The groundbreaking partnership that successfully treated a rare metabolic disorder in KJ Muldoon, or “Baby KJ,” with personalized CRISPR therapy last year has led therapy developers, researchers, and regulators, including the FDA, to craft a pathway for expanding the universe of gene therapies to advance the development of N-of-1 gene-editing therapies.
In February, the FDA unveiled its Plausible Mechanism Pathway draft guidance, a series of initiatives designed to increase regulatory flexibility and spur the development of bespoke gene-editing therapies for rare and ultra-rare disorders, which collectively total about 30 million individuals in the United States.
“The Agency anticipates that substantial evidence of effectiveness for individualized therapies could be established based on a single adequate and well-controlled clinical investigation with confirmatory evidence,” the draft guidance stated.
Last June, at a historic roundtable of cell and gene therapy researchers and clinicians hosted by the FDA, base editing pioneer David Liu, PhD, of Harvard University and the Broad Institute of MIT and Harvard, stated: “With sufficient organization and federal support and partnership with the FDA, I believe it will be possible by 2030 to treat at least 1,000 patients with personalized genetic treatments.”
Meanwhile, conventional gene therapy development continued in 2025. Last year saw four U.S. gene therapy approvals, bringing the number of FDA-approved gene and cell therapies up to 26, according to the American Society of Gene and Cell Therapies (ASGCT)—more than half of the 40 tallied by the organization as being approved worldwide.
Of those 26, 18 were gene therapies, of which 10 had disclosed sales high enough to be included on this A-List, which ranks top-selling gene therapies based on sales and net product revenue figures furnished by the companies in regulatory filings, annual reports, and/or press releases. Each gene therapy is listed with its sponsor(s), type, indication, and initial FDA approval date.
Not included are gene therapies with sales below the top 10, a category that includes two gene therapies approved in 2025: Precigen’s Papzimeos™ (zopapogene imadenovec-drba), which generated $3.4 million in net product revenue last year after becoming the first-and-only FDA-approved treatment for adults with recurrent respiratory papillomatosis (RRP) in August; and Abeona Therapeutics’ Zevaskyn® (prademagene zamikeracel), an autologous cell sheet-based gene therapy approved to treat wounds in adults and children with recessive dystrophic epidermolysis bullosa (RDEB).
Three gene therapies did not have disclosed sales in 2025, including:
- Encelto™ (revakinagene taroretcel-lwey), an allogeneic encapsulated cell-based gene therapy marketed by Neurotech Pharmaceuticals and indicated for the treatment of adults with idiopathic macular telangiectasia type 2 (MacTel).
- Imlygic® (talimogene laherparepvec), a genetically modified oncolytic viral therapy marketed by BioVex (Amgen) and indicated for local treatment of unresectable cutaneous, subcutaneous, and nodal lesions in patients with melanoma recurrent after initial surgery.
- Waskyra™ (etuvetidigene autotemcel), a cell-based gene therapy and the first FDA-approved treatment for Wiskott-Aldrich syndrome (WAS). Developer Fondazione Telethon is the first non-profit organization to have successfully led full development of an ex vivo gene therapy from lab research (at Milan’s San Raffaele Telethon Institute for Gene Therapy or SR-Tiget) to regulatory approval.
Also not included this year are sales of three gene therapies that had been marketed by Bluebird Bio: Beta thalassemia treatment Zynteglo™ (betibeglogene autotemcel), sickle cell disease treatment Lyfgenia® (lovotibeglogene autotemcel), and cerebral adrenoleukodystrophy (CALD) treatment Skysona® (elivaldogene autotemcel).
Last year, Bluebird Bio went private after being acquired by funds managed by Carlyle and SK Capital Partners, then rebranded in September as Genetix Biotherapeutics. Genetix does not disclose sales but did announce on March 2 that more than 100 patients received infusions of the three gene therapies during 2025.
Also last year, Pfizer halted development and commercialization of Beqvez™ (fidanacogene elaparvovec-dzkt), which had been co-marketed with Roche-owned Spark Therapeutics, after it generated no sales in 2024. Last August, Pfizer terminated its license agreement with Spark for Beqvez, an adeno-associated virus (AAV) vector-based gene therapy indicated for forms of moderate to severe hemophilia B in adults.
Top 10 Best Selling Gene Therapies
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1. Zolgensma® (onasemnogene abeparvovec-xioi)
2025 Sales: $1.232 billion 1
Sponsor(s): Novartis2
Type: AAV vector-based gene therapy
Indication(s): Treatment of pediatric patients less than two years of age with spinal muscular atrophy (SMA) with biallelic mutations in the survival motor neuron 1 (SMN1) gene.
Initial FDA Approval Date: May 24, 2019
2. Elevidys® (delandistrogene moxeparvovec-rokl)
2025 Sales: $898.7 million
Sponsor(s): Sarepta Therapeutics
Type: AAV vector-based gene therapy
Indication(s): Treatment of ambulatory pediatric patients aged four through five years with Duchenne muscular dystrophy (DMD) with a confirmed mutation in the DMD gene.3
Initial FDA Approval Date: June 22, 2023 (Accelerated Approval)
3. Vyjuvek® (beremagene geperpavec-svdt)
2025 Sales: $389.13 million
Sponsor(s): Krystal Biotech
Type: Herpes-simplex virus type 1 (HSV-1) vector-based gene therapy
Indication(s): Treatment of wounds in patients six months of age and older with dystrophic epidermolysis bullosa with mutation(s) in the collagen type VII alpha 1 chain (COL7A1) gene.
