The pace of FDA approvals has accelerated, although the timing is still uneven. Figure 1 shows approvals by indication as of May 20, 2025.
Figure 1: Single-administration gene* therapy approvals by indication as of May 20, 2025
* Gene addition and gene editing therapies; does not include gene-modified cell therapies (e.g., CAR-T)
RD = retinal dystrophy; SMA = spinal muscular atrophy; TDT = transfusion-dependent thalassemia; CALD = cerebral adrenoleukodystrophy; Hem A = hemophilia A; Hem B = hemophilia B; DMD = Duchenne muscular dystrophy; SCD = sickle cell disease; MLD = metachromatic leukodystrophy; AADC = aromatic L-amino acid decarboxylase deficiency
The Milliman DNA team is tracking 15 additional indications and indication expansions for single-administration gene therapies that have the potential to be FDA approved in the next 12 to 24 months, including two that have a 2025 Prescription Drug User Fee Act (PDUFA) date and one for which the manufacturer anticipates resubmission of a Biologic License Application (BLA) with supplemental data that will address FDA questions that arose during its 2024 PDUFA:
- Severe leukocyte adhesion deficiency type 1 (LAD-1) (prior PDUFA, expected sBLA)
- Sanfilippo syndrome type A (MPS Type IIIA) (PDUFA – August 2025)
- Hunter syndrome (mucopolysaccharidosis [MPS] Type II) (PDUFA – November 2025)
- Chronic heart failure, reduced ejection fraction (HFrEF) – end stage
- Fabry disease
- Fanconi anemia
- Glycogen storage disease type Ia
- Hereditary angioedema
- Huntington’s disease
- Neovascular (wet) age-related macular degeneration
- Osteoarthritis of the knee (Kellgren and Lawrence Grade 2 or 3, Osteoarthritis Research Society International Joint Space Grades 1 and 2)
- Retinitis pigmentosa
- Spinal muscular atrophy (SMA) (indication expansions)
- Xerostomia
- X-linked retinitis pigmentosa
We are monitoring the status of the pivotal clinical trials, FDA designations awarded to the therapies, and manufacturers’ chemistry, manufacturing, and controls (a.k.a. CMC) status to inform the likelihood and potential timing of FDA approval. Since we began tracking the pipeline of gene and cell therapies in 2016, we have observed a number of signals associated with the path to a successful FDA filing or with a discontinuation of the clinical trial and/or commercialization. We continually scan the market for clinical trial holds, suspensions or failures, funding constraints, BLA submission dates, and actions taken by the FDA. In addition, we monitor each manufacturer’s ability to scale commercial production and activate qualified treatment centers upon FDA approval. This multi-level surveillance feeds into our timing estimates for the first claim for each therapy.
The Milliman DNA team maintains the results of our dynamic surveillance in the research we publish for our clients. Reach out if you would like to understand how access to that research can free up your clinical team to support strategic activities.