Seaport Therapeutics, Inc. Key Takeaways from 1Q26 & Phase 1 MAD Results for GlyphAgo

Research evidence excerpt

Seaport Therapeutics, Inc. Key Takeaways from 1Q26 & Phase 1 MAD Results for GlyphAgo

J P M O R G A N North America Equity Research

08 June 2026

Seaport Therapeutics, Inc. Overweight

SPTX, SPTX US

Key Takeaways from 1Q26 & Phase 1 MAD Results for Price (05 Jun 26):$16.44

GlyphAgo

SMid Biotechnology

Tessa T Romero AC

(1-212) 622-4484

tessa.t.romero@jpmchase.com

Caroline Pocher

(1-212) 622-8204

caroline.pocher@jpmchase.com

We are encouraged by the company’s progress in advancing its lead programs,

Mariam Waggeh

GlyphAllo and GlyphAgo, “Glyphed” formulations of allopregnanolone and

(1-212) 622-1711

agomelatine, which have previously shown varying degrees of proof-of-mechanism/ mariam.waggeh@jpmchase.com

clinical proof-of-concept in Seaport’s areas of interest (major depressive disorder J.P. Morgan Securities LLC

(MDD) and generalized anxiety disorder (GAD), respectively). Recall, Seaport

recently completed its IPO (see our initiation report here for more details). For

GlyphAllo, enrollment continues in the phase 2b BUOY-1 trial in patients with MDD

with or without anxious distress with topline data expected in 1H27. We note that the

company now intends to enroll the full pre-specified target sample size of ~360

patients and no longer plans to perform a sample size re-estimation (SSRE), which

mgmt believes should increase the likelihood that the study could be registration-

enabling with more patients. Ahead of the expected BUOY-1 data, Seaport plans to

report topline data in 2H26 from the phase 1 trial assessing driving performance in

healthy volunteers receiving GlyphAllo; from this study, mgmt is hoping to see data

that is consistent with the PK/PD and safety profile observed previously for

GlyphAllo. For GlyphAgo, Seaport reported MAD results from the phase 1 study in