Newswise — The results from a clinical trial investigating the safety and feasibility of using focused ultrasound in twin-twin transfusion syndrome (TTTS) were recently published in the American Journal of Obstetrics and Gynecology.
The team examined the technical feasibility and safety of using a customized, ultrasound-guided high-intensity focused ultrasound device to occlude placental vascular targets in utero.
After successful focused ultrasound treatment, she went on to give birth to twin daughters who are now almost four years old.
A team from The Institute of Cancer Research in London designed and built the focused ultrasound device used in this study.
Both the Institute of Cancer Research and Imperial College London have been designated Focused Ultrasound Foundation Centers of Excellence.
Newswise — The results from a clinical trial investigating the safety and feasibility of using focused ultrasound in twin-twin transfusion syndrome (TTTS) were recently published in the American Journal of Obstetrics and Gynecology. This is the world’s first Phase 1 clinical trial of its type in early onset TTTS.
About TTTS
TTTS is a rare, serious, prenatal condition that can affect identical twins and multiples. In this syndrome, blood vessels are distributed abnormally within the placenta, leading to an imbalance in the blood exchange between twins. One twin, called the donor twin, gives away more blood than it receives and can suffer organ failure and even death. The other twin, the recipient twin, receives too much blood and is susceptible to overworking of the heart, heart failure, and death.
The diagnosis of TTTS is usually made upon routine prenatal ultrasound scans. Once identified, more advanced ultrasound techniques are used to grade the severity of TTTS. Depending on the severity of the disease, physicians will decide the proper treatment path, which might include early delivery of the twins or a surgical intervention with fetoscopic laser. It is estimated that approximately 15% of cases require invasive intervention.
Preclinical Research
The early research for focused ultrasound and TTTS was pioneered by Prof. Gail ter Haar from the Institute of Cancer Research, Prof. Dino Giussani from the University of Cambridge, and Prof. Christoph Lees from Imperial College London.
World-First Clinical Trial
The trial took place at Queen Charlotte’s and Chelsea Hospital and was led by Professor Christoph Lees, MD, FRCOG, head of fetal medicine at Imperial College Healthcare NHS Trust and professor of obstetrics at Imperial College London. The team examined the technical feasibility and safety of using a customized, ultrasound-guided high-intensity focused ultrasound device to occlude placental vascular targets in utero. In all, ten participants were treated, and 27 of 30 (90%) of the targeted vessels were successfully occluded. No treatment-related significant maternal or fetal adverse events were recorded, and 18 of 20 fetuses were alive 14 days post-treatment.
While clinical efficacy of the technique could not be formally evaluated, five participants required additional treatments using a fetoscopic laser. Finally, of the pregnancies treated, 12 of 20 neonates were alive at discharge. These outcomes are comparable to those reported with the current standard of care, fetoscopic laser treatment.
While the research suggests that focused ultrasound could be an effective treatment, the researchers have not yet established whether it can stabilize or reverse TTTS. To more fully understand the longer-term outcomes, a larger Phase II study is required.
“This is very promising research, confirming for the first time that this noninvasive procedure can be used safely in twin-twin transfusion syndrome,” said Prof. Lees. “That’s really encouraging, because at present we are only able to treat this condition by using a more invasive method, which has its own risks. We hope to follow this study with a bigger clinical trial with 50 to 100 women, so we can determine if it can successfully treat TTTS and understand whether this procedure could be a less risky and equally or more effective option for women and their twin babies. This study is the culmination of over 15 years of collaboration. I want to thank all the women and families for trusting us and taking part in our research, as well as the hospitals and centres who referred them to us. Research to find new treatments for TTTS is only possible with their help.”
Brioney Garrett, who lives in Cornwall, discovered she had TTTS at her 12-week scan in 2022. After successful focused ultrasound treatment, she went on to give birth to twin daughters who are now almost four years old.
“I’m so grateful to the hospital team and to everyone involved in the research,” she said. They saved my girls’ lives. It really means the world to me to have been part of the trial – not just for my family but for other women and babies who may be able to benefit from this in the future.”
The trial was funded by a grant from the Medical Research Council, the Wiseman Trust, and the UK Focused Ultrasound Foundation. A team from The Institute of Cancer Research in London designed and built the focused ultrasound device used in this study. Both the Institute of Cancer Research and Imperial College London have been designated Focused Ultrasound Foundation Centers of Excellence.
See the American Journal of Obstetrics and Gynecology (open access)
