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Intellia releases first Phase 3 readout for an in-body CRISPR therapy

Intellia releases first Phase 3 readout for an in-body CRISPR therapy

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By Newzino Staff |

Pivotal HAELO trial of lonvo-z for hereditary angioedema sets up a 2026 FDA filing

Today: First Phase 3 readout for an in-body CRISPR therapy

Overview

For decades, people with hereditary angioedema have lived with weekly injections, infusions, or pills to suppress unpredictable swelling attacks that can close off the airway. Intellia Therapeutics released topline data on April 27, 2026 from HAELO, a global Phase 3 trial of lonvoguran ziclumeran (lonvo-z) — the first late-stage clinical readout ever for an in-body CRISPR gene-editing therapy.

Why it matters

If in-body CRISPR works once and lasts, chronic genetic diseases stop being lifetime drug bills and start becoming one-time fixes.

Key Indicators

1st
Phase 3 readout for in-body CRISPR
No other in vivo gene-editing candidate has reached late-stage pivotal data.
80
Patients in HAELO
Two-thirds received lonvo-z; one-third received placebo in a randomized, double-blind design.
1 dose
Single infusion
A single 50 mg intravenous dose, contrasted with weekly or bi-weekly chronic prophylaxis.
97%
Attack-free in Phase 1/2
31 of 32 earlier-stage patients went attack-free off long-term prophylaxis at data cutoff.
H2 2026
Planned FDA filing
Intellia plans to submit a Biologics License Application later this year.
~1 in 50,000
U.S. HAE prevalence
A small but well-defined patient population, sized for a rare-disease launch.

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People Involved

John Leonard
John Leonard
Leading the HAELO readout and 2026 FDA submission

Organizations Involved

Intellia Therapeutics
Intellia Therapeutics
Clinical-stage biotechnology company
Sponsor of HAELO; planning 2026 BLA filing

Cambridge, Massachusetts gene-editing company spun out of CRISPR pioneer Jennifer Doudna's foundational patents and focused on in vivo therapies delivered via lipid nanoparticles to the liver.
Regeneron Pharmaceuticals
Regeneron Pharmaceuticals
Biopharmaceutical partner
Co-development and royalty partner on lonvo-z

Tarrytown, New York biopharma company that fronted Intellia's earliest CRISPR investment and shares economics on the lonvo-z program.
U.S. Food and Drug Administration
U.S. Food and Drug Administration
Federal regulatory agency
Will review BLA submission expected in second half of 2026

The U.S. agency that approves new drugs, biologics, and gene therapies for the American market.

Timeline

  1. First Phase 3 readout for an in-body CRISPR therapy

    Clinical milestone

    Intellia releases topline efficacy and safety data from HAELO. The readout is the pivotal evidence base for the planned U.S. Biologics License Application later in 2026.

  2. Intellia confirms readout date

    Statement

    Company announces topline HAELO data will be released April 27, 2026 with an 8:00 a.m. ET investor webcast.

  3. Pooled Phase 1/2 data: 97% attack-free

    Clinical

    Of 32 patients dosed at 50 mg in earlier studies, 31 were attack-free and off long-term prophylaxis at data cutoff, with follow-up extending up to three years.

  4. HAELO enrollment completed

    Clinical

    All 80 patients enrolled, exceeding the 60-patient minimum specified in the protocol.

  5. First patient dosed in HAELO

    Clinical milestone

    Pivotal dosing begins. The trial randomizes patients 2-to-1 to a single 50 mg infusion of lonvo-z or placebo.

  6. HAELO Phase 3 trial initiated

    Clinical

    Intellia launches the global Phase 3 HAELO study, the first late-stage trial of an in-body CRISPR therapy.

  7. Phase 2 data: deep, durable attack reduction

    Clinical

    Intellia reports a 98% reduction in monthly HAE attacks in the highest-dose Phase 2 cohort, supporting advancement to Phase 3.

  8. FDA approves first CRISPR medicine

    Regulatory

    Casgevy from Vertex and CRISPR Therapeutics becomes the first approved CRISPR therapy, but it is an ex vivo product — patient cells are removed, edited in a lab, and re-infused over months.

  9. First HAE patient dosed with NTLA-2002

    Clinical milestone

    Intellia begins the Phase 1 trial of NTLA-2002 (later renamed lonvo-z), targeting the KLKB1 gene that drives swelling attacks in hereditary angioedema.

  10. First human evidence that in-body CRISPR works

    Clinical milestone

    Intellia and Regeneron report Phase 1 data showing NTLA-2001 reduced a disease-causing protein in ATTR amyloidosis patients — the first time CRISPR editing inside the body had been shown to work in humans.

