Phase 3 Trial of Trofinetide Recruiting Girls and Young Women with Rett Syndrome in US

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by Alice Melao |

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A Phase 3 clinical trial is recruiting girls and young women with Rett syndrome to explore the safety and efficacy of the investigational oral therapy trofinetide.

The study, named LAVENDER, is planning to enroll 180 girls and women, 5 to 20 years old, at clinical sites in the U.S.

Participants will be assigned an oral solution of trofinetide or a placebo for 12 weeks. After the treatment period, they will be followed for 30 more days to assess the therapy’s safety.

The trial is investigating whether trofinetide lessens Rett syndrome’s neurobehavioral symptoms, as measured by caregivers with the Rett Syndrome Behaviour Questionnaire and by clinicians using the Clinical Global Impression Scale-Improvement.

“For patients living with this debilitating disease, and the families whose dedication to their care inspires us, the LAVENDER study is an important next step in what we hope will result in the first FDA [Food and Drug Administration]-approved treatment for Rett syndrome,” Serge Stankovic, MD, Acadia Pharmaceuticals‘ president, said in a news release.

The company holds an exclusive license from Neuren Pharmaceuticals to develop and market trofinetide in North America.

“We are grateful to study participants and their families, investigators,, and Neuren Pharmaceuticals who have played instrumental roles in advancing trofinetide to this stage of clinical development and look forward to building upon this work to further evaluate trofinetide,” Stankovic added.

All participants who complete LAVENDER will have the opportunity to continue on trofinetide, including those previously receiving the placebo, in a nine-month extension study called LILAC. A second extension trial, named LILAC-2, will follow with eligible patients who complete the LILAC study.

More information about LAVENDER and LILAC is available here.

LAVENDER and both extension trials are expected to provide clinical data on the long-term tolerability, safety, and efficacy of trofinetide to treat Rett syndrome. The data are expected to be included in a new drug application seeking approval of trofinetide in the U.S.

“I look forward to the outcomes of this clinical program evaluating trofinetide as a potentially new treatment for Rett syndrome,” said Jeffrey L. Neul, MD, PhD, director of the Vanderbilt Kennedy Center and LAVENDER study investigator.

Trofinetide, also known as NNZ-2566, is a synthetic derivative of a protein called insulin-like growth factor 1 (IGF-1). It has been designed to mimic the functions of glypromate (GPE), a product of IGF-1 breakdown. However, compared with GPE, trofinetide is intended to have more favorable pharmacological properties and remain for longer periods in the bloodstream.

Both IGF-1 and GPE are important to maintain the biological balance required for normal activity in the developing brain and to respond to disease, stress, and injury in the mature brain.

Results from a previous Phase 2 trial (NCT02715115) in 82 girls, 5 to 15 years old, revealed that treatment with 200 mg/kg trofinetide could significantly ease a range of Rett’s core symptoms compared with a placebo.

“The start of the trofinetide study has been highly anticipated by the Rett community,” said Melissa Kennedy, executive director of “We are hopeful for what this study means for patients and their families as it potentially brings us closer to improving the lives of many living with Rett syndrome.”

The FDA has granted fast track status and orphan drug designation to trofinetide for both Rett syndrome and fragile X syndrome. The therapy also received orphan designation in Europe for the same indications.