Shares of gene editing therapy companies mostly surged by double digits this past week on two growth catalysts. One catalyst was expected: The European Society of Gene and Cell Therapy’s 33rd ESGCT Annual Congress, which finished Friday in Hamburg, Germany, brought forth the usual flurry of data presentations, including many positive readouts by developers of new editing-based therapies.

The other catalyst happened October 27 when the FDA issued draft guidance (FDA-2026-D-11783) intended to help sponsors develop and pursue approvals for personalized gene therapies designed to treat patients with rare genetic diseases. The guidance, Individualized Human Genome Editing Products: Considerations for BLA Submission and Postapproval Management, offers a regulatory framework for submitting and managing Biologics License Applications (BLAs) for individualized genome editing products.

“For patients with rare genetic diseases, a one-size-fits-all approach to treatment simply does not work and neither should a one size fits all approach to regulation,” FDA acting commissioner Kyle Diamantas, said in a statement.

Maury Raycroft, PhD, equity analyst at Jefferies, viewed the draft guidance positively in a Friday note: “Gene editing cos have underperformed the past yr, but we anticipate a range of de-risking data & reg catalysts ahead; recent constructiveness from FDA/gov should keep momentum going.”

The draft guidance introduces to the FDA the concept of the Individualized Feature Space (IFS), a set of pre-defined limits describing allowable limits of variation for genome edited (GE) components of an individualized GE product, so such therapies can vary from patient to patient without needing to perform additional clinical trials, while remaining within the scope of a single BLA.

“For a GE product whose only variable feature is a gRNA spacer sequence, the IFS should describe which types of spacer sequences are allowable in the BLA—such as any spacer sequence that targets a defined class of pathogenic gene variants in a specified gene and results in the same editing outcome (e.g., correcting the gene so that it encodes the wild-type protein),” the draft guidance explains.

The FDA is soliciting public comment through November 27, both online and via mail.

Mostly positive impact

Since the draft guidance was issued after the close of markets, investors had to wait until Wednesday to see the impact of the proposed rules plus ESGCT data on gene editing stocks. That impact turned out to be mostly positive, with shares of four gene editing therapy developers rising between 4% and 29%. Even higher gains earlier in the week were dampened by a nearly 3% drop in the Nasdaq Composite on Friday, sparked by disappointing third-quarter earnings reported by tech and artificial intelligence (AI) companies.

The biggest gainer this past week was Prime Medicine (Nasdaq: PRME), whose shares enjoyed a five-day leap of 29% from $3.67 to $4.72—a 20% falloff from the 52-week high Prime reached on Thursday, when its share peaked at $5.91 at 9:57 a.m. ET.

The draft guidance continued a month-long 53% surge sparked by a pair of positive clinical developments: Last month Prime received FDA clearance allowing the launch of a planned Phase I/II trial for its in vivo Prime Editor PM647 in alpha-1 antitrypsin deficiency (AATD).

And on October 5, Prime dosed the first patient in a Phase I/II open-label trial (NCT07748403) assessing its in vivo Prime Editor PM577a in adults and teens as a treatment for H1069Q-mutated Wilson disease, the first reported instance of prime editing being used to edit DNA directly in a person. Prime says initial data from the trial is expected in 2027.

“Overall, we see promise over the long-term for the pipeline and could consider becoming more constructive on the stock as we move closer to value-creating milestones (initial clinical data) in 2027,” Tessa T. Romero, a senior analyst focused on biotechnology equity research with J.P. Morgan, commented in a June 18 research note that followed clinical trial clearance for PM577a in New Zealand.

Second highest among editing stocks this week with a 13% jump is Beam Therapeutics (Nasdaq: BEAM). The developer of CRISPR base editing therapies saw its shares climb from $24.05 on October 23 to $27.23 Friday, driven in part by positive initial data from its Phase I/II trial (NCT06735755) showing clinical proof of concept for BEAM-301 for the treatment of glycogen storage disease type Ia (GSDIa).

BEAM-301 is a liver-targeting lipid-nanoparticle (LNP) formulation of base editing reagents designed to correct the R83C mutation, which is associated with the most severe form of GSDIa.

