Denali Therapeutics CEO: 2026 Pivotal With Hunter Syndrome FDA Decision and New TV Trial Readouts

Key Points

• Denali expects 2026 to be pivotal with an FDA decision on tividenofusp alfa for Hunter syndrome after the PDUFA moved to April 5 due to a molecular‑weight miscalculation; the company says CMC review is complete, remains confident in its clinical and biomarker package, and will focus on patient starts rather than near‑term revenue while navigating reimbursement challenges.
• In Sanfilippo, Denali found weekly dosing better tolerated than every‑other‑week, has fully enrolled key efficacy cohorts with a planned data cut in September, and is targeting a 2027 BLA/approval timeline while warning that manufacturing at its new facility could be a rate‑limiting step.
• Denali is broadening its transport vehicle (TfR) platform into Pompe and two Alzheimer’s programs (clinical starts this year, readouts guided to 2027), stressing engineering differentiation—such as a cis‑LALA mutation—to improve brain/muscle delivery, tolerability and competitive positioning.

Denali Therapeutics NASDAQ: DNLI founder and CEO Ryan Watts said 2026 is shaping up to be a pivotal year for the company as it approaches a potential first product approval and advances multiple transport vehicle-enabled programs across rare disease and neurodegeneration.

Speaking in a moderated discussion, Watts highlighted the company’s pending FDA decision for tividenofusp alfa in Hunter syndrome, additional expected data in Sanfilippo syndrome and progranulin deficiency, and a readout for its LRRK2 program. He also said Denali is expanding its transport vehicle platform into new clinical trials, including two Alzheimer’s disease programs and a Pompe disease program.

Hunter syndrome filing and FDA timeline reset

Watts described Denali as being in the “very final stages” of its first approval process for tividenofusp alfa in Hunter syndrome, an area he said has not seen an approved medicine for 20 years. He emphasized that Denali’s approach is designed to cross the blood-brain barrier and address neurological manifestations of the disease while maintaining peripheral disease control.

Asked about the FDA environment for rare disease and accelerated approval, Watts acknowledged it has been an “unusual” period, particularly around the use of biomarkers that are “reasonably likely to predict clinical benefit.” He said Denali remains confident, pointing to what he called robust clinical and biomarker data and “fantastic engagement” with the FDA over the last nine months.

Watts also explained why the company’s Prescription Drug User Fee Act (PDUFA) date moved. He said Denali’s original PDUFA date was January 5, but a “miscalculation of a molecular weight” for tividenofusp alfa led to a major amendment and a statutory extension to April 5. Watts said the issue was resolved quickly, but the timeline shift reduced the time pressure that typically accompanies late-cycle review and contributed to a longer cycle for chemistry, manufacturing and controls (CMC) review, which he said is now completed.

Launch expectations: “switch market” and focus on patient starts

On potential commercialization, Watts characterized the Hunter syndrome opportunity as largely a “switch market,” with newly diagnosed patients also important. He said Denali expects minimal revenue in the first year, with early efforts focused more on “patient starts” than near-term sales. He cited reimbursement as a key challenge in rare disease launches.

Watts declined to discuss potential label specifics or pricing given proximity to the FDA decision, but he framed the therapy as more than incremental relative to current standard of care because of its ability to access the central nervous system while treating peripheral disease.

On disease presentation, Watts said clinicians generally view Hunter syndrome as a spectrum rather than two distinct categories. He noted that even attenuated patients can develop neurological issues such as hearing loss over time, while patients with severe mutations may show neurological symptoms early, around ages two to four.

Sanfilippo update: dosing insights, September data cut, and manufacturing as a gating factor

Watts said Denali recently presented data from the first eight patients in its Sanfilippo program and used that cohort to explore dose levels and dosing frequency. A key takeaway, he said, was that weekly dosing appeared better tolerated than every-other-week dosing, which he attributed in part to infusion-related reactions and the development of anti-drug antibodies commonly seen with enzyme replacement therapies.

He said Denali has now established “key efficacy cohorts,” which are fully enrolled, with a data cut planned for September. Watts outlined a targeted timeline of a biologics license application (BLA) filing in 2027 and approval in 2027, describing “first half” filing and “second half” approval as a reasonable way to think about timing.

