Gene Editing Weekly — October 10–16, 2026: a base editor restores glucose production in GSDIa patients, and a census finds two individualized editing trials
Beam Therapeutics' in vivo base editor restored endogenous glucose production in six patients with glycogen storage disease type Ia, and a census of the clinical trial registry found two individualized editing constructs among 148 gene-editing studies.
The coverage window for this issue is October 10 – October 16, 2026, Eastern Time. The week produced one new set of human data, and it arrived in a company press release: Beam Therapeutics reported initial Phase 1/2 results for BEAM-301, an in vivo base editor for glycogen storage disease type Ia. Around that readout, Intellia named a chief medical officer, Editas and Cellectis put gene-editing posters on the European society's congress programme, and the FDA renewed the committee that reviews cell and gene therapy applications. A census of the public trial registry also counted how few individualized editing studies sit on file.
| Track | What changed | Evidence boundary | Next milestone |
|---|---|---|---|
| Clinical | Beam reported initial Phase 1/2 data for BEAM-301, an in vivo base editor for GSDIa: six patients dosed, and both evaluable patients at 40 mg reached the protocol's maximum controlled fasting duration. 1 | A company press release, a June 26, 2026 data cutoff, and two evaluable patients at the higher dose. 1 | Updated data in poster P0219 on October 28, and an investor webcast on October 27. 1 |
| Company | Intellia appointed Jing L. Marantz executive vice president and chief medical officer, effective October 26. 2 | A leadership appointment; the trial timelines it oversees were unchanged. 2 | lonvo-z, the company's first potential in vivo product, is under FDA review. 2 |
| Company | Editas announced two ESGCT posters, one on in vivo CAR-T generation and one on a GMP-ready manufacturing platform for targeted lipid nanoparticles. 3 | Poster titles and session times only; the abstracts stay delegate-only until October 27. 34 | Poster session 1 on October 28. 3 |
| Data calendar | The ESGCT congress programme reached registered delegates on October 13, ahead of the October 27–30 meeting in Hamburg. 4 | Abstracts are delegate-only, and public communication of them is embargoed until October 27. 4 | October 27–30. 4 |
| FDA ledger | The biologics ledger posted two blood-donation compliance-policy guidances dated October 14, one on donor suitability and one on blood pressure and pulse eligibility. 5 | A weekly posting ledger, which records what the agency chose to publish. 5 | Applications for the Expedited IND pilot close on October 30. 6 |
| Governance | The FDA renewed the Cellular, Tissue, and Gene Therapies Advisory Committee. 7 | A Federal Register notice; the committee's authority would otherwise have lapsed on October 28. 7 | The committee's next meeting. 7 |
| Governance | A census of ClinicalTrials.gov found seven of 148 eligible gene-editing studies individualized or platform-designated, and two describing a construct designed for one participant. 8 | A single-journal cross-sectional census of registry records, with moderate agreement between the two screeners. 8 | Whether sponsors begin registering individualized designs as their own category. 8 |
| Research | One preprint, three articles and one editorial notice appeared, covering bystander prediction in base editing, a single-cell screen in blood stem cells, reviews on artificial intelligence and nonviral delivery, and an expression of concern. 9101112 | The preprint awaits peer review, and the journal articles are read here at the depth of their abstracts. 9 | Peer review of the preprint. 9 |
Clinical
Beam's base editor restored glucose production in GSDIa patients
Beam Therapeutics said on October 13 that BEAM-301 reached clinical proof of concept in glycogen storage disease type Ia, or GSDIa. 1 The claim rests on six patients who each received a single intravenous infusion. 1
As of a June 26, 2026 data cutoff, three patients had received 20 mg and three had received 40 mg. 1 Median follow-up was 313 days in the 20 mg cohort, with a range of 249 to 453 days, and 53 days in the 40 mg cohort, with a range of 5 to 110 days. 1 One patient in the higher-dose cohort fell outside the efficacy analysis, which left two. 1
The clearest signal was how long patients could go without food. 13 Median time to fasting hypoglycaemia was 2.9 hours at baseline in the 20 mg cohort and 2.5 hours in the 40 mg cohort. 1 By day 36 the 20 mg median had risen to 4.3 hours, and both evaluable patients at 40 mg reached the protocol's maximum controlled fasting duration of at least 15 hours. 1
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That 15-hour figure is the ceiling of the fasting test, and the measurement stops there. 1 The 40 mg result rests on two patients, and Beam reads both of them reaching the ceiling as restored endogenous glucose production. 1
Prescribed starch intake also fell over the same period, and the 20 mg cohort shows how unevenly. 1 Reductions from baseline in that cohort were 74% at day 128, 71% at day 227 and 11% at day 387; at 40 mg they were 71% at day 50 and 92% at day 93. 1 Daily starch doses fell by zero to four at 20 mg and by two to four at 40 mg, from baselines of six to seven and five to six doses. 1 Triglyceride levels were comparable to baseline at the last follow-up. 1
