A team from Stockholm (the Research & Translational Science Unit, Swedish Orphan Biovitrum AB) have recently published the results of a new approach to the treatment of MPS IIIA.
When recombinant enzyme is given intravenously, it is cleared very quickly by cells through their M6P receptors. So little or no enzyme is available for uptake by the brain. The Stockholm team modified the enzyme in such a way that its uptake by M6P receptors was blocked. So the enzyme remained in the circulation for much longer. The results were striking, with significant reduction in levels of heparan sulfate, lysosomal pathology, and inflammation. Importantly, clinical improvement was also seen in several areas.
This approach has been tried before, with limited success. However, the Stockholm team have introduced some important modifications, and their results are certainly superior.
While acknowledging that more work needs to be done, the results have been sufficiently encouraging; the company have now commenced clinical trials. The links are
Here is a link to the published paper