1.1 Elosulfase alfa is recommended, within its marketing authorisation, as an option for treating mucopolysaccharidosis type 4A (MPS 4A) for people of all ages. It is only recommended if the company provides elosulfase alfa according to the commercial arrangement.
Why the committee made these recommendations
This guidance reviews the evidence for elosulfase alfa for treating MPS 4A, including new evidence collected as part of the managed access agreement (NICE highly specialised technologies guidance 2).
MPS 4A is rare and progressive, and has a significant effect on the quality of life of people with the condition, and their families and carers. It causes abnormalities in the joints and bones, respiratory symptoms, pain, fatigue and increasing dependence on a wheelchair. Current treatment options are limited.
The company used the same limited economic model structure for the review as for the original guidance. This was despite encouragement to improve the structure to better reflect the characteristics of MPS 4A, target population and treatment benefits of elosulfase alfa. There is uncertainty around the model because it:
relies on wheelchair use, which does not represent well enough how the condition progresses
uses several uncertain assumptions to capture the long-term benefit of elosulfase alfa
uses utility values based on managed access data that includes only a small number of people.
Clinical trial evidence, data from the managed access agreement, and feedback from patient and carer experience were collected. These suggest that MPS 4A is likely to progress more slowly when treated with elosulfase alfa compared with standard care. The health and quality-of-life benefits of elosulfase alfa are considered to be substantial. Also, data from younger people who may benefit more from elosulfase alfa is not specifically included, and additional skeletal benefits may not be fully captured.
Taking these factors into account, the cost-effectiveness estimates are within the range that NICE considers acceptable for highly specialised technologies. So, elosulfase alfa is recommended for people with MPS 4A.