1Q26: Two Catalysts in View; SION-719 Ph2a PreciSION CF and SION-451 Ph1 HV Both Summer 2026 Readouts

Research evidence excerpt

1Q26: Two Catalysts in View; SION-719 Ph2a PreciSION CF and SION-451 Ph1 HV Both Summer 2026 Readouts

May 12, 2026 Sionna Therapeutics, Inc.

(SION, Buy, $58 PT)

Kambiz Yazdi

1Q26: Two Catalysts in View; SION-719 Ph2a PreciSION CF and (212) 588-6580 kyazdi@btig.com

SION-451 Ph1 HV Both Summer 2026 Readouts Company Data

Closing Price $40.94

WHAT YOU SHOULD KNOW: Sionna reported 1Q26 financial results and provided a Price Target $58.00BIOTECHNOLOGY pipeline update highlighted by the completion of enrollment in the Phase 2a PreciSION

Market Cap (M) $1,848.44 CF trial, a randomized, double-blind, placebo-controlled crossover study evaluating

SION-719 added to Trikafta (standard of care) vs. placebo added to Trikafta in F508del Shares Out (M) 45.15

homozygous CF patients. The SION-451 dual combination Ph1 healthy volunteer study Avg Daily Vol-3 Months (M) 0.36EQUITY will now also have data in the summer of 2026. Revisions

■ Confidence in SION-719 is well-grounded. Robust preclinical data spanning CFTR Previous Current

maturation, DSLS, and CF HBE assays, combined with Phase 1 PK results showing Rating Buy Buy

strong exposures at lower doses and a favorable tolerability profile in healthy Price Target $58.00 $58.00

volunteers, underpin our conviction that SION-719 will meet its key endpoints in CY26E REV 0.00 0.00

PreciSION CF. CFTR maturation studies demonstrated that SION-719 in addition toRESEARCH CY27E REV 0.00 0.00 ETI (Trikafta's ingredients) restored CFTR function, and SION-719 was highly active

in the CF HBE model with the potential to return CFTR to near wild-type function. CY26E EPS (2.23) (2.55)

CY27E EPS (2.17) (2.54)

■ The sweat chloride bar matters. Nearly two-thirds of CF patients on currently