Every patient had at least one treatment-emergent adverse event that Beam considered related to BEAM-301. 1 Five serious adverse events resolved within two to ten days, and three of those were Grade 3 infusion-related reactions. 1 Beam attributes the Grade 3 reactions in part to the shorter-acting steroid premedication typical in this population, and the regimen has since been changed. 1 Transaminase elevations were transient and resolved without intervention; a single elevation reached Grade 2 and the rest were Grade 1. 1 The trial recorded zero dose-limiting toxicities, zero discontinuations and zero deaths. 1
GSDIa comes from mutations in G6PC1, which encodes glucose-6-phosphatase, the enzyme that releases glucose from stored glycogen. 1 Patients carrying the R83C variant can become hypoglycaemic within one to three hours without food, so standard care is repeated cornstarch dosing, including overnight. 13
BEAM-301 is a liver-targeting lipid nanoparticle carrying base-editing reagents built to correct R83C, one of the most common disease-causing variants and the one associated with the severe form. 1 A base editor converts one base pair at a defined position without cutting both DNA strands, so BEAM-301 repairs the patient's own gene at the mutated codon. 13
Follow-up continues, and Beam will present updated data in poster P0219 at the European Society of Gene and Cell Therapy congress on October 28. 1 The company also scheduled an investor webcast on the data for October 27 at 8:00 a.m. Eastern. 1
Company and pipeline
Intellia hired a chief medical officer
Intellia Therapeutics appointed Jing L. Marantz as executive vice president and chief medical officer on October 13, effective October 26. 2 Marantz takes responsibility for translational, development, regulatory and medical affairs. 2
She was most recently chief medical officer at Scholar Rock, where the development organization ended in US approval of ISEMBYLD for spinal muscular atrophy. 2 Her earlier roles include Krystal Biotech, Acceleron, Alnylam, Alexion, Biogen, ARIAD and Millennium Pharmaceuticals, and she sits on the board of Arcturus Therapeutics. 2
Chief executive John Leonard framed the hire around commercializing lonvo-z, the company's first potential in vivo gene editing product, and advancing Phase 3 trials of nex-z in transthyretin amyloidosis. 2 This briefing reported the FDA's priority review of lonvo-z, with a March 10, 2027 target action date, in its September 11 issue.
The appointment is the sector's second chief medical officer change in five weeks. Editas Medicine named Dan Ory to the same role in September, which this briefing covered on September 11.
Editas put two posters on the ESGCT programme
Editas Medicine said on October 14 that it will present two posters at the 33rd ESGCT congress. 3 One reports in vivo CAR-T cell generation from targeted lipid nanoparticle delivery, with therapeutically relevant B-cell depletion; the other describes a configurable, GMP-ready manufacturing platform for targeted lipid nanoparticle therapeutics. 3 Both sit in poster session 1 on October 28, presented by Harry An, the company's director of process development. 3
Editas's public programme this year has centred on EDIT-401, an in vivo editor that raises LDL receptor expression, whose first human trial this briefing reported clearing on October 8. The two poster titles point the same delivery technology at immune cells and at manufacturing, a different target class from EDIT-401's hepatocyte target. 3
Management will also take part in a Guggenheim healthcare conference fireside chat on November 10. 3
The congress programme now lists the editing posters
The 33rd ESGCT congress runs October 27–30 in Hamburg. 4 Abstracts became available to registered delegates on October 13, and public communication of them is embargoed until October 27. 4
| Company | Program and modality | Poster | Session |
|---|---|---|---|
| Beam Therapeutics | BEAM-301, lipid-nanoparticle base editor correcting G6PC1 R83C in GSDIa | P0219 | Poster session I, October 28, 1:30–3:30 p.m. CET 1 |
| Editas Medicine | In vivo CAR-T cell generation by targeted lipid nanoparticle delivery | P0361 | Poster session 1, October 28, 1:30–3:30 p.m. CET 3 |
| Editas Medicine | Configurable, GMP-ready manufacturing platform for targeted LNP therapeutics | P0781 | Poster session 1, October 28, 1:30–3:30 p.m. CET 3 |
| Cellectis | In vivo editing of human APOC3 by a TALE base editor in animal models | P0208 | October 29, 2–4 p.m. CET 14 |
| Cellectis | TALE: developing a global framework for genome engineering | P0956 | October 29, 2–4 p.m. CET 14 |
Those five posters are the ones announced by gene-editing companies this briefing follows, and the abstracts themselves stay behind the delegate wall until October 27. 4
Regulatory, policy and governance
The week's CBER ledger
The FDA's "What's New for Biologics" list added two postings dated October 14, both compliance-policy guidances. 5 One covers blood and blood-component donation suitability, donor eligibility and source plasma quarantine hold requirements; the other covers blood pressure and pulse donor-eligibility requirements. 5 Both concern blood and plasma collection. 5
The ledger's genome-editing line carried nothing new in the window, so this week added no editing approval, complete response letter, advisory committee action, IND clearance or BLA acceptance. 5
The FDA renewed its gene-therapy advisory committee
The FDA published a notice on October 14 renewing the Cellular, Tissue, and Gene Therapies Advisory Committee. 7 Authority for the committee would have expired on October 28, 2026 unless the Commissioner determined that renewal was in the public interest, and the Commissioner made that determination. 7 The notice runs under docket FDA-2026-N-0008 and is printed at 91 FR 65223. 7
