Since CRISPR-Cas9 gene editing burst onto the biomedical scene in 2012, the field has evolved from

proof-of-concept laboratory studies to human clinical trials. As of mid-2025, multiple CRISPR-based

First, it is worth recalling that CRISPR (Clustered Regularly Interspaced Short Palindromic Repeats)
technology employs a guide RNA (gRNA) to direct the Cas9 endonuclease to a specific DNA locus,
enabling precise cuts and subsequent repair. Early clinical worksuch as the 2020 CRISPR-mediated editing
of hematopoietic stem cells to treat sickle cell diseaseshowed dramatic results, with patients achieving
transfusion independence and robust expression of fetal hemoglobin. However, these initial trials still
relied on ex vivo editing, wherein cells are edited outside the body and then reinfused. The real
milestone in 2025 is the maturation of in vivo delivery methodswhere CRISPR components are delivered
directly to target tissues via viral vectors, lipid nanoparticles (LNPs), or novel polymer systems.

One of the most significant advances in 2025 has been Intellia Therapeutics and Regenerons Phase II trial
of NTLA-2001, an in vivo CRISPR therapy for transthyretin amyloidosis (ATTR). ATTR is caused by a
mutation in the TTR gene leading to misfolded transthyretin protein accumulation in peripheral nerves
and the heart. In February 2025, interim data from 60 patients showed that a single intravenous infusion
of NTLA-2001 reduced serum TTR protein levels by an average of 95 percent at six months, with no
serious adverse events related to off-target editing. The therapy uses an LNP formulation to deliver
mRNA encoding a modified Cas9 along with gRNA targeting the TTR gene. These results led the U.S. Food
and Drug Administration (FDA) to grant Breakthrough Therapy designation in March 2025, accelerating
the review process. If pivotal Phase III data replicate these results, NTLA-2001 could become the first in
vivo CRISPR therapeutic approved, possibly as early as late 2026.

Another high-profile trial in 2025 is Editas Medicines Phase I/II trial of EDIT-101 for Lebers congenital
amaurosis type 10 (LCA10), a rare inherited form of blindness caused by a CEP290 gene mutation. EDIT-
101 employs an adeno-associated virus (AAV) vector to deliver CRISPR machinery to photoreceptor cells.
In February 2025, Editas announced that among the first cohort of 12 participants, three showed a
measurable improvement in visual acuitygaining the ability to read large-print text under low-light
conditionswithout any immune-related adverse events. These results bolster hopes that CRISPR can
target post-mitotic cells in vivo, and they prompted the European Medicines Agency (EMA) to expedite
its own review under the PRIority MEdicines (PRIME) scheme. However, long-term safety remains under
close observation; clinicians will monitor for insertional mutagenesis or unintended edits in neighboring
retinal cells over the next two years.

Hard-to-reach tissues like the brain and lungs have also become targets. In March 2025, a collaborative
team from the Broad Institute and UC Berkeley published preclinical data demonstrating successful in
vivo base editing of the PCSK9 gene in nonhuman primates. Base editing, a next-generation CRISPR
approach, enables conversion of a single nucleotide without inducing double-strand breaksthereby
reducing the risk of unwanted chromosomal translocations. The researchers used a lipid nanoparticle
formulation to deliver an adenine base editor (ABE) mRNA and a gRNA targeting PCSK9, achieving a 75
percent reduction in circulating PCSK9 protein levels within four weeks. Since PCSK9 inhibition can lead
to lower LDL cholesterol, this approach holds promise for lifelong cardiovascular risk reduction from a
single infusion. A start-up named Elevate Bio licensed the ABE platform and plans to file an
Investigational New Drug (IND) application in late 2025 for a first-in-human trial targeting familial
hypercholesterolemia.

On the ex vivo front, CRISPR-based cell therapies have become more sophisticated. Vertex
Pharmaceuticals and CRISPR Therapeutics CTX001 (also known as luvutrisiran for hemoglobinopathies)
moved into Phase III trials for both sickle cell disease and beta-thalassemia in January 2025. CTX001 uses
ex vivo editing of patient-derived hematopoietic stem cells to knock out the BCL11A gene enhancer,
thereby reactivating fetal hemoglobin production. Earlier results showed that all subjects in the Phase II
cohort achieved transfusion independence, with minimal off-target effects and durable editing above 85
percent. With 250 patients enrolled worldwide, CTX001s ongoing Phase III study is the largest CRISPR
gene therapy trial to date. If successful, CTX001 could receive approval from the FDA and EMA in late
2026, setting a precedent for CRISPR-based treatments in monogenic blood disorders.

