Background and Aims: CLN2 disease is the only NCL with an approved treatment, cerliponase alfa (Brineura), an enzyme replacement therapy (ERT) indicated to slow the loss of ambulation. We aimed to understand parental/patient experiences of symptom outcomes after ERT.
Methods: In collaboration with patient organizations, we invited parents of CLN2 disease-affected children, and affected adults to complete a survey regarding their experiences with intracerebroventricular (ICV) Brineura infusions. Within the survey, respondents rated changes in symptoms after commencing ERT.
Results: Parents of 25 affected children (n = 22 females) and one affected adult able to self-report completed the survey. Excluding the adult, average age of affected individuals= 8.5 years (SD=4.7, range=1.5-23.0); average age of diagnosis= 4.6 years (SD=4.6, range=1.9-18). At the time of survey completion, 21 individuals were receiving Brineura treatment and 5 had previously received treatment. Respondents reported improvements in motor function (n=8, 30.8%) and verbal communication (n=10, 38.5%), and stabilization in motor function (n=10, 38.5%), communication (n=7, 26.9%), and vision (n=4, 15.4%). Respondents also noted attenuated symptom progression: motor (n=11, 42.3%), communication (n=14, 53.8%), and vision (n=9, 24.6%). 42% (n=11) reported initial improvement or stabilization in one or more symptoms, followed by worsening. This experience included children initiating treatment at a young age and/or with few initial symptoms. Expectations regarding anticipated treatment effects were mixed. Most respondents did not expect vision loss to be slowed or stopped by ERT, but for motor and language skills, some anticipated greater symptom improvement or stabilization, or slower progression than was achieved.
Conclusion: Per parent- and self-report, the disease modifying effects of ERT may go beyond slowing the loss of ambulation, but symptom progression does eventually occur. Parental expectations regarding changes to language and motor function were mixed. Some limitations include small sample size, lack of a comparison group, and unknown treatment length.