Summary: development and regulatory status as of October 2026

The FDA approved a supplemental new drug application (NDA 219132, supplement 2) for levacetylleucine (Aqneursa) for oral suspension on 18 September 2026 for the treatment of ataxia in adults and pediatric patients with ataxia-telangiectasia (A-T) weighing at least 15 kg. The approval was granted to IntraBio Inc., and the FDA describes Aqneursa as the first treatment approved for ataxia in patients with A-T. The supplement was dated and received on 19 March 2026. IntraBio announced in May 2026 that the FDA had accepted it with priority review and a PDUFA target action date of 19 September 2026. Levacetylleucine has held orphan drug designation for A-T since 2 October 2018, and the FDA orphan drug record lists the exclusivity end date for the A-T approval as "TBD". Efficacy was evaluated in one randomized, double-blind, placebo-controlled, two-period crossover study of 73 participants (Trial 2, NCT06673056). IntraBio stated in its approval announcement that the product was commercially available. Levacetylleucine was first approved on 24 September 2024 for neurological manifestations of Niemann-Pick disease type C (NPC) with priority review, fast track, orphan drug, and rare pediatric disease designations, and a rare pediatric disease priority review voucher was granted with that approval. The Orange Book lists new chemical entity exclusivity through 24 September 2029, orphan drug exclusivity for the NPC indication through 24 September 2031, and four patents expiring 19 April 2037, one of which (patent 12144792, use code U-4603, submitted 23 September 2026) carries a use code for A-T. In the European Union, Aqneursa was authorised for NPC on 19 January 2026. IntraBio announced a variation application for A-T in June 2026, and the draft agenda of the CHMP meeting of 14 to 17 September 2026 lists the extension of indication for adoption. Acetylleucine has held European Union orphan designation for A-T since 11 January 2019.

Regulatory submission: sNDA submitted March 2026 and approved September 2026

“Please refer to your supplemental new drug application (sNDA) dated March 19, 2026, received March 19, 2026, and your amendments, submitted under section 505(b) of the Federal Food, Drug, and Cosmetic Act (FD&C Act) for Aqneursa (levacetylleucine), for oral suspension.” (opens the source at this quote in a new tab)
“This Prior Approval sNDA provides for use of Aqneursa as a treatment of ataxia in adults and pediatric patients with ataxia-telangiectasia weighing ≥ 15 kg.” (opens the source at this quote in a new tab)
“We have completed our review of this application, as amended. It is approved, effective on the date of this letter, for use as recommended in the enclosed agreed-upon labeling.” (opens the source at this quote in a new tab)

“IntraBio Inc. today announced the submission of a supplemental New Drug Application (sNDA) to the U.S. Food and Drug Administration (FDA) for levacetylleucine for the treatment of Ataxia-Telangiectasia (A-T), a rare, progressive, inherited neurodegenerative disorder.” (opens the source at this quote in a new tab)

Action date	Submission	Supplement categories or approval type
“09/18/2026”	“SUPPL-2”	“Efficacy-New Indication”

Launch: Commercially available at approval in September 2026

“AQNEURSA is commercially available now” (opens the source at this quote in a new tab)
“Second FDA-approved indication for AQNEURSA, following previous approval for Niemann-Pick disease type C (NPC)” (opens the source at this quote in a new tab)

Field	Quoted record
Marketing approval date	“09/18/2026”
Approved labeled indication	“treatment of ataxia in adults and pediatric patients with ataxia-telangiectasia (A-T) weighing > or = 15 kg”

FDA approval on 18 September 2026

“The U.S. Food and Drug Administration has approved Aqneursa (levacetylleucine) for oral suspension to treat ataxia in adults and pediatric patients with ataxia-telangiectasia weighing at least 15 kg (about 33 pounds).” (opens the source at this quote in a new tab)
“Aqneursa was previously approved in 2024 to treat the neurological manifestations of Niemann-Pick disease type C.” (opens the source at this quote in a new tab)
“Today’s approval makes Aqneursa the first treatment approved for ataxia in patients with ataxia-telangiectasia.” (opens the source at this quote in a new tab)
“Approval was granted to IntraBio Inc.” (opens the source at this quote in a new tab)

“IntraBio Inc., a leader in the discovery, development, and commercialization of novel therapies for rare and common neurodegenerative diseases, today announced that the U.S. Food and Drug Administration (FDA) has approved AQNEURSA® (levacetylleucine) for the treatment of ataxia in adult and pediatric patients with ataxia-telangiectasia (A-T) weighing ≥15 kg.” (opens the source at this quote in a new tab)
“AQNEURSA is the first and only drug approved for the treatment of A-T anywhere in the world.” (opens the source at this quote in a new tab)

“Initial U.S. Approval: 2024” (opens the prescribing information at this quote)
“Indications and Usage (1.2) 9/2026” (opens the prescribing information at this quote)
“Revised: 9/2026” (opens the prescribing information at this quote)

