Passage Bio, Inc. · NASDAQ:PASG
Passage Bio — Merger or Acquisition (July 2026)
38 slides from Passage Bio's merger presentation, Jul 22, 2026
Slide 1: Modulating RNA Processing to Target the Undruggable
Modulating RNA Processing TO TARGET THE UNDRUGGABLEInvestor Presentation July 2026 Filed by Passage Bio, Inc. pursuant to Rule 425 under the Securities Act of 1933 and deemed filed pursuant to Rule 14a-12 under the Securities Exchange Act of 1934 Subject Company: Passage Bio, Inc. Filer’s SEC File N
Slide 2: Disclaimers
Disclaimers Important Information for Investors This confidential presentation (“Presentation”) is for informational purposes only and is being provided to interested parties solely in their capacity as potential investors for the purpose of evaluating a potential private offering of securities (the
Slide 3: Risk Factors
Risk Factors Risk Factors Both Remix and Passage are subject to various risks associated with their businesses and their industries. In addition, the Proposed Transaction, including the possibility that the Proposed Transaction may not be completed, poses a number of risks to each company and its re
Slide 4: Additional Disclaimers
Additional Disclaimers Additional Information and Where to Find It This presentation relates to a proposed transaction involving Passage Bio and Remix and may be deemed to be solicitation material in respect of the proposed transaction. In connection with the proposed transaction, Passage Bio intend
Slide 5: Merger of Remix Therapeutics and Passage Bio
Merger of Remix Therapeutics and Passage Bio Overview Transaction Summary Management and Board Remix, a clinical-stage biotechnology company developing novel small molecule therapies designed to reprogram RNA processing and address disease drivers at their origin intends to merge with Passage Bio, I
Slide 6: REM-422: A De-Risked Oncology Asset at a Critical Inflection Point
REM-422: A De-Risked Oncology Asset at a Critical Inflection Point REM-422: The first drug candidate observed to inhibit MYB with meaningful clinical activity in ACC Adenoid Cystic Carcinoma (ACC): >1,500 US incidence and 13-15K US prevalence MYB driven cancer with no FDA approved treatments REM-422
Slide 7: Experienced management team with deep domain expertise
Experienced management team with deep domain expertise PETE SMITH Co-Founder, President & CEO H3 Biomedicine, Takeda, Millennium HEATHER WASSERMAN Chief Business / Operating Officer Eli Lilly, Human Genome Sciences MYTHILI KONERU Chief Medical Officer Legend, Marker, Eli Lilly DOM REYNOLDS Chief Sci
Slide 8: Small molecule pipeline targeting high value oncology targets
Small molecule pipeline targeting high value oncology targets Target/Compound Mechanism Indications Discovery Pre-Clinical Clinical Rights Anticipated Milestone MYB/REM-422 mRNA degrader Adenoid Cystic Carcinoma ORR / DoR Data Mid ’27 MYB AML/MDS RP2D Data Mid '27 Others (e.g. BRCA, lymphoma, CRC) O
Slide 9: REM-422 offers compelling value proposition in ACC
REM-422 offers compelling value proposition in ACC High unmet need in ACC, with no FDA-approved treatments Therapeutic candidate designed to target molecular driver of ACC Favorable clinical results: Robust results – 43% ORR* at RP2D, 100% disease control rate Historical controls for ORR range 0-15%
Slide 10: Adenoid Cystic Carcinoma has a high unmet medical need
Adenoid Cystic Carcinoma has a high unmet medical need Malignant epithelial tumor arising predominantly in salivary glands and other glandular tissues; high rates of perineural invasion and relentless growth/metastasis 1,500+ new patients¹ per year in the US; prevalence is ~13K – 15K² MYB a key driv
Slide 11: Current SoC: only 11-15% ORR with available therapy
Current SoC: Up to 75% of ACC patients will require systemic therapy, but only 11-15% ORR with available therapy *Lenvatinib, ¹Tchekmedyian et al., ²J Clin Oncol. 2019, Locati et al., Cancer, 2020, ³ Laurie SA et al., Lancet Oncol 2011 ⁴Putnam Associates, Qualitative Research (Q1 2021) & KOL discuss
Slide 12: REM-422 the first MYB inhibitor in clinical development
REM-422 the first MYB inhibitor in clinical development Majority of ACC patients express oncogenic MYB REM-422 designed to induce degradation of MYB mRNA MYB Expression* MYB translocation drives high expression MYB Expression The MYB poison exon is detectable using an IUO assay in clinical trials *S
