1Q26: EMBOLDEN Dosing To Complete In 2Q26; Updated Ph1/2 '401 Data In Mid-2026

Research evidence excerpt

1Q26: EMBOLDEN Dosing To Complete In 2Q26; Updated Ph1/2 '401 Data In Mid-2026

TD Cowen Neurogene

Global Research May 13, 2026

Per NGNE, in their START program and BTD discussions with FDA, the agency encouraged a 12-

month primary analysis to support full approval, noting that a 6-month endpoint may not be

considered clinically meaningful. We still believe a 12-month readout is clinically appropriate

to support full approval, in alignment with historical precedent, and ultimately differentiating,

as it allows for better capture of durability, trajectory of functional gains, and consistency of

response over time, which are critical considerations in Rett.

We continue to believe the recent, updated Ph1/2 '401 dataset bodes well for the registrational

EMBOLDEN study expected in 2027. We expect the compelling Phase 1/2 efficacy and safety

data will likely be reproduced in the registrational trial, generating a robust efficacy and safety

dataset adequate for FDA review and approval.

ASGCT 2026: ICV Delivery Is A Routine, Well-Established Procedure That Enables Broader

CNS Biodistribution

At ASGCT 2026, NGNE presented a poster outlining the clinical rationale, administration

approach, and clinical safety of intracerebroventricular (ICV) delivery in the ongoing Ph1/2 study

of NGN-401 in Rett, with a clear focus on reinforcing ICV infusions as both the optimal biological

approach and a de-risked clinical modality.

Intracerebroventricular (ICV) delivery is a well-established, routinely performed neurosurgical

procedure that is commonly used for shunt placement, enzyme replacement, and

chemotherapy delivery. Importantly, administration itself is straightforward (~10 min),

highlighting that procedural complexity is low and reproducibility is high. Unlike ERT or