Slide 1: 4th LNP Formulation & Process Development Summit: The PEG Dilemma – A Solution
HIGHLY CONFIDENTIAL & TRADE SECRET 1 April 15, 2025 4th LNP Formulation & Process Development Summit – Boston, MA “The PEG Dilemma” – A Solution Randall Moreadith, MD, PhD, Chief Development Officer rmoreadith@serinatherapeutics.com
Slide 2: POZ Platform for Programmable Drug Delivery
Small Molecules1 / Lipid Nanoparticles / Antibody Drug Conjugates POZ Platform® for Programmable Drug Delivery April 2025 Non-confidential Presentation NYSE: SER 1 Moreadith, et al, Clinical development of a poly(2-oxazoline) (POZ) polymer therapeutic for the treatment of Parkinson’s disease – Proof
Slide 3: Forward Looking Statements
Forward Looking Statements NON-CONFIDENTIAL 3 This presentation contains forward-looking statements that are based on management’s beliefs and assumptions and on information currently available to management. In some cases, you can identify forward-looking statements by the following words: “may,” “
Slide 4: Anatomy of LNPs
Anatomy of LNPs "What if replacing the PEG-lipid with a POZ-lipid resulted in something extraordinary ?” 4 Ionizable lipid Cholesterol mRNA Phospholipid PEG-lipid Ionizable lipid Cholesterol mRNA Phospholipid POZ-lipid
Slide 5: Anti-PEG antibodies, anaphylaxis and loss of efficacy summary
T • Consecutive cohort studies show that anaphylaxis occurs at an unusually high incidence rate in patients receiving the approved mRNA vaccines; current data suggest this is not classically described IgE-mediated (mast cell degranulation) • The high titers of anti-PEG IgM & IgG that are boosted by
Slide 6: Balancing immunogenicity and reactogenicity Review
Balancing immunogenicity and reactogenicity Review 6
Slide 7: List of adverse events reported with the mRNA vaccines
Balancing immunogenicity and reactogenicity List of adverse events reported with the mRNA vaccines 7
Slide 8: Anaphylaxis incidence in Stanford Medical Center cohort study
In A Consecutive Cohort Study in Stanford Medical Center Network The incidence rate of anaphylaxis meeting Brighton anaphylaxis criteria was 1:2,287 (the incidence of anaphylaxis with flu vaccine is ~ 1:2,000,000) Assessment of Allergic and Anaphylactic Reactions to mRNA COVID-19 Vaccines With Confi
Slide 9: Basophil activation assays in anaphylaxis patients
9 Eleven of the seventeen patients consented to additional studies. BAT assays revealed that patients with anaphylaxis gated activated CD63+ basophils in the presence of vaccine (A), PEG (not shown) - but not saline (C) The Anti-IgE panel (B) is the positive control IgG-mediated degranulation of bas
Slide 10: Is PEG the culprit? Yes.
Is PEG the culprit ? Yes. 10 of 11 patients had positive basophil activation tests to PEG 11 of 11 patients had positive basophil activation tests to the administered vaccine 10
Slide 11: We've seen this before: The Regado Bioscience story
We’ve seen this before … The Regado Bioscience story 11 • The REG1 system was a rationally-designed strategy to replace the anticoagulant heparin in the cardiac catheterization lab as an adjunct to percutaneous coronary artery procedures • Pegnivacogin (RB006) was a 40 kDa methoxy-PEG attached to an
Slide 12: We've seen this before: The Regado Bioscience story
We’ve seen this before … The Regado Bioscience story 12 • All three patients were female with a history of allergic reactions • The onset of these SAEs occurred within minutes of the infusion • Review of the nonhuman primate studies revealed no aggregation, degradation or evidence of inflammatory cy
Slide 13: We've seen this before: The Regado Bioscience story
We’ve seen this before … The Regado Bioscience story 13 • The IgGs in these patients were shown to bind linear PEG and branched PEG, presented as either methoxyPEG or hydroxyPEG (PEG diol) • The anti-PEG IgG titers ranged from 1:120 to 1:3100 • The anti-PEG antibodies also bound PEGloticase (Krystex
Slide 14: We've seen this before: The Regado Bioscience story
We’ve seen this before … The Regado Bioscience story 14 • The trial was halted due to an excess of SAEs in the Pegnivacogen arm vs Bivalirudin; included one fatality • Of the 16 patients who developed SAEs in < 1 hr in the Pegnivacogen arm 15 (94%) had high titer IgGs to PEG • The authors speculated
Slide 15: Does vaccination induce high titers of anti-PEG antibodies?
