Acadia Opening Phase 2/3 Trial of Trofinetide in Young Girls, 2-5

Marisa Wexler MS avatar

by Marisa Wexler MS |

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trofinetide trials Rett syndrome | Rett Syndrome News | clinical trials underway

Acadia Pharmaceuticals is launching an open-label clinical trial of its oral investigational medication trofinetide in toddlers and young girls with Rett syndrome, the company announced in a letter to the Rett community.

The 12-week Phase 2/3 trial, called DAFFODIL (NCT04988867), aims to enroll about 10 children, ages 2 to 5. All study participants will be treated with 10–30 mL of trofinetide solution twice daily, with doses based on an individual’s weight.

Its main goal is to assess the safety and tolerability of trofinetide, as well as the experimental medicine’s pharmacokinetics — that is, how the compound moves into, through, and out of the body. Those who complete the 12-week study may be invited to continue receiving trofinetide for up to an additional 21 months in an extension trial.

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Trial sites are not yet available, but those interested can inquire using contact information on the trial document, or by emailing Acadia at [email protected], it stated in the letter.

Weight is among DAFFODIL’s enrollment criteria: all participants must weigh at least 9 kg (about 20 lbs). Girls between the ages of 2 and 4 must also weigh less than 20 kg (about 44 lbs), while 5-year-olds must also weigh less than 12 kg (about 26.5 lbs).


In its letter, Acadia noted that precautions related to COVID-19 are being taken to protect study participants and clinical staff where the trial is conducted, while still ensuring the integrity of the study.

Trofinetide (previously, NNZ-2566) is a modified version of glypromate, a protein fragment that is thought to lessen inflammation and promote the development of connections between neurons in the brain. The investigational medication is administered orally or through a gastrostomy tube.

An ongoing Phase 3 clinical trial (NCT04181723), called LAVENDER, enrolled about 180 girls and women with Rett syndrome, ages 5 to 20. Participants are randomized to either trofinetide or a placebo given twice daily for 12 weeks; those who complete the trial will have the opportunity to enroll in an open-label extension study, called LILAC.

LAVENDER is due to conclude in October, and top-line results are expected by year’s end.

Its main goal is to determine the effect of treatment on neurobehavioral symptoms, as measured both by caregivers using the Rett Syndrome Behaviour Questionnaire, and by clinicians via the Clinical Global Impression Scale-Improvement.

In the U.S., trofinetide has been granted rare pediatric disease designation, fast track designation, and orphan drug designation. It also has been designated an orphan drug in the European Union.

Acadia owns the right to develop and commercialize trofinetide in North America under an agreement with Neuren Pharmaceuticals, which still owns all rights to the compound elsewhere.