Adolescents and adults with Angelman syndrome have a poor overall health-related quality of life (HRQoL) compared to the general population in the U.S., according to an exploratory analysis of a Phase 2 clinical trial.
The analysis also revealed that self-care activities is the HRQoL domain most affected by symptoms associated with the disease.
The results, “Quality of Life in Adolescent and Adult Individuals with Angelman Syndrome: Baseline Results from the Phase 2 STARS Study,” were presented at the 2020 American Academy of Neurology (AAN) Science Highlights virtual platform.
Angelman syndrome is a genetic neurodevelopmental disorder usually associated with severe intellectual disability, difficulty speaking, loss of movement control (ataxia), and epileptic seizures that fail to respond to anti-seizure medications.
Despite being a severe condition that is associated with a series of comorbidities that likely have a negative impact on patients’ HRQoL, no published study has reported on HRQoL and utility scores in Angelman patients.
Here, researchers reported the findings of an exploratory analysis of a previously completed Phase 2 trial (NCT02996305) enrolling adults and adolescents with Angelman that sought to assess participants’ HRQoL at the beginning of the study (baseline).
The trial, called STARS, assessed the safety and effectiveness of two dosing regimens of OV101 (gaboxadol), Ovid Therapeutics’ oral investigational therapy for Angelman and fragile X syndrome, another genetic neurodevelopmental disorder.
Patients’ HRQoL and utility scores were derived from the 5-level EuroQoL 5-Dimensions Questionnaire (EQ-5D-5L), which was given to caregivers to complete due to patients’ limited abilities to respond to questionnaires.
The EQ-5D-5L questionnaire has five different domains — mobility, self-care, usual activities, pain or discomfort, and anxiety or depression. Each must be given a score ranging from 1 (no problems) to 5 (extreme problems).
In addition to these domains, the EQ-5D-5L questionnaire also includes a visual analog scale (VAS) ranging from 0 (the worst possible health state) to 100 (the best possible health state).
All different possible health states defined by the EQ-5D-5L descriptive system also can be converted into a single value, called the utility score, that uses population-specific value sets that reflect the societal valuation of health states. It ranges from 0 (equivalent to being dead) to 1 (best possible health) and measured in decimal increments.
Baseline EQ-5D-5L data was available for 87 trial participants (61 men and 39 women), with a mean age of 23 years. Of those, 21 were adolescents and 66 were adults.
According to caregivers, the EQ-5D-5L domains in which patients had the most extreme problems were self-care, usual activities, and mobility.
Indeed, all adolescents and 93% of adults included in the analysis were claimed by their caregivers to have at least moderate problems performing certain self-care activities, including dressing or washing themselves.
Additionally, more than half of the patients in both age groups also had at least moderate problems with mobility or engaging in usual activities, according to their carers.
About 30% of adolescents and adults had moderate-to-extreme problems with anxiety or depression, while most study participants (in both age groups) had only slight, or no, pain or discomfort.
Patient utility scores were quite low across all age groups (0.42 in adolescents and 0.44 in adults), indicating Angelman is associated with a relatively poor HRQoL.
In contrast, mean VAS scores were relatively high across groups (82 for adolescents and 85 for adults). The researchers believe this may be explained by the fact that “utility scores represent a societal assessment of participant’s health state,” while VAS scores represent caregivers’ perception of participants’ own assessment of their health state.
However, the researchers noted the study had some limitations, namely that it measured HRQoL from a caregiver perspective that may not completely reflect what individuals with Angelman experience.
While future analysis will be necessary to evaluate the value of the EQ-5D-5L in the Angelman population, the team believes this data indicate “rather poor QoL among individuals with AS across age groups and support the conclusion that there is a high unmet need in this population.”