Does vaccination induce high titers of anti-PEG antibodies ? Review of recent literature 15
Slide 16: Vaccination induces anti-PEG antibodies: Pfizer/BioNTech vs Moderna
Does vaccination induce high titers of anti-PEG antibodies ? Absolutely. But there are differences between Pfizer/BioNTech vs Moderna. 16 Anti-PEG Abs were present in 71% of patients prior to vaccination Moderna vaccination induced a much higher titer of both IgG and IgM post- boost than the Pfizer
Slide 17: Do these antibodies bind to immune cells?
Does vaccination induce high titers of anti-PEG antibodies ? Do these antibodies bind to immune cells ? 17
Slide 18: Anti-PEG IgG binds granulocytes, monocytes and ONPATTRO
Does vaccination lead to binding of nanoparticles to immune cells ? High titers of anti-PEG IgG bind to granulocytes & monocytes – and bind ONPATTRO 18 The high titers of anti-PEG IgG lead to association of Onpattro nanoparticles to the granulocyte and monocyte populations of immune cells in the pla
Slide 19: Does vaccination lead to complement activation?
19 Does vaccination lead to complement activation ? It is clear that the anti-PEG antibodies bind complement … but do they compromise the LNP (study 2022) ?
Slide 20: Does vaccination alter response to PEGylated therapies? Yes.
20 Does vaccination alter response to PEGylated therapies ? Yes. • Both patients were stable (without bleeding events) on standard short- acting rFVIII • Both patients were transitioned to the longer-acting PEGrFVIII formulation (Patient 1 - turoctocog alfa pegol; Patient 2 – damoctocog alfa pegol)
Slide 21: Acute hemorrhage in a Hemophilia A patient following Moderna vaccination
21 Does vaccination alter response to PEGylated therapies ? Yes. Acute hemorrhage in a Hemophilia A patient following Moderna vaccination • The patient is a 21 yo who has been treated with QOD infusions of rFVIII since age 3; transitioned to PEGrFVIII • He had previously been tested for anti- PEG an
Slide 22: Anti-PEG IgG & IgM alter response to ONPATTRO therapy
22 Anti-PEG IgG & IgM alter response to ONPATTRO therapy The loss of efficacy was linearly correlated with anti-PEG antibody levels This study followed the therapeutic response to ONPATTRO in patients in Vasterbotten County, Sweden (n=21) In 7 of 21 patients there was an abnormal response to therapy
Slide 23: Anti-PEG IgG & IgM alter response to ONPATTRO therapy
23 Anti-PEG IgG & IgM alter response to ONPATTRO therapy The loss of efficacy was linearly correlated with anti-PEG antibody levels The loss of efficacy correlated with ELISA levels of anti-PEG IgG & IgM (p<0.001, p<0.002, respectively) Patients were transitioned to vutrisiran with an enhanced thera
Slide 24: Substituting PEG Lipids with Poly(2-ethyl-2-oxazoline) Lipids Improves LNP Repeat Dosing
24 Research Article Substituting Poly(ethylene glycol) Lipids with Poly(2-ethyl-2-oxazoline) Lipids Improves Lipid Nanoparticle Repeat Dosing Alejandro J. Da Silva Sanchez, David Loughrey, Elisa Schrader Echeverri, Sebastian G. Huayamares, Afsane Radmand, Kalina Paunovska, Marine Hatit, Karen E. Tie
Slide 25: PEOZ-lipid LNPs Have Unique Properties
PEOZ-lipid LNPs Have Unique Properties LNPs which incorporate PEOZ-lipid selectively express the payload in macrophage (M) and dendritic (D) cells 25 • In vivo results are reproducible and generalizable to other LNP formulations • The initial observation that a PEOZ- lipid LNP selectively targets an
