đź’Š Casgevy: The First Approved CRISPR Therapy, Edited Outside the Body Then Returned
Vertex Pharmaceuticals and CRISPR Therapeutics' Casgevy (exagamglogene autotemcel), the first CRISPR-based gene-editing therapy approved for human use, has now treated over 200 patients globally since its initial approvals in late 2023 for sickle cell disease and transfusion-dependent beta-thalassemia. As of May 2026, Casgevy is approved in the United States (FDA, December 2023), the United Kingdom (MHRA, November 2023), the European Union (EMA, February 2024), and Saudi Arabia (SFDA, January 2024).
Vertex has now filed a supplemental Biologics License Application with the FDA to expand the indication to pediatric patients aged 5-11 with transfusion-dependent beta-thalassemia, citing data from ongoing trials showing sustained fetal hemoglobin levels above 30% in this age group.
Vertex CEO Reshma Kewalramani announced at the May 2026 American Society of Gene and Cell Therapy conference that the company is investing $900 million to expand manufacturing capacity, which has been the primary bottleneck limiting patient access. The current cost per treatment is $2.2 million in the US, though Vertex has negotiated outcomes-based agreements with several national health systems. A pivotal trial for Casgevy in a third indication—pyruvate kinase deficiency—is enrolling patients with results expected in early 2027.
Two Different Ways to Edit Genes
⚖️ Editing Genes Directly Inside the Body
Intellia Therapeutics, co-founded by CRISPR pioneer Jennifer Doudna, achieved a major milestone in May 2026 when it dosed the first patient with NTLA-3001, a CRISPR treatment delivered directly into the body for alpha-1 antitrypsin deficiency. Unlike Casgevy, which edits cells outside the body before reinfusion, NTLA-3001 packages CRISPR editing tools inside tiny fat-based particles and delivers them straight to liver cells. The therapy aims to permanently knock out the faulty SERPINA1 gene that produces misshapen protein, which builds up in the liver and causes cirrhosis and lung damage.
The Phase 1 trial is enrolling 36 patients at sites in the US, UK, and New Zealand.
Direct delivery into the body represents the holy grail of gene editing because it could dramatically reduce treatment complexity and cost. Intellia's earlier candidate delivered inside the body NTLA-2001 for transthyretin amyloidosis (a disease where abnormal proteins build up in nerves and organs) has shown durable TTR protein reductions exceeding 90% in Phase 1 patients dosed over three years ago, validating the approach. Newer candidates in Intellia's pipeline target hereditary angioedema (a condition causing sudden swelling attacks) and hemophilia B, with interim Phase 2 data showing normal clotting factor IX levels in 80% of treated hemophilia patients at 18 months post-infusion.
đź’Š Editas Medicine: CRISPR Delivered Inside the Eye for Inherited Blindness
Editas Medicine reported updated results from the Phase 1/2 BRILLIANCE trial in May 2026 showing durable vision improvements in 8 of 10 patients treated with EDIT-101, a CRISPR therapy injected beneath the retina targeting the CEP290 mutation that causes a rare inherited form of blindness (Leber congenital amaurosis type 10). The treatment was delivered as a single injection beneath the retina, and patients showed sustained improvement in best-corrected visual acuity and light sensitivity at 24 months of follow-up.
The eye has become an attractive target for CRISPR delivered directly into the body because it is immune-privileged, easily accessible, and requires very small doses. Editas plans to file for FDA approval in 2027 if Phase 2 data continues to show a positive risk-benefit profile. The FDA's May 2026 guidance designating certain CRISPR-edited T-cell therapies for solid tumors as eligible for breakthrough therapy designation signals regulatory comfort with the technology and is expected to accelerate the pipeline of CRISPR-based cancer therapies.