CLDX Ph2 PN Misses with Limited Readthrough to Ph3 CSU Data in Sept/Oct

Research evidence excerpt

CLDX Ph2 PN Misses with Limited Readthrough to Ph3 CSU Data in Sept/Oct

USA | Biotechnology

Celldex Therapeutics, Inc. EquityJulyResearch21, 2026

FLASH NOTECLDX Ph2 PN Misses with Limited Readthrough

RATING BUYto Ph3 CSU Data in Sept/Oct

PRICE $35.66^

We view PN as a near-free call option. While disappointing, the negative Ph2

is unlikely to materially change expectations for barzolvolimab (c-kit mAb). PRICE TARGET | % TO PT $68.00 | +91%

Ph2 PN study achieved profound/sustained mast cell depletion w/o clinical 52W HIGH-LOW $40.30 - $19.72

benefit. We see limited efficacy readthrough to CSU/ SD/ ColdU, where barzol FLOAT (%) | ADV MM (USD) 114.7% | 41.72

has generated strong pbo-controlled Ph2 data. Encouragingly, safety remained MARKET CAP $2.4B

favorable w/ the 450mg loading dose+300mg Q4W regimen used in CSU pivotal TICKER CLDX ^Prior trading day's closing price unless otherwise

studies. noted.

Bottom line. We and most investors view PN as a near-free call option vs a key component of

the CLDX base thesis. While the result is disappointing, we do not expect the readout to materially

change investor expectations for barzolvolimab in CSU/ CIndU. Importantly, Ph2 PN achieved

profound and sustained mast cell depletion while failing to show clinical benefit, suggesting the

failure is more likely attributable to PN biology. We see limited efficacy readthrough to CSU/ SD/

ColdU, where barzol has already demonstrated robust pbo-controlled Ph2 efficacy. Importantly, the

study provides additional reassurance around safety of 450mg loading dose + 300mg Q4W regimen

used in the pivotal program (readout in Sept/Oct '26). Net net, we would anticipate a modest negative

stock reaction (~5-10%).

Ph2 PN failed to meet 1EP and key 2EPs at W12 across both dose arms. The proportion of