Slide 26: PEG-dmg vs PEOZ-dmg – Intravenous injection
PEG-dmg vs PEOZ-dmg – Intravenous injection X 4 The payload in this experiment is an mRNA encoding luciferase Strictly Confidential 26 • Two groups of mice – Group A received a single injection, Group B received four injections • Luminescence was measured in liver and spleen 48 hrs post-dose • Accel
Slide 27: Evaluation of Pfizer/BioNTech LNP in rat - PEG-dma
27 Evaluation of Pfizer/BioNTech LNP in rat - PEG-dma Rat immunogenicity study (The LNPs in this study employed ALC-0315 and ALC-0159 (Acuitas) at identical mol% for the published vaccine) Nature Vaccines (2023)
Slide 28: Vaccination with clinically relevant dosing of LNPs (PEG-dma)
28 Vaccination with clinically relevant dosing of LNPs (PEG-dma) Rat immunogenicity study (Pfizer/BioNTech vaccine formulation) Clinically relevant dosing modeled after C-19 vaccines
Slide 29: Anti-PEG antibody induction in rat (PEG-dma)
Anti-PEG antibody induction in rat (PEG-dma) Anti-PEG antibodies - IgM and IgG are both boosted (similar to human data) Both anti-PEG IgM and IgG antibodies are induced in the rat following vaccination of relevant doses of LNPs Low levels of antibodies are produced by the Low Dose Higher levels of a
Slide 30: Serina study design: PEOZ-dma vs PEG-dma anti-PEG response
30 Does vaccination with PEOZ-dma vs PEG-dma lead to different anti-PEG response Serina study design to evaluate PEOZ-dma and PEG-dma Day 0 3 5 7 10 14 17 19 21 24 28 First Injection Second Injection _______ This study design dosed rats with two injections (two doses – mid & high) at a 14-day interv
Slide 31: LNP phospholipid content, particle size, zeta potential and encapsulation efficiency
Phospholipid content, Particle size, Polydispersity, Zeta Potential & Encapsulation efficiency After Buffer Exchange in Tris-HCl, pH 7.1 Sample Name Z-Average (nm) Polydispersity Index (PI) Zeta Potential (mV) Encapsulation Efficiency PEG LNP after BXC (Avg) 88.26 0.1592 -16.43 >98% PEOZ LNP after B
Slide 32: Anti-IgM antibodies to PEG-dma vs PEOZ-dma
32 Anti-IgM antibodies to PEG-dma vs PEOZ-dma Serina LNP Laboratory Anti-IgM antibodies are readily detected, and boosted, at the High Dose and Mid Dose when LNPs employing PEG-dma are injected (similar to published data) LNPs prepared with PEOZ-dma failed to elicit an IgM response at either the Hig
Slide 33: Anti-IgG antibodies to PEG-dma vs PEOZ-dma
33 Anti-IgG antibodies to PEG-dma vs PEOZ-dma Serina LNP Laboratory Anti-IgG antibodies are readily detected at both the High Dose and Mid Dose when LNPs employing PEG-dma are injected (similar to published data) LNPs prepared with PEOZ-dma failed to elicit an IgG response at either the High Dose or
Slide 34: POZ-lipids disclosed in patent
The POZ-lipids described in the studies presented are all disclosed in this patent
Slide 35: Summary and conclusions
T • Anaphylaxis to the vaccines appears to be primarily due to basophil degranulation, likely the result of high titer IgG (possibly IgM) to the PEG in the formulation • Now recognized as an uncommon mechanism of anaphylaxis, first described clinically ~ 15 years ago • The high titers of IgM & IgG a
Slide 36: Acknowledgements
HIGHLY CONFIDENTIAL & TRADE SECRET 36 Acknowledgements Team Serina The James Dahlman Lab Gaurav Sahay, Serina SAB Pfizer Vaccines Other Collaborators