Syndax Pharmaceuticals Inc. (SNDX): R&D day highlights confidence in IPF ahead of Ph2 data 4Q26; new expansion opportunities

Research evidence excerpt

Syndax Pharmaceuticals Inc. (SNDX): R&D day highlights confidence in IPF ahead of Ph2 data 4Q26; new expansion opportunities

Goldman Sachs Syndax Pharmaceuticals Inc. (SNDX)

tolerability while maintaining activity against L858R, atypical mutations, and the

C797S resistance mutation. Preclinically, SNDX-4321 demonstrated robust mutant

selectivity, CNS penetration, and intracranial activity comparable or superior to

osimertinib. It also demonstrated dose-dependent tumor regressions in

L858R-mutant models, as well as improved efficacy and delayed tumor regrowth

when combined with osimertinib without evidence of additive toxicity.

n Clinical development strategy and proof-of-concept objectives for SNDX-4321.

SNDX plans to submit an IND for SNDX-4321 by YE26 and initiate a Ph1 study in

2027 in patients with EGFR-mutant NSCLC harboring L858R or atypical activating

mutations (excluding Exon 19 deletions and Exon 20 insertions), who have

progressed following prior EGFR TKI therapy (most likely osimertinib). SNDX’s

development strategy is to first establish monotherapy activity in a

TKI-resistant/refractory setting (initial data expected early 2028) before rapidly

transitioning into combination cohorts with osimertinib, with the ultimate goal of

advancing the combination into the frontline setting for susceptible EGFR-mutant

disease. Early proof-of-concept data will focus on demonstrating clear single-agent

activity in heavily pretreated patients, and confirming a wild-type EGFR-sparing

tolerability profile that could enable both rapid dose escalation and high dose

intensity, particularly for atypical mutations. In combination, they ultimately hope to

establish additive or synergistic anti-tumor activity, while delaying resistance

emergence and avoiding overlapping toxicities.