abnormalities, and in isolated cases, on lung size and position of the liver. Severe hypoplasia is defined by a contralateral lung size < 25% on ultrasound; moderate hypoplasia is when that lung measures between 25 and 45% of the normal. In fetuses with predicted poor postnatal outcome a procedure that reverses pulmonary hypoplasia may be considered. In uncontrolled studies, fetoscopic endoluminal tracheal occlusion (FETO) improved neonatal outcome. Recently, two randomized controlled trials compared the neonatal and infant outcomes in fetuses with isolated CDH (www.totaltrial.eu). In severe cases, FETO was carried out at 27⁺⁰ -29⁺⁶ weeks' gestation (referred to as "early") and in moderate at 30⁺⁰ -31⁺⁶ weeks ("late"). Survival to discharge from the neonatal intensive care unit increased by 25% (95%-CI:+6 - +46; P=.0091) and 13% (-1 - +28; P=.059), in fetuses with severe and moderate cases, respectively. Following FETO gestational age at delivery was on average 3.2 (2.3-4.1) weeks earlier following early and 1.7 (1.1 - 2.3) following late FETO. Here the strengths and weaknesses of the TOTAL trials and their translation to the clinic are debated. Discussants are the lead for the trial (JD) and a colleague (AF) not involved. The discussant notes that the observed survival, both in treated and expectantly managed fetuses, was overall less than what is reported by some high volume centers, particularly in North America. Additional criticisms are the potential effects of prematurity on the long term, the inclusion of low-volume centers, and the potential of FETO for severe iatrogenic complications. Therefore results may not be generalizable. The discussants concluded that although FETO may have its value it remains a procedure with a high risk for prematurity and it can be lethal when the balloon cannot be removed prior to delivery. This article is protected by copyright. All rights reserved.

Professional integrity in maternal - fetal innovation and research: an essential component of perinatal medicine

OBJECTIVES

Clinical innovation and research on maternal-fetal interventions have become an essential for the development of perinatal medicine. In this paper, we present an ethical argument that the professional virtue of integrity should guide perinatal investigators.

METHODS

We present an historical account of the professional virtue of integrity and the key distinction that this account requires between intellectual integrity and moral integrity.

RESULTS

We identify implications of both intellectual and moral integrity for innovation, research, prospective oversight, the role of equipoise in randomized clinical trials, and organizational leadership to ensure that perinatal innovation and research are conducted with professional integrity.

CONCLUSIONS

Perinatal investigators and those charged with prospective oversight should be guided by the professional virtue of integrity. Leaders in perinatal medicine should create and sustain an organizational culture of professional integrity in fetal centers, where perinatal innovation and research should be conducted.