Slide 13: REM-422 Mechanism: mRNA degradation through Poison Exon inclusion
REM-422 Mechanism: mRNA degradation through Poison Exon inclusion PE excluded from mature mRNA due to unfavorable interaction between the U1snRNP splicing complex and the weak 5’ splice site of the PE U1snRNP U1snRNP REM-422 acts as a specific small molecule molecular glue that enhances the interact
Slide 14: Tumor regressions observed in additional ACC PDX models
ACC PDX model Tumor regressions observed in additional 2 ACC PDX models Biomarker positive treated with REM-422 REM-422 demonstrated antitumor activity in biomarker positive ACC PDX models Biomarker/Poison Exon positive MYB NFIB ACC PDX model Biomarker/Poison Exon negative MYB NFIB Poison exon REM-4
Slide 15: A Poison Exon in MYB defines the majority of High-Risk ACC Patients
A Poison Exon in MYB defines the majority of High-Risk ACC Patients ~25% ACC-I ~ 75% ACC-II ~25-30% ACC-I ~70-75% ACC-II 86% PE +ve 53% PE +ve Molecular profiling data from 307 ACC patients* Poor prognosis regardless of ACC subtype PE +ve PE -ve MYB biomarker (Poison Exon) present in ~60-65% of ACC
Slide 16: REM-422 offers potential to become the new standard of care for ACC
REM-422 offers potential to become the new standard of care for ACC REM-422 U.S. Sales Estimate: $600M+ Remix is preparing for potential commercial readiness in 2028 CDx Testing Education Patient Support Scaling Potential U.S. Commercial Capabilities for REM-422 ACC Patient Flow¹ Over the course of
Slide 17: REM-422 Phase studies: ACC and AML/HR-MDS
REM-422 Phase 1 studies: Adenoid Cystic Carcinoma AML and High-Risk MDS
Slide 18: Ph1/2 ARIA study design in ACC
18 and 24mg doses evaluated to identify optimal dose Ph1 DOSE ESCALATION (all-comers): N = 69 Abbreviations: PK = Pharmacokinetics; PD = Pharmacodynamics; RP2D = Recommended Phase 2 Dose; R/M = Recurrent/Metastatic; ACC = Adenoid Cystic Carcinoma; DL = Dose Level; N = Number; ORR = Objective Respons
Slide 19: Demographics and disease characteristics
Datacut: 24Apr2026 Abbreviations: ECOG = Eastern Cooperative Oncology Group (Performance Status) *MYB PE positive + MYB IHC high/PE unknown &ACC Subtype as defined by Ferrarotto et al., 2021 PRIMARY SITE Salivary Major Minor Non-Salivary Trachea/Bronchial/Lung Lacrimal Breast Esophageal 41 (59%) 13
Slide 20: REM-422 PK/PD
REM-422 PK/PD REM-422 plasma exposure by dose level Abbreviations: PK = Pharmacokinetics; PD = Pharmacodynamics; RP2D = Recommended Phase 2 Dose 30mg Protein (IHC) Screening On Treatment MYB levels in tumor Observed dose proportional increase in exposures Robust target engagement observed in tumor b
Slide 21: Overall summary of treatment-related adverse events
Notes: TEAEs were reported using Medical Dictionary for Regulatory Activities, version 28.0; Percentages rounded to nearest whole number; # of subjects (%) reported in table Abbreviations: TEAE = Treatment-Emergent Adverse Event; TRAE = Treatment-Related Adverse Event; SAE = Serious Adverse Event; D
Slide 22: Treatment-related adverse events by dose level
3mg QDN = 6 6mg QD N = 4 12mg QDN = 4 18mg QDN = 16 24mg QD N = 15 30mg QDN = 9 38mg QDN = 9 48mg QDN = 6 TOTALN = 69 Lymphocyte count decreased 1 (17) 0 0 1 (6) 0 1 (11) 3 (33) 2 (33) 8 (12) Neutrophil count decreased 0 0 0 0 0 0 1 (11) 1 (17) 2 (3) White blood cell count decreased 0 0 0 0 0 0 1 (1
Slide 23: Change in tumor size from baseline by biomarker status
Radiographic images Baseline On-treatment (M5) Note: Efficacy dataset includes all patients with measurable target lesions at baseline and at least 1 post-treatment scan (N = 60) Change in tumor size from baseline by biomarker status Biomarker positive tumors demonstrated robust anti-tumor activity
Slide 24: Best percentage change in tumor size by dose
Response evaluable subgroup N # of Responders ORR (%) DCR (%) BM+ ≥ 24mg 19 7 37% 95% BM+ at 24mg 7 3 43% 100% Notes: 1) ORR includes uPR; 2) Patients with starting doses ≥30mg who remain on treatment reduced to 24mg; 3) One patient (30mg) excluded due to treatment discontinuation unrelated to REM-4
Slide 25: Sustained objective responses across ACC subtypes
