Future path4 min read

In vivo gene editing

Organ or systemLiverOrgan

Detail level

In in vivo gene editing the editing tools are given to the patient to correct a genetic fault in cells where they are, instead of removing cells and modifying them outside the body as in the approved sickle cell treatment. In 2025 NIH announced the first known case of a personalized gene-editing medicine given to a single patient.

An infant with carbamoyl phosphate synthetase 1 (CPS1) deficiency was treated with CRISPR-based "base editing" to precisely correct their rare mutation, and the editing molecules were packaged in lipid nanoparticles and delivered to the liver. The path from diagnosis to treatment took only six months.

Researchers are aiming for a platform built on reusable components and rapid customisation, which could serve precision medicine for hundreds of rare diseases. In the clinical trial registry there is a phase III study of a CRISPR/Cas9-class therapy given by intravenous infusion for transthyretin amyloidosis with cardiomyopathy, recruiting participants according to the registry as read on 8 October 2026.

Where it stands today — maturityIn clinical trials¹²³⁴

In widespread clinical use
Approved for specific uses
In clinical trials
Preclinical
Concept

The first known case of personalised editing for a single patient was announced in 2025, and a registered phase III study exists of an editing therapy given inside the body; whereas the approved CRISPR therapy for sickle cell disease modifies cells outside the body.

Personalised treatment for a rare metabolic disease (CPS1 deficiency)
A single infant case announced by the NIH in 2025, with a need for long-term follow-up.¹²
Transthyretin amyloidosis with cardiomyopathyIn clinical trials
A registered phase III study (NCT06128629) that began in December 2023 and compares the therapy with a placebo, with an estimated 1,200 participants.³
For comparison: editing cells outside the body for sickle cell diseaseApproved for specific uses
Approved by the FDA in December 2023, and made from the patient's blood stem cells after they are modified; see Gene editing (CRISPR).⁴

Status last checked: 2026-10-08 · What the maturity levels mean

What is this path?

In the case announced by the NIH, an advanced technology called CRISPR-based "base editing" was used to modify and precisely correct the rare mutation.

The editing molecules were packaged in lipid nanoparticles and delivered to the liver, meaning that the editing took place inside the body.

This differs from the two sickle cell disease therapies approved in 2023, which are made from the patient's blood stem cells after they are modified.

Where does the research stand?

In May 2025 the NIH announced the first known case of a personalised CRISPR-based drug given to a single patient, an infant with CPS1 enzyme deficiency in liver cells.

The path from diagnosis to treatment took only six months.

The clinical trial registry shows a phase III study of a CRISPR/Cas9-class therapy given by intravenous infusion for transthyretin amyloidosis with cardiomyopathy, recruiting participants according to the registry as read on 8 October 2026.

What separates it from clinical use?

Researchers point to the need for long-term follow-up to fully test the safety and effectiveness of this therapy.

This field still has much work ahead of it, and researchers are cautiously optimistic about the infant's progress.

Researchers aim for a platform of reusable components and rapid customisation, meaning that turning an individual case into a treatment available to many patients is still a goal.

Common questions

Can any genetic disease be corrected today by in vivo gene editing?

No; the case announced by the NIH in 2025 was for a single patient and with a need for long follow-up, and the other studies are still at the trial stage. The doctor specialising in genetic diseases decides the options available for each case.²³

Questions for your doctor

Is there an approved therapy or clinical trial for my genetic condition?
What long-term follow-up is needed for any gene therapy?

References

1
NIH. Infant with rare, incurable disease is first to successfully receive personalized gene therapy treatment. www.nih.gov/news-events/news-releases/infant-rare-incurable-disease-first-successfully-receive-personalized-gene-therapy-treatment
Health agencies & guidelines · Accessed 2026-10-08
2
NIH Research Matters. Infant with rare disease receives customized gene therapy. www.nih.gov/news-events/nih-research-matters/infant-rare-disease-receives-customized-gene-therapy
Health agencies & guidelines · Accessed 2026-10-08
3
ClinicalTrials.gov (U.S. NIH). Study record NCT06128629 — phase 3 study of an in-body CRISPR therapy for transthyretin amyloidosis with cardiomyopathy. clinicaltrials.gov/study/NCT06128629
Health agencies & guidelines · Accessed 2026-10-08
4
U.S. FDA. FDA Approves First Gene Therapies to Treat Patients with Sickle Cell Disease. www.fda.gov/news-events/press-announcements/fda-approves-first-gene-therapies-treat-patients-sickle-cell-disease
Health agencies & guidelines · Accessed 2026-10-08

Review status: Edited content · Last updated: 2026-10-08

Change log

2026-10-08 — Page created.

Educational content only — no diagnosis, and no substitute for a clinician.