Maximum outcomes

As of data cutoff August 17, two of three patients in the trial’s 40 mg cohort achieved the trial protocol’s maximum 15-hour controlled fasting duration—a result consistent with restored endogenous glucose production, Beam said. The two also saw 100% reduction in daily starch requirements, no longer requiring starch supplementation, and improved glucose control with more time spent in the euglycemic range and less in the hyperglycemic range.

“BEAM-301 appears impressive at first clinical data look,” Myles R. Minter, PhD, a partner and biotechnology analyst with William Blair, wrote in a research note. Minter has estimated that BEAM-301 will generate peak annual sales of $475 million.

That would be 31% above the $362 million in peak sales modeled by Minter’s colleague at William Blair, Sami Corwin, PhD, a biotechnology-focused healthcare analyst, for Genglycos® (pariglasgene brecaparvovec-opnr), which won FDA approval in August as the first-ever drug authorized to treat GSDIa in adults and children ages 8 and older. Genglycos is marketed by Ultragenyx Pharmaceutical (Nasdaq: RARE).

The third 40 mg patient showed no time to fasting hypoglycemia (TTH) increase, potentially due to high body mass index (BMI) and heterozygosity for the R83C mutation, according to Beam.

“This could be solved with moving to the higher 60 mg dose or could warrant a BMI restriction in future cohort or even evaluation of potential weight-based dosing,” Minter added.

Based on the data, Beam is advancing BEAM-301 to a 60 mg cohort, where it has begun enrollment, and plans to engage with the FDA about a potential approval path.

Beam and Prime are likely to benefit from the FDA’s framework for genome editing drugs, Jefferies analyst Raycroft said: “We believe the framework could support/accelerate [Beam’s] PKU program entering the clin YE26/early’27 by leveraging data across 3 mut[ation]-specific PAH base editors.”

As for Prime, Raycroft noted that the company has FDA alignment to develop additional mutations under the same IND using most of the H1069Q package: “Follow-on editors may need only mut[ation]-specific off-target work and limited clin data for pot’l licensure.”

Data presented and awaited

Editas Medicine (Nasdaq: EDIT) saw its shares rise 11% this past week, from $2.40 October 23 to $2.67 Friday. The company presented two posters at ESGCT: One detailed a configurable, GMP-ready manufacturing platform for targeted LNP therapeutics shown to enable rapid evaluation of novel binders and cargos while maintaining consistent T-cell targeted LNP (tLNP) quality across scales, binders, and batches.

The other showed robust in vivo delivery of mRNA to targeted T cells using its scalable tLNP platform, which allowed for transient expression of CAR in targeted T cells, resulting in deep B-cell depletion in the blood within 24 hours post-dose. Researchers also reported seeing therapeutically relevant B-cell depletion in lymphoid tissues, “creating the potential for clinically meaningful immune reset for autoimmune therapy.”

Intellia Therapeutics (Nasdaq: NTLA) shares also grew 11% week-over-week, from $11.21 to $12.47. Intellia investors are also waiting for clinical data on lonvoguran ziclumeran (Lonvo-z), a one-time CRISPR/Cas9 gene-editing therapy being developed to treat hereditary angioedema (HAE). Those results are to be presented in two oral presentations and five poster presentations at the American College of Allergy, Asthma & Immunology (ACAAI) 2026 Annual Scientific Meeting, set for November 12–16 in Phoenix. The presentations include four-year follow-up data from patients who received a one-time 50 mg dose of lonvo-z.

On November 12, Intellia executives and HAE key opinion leaders plan to discuss the company’s preparations for the commercial launch of lonvo-z during a conference call with analysts.

CRISPR Therapeutics (Nasdaq: CRSP) shares rose 4% this past week from $49.39 to $51.42 Friday as investors await third-quarter results set to be released this month, and clinical data updates such as a planned readout from the Phase Ib trial (NCT07491172) of CTX310^®, a CRISPR/Cas9 in vivo gene editing therapy candidate targeting angiopoietin-related protein 3 (ANGPTL3), in patients with severe hypertriglyceridemia. That data will be presented at the American Heart Association (AHA) Scientific Sessions 2026, set for November 6–9.

