On November 16, 2023, the UK approved Casgevy, a therapy for sickle cell disease and beta thalassemia that edits a patient's own blood stem cells with CRISPR. The US FDA approved it on December 8. It was the first CRISPR medicine anywhere to be approved, and Vertex set its price at $2.2 million per patient.

You might expect a first approval to trigger a rush of new trials. We checked the registry. It did not, at least not in the way the headlines suggest.

Did the first approval set off a rush?

ClinicalTrials.gov lets anyone count registered studies by start date. We counted interventional trials that mention CRISPR, gene editing, genome editing, base editing, Cas9, zinc finger nucleases or TALENs, for each year from 2014.

1. 12020: Nobel Prize in Chemistry for CRISPR
2. 22023: First approvals: UK in November, US in December

Source: ClinicalTrials.gov API v2, queried October 4, 2026. The query matches the terms anywhere in a record, so it counts trials that mention gene editing, not only trials of gene-edited therapies.

View data

year	trials
2014	2
2015	3
2016	8
2017	11
2018	13
2019	13
2020	13
2021	14
2022	19
2023	25
2024	34
2025	30
2026*	33

The pattern is steady growth, not a jump. Between 2016 and 2020 new trials rose from 8 to 13 a year and then stalled. From 2021 they grew again, to 19 in 2022 and 25 in 2023. The year after the approval, 2024, had 34 new trials, 36% more than 2023. In 2025 there were 30. So far in 2026 there are 33, which is already more than all of 2025.

That is real growth. New trials per year are 2.6 times the 2020 level, and the share of all new interventional trials that mention gene editing rose from 0.04% in 2016 to 0.11% in 2024. But the absolute numbers are small. In 2024, ClinicalTrials.gov recorded 30,591 interventional trials starting, and 34 of them matched our gene-editing terms.

What did the approval change?

It proved the path exists. Casgevy was approved about eleven years after the 2012 paper that showed CRISPR-Cas9 could be programmed to cut DNA. It also showed what the first generation costs.

At $2.2 million per patient, with a process that requires collecting, editing and returning a patient's own cells, Casgevy is a treatment that health systems must plan for one patient at a time. The approval answered whether CRISPR can work as a medicine. It did not answer how a health system pays for it at scale.

What we did not measure

The chart counts trials that start, not trials that succeed. It says nothing about which gene-editing approaches are working. It also depends on search terms: trials that describe their method in other words will be missed, and some trials that only mention CRISPR will be counted. Registrations can be added late, so the most recent years may be revised up.

Sources

1. ClinicalTrials.gov, Data API. Query: interventional studies matching CRISPR, "gene editing", "genome editing", "base editing", Cas9, "zinc finger nuclease" or TALEN, grouped by start date, retrieved October 4, 2026. Yearly totals of all interventional trials come from the same API.
2. Nobel Prize, The Nobel Prize in Chemistry 2020, awarded to Emmanuelle Charpentier and Jennifer Doudna for developing a method for genome editing.
3. US FDA, FDA approves first gene therapies to treat patients with sickle cell disease, December 8, 2023.
4. Labiotech, FDA approves Casgevy, the first CRISPR-based therapy: UK MHRA approval on November 16, 2023.
5. Genetic Literacy Project, Casgevy costs $2.2 million.