Evidence supporting approval

“The safety and efficacy of AQNEURSA for the treatment of ataxia in patients with A-T were evaluated in a randomized, double-blind, placebo-controlled, two-period crossover study that evaluated the efficacy of AQNEURSA in 73 patients (Trial 2; NCT06673056).” (opens the prescribing information at this quote)

“The effectiveness of Aqneursa was evaluated in a randomized, double-blind, placebo-controlled, two-period crossover study (NCT06673056) of 73 patients aged 4 years or older with a confirmed diagnosis of ataxia-telangiectasia.” (opens the source at this quote in a new tab)

“The approval is supported by the pivotal IB1001-303 study (NCT06673056), a randomized, double-blind, placebo-controlled, crossover trial that enrolled 73 patients aged 4 to 50 years with genetically confirmed A-T across 10 clinical trial sites in Germany, Slovakia, Spain, Switzerland, the United Kingdom, and the United States.” (opens the source at this quote in a new tab)
“These findings were published in the July 2026 issue of The Lancet Neurology.” (opens the source at this quote in a new tab)

Supplemental application timeline: topline results and planned submissions

“Based on these results, IntraBio plans to immediately advance regulatory submissions to the US Food and Drug Administration (FDA) and the European Medicines Agency (EMA), and additional global regulatory authorities.” (opens the source at this quote in a new tab)
“Levacetylleucine is an investigational drug for A-T and has not yet been approved by the FDA or any other regulatory authority for this indication.” (opens the source at this quote in a new tab)

“Based on the robust findings from the study, IntraBio is proceeding immediately with regulatory submissions to the US Food and Drug Administration (FDA) and the European Medicines Agency (EMA), and additional global regulatory authorities, to support the label expansion of levacetylleucine for A-T.” (opens the source at this quote in a new tab)

Supplemental application timeline: sNDA submission

“This submission represents the first regulatory application submitted to the U.S. Food and Drug Administration seeking approval of a therapy for the treatment of Ataxia-Telangiectasia.” (opens the source at this quote in a new tab)
“The sNDA seeks to expand the label of levacetylleucine, marketed as AQNEURSA®, to include A-T.” (opens the source at this quote in a new tab)
“The submission is supported by data from a pivotal Phase III clinical trial evaluating levacetylleucine in adult and pediatric patients with A-T.” (opens the source at this quote in a new tab)

Supplemental application timeline: FDA acceptance and priority review

“IntraBio Inc., a global biopharmaceutical company focused on developing and commercializing therapies for neurological diseases, today announced that the U.S. Food and Drug Administration (FDA) has accepted for review its supplemental New Drug Application (sNDA) for AQNEURSA® (levacetylleucine) for the treatment of Ataxia-Telangiectasia (A-T) in adults and pediatric patients.” (opens the source at this quote in a new tab)
“The FDA simultaneously granted Priority Review and assigned a PDUFA target action date of 19 September 2026.” (opens the source at this quote in a new tab)

Expedited programs: priority review and orphan drug designation for A-T

“Aqneursa received Orphan Drug designation and Priority Review for the ataxia-telangiectasia indication.” (opens the source at this quote in a new tab)

Special FDA designations: orphan drug designation for A-T

Field	Quoted record
Generic name	“levacetylleucine”
Trade name	“Aqneursa”
Date designated	“10/02/2018”
Orphan designation	“Treatment of Ataxia Telangiectasia”
Orphan designation status	“Designated/Approved”
Sponsor	“IntraBio Inc.”
Marketing approval date	“09/18/2026”
Exclusivity end date	“TBD”

Exclusivity listed in the Orange Book

Exclusivity code	Exclusivity expiration
“NCE”	“09/24/2029”
“ODE-498”	“09/24/2031”

Patents listed in the Orange Book

Patent number	Patent expiration	Patent use code	Submission date
“11400067”	“04/19/2037”	“U-4170”	“04/22/2025”
“12144792”	“04/19/2037”	“U-4603”	“09/23/2026”
“12433862”	“04/19/2037”	“U-4284”	“10/22/2025”
“12433863”	“04/19/2037”	“U-4285”	“10/22/2025”

Patent listing requirement for the supplement

“You must submit the patent information required by 21 CFR 314.53(d)(2)(i)(A) through (C) and 314.53(d)(2)(ii)(A) and (C), as applicable, to FDA on Form FDA 3542 within 30 days after the date of approval of the supplement for the patent information to be timely filed (see 21 CFR 314.53(c)(2)(ii)).” (opens the source at this quote in a new tab)

U.S. patents marked by the manufacturer

“The following U.S. patents apply to IntraBio Inc’s product, AQNEURSA®:” (opens the source at this quote in a new tab)
“and other pending patent applications.” (opens the source at this quote in a new tab)

Product history: first FDA approval for Niemann-Pick disease type C in 2024

“Today, the U.S. Food and Drug Administration approved Aqneursa (levacetylleucine) for the treatment of neurological symptoms associated with Niemann-Pick disease type C (NPC) in adults and pediatric patients weighing at least 15 kilograms.” (opens the source at this quote in a new tab)
“The FDA granted Aqneursa Priority Review, Fast Track, Orphan Drug and Rare Pediatric Disease designations for this application.” (opens the source at this quote in a new tab)

