Denali slumps on mixed data for DNL310 in Hunter syndrome

Shares of US biotech Denali Therapeutics (Nasdaq: DNLI) closed down more than 15% at $54.14 yesterday, after it announced additional interim data from a Phase I/II study evaluating ETV:IDS (DNL310), an investigational brain-penetrant enzyme replacement therapy intended to treat both central nervous system (CNS) and peripheral manifestations of Hunter syndrome (MPS II) that, while billed as positive, disappointed investors.

The interim results were presented at MPS 2021, the 16th International Symposium on MPS and Related Diseases, and included safety data up to Weeks 43 and 25 from Cohorts A and B, respectively, six-month biomarker data from Cohort A and up to three-month biomarker data from Cohort B.

The bad news was that levels of neurofilament light (Nf-L), which is a potential biomarker of neuronal damage, increased. Denali had hoped the Nf-L levels would decrease. However, the interim results were only from five patients after six months of treatment with DNL310.