Comment from Anonymous

Public Comment on Regulatory Dossier FDA-2026-N-4162 To: VRBPAC Meeting Date: June 18, 2026 Agenda Item: BLA STN 125869/0 — MFLUSIVA (Influenza Vaccine, mRNA), Moderna TX Inc. Subject: Review of Novel Influenza Platform Interactions with Host Cellular Replication Dynamics 1. Executive Summary This submission introduces into the administrative record peer-reviewed pathways demonstrating that nucleoside-modified mRNA platforms possess mechanisms for nuclear entry and genomic interaction during cell division. Because these dynamics are governed by foundational principles of mammalian mitosis and retrotransposition, a deferred postmarketing observational trial to monitor long-term oncological outcomes does not satisfy standard pre-market safety thresholds. This profile is distinct from traditional influenza vaccines and warrants independent evaluation. 2. Open Mitosis and Nuclear Barrier Dissolution Mammalian cell division relies on "open mitosis," requiring complete dissolution of the nuclear envelope (Nuclear Envelope Breakdown, or NEBD) during M-phase. This breakdown temporarily removes the physical compartmentalization separating the cytoplasm from the nucleus, exposing host chromosomes directly to stabilized transcripts, engineered delivery vehicles, or active catalytic complexes residing within the cytosol. 3. LINE-1 Chromosomal Binding and Target-Primed Reverse Transcription The machinery required for host reverse transcription—Long Interspersed Nuclear Element-1 (LINE-1)—exploits this mitotic window. LINE-1 ribonucleoprotein (RNP) complexes generated in the cytoplasm are typically too large to traverse intact nuclear pore complexes during interphase [1]. Instead, these endogenous RNP complexes rely on nuclear envelope breakdown during mitosis to bind directly to exposed host chromosomes, enabling nuclear entry and integration [1]. The human LINE-1 ORF2 protein (ORF2p) possesses functional, conserved endonuclease and reverse transcriptase domains [2] that execute Target-Primed Reverse Transcription (TPRT) by directly latching onto an RNA transcript, cleaving a target site on the host chromosome, and copying the sequence directly into host DNA [3]. 4. Vehicle-Induced Upregulation and Reverse Transcription in Aging Tissues The intersection of these intracellular dynamics with the unique pharmacology of Moderna’s lipid nanoparticle (LNP) formulation introduces specific regulatory considerations. LINE-1 is an endogenous network upregulated by universal cellular stress, immune signaling cascades [4], and chronological aging [5]. Signaling involving nitric oxide synthases (NOS2) and oxidative stress induces DNA hypomethylation, which relaxes the epigenetic locks that normally suppress LINE-1 expression [6]. Because the LNP delivery vehicle inherently triggers localized cellular reactogenicity and inflammatory cascades, the platform itself provides a physiological stimulus associated with endogenous LINE-1 activation. Independent data has captured human cell lines reverse-transcribing synthetic vaccine mRNA into genomic DNA counterparts via this endogenous retrotransposition pathway [7]. When stabilized, immune-evading synthetic transcripts delivered by engineered LNPs intersect with active LINE-1 machinery during open mitosis in cycling tissues, it triggers immediate replication stress and DNA damage signaling cascades within the dividing cell. Pan-cancer whole-genome analyses demonstrate that active LINE-1 mobilization is associated with genomic instability, structural rearrangements, deletions, and chromosomal breakages that initiate oncogenesis [8]. 5. Regulatory Observation Entering these peer-reviewed mechanisms into the public record indicates that a deferred postmarketing observational trial lacks the diagnostic capability to isolate, measure, or mitigate low-frequency chromosomal integration events. With nearly 90% of the body's 330 billion daily cell divisions heavily skewed toward the hematopoietic lineage, delivering reactogenic LNPs systemically guarantees a high-frequency intersection with vulnerable bone marrow progenitor cells during open mitosis. Since the molecular pathways for genomic interaction during cell division are documented in the literature detailed herein, the Committee should require the sponsor to rule out these platform-mediated mechanisms via definitive genotoxicity testing prior to regulatory clearance 6. Technical References [1] Zernia S, et al. Sci Adv. 2025;11(22):eadt9318. [2] Baldwin ET, et al. Nature. 2024;626:194–206. [3] Ghanim GE, et al. Science. 2024;383(6679):eads8412. [4] Li X, Liu N, et al. Trends Genet. 2025;41(7):577-589. [5] De Cecco M, et al. Nature. 2019;566:73–78. [6] Switzer CH, et al. PNAS. 2022;119(27):e2200022119. [7] Aldén M, et al. Curr Issues Mol Biol. 2022;44(3):715–726. [8] Rodriguez-Martin B, et al. Nat Genet. 2020;52:306–319.