Real-world delivery challenges have driven advances in vector development. In late 2024, researchers at
the University of Pennsylvania published a novel hybrid vector combining AAV and bacteriophage capsid
proteins, enabling a smaller payload size and higher tropism for cardiomyocytes. This PhiAAV system was
licensed by a biotech called CardioGene Therapeutics in early 2025. In May 2025, CardioGene announced
promising preclinical results for its lead candidate, CGT-001, targeting an inherited form of hypertrophic
cardiomyopathy caused by a MYH7 mutation. In a pig model, a single intracoronary infusion of PhiAAV-
delivered base editors achieved 60 percent correction of the pathogenic allele in ventricular tissue with
minimal immune response. The company hopes to file an IND in mid-2026, pending toxicology studies in
nonhuman primates.

Ethical considerations remain at the forefront. In March 2025, the National Academies of Sciences,
Engineering, and Medicine (NASEM) convened a Global Summit on Germline Gene Editing, bringing
together ethicists, researchers, patient advocates, and policymakers. While somatic cell editing
(targeting nonreproductive cells) has broad support, the summit reaffirmed that germline editing in
humans remains off-limits for clinical applicationsciting risks of unintended heritable changes and equity
concerns. The summits final report, published in April 2025, recommended the establishment of an
international monitoring body to oversee any future germline editing research, should it ever be
pursued. This recommendation followed an incident in early 2025 where an unauthorized research
group in Eastern Europe published a preprint claiming to have edited embryos to confer resistance to
HIV. The group did not seek regulatory approval and was swiftly condemned by the World Health
Organization (WHO). WHO issued new guidelines in May 2025, calling for mandatory registration of all
human embryo research using any gene-editing tools.

Intellectual property (IP) battles have also heated up. The decade-long dispute between the Broad
Institute (associated with Feng Zhangs patent filings) and the University of California, Berkeley
(associated with Jennifer Doudnas team) was finally settled in January 2025. Under the new licensing
agreement, any CRISPR-Cas9-based therapeutic product must pay royalties to a newly formed joint
patent poolmanaged by a nonprofit entity called CRISPR IP Trust. The pools bylaws stipulate that
revenues will be reinvested into CRISPR research in low- and middle-income countries (LMICs). This
resolution was widely praised by biotech startups, which had been concerned about prohibitive licensing
fees. The first licensing round under this trust has already funded three academic labs in Nigeria, Kenya,
and India to develop CRISPR-based diagnostics for sickle cell disease and beta-thalassemiaconditions
highly prevalent in those regions.

Commercial partnerships are accelerating the translation of CRISPR research into therapies. In February
2025, Novartis announced a .2 billion collaboration with Beam Therapeutics to co-develop base-editing
therapies for metabolic liver diseases. Under the agreement, Novartis will provide Protein Manufacturing
capabilities, while Beam focuses on editing constructs and delivery platforms. The first joint candidate
targets phenylketonuria (PKU), a rare metabolic disorder caused by PAH gene mutations. Preclinical
studies in mouse models demonstrated that a single injection of LNPdelivered cytosine base editors
corrected 70 percent of hepatocytes, normalizing blood phenylalanine levels and preventing neurological
deficits. Beam projects IND submission for the PKU candidate by Q1 2026.

Investment flows into CRISPR startups reached record levels in 2024 and early 2025. According to
PitchBook data, venture funding for gene-editing companies exceeded billion in 2024a 40 percent
increase from the previous year. Major crossover funds and strategic corporate investors have poured
money into both platform developers (e.g., Scribe Therapeutics, Prime Medicine) and disease-specific
developers (e.g., Graphite Bio, Metagenomi). In April 2025, Scribe Therapeutics announced a million
Series C to advance its next-generation CRISPR systemcalled ShERPawhich uses a smaller Cas protein
with reduced immunogenicity and higher specificity. The company plans to test ShERPa in a Phase I trial
for a rare immune disorder (Wiskott-Aldrich syndrome) by Q3 2026.