Initial FDA Approval Date: May 19, 2023
4. Adstiladrin® (nadofaragene firadenovec-vncg)
2025 Sales: €172.673 million ($199.329 million)
Sponsor(s): Ferring Pharmaceuticals
Type: Non-replicating adenoviral vector-based gene therapy
Indication(s): Treatment of adults with high-risk Bacillus Calmette-Guérin (BCG)-unresponsive non-muscle invasive bladder cancer (NMIBC) with carcinoma in situ (CIS) with or without papillary tumors.
Initial FDA Approval Date: December 16, 2022
5. Casgevy® (exagamglogene autotemcel; “exa-cel”)
2025 Sales: $115.8 million
Sponsor(s): Vertex Pharmaceuticals and CRISPR Therapeutics
Type: Autologous genome-edited hematopoietic stem cell-based gene therapy
Indication(s): Treatment of patients aged 12 years and older with sickle cell disease with recurrent vaso-occlusive crises (VOCs), or transfusion-dependent β-thalassemia (TDT).
Initial FDA Approval Date: December 8, 2023
6. Hemgenix® (etranacogene dezaparvovec-drlb)
2025 Sales: A$92 million ($64.9 million)4
Sponsor(s): CSL Behring
Type: AAV vector-based gene therapy
Indication(s): Treatment of adults with Hemophilia B (congenital Factor IX deficiency) who currently use Factor IX prophylaxis therapy, or have current or historical life-threatening hemorrhage, or have repeated, serious spontaneous bleeding episodes.
Initial FDA Approval Date: November 22, 2022
7. Kebilidi™ / Upstaza® (eladocagene exuparvovec-tneq)5
2025 Sales: $56.626 million
Sponsor(s): PTC Therapeutics
Type: AAV vector-based gene therapy
Indication(s): Treatment of adult and pediatric patients with aromatic L-amino acid decarboxylase (AADC) deficiency.
Initial FDA Approval Date: November 13, 2024
8. Luxturna® (voretigene neparvovec-rzyl)
2025 Sales: CHF 41 million ($51.8 million)
Sponsor(s): Spark Therapeutics (Roche)
Type: Adeno-associated virus vector-based gene therapy
Indication(s): Treatment of patients with confirmed biallelic RPE65 mutation-associated retinal dystrophy. Patients must have viable retinal cells as determined by the treating physician(s).
Initial FDA Approval Date: December 18, 2017
9. Lenmeldy™ / Libmeldy™ (atidarsagene autotemcel)6
2025 Sales: ¥6.4 billion ($40.2 million)
Sponsor(s): Orchard Therapeutics (a wholly owned subsidiary of Kyowa Kirin)
Type: Autologous hematopoietic stem cell-based gene therapy
Indication(s): Treatment for children with pre-symptomatic late infantile (PSLI), pre-symptomatic early juvenile (PSEJ), or early symptomatic early juvenile (ESEJ) metachromatic leukodystrophy (MLD).
Initial FDA Approval Date: March 18, 2024
10. Roctavian® (valoctocogene roxaparvovec-rvox; “val-rox”)
2025 Sales: $36 million
Sponsor(s): BioMarin Pharmaceutical
Type: AAV vector-based gene therapy
Indication(s): Treatment of adults with severe hemophilia A (congenital factor VIII deficiency with factor VIII activity < 1 IU/dL) without pre-existing antibodies to AAV serotype 5 detected by an FDA-approved test.
Initial FDA Approval Date: June 30, 2023
| References |
- Includes sales of ITVISMA® (onasemnogene abeparvovec-brve), approved by the FDA in November 2025 to treat SMA in adult and pediatric patients two years of age and older with a confirmed mutation in the SMN1 gene. ITVISMA has the same active ingredient as Zolgensma but is administered via a single intrathecal injection, while Zolgensma is administered intravenously.
- Novartis is the successor to AveXis, which successfully completed the development of Zolgensma in 2019 by receiving FDA approval for the therapy. In 2014, AveXis licensed from REGENXBIO the AAV9 vector used in the Phase I SMA clinical trial at Nationwide Children’s Hospital. REGENXBIO licensed exclusive rights to key intellectual property covering novel recombinant AAV vectors discovered at the University of Pennsylvania in the lab of James M. Wilson, MD, PhD.
- Following the deaths of two DMD patients receiving Elevidys last year, Sarepta halted shipments of Elevidys for non-ambulatory patients and paused the Phase III ENVISION trial (NCT05881408). The study remained paused at deadline. Following a third death, that of an eight-year-old Brazilian boy, the FDA demanded Sarepta pause shipments of Elevidys to ambulant patients. Sarepta initially refused before agreeing in July 2025. A few days later, after an FDA reversal, Sarepta resumed Elevidys shipments to ambulant patients, after Brazilian authorities ruled out treatment with the gene therapy as a factor in the boy’s death.
- Sales figure is for the fiscal year ending June 30, 2025. CSL Behring has since disclosed sales of $57 million ($40.2 million) for July–December 2025 but has only furnished a comparison to the year-ago period in terms of constant currency without disclosing a specific sales figure.
- Eladocagene exuparvovec-tneq is marketed as Kebilidi in the U.S. and as Upstaza outside the U.S.
- Atidarsagene autotemcel is marketed as Lenmeldy in the U.S. and as Libmeldy within the European Union.