However, Watts cautioned that manufacturing could be the rate-limiting step. He said Denali plans to manufacture the medicine at its own facility and hopes to engage the FDA through a “pre-check effort” given that it is a new facility.

On the potential market size for Sanfilippo, Watts said there is less clarity because there is no standard of care, but he believes it is likely similar in size and geographic distribution to Hunter syndrome.

Pompe and Alzheimer’s programs: expanding the transport vehicle platform

Watts discussed how Denali is applying its transferrin receptor (TfR) transport vehicle technology beyond brain delivery. In Pompe disease, he said the transferrin receptor can enhance delivery to muscle as well as brain. He contrasted this with the mannose-6-phosphate receptor approach used for biodistribution in Pompe, which he said appears limited in skeletal muscle. Denali’s goal, he said, is to compete in late-onset Pompe disease (LOPD), with consideration of infantile-onset Pompe disease (IOPD) as well due to an untreated central nervous system component in more severe cases.

For the three programs starting clinical studies this year—Pompe and two Alzheimer’s programs—Watts said Denali is guiding to 2027 readouts and is looking to move as quickly as possible using biomarker-driven development. He cited examples including Hex4 or muscle-specific biomarkers in Pompe, and amyloid or tau PET measures in Alzheimer’s disease.

In Alzheimer’s, Watts pointed to emerging “brain shuttle” data from trontinemab as reinforcing the promise of TfR-enabled delivery, citing observations he summarized as faster plaque reduction at lower doses and lower rates of ARIA, while adding that the link between faster plaque clearance and clinical benefit remains uncertain. He also described Denali’s engineering focus on tolerability, including a “cis-LALA mutation” intended to engage TfR for brain delivery without triggering unwanted immune interactions on reticulocytes. Watts also raised stability and immunogenicity as challenges for fusion-protein brain shuttle formats.

Discussing Denali’s amyloid targeting approach, Watts said the company is aiming to build on clinical learnings rather than “reinvent” target biology. He said antibodies that bind monomeric amyloid-beta without binding aggregated forms have failed in studies, while molecules binding aggregated amyloid-beta—plaque and oligomers—have shown more promise. Denali’s amyloid arms, he said, target aggregated amyloid-beta and are less preferential to monomeric forms.

On tau, Watts said Denali’s preclinical work supports the feasibility of delivering oligonucleotides across the blood-brain barrier and into brain cells to knock down gene expression, and that its humanized mouse model has been predictive for enzymes and antibodies. Asked about a Biogen tau program (BIIB080), Watts said a key lesson from earlier data was that tau PET signal reduction suggested neurofibrillary tangles may be in equilibrium, but he cautioned that clinical endpoints in Alzheimer’s require careful interpretation given sample sizes.

Competitive landscape for brain shuttles

Watts said he views the rising number of transferrin receptor-enabled programs as validating, noting the concept dates back to the 1980s but took decades to “industrialize.” He argued that differentiation will depend on engineering and how it translates into biology, including the role of Fc domains in enzyme delivery, pharmacokinetics, and tolerance.

He closed by reiterating that Denali is “fully prepared to launch” if approved and intends to “lead the area of blood-brain barrier engineering,” while continuing to advance additional transport vehicle-enabled medicines.

About Denali Therapeutics NASDAQ: DNLI

Denali Therapeutics is a clinical‐stage biopharmaceutical company focused on developing therapies for neurodegenerative diseases. The company's research leverages a proprietary Blood–Brain Barrier Transport Vehicle (TV) platform designed to enable large molecules, including antibodies and enzymes, to penetrate the central nervous system. Denali's approach includes small molecules, monoclonal antibodies and gene therapy candidates aimed at key drivers of disorders such as Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis (ALS) and frontotemporal dementia.

Among Denali's lead programs is an orally delivered leucine‐rich repeat kinase 2 (LRRK2) inhibitor for Parkinson's disease, and an anti‐TREM2 antibody designed to modulate microglial activity in Alzheimer's patients.

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