Notes: *Treatment beyond progression; + = ongoing; †Pt on tx-hold; ACC Subtype as defined by Ferrarotto et al., 2021 Abbreviations: cPR= confirmed PR; uPR = unconfirmed PR; Pt = Patient, TL = Target Lesions; Tx = treatment; DOT = Duration of Treatment; DOR = Duration of Response Pt ID Dose Level Res
Slide 26: REM-422 ACC Program Summary
REM-422 ACC Program Summary Adenoid Cystic Carcinoma is a high unmet medical need tumor with no FDA approved therapies Prior therapies demonstrate an ORR range 0-15%, mPFS ~7 months highlighting need for more effective therapies ORR of 43% & DCR of 100% at RP2D with durable responses observed at las
Slide 27: AML and High-Risk MDS are MYB-driven malignancies
AML and High-Risk MDS are MYB-driven malignancies Acute myelogenous leukemia (AML) & high-risk myelodysplastic syndrome (HR-MDS) ~25,000 treatable AML/HR-MDS patients in the US MYB is a master transcriptional regulator of leukemogenesis REM-422 is active across multiple genetic subtypes in AML precl
Slide 28: REM-422: Robust monotherapy/combination activity in AML models
REM-422: Robust monotherapy/combination activity in AML models M4 (myelomonocytic) AML pt relapsed after chemotherapy with complex cytogenetics Vehicle REM-422 10 mg/kg SURVIVAL BENEFIT IN PDX MODEL Monotherapy Activity ERADICATED hCD45+ AML BLASTS Combination Activity ADDITIVE/SYNERGISTIC ACTIVITY
Slide 29: Ph1 Study in Patients with R/R AML or HR-MDS
Ph1 Study in Patients with R/R AML or HR-MDS DOSE ESCALATION Up to 2 dose levels evaluated to identify optimal dose PRIMARY OBJECTIVE — SAFETY, MTD, RP2D Secondary and exploratory objectives — PK, PD and efficacy DL1 (1mg) No. treated = 3 DL2 (3mg) No. treated = 4 DL3 (6mg) No. treated = 5 DL4 (12mg
Slide 30: Preliminary Anti-tumor Activity in AML/HR-MDS
Preliminary Anti-tumor Activity. RP2D not reached Dose dependent reduction of MYB mRNA levels was observed in bone marrow biopsies Additional patients with blast count reductions observed in ongoing dose escalation study From live database last updated Mar 18, 2026 Indication Dose (mg) Prior Therapi
Slide 31: REM-422 indication expansion potential in heme and solid tumors
REM-422 indication expansion potential in heme and solid tumors Breast Cancer MYB dysregulation MYB high expression Lymphoma Overexpression Colon Cancer Overexpression Disease Tumor agnostic Fusion & amplification MYB DEPENDENCY ACROSS SEVERAL LINEAGES (DepMap) MYB DYSREGULATION IN BREAST CANCER PMI
Slide 32: Pipeline programs
Pipeline programs _ it Femmix
Slide 33: Genetically Defined Diseases Patient Selection Criteria
Genetically Defined Diseases Patient Selection Criteria REMIX TARGETS& DRUGS DATA SCIENCE Integrated database of >350k internal and external transcriptome datasets Proprietary algorithms & AI/ML BIOLOGY & BIOMOLECULAR SCIENCES Functional & genetic validation of targets Fit for purpose high- throughp
Slide 34: Targeting MYC, an oncogenic transcription factor dysregulated across cancer
Targeting MYC, an oncogenic transcription factor dysregulated across cancer MYC amplification/activation occurs in ~28% of all tumors Remix developing a novel mRNA degrader approach targeting a regulator of MYC to prevent signaling via all 3 MYC paralogs Indication Total US New Cases (k/yr) MYC dysr
Slide 35: Discovery program targeting oncogenic MYC signaling
Discovery program targeting oncogenic MYC signaling high prevalence dysregulation across multiple solid and heme malignancies MYC-dependent upregulated pathways MYC-dependent downregulated pathways Small molecule mRNA degrader phenocopies genetic knockdown Regulator siRNA MYC siRNA Small molecule Po
Slide 36: RXSM-1244 target engagement and tumor growth inhibition in mouse CDX model
RXSM-1244 demonstrated potent mRNA and protein target engagement and robust tumor growth inhibition in a mouse CDX model protein reduction mRNA reduction QDx3 study. mRNA and protein analysis from samples collected 6 hr post-last dose poison exon inclusion anti-Target Protein anti-Vinculin RXSM-1244
Slide 37: Remix Therapeutics is Well-Positioned For Significant Growth
Remix Therapeutics is Well-Positioned For Significant Growth Near-Term Inflection Points Experienced Management Team and Investors Strong Pro-Forma Balance Sheet REM-422 in ACC - ORR and DoR data expected in mid’27, potential for NDA filing as early as H2'27 REM-422 in AML/MDS: RP2D and initial data
Slide 38: Thank you
\ remix therapeutics Thank you. 38 | NON-CONFIDENTIAL