FDA tightens Skysona label, restricting use to CALD patients without alternative options due to increased blood cancer risk
The FDA approved labeling changes for Skysona to include new safety information on an increased risk of hematologic malignancy, updating the Boxed Warning, Indications and Usage, Warnings and Precautions, and Adverse Reactions sections35.
Use of Skysona is now restricted to CALD patients who lack suitable alternative treatment options, specifically those without an available HLA‑matched allogeneic hematopoietic stem cell donor2.
The restriction follows an FDA review showing hematologic malignancies diagnosed in 10 of 67 clinical trial participants (15%) as of July 2025, up from earlier reports2.
The FDA’s action formalizes safety concerns first flagged after additional reports of AML and MDS emerged post-approval, prompting a safety review launched in late 20242.
FDA’s August 7, 2025 supplement approval letter confirms the label revisions and cites section 505(o)(4) authority for required safety labeling changes3.
The FDA’s Skysona product page highlights the latest safety information and links to the updated package insert and approval letter dated August 7, 20255.
Media coverage notes that the incidence of blood cancers more than tripled from prior estimates and that the label now narrows the eligible patient population21.
Sources:
1. https://www.biospace.com/policy/fda-restricts-patient-pool-for-bluebirds-skysona-amid-safety-concerns
2. https://www.cellgenetherapyreview.com/3972-News/620757-FDA-restricts-use-of-bluebird-s-Skysona-citing-increased-hematologic-malignancy-risk/