Presentation (CTI)

OBJECTIVES: Sanfilippo syndrome type A, or mucopolysaccharidosis type IIIA (MPS IIIA) is a severe, progressive, genetic disorder that leads to irreversible brain damage and early death. MPS IIIA results in cognitive decline, delayed speech and language development, behavioral disturbance, and loss of motor function leading to death in the second decade. Currently, there are no treatments approved for MPS IIIA, but there are several potential therapies in development. We aimed to develop a conceptual framework for a cost effectiveness model that captures the progressive nature of MPS IIIA and potential efficacy of future treatments.
METHODS: The de novo model conceptualization was based on a targeted literature review considering epidemiology, clinical trials, new therapies, quality of life, costs, economics, and disease burden in MPS IIIA. The targeted literature review did not identify any existing model frameworks in MPS IIIA. Therefore, we reviewed economic studies in Duchenne muscular dystrophy, metachromatic leukodystrophy, sickle cell disease, and Batten disease, which share disease attributes with MPS IIIA (e.g., progressive, multi-comorbidities/complications, motor/neuron/cognitive decline, sleep disturbance, and loss of communication).
RESULTS: Based on the targeted literature review and feedback from the experts, a de novo ten-state Markov model framework encompassing the natural history of MPS IIIA was developed. The framework spanned two domains: cognition and motor function, each with four levels of severity. The health states were further defined by two sleep-related and four communication-related sub‑health states. The levels of severity were informed by expert clinical opinion and were linked to specific elements of the Bayley ‑III test.
CONCLUSIONS: A conceptual Markov model framework was considered the most appropriate to estimate the lifetime costs and benefits and evaluate the cost-effectiveness of potential new treatments for MPS IIIA.