Scenarios

1

FDA approves first in-body CRISPR therapy in 2027

Discussed by: Endpoints News, STAT, sell-side analysts at Leerink and Stifel

Topline HAELO data show a clear, statistically significant reduction in HAE attacks with a clean safety profile. Intellia files its BLA in the second half of 2026, the FDA grants priority review, and lonvo-z is approved in 2027 as the world's first in-body CRISPR medicine. Approval validates the platform and accelerates programs from Verve, Beam, and others into expanded pivotal trials.

2

Strong efficacy, but safety questions slow the launch

Discussed by: FDA review precedents in gene therapy; analyst reports flagging liver enzyme signals seen in earlier in vivo studies

The trial hits its primary endpoint, but rare adverse events — transient liver enzyme elevations or off-target editing concerns — prompt the FDA to require additional long-term follow-up or a black-box label. Approval comes, but with usage restrictions that limit early uptake against Takhzyro and other biologics that already have a multi-year safety record.

3

Mixed readout reopens questions about in-body CRISPR

Discussed by: Cautious commentary from biotech investors who note placebo effects in HAE trials and the small 80-patient sample

The reduction in attacks is meaningful but smaller than Phase 1/2 suggested, or the placebo arm performs unexpectedly well, narrowing the treatment effect. Intellia still files, but the data complicate pricing, payer negotiations, and the broader investment case for in vivo gene editing across the sector.

4

Approval reshapes the HAE drug market

Discussed by: Patient advocacy groups including the U.S. Hereditary Angioedema Association; market analysts covering Takeda's Takhzyro

A successful one-time therapy directly competes with Takeda's Takhzyro (about $1.7 billion in annual sales) and CSL Behring's prophylactic biologics. Even at a high one-time price, payers prefer it over decades of recurring drug costs. Within five years, in-body CRISPR is the standard of care for severe HAE, and chronic prophylaxis revenues collapse.

Historical Context

Casgevy approval (December 2023)

December 2023

What Happened

The FDA approved exagamglogene autotemcel (Casgevy) from Vertex and CRISPR Therapeutics for sickle cell disease, then quickly for transfusion-dependent beta thalassemia. It was the first CRISPR-based medicine ever approved, treating a population of about 16,000 eligible U.S. sickle cell patients.

Outcome

Short Term

Casgevy proved CRISPR could clear regulators, but its ex vivo manufacturing — extracting stem cells, editing them in a lab over weeks, then giving the patient chemotherapy before re-infusion — limited initial uptake to a handful of certified treatment centers.

Long Term

The approval established the regulatory template for gene-editing medicines and crystallized the next question: could the same kind of edit be made directly inside a patient's body, without the months-long cell processing?

Why It's Relevant Today

Casgevy answered whether CRISPR could be a medicine. HAELO is the first answer to whether in-body CRISPR can be one — a far simpler patient experience if it works.

Luxturna approval (December 2017)

December 2017

What Happened

The FDA approved voretigene neparvovec (Luxturna) from Spark Therapeutics for an inherited form of blindness caused by RPE65 mutations. It was the first directly administered gene therapy approved in the United States, delivered as an injection beneath the retina to roughly 1,000–2,000 eligible patients.

Outcome

Short Term

Luxturna launched at $850,000 per patient and uptake was slow, hampered by its narrow indication and the complex retinal surgery required.

Long Term

The approval validated in vivo gene therapy as a regulatory pathway and informed the framework regulators now use to review durability, immunogenicity, and pricing of one-time genetic medicines.

Why It's Relevant Today

Luxturna showed regulators would approve a one-time in-body genetic medicine. Lonvo-z would be the first to do it using CRISPR rather than a viral vector that adds a new gene copy.

Glybera (2012, withdrawn 2017)

October 2012

What Happened

The European Medicines Agency approved alipogene tiparvovec (Glybera) for lipoprotein lipase deficiency, making it the first gene therapy approved in the Western world. Priced at roughly $1 million per treatment, it was used by approximately 30 patients before being pulled from the market in 2017.

Outcome

Short Term

Demand was minimal — the indication was vanishingly rare and payers balked at the price tag for a therapy with limited long-term outcomes data.

Long Term

Glybera became a cautionary tale about commercializing gene therapies for ultra-rare diseases and pushed developers toward larger patient populations with clear chronic-care economics to displace.

Why It's Relevant Today

HAE has the kind of population and pre-existing $6+ billion treatment market Glybera lacked. Whether one-time gene editing can win on price and durability against entrenched chronic biologics is the commercial question lonvo-z will test.

Sources

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+2
Intellia Therapeutics Investor Relations GlobeNewswire Stock Titan ClinicalTrials.gov U.S. Food and Drug Administration Regeneron Investor Relations Intellia Therapeutics Investor Relations Intellia Therapeutics Investor Relations