Not all editing therapy stocks reaped the fruits of the FDA guidance and ESGCT data announcements. Shares of Caribou Biosciences (Nasdaq: CRBU), a CRISPR therapeutics developer whose co-founders include Jennifer Doudna, PhD, dropped nearly 21% from 53 cents on October 23 to 42 cents Friday. Caribou thus continued a slide triggered by its review of strategic alternatives and plans to reduce a “substantial” portion of its workforce—a decline that has caused the company’s stock to plunge 66% over the past month from $1.27 on September 30.

Anthropic details acquisition, partnerships

Anthropic used a press release rather than the Form S-1 Registration Statement disclosing its initial public offering (IPO) plans to flesh out its progress and plans in the drug development space it has targeted as one key area of future growth.

The AI giant—which filed for its long-awaited IPO  on October 26—acknowledged pursuing its own drug discovery efforts and disclosed that in August, it acquired Mithril Medicine, a developer of treatments for two rare forms of muscular dystrophy staffed by a single person, founder Cody Tranbarger, a biotech entrepreneur and investor. Tranberger used Claude to organize contracts, logistics, and experiments with 11 external labs, as well as to delegate “many other aspects of Mithril’s operations.” Mithril has advanced within 18 months a therapy for one form of muscular dystrophy from an idea to positive results in mice.

“If his drug candidates continue to hold up, we expect a drug to be ready to start clinical trials in humans as soon as late 2028,” Anthropic predicted.

“Deep research partnerships”

Anthropic also listed a series of six “deep research partnerships” with drug developers. Two of the six are public companies, Bristol Myers Squibb (BMS; NYSE: BMY) and Generate: Biomedicines (Nasdaq: GENB), which in February carried out its own $400 million IPO (of which $369.3 million was net proceeds). The other four partners are private companies: BigHat Biosciences, Divergence Labs, Enveda, and The Column Group (TCG).

Anthopic’s release also offered some details of its work with collaboration partners:

• BMS: The pharma giant used Anthropic’s Claude family of large-language models to estimate the likelihood of success for planned clinical trials of an unidentified early-stage drug. “Together, we plan to expand this work in 2027 to understand its potential for increasing the probability of success in early development,” Anthropic said.
• Generate: Six Generate scientists used Claude Code to propose new designs for part of a chimeric antigen receptor T cell (CAR T) therapy’s genetic instructions, creating room for additional instructions addressing other types of cancer. One design “about 70%” shorter showed greater effectiveness than the standard version in lab tests: “Compact ICDs [intracellular domains] may lower the dose needed to generate CAR T cells in vivo and enable more complex CAR therapies, such as CAR cocktails,” Generate concluded.
• BigHat: Researchers from the protein and antibody drug developer joined Anthropic in applying Claude to improve binding, stability, and anti-clumping properties of two antibody fragments that could become parts of future drugs: one designed to target cancer cells, and one designed to keep a drug in the body longer.
• Enveda: The developer of molecules based on living organisms “reduced human review time by 89%, from over 25 hours to less than three, by linking its manufacturing documents to Claude. After reviewing 1,061 pages of documentation, Anthropic Claude caught all 11 issues that human reviewers had spotted and flagged seven they missed: “A promising development for future use cases in decreasing the time, cost, and error rates in drug development,” Enveda concluded.
• TCG: A spinout of the venture capital firm, called Pleiades, will use Claude to reduce scientific, operational, and administrative overhead as it runs more, and more complex, drug development programs “than is usual for a small team,” Anthropic said, adding: “The savings will enable previously untenable risks on a larger array of challenging and innovative projects.”
• Divergence: Using Claude, the food allergy drug developer generated “roughly 35,000” antibody designs in about a month for testing. Divergence found three design arms designed to bind tightly to IgE, and 20 that could help dislodge IgE from the immune cell (three of which dislodged more IgE than standard medication). Divergence plans to build a drug that combines the two types of arms, stating in a study: “We expect biparatopic construction … to provide a significant boost to potency and disruptive efficacy.”

In a LinkedIn post, however, Geoff Harris, PhD, CSO and co-founder of Excellergy—an indirect, wholly owned subsidiary of Novartis (SIX Swiss: NOVN and NYSE: NVS) acquired for up to $2 billion in June—said Divergence Labs’ study “doesn’t describe a drug, but the components of what might be a drug someday, maybe, which is years behind the competition.”