Action date	Submission	Action type	Submission classification	Review priority; orphan status
“09/24/2024”	“ORIG-1”	“Approval”	“Type 1 - New Molecular Entity”	“PRIORITY; Orphan”

“Please refer to your new drug application (NDA), dated and received January 24, 2024, and your amendments, submitted under section 505(b) of the Federal Food, Drug, and Cosmetic Act (FDCA), for Aqneursa (levacetylleucine) for oral suspension.” (opens the source at this quote in a new tab)

Product history: rare pediatric disease priority review voucher granted with the 2024 approval

“We also inform you that you have been granted a rare pediatric disease priority review voucher, as provided under section 529 of the FDCA.” (opens the source at this quote in a new tab)
“This priority review voucher (PRV) has been assigned a tracking number, PRV NDA 219132.” (opens the source at this quote in a new tab)

“FDA has determined that AQNEURSA (levacetylleucine), approved on September 24, 2024, manufactured by IntraBio Inc., meets the criteria for a priority review voucher.” (opens the source at this quote in a new tab)

Product history: advisory committee for the original application

“Your application for Aqneursa was not referred to an FDA advisory committee because the application did not raise significant public health questions on the role of the drug in the diagnosis, cure, mitigation, treatment, or prevention of a disease.” (opens the source at this quote in a new tab)

Pivotal trial enrollment milestone

“IntraBio’s Phase III Pivotal trial investigating N-Acetyl-L-Leucine (levacetylleucine) for Ataxia-Telangiectasia has completed recruitment in under two months, ultimately over-enrolling the trial by over 167%. Data readout is expected in Q1 of 2026.” (opens the source at this quote in a new tab)

Regulatory status outside the United States: European Union authorisation for Niemann-Pick disease type C

“Aqneursa received a marketing authorisation valid throughout the EU on 19 January 2026.” (opens the source at this quote in a new tab)
“Aqneursa is a medicine used to treat neurological symptoms (symptoms affecting the brain and nerves) of Niemann-Pick type C (NPC) disease in adults and children aged 6 years and older who weigh at least 20 kg.” (opens the source at this quote in a new tab)

Field	Quoted record
EMA product number	“EMEA/H/C/006327”
Marketing authorisation holder	“Intrabio Ireland Limited”
Opinion adopted	“13/11/2025”
Marketing authorisation issued	“19/01/2026”

Regulatory status outside the United States: European Union orphan designation for A-T

“On 11 January 2019, orphan designation (EU/3/18/2124) was granted by the European Commission to IntraBio Limited, United Kingdom, for acetylleucine for treatment of ataxia telangiectasia.” (opens the source at this quote in a new tab)
“The sponsorship was transferred to IntraBio Ireland Ltd, Ireland, in April 2019.” (opens the source at this quote in a new tab)

Regulatory status outside the United States: variation application to the EMA for A-T

“IntraBio Inc. today announced the submission of a variation application to the European Medicines Agency (EMA) to expand the approved Marketing Authorization Application (MAA) for AQNEURSA® (levacetylleucine) to include the treatment of Ataxia-Telangiectasia (A-T).” (opens the source at this quote in a new tab)
“This submission represents the first regulatory application submitted to the EMA seeking approval of a therapy for the treatment of A-T, a rare, progressive, inherited neurodegenerative disorder.” (opens the source at this quote in a new tab)
“The variation application is subject to EMA validation before the start of formal scientific review.” (opens the source at this quote in a new tab)

Regulatory status outside the United States: scope of the European Union variation under CHMP review

“AQNEURSA - Levacetylleucine - ORPHAN - EMA/VR/0000354947” (opens the source at this quote in a new tab)
“C.6: Extension of indication to include treatment of Ataxia-telangiectasia for AQNEURSA based on results from study IB1001-303.” (opens the source at this quote in a new tab)
“As a consequence, sections 4.1, 4.2, 4.8 and 5.1 of the SmPC are updated.” (opens the source at this quote in a new tab)
“Version 2.0 of the RMP has also been submitted.” (opens the source at this quote in a new tab)
“C.6: Modification of the approved indication for Niemann-Pick type C disease to include treatment of the neurological manifestations in patients aged 4 years and older and weighing at least 15 kg based on results from study IB1001-301.” (opens the source at this quote in a new tab)
“Action: For adoption” (opens the source at this quote in a new tab)

Regulatory status outside the United States: extensions of indication recommended at the September 2026 CHMP meeting

“The committee recommended extensions of indication for another 10 medicines that are already authorised in the European Union (EU): Abiraterone Mylan, Cosentyx, Enhertu, Jyseleca, Keytruda, Ocrevus, Padcev, Pepaxti, Sogroya, and Tecvayli.” (opens the source at this quote in a new tab)