Assessing Experiences With Trofinetide for Rett Syndrome: Interviews With Caregivers of Participants in Clinical Trials

Purpose: Rett syndrome (RTT) is a rare neurodevelopmental disorder that mainly affects girls and women. Trofinetide is approved for the treatment of RTT in adults and children aged ≥2 years. To gain insight into experiences with RTT and effects of trofinetide treatment at different stages of RTT, interviews with caregivers of individuals with RTT were conducted upon their exit from the open-label trofinetide trials.

Methods: Interviews were conducted with caregivers of participants in the LILAC/LILAC-2 open-label extension trials of the phase 3 LAVENDER trial in participants aged 5 to 20 years, and in DAFFODIL, an open-label trial in participants aged 2 to 4 years. Caregivers were asked about the RTT effects, experiences with trofinetide, meaningfulness of treatment effects, and satisfaction. Qualitative thematic analysis was performed.

Findings: Caregivers of 33 participants from the open-label trials were interviewed, including 26 from LILAC/LILAC-2 (mean age, 12.3 years) and 7 from DAFFODIL (mean age, 4.5 years). The most commonly reported effects of RTT in LILAC/LILAC-2 were no verbal communication (24/26 [92.3%]), unable to use hands (15/26 [57.7%]), repetitive hand movements (15/26 [57.7%]), unable to walk (15/26 [57.7%]), and seizures (14/26 [53.8%]). In DAFFODIL, the most commonly reported effects of RTT were no verbal communication (7/7 [100%]), impaired balance (4/7 [57.1%]), unable to use hands (3/7 [42.9%]), repetitive hand movements (3/7 [42.9%]), mood disturbance (3/7 [42.9%]), constipation (3/7 [42.9%]), and limited ability to use hands (3/7 [42.9%]). Caregivers most commonly reported improvements in hand use (11/26 [42.3%]), engagement with others (11/26 [42.3%]), eye gaze (8/26 [30.8%]), use of the Tobii eye tracking device (7/26 [26.9%]), and attention/focus/concentration (7/26 [26.9%]) in LILAC/LILAC-2. In DAFFODIL, caregivers reported improvements in new words (5/7 [71.4%]), hand use (4/7 [57.1%]), and eye contact (4/7 [57.1%]). Nearly all (31/32) caregivers were very satisfied or satisfied with trofinetide.

Implications: Caregivers of participants in open-label trofinetide trials reported improvements in RTT with meaningful impact in areas of motor function, communication, and engagement.