“A monoclonal antibody drug that is exceptional at disarming the IgE axis already exists and is in the clinic today,” Harris added, namely Excellergy’s lead candidate EXL-111, a trifunctional allergic effector cell response inhibitor designed to treat allergic diseases by targeting the IgE axis. EXL-111 is in a Phase I trial (NCT07356713) with an estimated primary completion date of December 7.

Anthropic says it envisions Divergence and its other partners applying Claude to ultimately bring their candidates into the clinic as well: “We plan to continue extending Claude’s role into clinical trials as these drug programs advance, and as we partner with more organizations whose drug development programs are already at the clinical stage.”

Leaders and laggards

Acumen Pharmaceuticals (Nasdaq: ABOS) shares cratered 91% from $2.29 to just 21 cents Friday after the developer of Alzheimer’s disease (AD) drugs targeting amyloid beta oligomers announced that it was ceasing development of its lead pipeline candidate sabirnetug (ACU193) and evaluate its strategic options after the humanized monoclonal antibody failed the Phase II ALTITUDE-AD trial (NCT06335173) in participants with early AD. Sabirnetug missed its primary endpoint of change from baseline in cognitive and functional decline as measured by the Integrated Alzheimer’s Disease Rating Scale (iADRS) at 18 months vs. placebo at either the 35 mg/kg or the 50 mg/kg dose. Sabirnetug also failed to achieve statistical significance on key secondary efficacy endpoints, including the Clinical Dementia Rating–Sum of Boxes (CDR-SB), and did not show any meaningful difference between the sabirnetug and placebo treatment arms. Acumen said it plans to take steps to carry out cash conservation measures and explore strategic options.

Aspen Neuroscience (ASPE) shares dipped 0.7% from its initial public offering (IPO) price of $15 a share to $14.89 Friday as the developer of autologous induced-pluripotent stem cell (iPSC)-derived therapies for neurodegenerative diseases began its first full day of trading. Shares began the day at $14.70, below the IPO price—the low end of its $15-$17 price range when it priced 9.375 million shares, raising $140.625 million in gross proceeds. Proceeds are intended to fund clinical trials for its lead candidate, the Parkinson’s disease therapy sasineprocel, now in the Phase I/IIa ASPIRO open-label dose escalation study (NCT06344026), as well as development of the company’s microglia programs, including initiating IND-enabling studies.

Genmab (Nasdaq: GMAB) shares jumped 28% from $44.67 to $57.29 Wednesday after the antibody drug developer announced data from the global Phase III LiGeR-HN1 trial (NCT06525220) assessing petosemtamab in combination with pembrolizumab, the cancer immunotherapy blockbuster marketed by Merck & Co. (NYSE: MRK) as Keytruda®, vs. pembrolizumab alone in patients with first-line (1L) PD-L1 positive recurrent/metastatic head and neck squamous cell carcinoma (HNSCC). Based on the first interim analysis assessed by an independent data monitoring committee, treatment with the petosemtamab combination showed a “statistically significant and clinically meaningful” improvement in overall survival (OS), reducing the risk of death by 50%, and objective response rate (ORR) vs. pembrolizumab [OS hazard ratio 0.50, p<0.0001; ORR odds ratio 3.17 p<0.0001), meeting the trial’s dual primary endpoints regardless of HPV status.

Iovance Biotherapeutics (Nasdaq: IOVA) shares tumbled 35% from $14.81 to $9.56 Thursday after the tumor infiltrating lymphocyte (TIL) cell therapy developer announced data from Cohorts 1 and 2 of its Phase II IOV-LUN-202 trial (NCT04614103) evaluating lifileucel in previously treated metastatic non-small cell lung cancer. As of the October 14 data cutoff 17 of 69 patients responded, an ORR of 24.6%, consistent with the 25.6% ORR previously reported in 39 patients but less than what investors expected. Iovance said a retrospective analysis found a biomarker-enriched subgroup defined by Kirsten rat sarcoma viral oncogene homolog (KRAS) wild-type status, human epidermal growth factor receptor 2 (HER2) wild-type status, and current or former smoking.