Velmanase alfa is recommended as an option for treating the non-neurological signs and symptoms of mild to moderate alpha‑mannosidosis, only if:
treatment is started in people under 18 years (it can be continued in people who turn 18 while on treatment)
the company provides it according to the commercial arrangement.
This recommendation is not intended to affect treatment with velmanase alfa that was started in the NHS before this guidance was published. People having treatment outside this recommendation may continue without change to the funding arrangements in place for them before this guidance was published, until they and their NHS clinician consider it appropriate to stop. For children and young people, this decision should be made jointly by them, their clinician, and their parents or carers.
Alpha‑mannosidosis is an ultra-rare and serious condition that severely affects the quality of life of people with the condition, and their families and carers. For this evaluation, the company asked for velmanase alfa to be considered only for people under 18 years and people who turn 18 while on treatment. This does not include everyone it is licensed for.
Clinical trial evidence suggests that velmanase alfa may lead to improvements in functions such as walking, stair climbing and lung capacity, and quality of life, for people with alpha‑mannosidosis. But the size and nature of these benefits are highly uncertain because of the ultra-rare nature of the condition, which makes evidence generation difficult.
The most likely cost-effectiveness estimate for velmanase alfa is around what is considered value for money in the context of a highly specialised service. Although there are some uncertainties in the economic model, when taking into account all the evidence and the factors affecting the decision, velmanase alfa is recommended.