Based on the information provided, I was unable to find specific studies or data about significant improvements in memory with sapropterin. However, sapropterin is a medication used to reduce the frequency of severe episodes in people with phenylketonuria (PKU), a genetic disorder that can cause intellectual disability, seizures, and other serious health problems if left untreated [1].

Sapropterin works by helping the body break down an amino acid called phenylalanine, which is found in high-protein foods such as meat, dairy, and eggs. People with PKU are unable to properly break down phenylalanine, leading to its buildup in the body and causing the symptoms of the disorder [1].

While there is no mention of significant improvements in memory specifically, it is possible that sapropterin may help improve cognitive function in people with PKU by reducing the buildup of phenylalanine in the body. However, more research is needed to confirm this [2].

In summary, while sapropterin has been shown to be effective in reducing the frequency of severe episodes in people with PKU, there is no specific information available about significant improvements in memory with the drug.

Sources:

* [1] National Institutes of Health. (2021). Phenylketonuria. Genetics Home Reference. <https://medlineplus.gov/genetics/condition/phenylketonuria/>
* [2] DrugPatentWatch.com. (2022). Sapropterin. <https://www.drugpatentwatch.com/drugs/sapropterin>