CTGTAC advises the agency's biologics center on cell and gene therapy products, which covers every editing program in this briefing. 7 The same docket lists two other FDA advisory committees renewed on October 1, for antimicrobial drugs and for dermatologic and ophthalmic drugs. 7
Nineteen months on, the registry holds two individualized editing constructs
A census published in Cureus on October 15 counted interventional studies of human gene-editing agents registered on ClinicalTrials.gov, using a census date of September 17, 2026. 8 The authors retrieved 212 records and judged 148 of them eligible. 8
Four were single-participant or n-of-1 designs and three were multi-variant umbrella or platform-designated designs, for a total of seven. 8 The remaining 140 were conventional cohorts, plus one editing arm inside a non-editing platform trial. 8 Two of the 148 describe a construct designed for the individual participant. 8
The authors searched the registry and public FDA records for the regulatory route behind the index case, the 2025 individualized base-editing treatment for an infant with carbamoyl phosphate synthetase 1 deficiency, and came away with nothing. 8 The same search returned zero expanded-access records and zero publicly verifiable platform-technology designations. 8
Two independent screeners classified the records, and their agreement on design class was moderate, at a kappa of 0.540 with a 95% confidence interval of 0.264 to 0.815. 8 The counts describe what the registry records. 8
Research
The window brought one preprint, three articles and one editorial notice.
A model for the bystander problem in base editing
Furkan Özden and Peter Minary, both at the University of Oxford, posted a preprint on October 12 describing crispAIBE, a probabilistic framework for predicting base-editing outcomes. 9 A base editor converts a single base pair, and when several susceptible positions sit inside the editing window the enzyme can convert more than one, which produces bystander alleles. 9
crispAIBE trains transformer and convolutional networks separately to predict distributions for editing efficiency and for the composition of edited products, then calibrates prediction regions on reserved data. 9 On held-out data it reports Pearson correlations of 0.669 for efficiency and 0.896 for composition, with empirical coverage close to the nominal 0.90 level. 9
The work is a preprint and awaits peer review. 9 The authors were funded by DeepMind and have released the models and processing scripts. 9
A single-cell map of the regulators that steer blood stem cells
A Cell Stem Cell paper published on October 13 reported a single-cell CRISPR screen in primary human hematopoietic stem and progenitor cells. 10 The screen profiled 322 regulators across 172,382 single-perturbed cells. 10
SMYD3 emerged as a negative regulator of long-term regenerative capacity. 10 KMT5B, TRIM24, SETD7 and NSD3 were associated with lineage-biased outputs. 10
Two reviews map where AI and nonviral delivery are heading
Molecular Cell published a review on October 15 on artificial intelligence in genome editing. 11 Its account runs from early predictors of guide RNA activity, off-target effects and editing outcomes to transformer-based protein language models that evolve editing proteins and generate new enzymes. 11
Human Gene Therapy published a review on October 14 covering nonviral gene transfer and genome engineering. 12 The systems it describes include Sleeping Beauty and piggyBac DNA transposons, R2 retrotransposon platforms, CRISPR-associated transposons and prime editing. 12
An expression of concern on a CRISPR screen paper
Science Translational Medicine issued an Editorial Expression of Concern on October 14 for a research article titled "In vivo CRISPR activation screen identifies acyl-CoA-binding protein as a driver of bone metastasis". 15 The notice appears under DOI 10.1126/scitranslmed.aem8786. 15
Editorial view
The week's only clinical readout and its only methods preprint both turn on writing one precise base and knowing which base was written. 19 BEAM-301's claim is that it corrected a single specified codon, R83C, in patients. 1 crispAIBE's claim extends that work to the composition of edited products, beyond the efficiency of the edit. 9
The registry census puts a number on the individualized end of that work. 8 Nineteen months after the first bespoke CRISPR treatment, two registered studies describe a construct made for one participant, and the regulatory route behind the index case is absent from the public record. 8
The regulatory side of the week was maintenance: a ledger with no editing action, and a committee renewed for another term with its next meeting still to be set. 57
The next two weeks carry five dated items. 1 Beam holds its investor webcast on October 27 at 8:00 a.m. Eastern, and the ESGCT abstract embargo lifts the same day. 14 The Beam and Editas posters present on October 28 and the Cellectis posters on October 29. 1314 Applications for the FDA's Expedited IND pilot close on October 30. 6
References
- 1
- 2
- 3
- 4ESGCT Congress 2026 submission guidelines
esgctcongress.com
- 5What's New for Biologics
fda.gov
- 6
- 7
- 8
- 9
- 10
- 11
- 12
- 13Base Editor Restores Glucose Production in GSDIa Patients
crisprmedicinenews.com
- 14The ESGCT 33rd Annual Congress
cellectis.com
- 15
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