Manufacturing and scale-up remain critical bottlenecks. Producing clinical-grade LNPs or viral vectors at
scale requires specialized facilities, stringent quality controls, and significant capital expenditure. To
address this, the U.S. National Institutes of Health (NIH) launched the Gene Therapy Manufacturing
Consortium in January 2025, providing grants to 10 Centers of Excellence focused on modular vector
production. These centers, located at institutions such as the University of North Carolina and Stanford
University, aim to standardize manufacturing processes, develop best-practice protocols for scalable
vector purification, and train technical personnel. In the same vein, the FDA recently released new
Guidance for Industry (May 2025) on Chemistry, Manufacturing, and Controls (CMC) considerations
specific to CRISPR-based therapiesemphasizing the importance of vector traceability, batch-to-batch
consistency, and robust assays for off-target analysis.

Patient advocacy groups are playing an increasingly active role in shaping clinical trial design and
regulatory expectations. For instance, the Sickle Cell Disease Association of America (SCDAA) convened a
workshop in March 2025 to discuss patient-reported outcome measures (PROMs) for CTX001s Phase III
trial. As a result, Bioethics panels integrated PROMs related to quality of lifesuch as pain frequency and
medication useinto the final trial protocol. Similarly, the Foundation Fighting Blindness (FFB) collaborated
with Editas Medicine to design the endpoint metrics for EDIT-101s LCA10 trial, ensuring that functional
vision tests align with daily activities (e.g., navigating low-light environments). These patient-centric
measures are now considered best practice, reflecting a shiftparticularly in rare disease
communitiestoward co-developing therapies alongside the people most affected.

Long-term monitoring and follow-up are key for CRISPR therapies, given the potential for delayed
adverse events such as immunogenic responses or off-target oncogenesis. Per FDA requirements, all
pivotal CRISPR trials now incorporate five-year safety follow-up protocols. In addition, the National
Cancer Institute (NCI) has partnered with several academic medical centers to launch the Genome
Editing Safety Registry in April 2025a centralized database that tracks all patients treated with genome
editing, recording any genotoxic events, autoimmune reactions, or secondary malignancies. The registry
will enable researchers and regulators to identify rare safety signals that might not be apparent in
individual trials. Early enrollment includes over 300 patients from Phase I/II oncology trials testing
CRISPR-edited T-cells for refractory leukemias.

Finally, ethical and equitable access considerations remain critical. As promising as CRISPR-based
therapies are, most have price tags in the range of 000 to million per patientplacing them out of reach
for many in low- and middle-income countries. To address this, global health organizations like Unitaid
and the Bill & Melinda Gates Foundation have pledged over million in early 2025 to fund tieredpricing
models and technology transfer initiatives. One notable program is the CRISPR Access Catalyst, aimed at
licensing select CRISPR platform technologies royalty-free to academic labs in LMICsprovided those labs
commit to developing treatments for diseases prevalent in their regions. In May 2025, a consortium led
by the Wellcome Trust in the U.K. announced funding to train African scientists in GMP (Good
Manufacturing Practice) vector production, with the goal of producing autologous cell therapies for
sickle cell disease within Kenya and Nigeria by 2027.

In summary, the year 2025 stands as a watershed moment for CRISPR-based gene therapy. In vivo
treatments for ATTR and LCA10 have demonstrated unprecedented efficacy and safety in early trials,
propelling regulatory designations and commercial partnerships. Base editing is expanding the
therapeutic scope to cardiovascular and metabolic diseases, while hybrid vector innovations offer hope
for targeting hard-to-reach tissues like the heart and brain. Nonetheless, challenges remain: scaling
manufacturing, ensuring long-term safety, navigating IP landscapes, and addressing ethical concerns
around equitable access. As clinical data accumulate and regulatory frameworks solidify, the next two
years will likely see the first approved in vivo CRISPR medicines, followed by broader adoption in genetic
and non-genetic diseasespotentially transforming the standard of care across multiple fields of medicine.