1Q26 - Setrusumab Regulatory Discussions Ongoing. Europe Rights to Vantictumab in Osteopetrosis Likely Underappreciated Ahead of Phase 2 Initiation in 2H26.

Research evidence excerpt

1Q26 - Setrusumab Regulatory Discussions Ongoing. Europe Rights to Vantictumab in Osteopetrosis Likely Underappreciated Ahead of Phase 2 Initiation in 2H26.

Investment Thesis

MREO has engaged in conversations with regulatory agencies on a potential path forward for setrusumab to be approved

in pediatric osteogenesis imperfecta (OI). Additional analyses from Phase 3 Orbit and Cosmic trials have been completed.

Management plans to provide updates after receiving definitive feedback from regulatory agencies. Activities to support potential

partnering for Phase 3 development and commercialization are ongoing for alvelestat in alpha 1 anti-trypsin deficiency (AATD).

MREO anticipates needing a single Phase 3 trial enrolling ~220 early- and late-stage AATD-LD patients to evaluate alvelestat over

an 18mo. period. The primary endpoints will be St. George's Respiratory Questionnaire (SGRQ) score for FDA approval, and lung

density via CT scan for EMA approval. On vantictumab (anti-FZD receptor mAb), development in autosomal dominant osteopetrosisBIOTECHNOLOGY Type 2 (ADO2) is expected to continue as planned, with a Phase 2 trial expected to be initiated in 2H26. MREO ended 1Q26 with

$36.2M in cash and equivalents, which the company is guiding as sufficient to fund operations into mid-2027.

Upcoming Catalysts Price PerformanceEQUITY ■ Vantictumab Phase 2 initiation in ADO2 - 2H26 $3.5

$3

$2.5

$2

$1.5RESEARCH $1

Base Case Assumptions: $1 Price Target $0.5

■ Setrusumab in OI (royalties from RARE): 30% probability of success, 2027 launch, $0

12.1k pts on Tx at peak Jun-25 Jul-25 Aug-25 Sep-25 Oct-25 Nov-25 Dec-25 Jan-26 Feb-26 Mar-26 Apr-26 May-26 ■ Setrusumab in OI (ex-US sales): 30% probability of success, 2027 launch, 4.6k pts

on Tx at peak MREOS&P 500 (rebased)

Source: FactSet