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Okaz et al. Rare Dis Orphan Drugs J. 2025;4:24 https://dx.doi.org/10.20517/rdodj.2025.15 Page 7 of 11

associated with synthetic carriers. EVs can be readily functionalized with targeting moieties, including
peptides, aptamers, and antibodies, to enhance specificity toward target cells and thereby improve
therapeutic efficacy. The use of specific ligands to functionalize EVs for targeted delivery to the brain and
lung has been demonstrated [34,37] . It is likely that targeted “designer” EVs offer a tractable approach with the
potential to overcome key challenges in NF1 gene delivery. Additional studies to refine EV-based
nanocarriers, enhancing their tropism to Schwann cells and increasing their relevance for NF1 therapies, are
warranted.

Promising novel gene delivery technologies: The development of novel and disruptive gene delivery
technologies with inherent biological effects holds significant promise. A systemic lupus erythematosus-
associated autoantibody (4H2) can be repurposed as a dual-function therapeutic and gene delivery platform.
[38]
4H2 binds endogenous RNA, activates the cytosolic DNA/RNA sensor cGAS , and initiates STING-driven
inflammatory signaling that is selectively cytotoxic to brain, lung, and breast cancer cells while sparing
normal epithelium. In orthotopic glioblastoma models, intravenously delivered 4H2 accumulated in the
tumor microenvironment, prolonged survival in a T cell-dependent manner, and enhanced the efficacy of
immune-checkpoint blockade. Beyond immunomodulation, 4H2 also served as a non-viral nucleic acid
delivery carrier: when complexed with exogenous RNA, it delivered functional transcripts to tumor, brain,
and muscle tissues in vivo. These data establish a dual strategy with translational potential for cancer
[39]
immunotherapy and for gene-replacement approaches . Preliminary data in NF2 highlight the potential of
this dual-acting antibody approach, which effectively delivers the NF2 gene into diseased cells while
simultaneously eliciting an innate immune response via activation of the cGAS-STING signaling
pathway . This dual functionality positions the autoantibody-based immunomodulation/gene delivery
[40]
strategy as a potentially promising avenue for other genetic diseases such as NF1.

Exploring nonsense suppression as a treatment for NF1
Nonsense mutations, which introduce premature termination codons (PTCs) in the NF1 gene, account for
approximately 20% of NF1 cases and lead to truncated, unstable neurofibromin protein. These mutations
reduce neurofibromin expression by triggering nonsense-mediated mRNA decay (NMD) or premature
translation termination. Readthrough (RT) agents are small molecules capable of inducing ribosomal
readthrough of PTCs to restore the expression of full-length functional protein. Such agents have
demonstrated efficacy in treating genetic disorders caused by nonsense mutations, including cystic fibrosis
and Duchenne muscular dystrophy (DMD) .
[41]
Ongoing research efforts to accelerate the development and validation of high-throughput screening assays
to identify novel RT agents that can suppress PTCs and/or inhibit NMD in NF1 hold promise. In addition,
testing the efficacy of RT agents in NF1-specific cell and mouse models carrying distinct PTCs, which
mimic the cutaneous and plexiform neurofibromas, as well as the skin hyperpigmentation observed in NF1
patients, is essential. Optimization of the pharmacokinetics and pharmacodynamics of RT agents, with a
focus on their impact on neurofibromin expression, Ras signaling, and NF1-associated phenotypes, is also
ongoing. Further research is needed to yield critical insights into the molecular mechanisms and therapeutic
potential of RT agents for NF1 treatment [42,43] .

Exon skipping to treat NF1
For specific NF1 variants, antisense oligonucleotides (ASOs) can be employed to promote exon skipping,
restoring functional neurofibromin expression to mitigate tumorigenesis or slow tumor growth. This
strategy targets RNA splicing by designing ASOs to exclude specific exons during mRNA processing,
effectively “skipping over” pathogenic variants. Exon skipping is a proven therapeutic approach, currently