Aqneursa
levacetylleucine
Species
RatDog
Longest study
39 wk
Genotox
Conducted Conducted
Carcinogenicity
Not conducted Not conducted
Repro
Conducted Conducted
First dose
Not conducted Not stated publicly
Speciesopen answer page →
Species
Rat and dog
“Repeat dose oral toxicity 26-week rat and 39-week dog study reviews included below are from PharmTox review by Dr. Miyun Tsai-Turton, dated December 16, 2021, conducted under the IND.”
Why that species
Not stated in public reviews
The reviews list the species but not why. For small molecules, ICH M3(R2) expects one rodent and one non-rodent species, chosen with in vitro metabolism, protein binding and exposure data compared with human.
“In vitro metabolic and plasma protein binding data for animals and humans and systemic exposure data (ICH S3A, Ref. 7) in the species used for repeated-dose toxicity studies generally should be evaluated before initiating human clinical trials.”
✓ VerifiedICH 2009: ICH M3(R2): Guidance on Nonclinical Safety Studies for the Conduct…, p. 11Source ↗
Surrogate molecule
No surrogate; the clinical compound was tested
“Levacetylleucine (0, 100, 200, and 600 mg/kg/day) administered by oral gavage in dogs in a 39-week toxicity study followed by a 4-week treatment-free period was without adverse effects with NOAEL of 600 mg/kg/day.”
Species: general tox
Rat (26-week) and dog (39-week), oral gavage
“There were no toxicologically significant findings in the 26-week rat and 39-week dog oral gavage toxicology studies conducted with levacetylleucine.”
Species: DART
Rat and rabbit (dose-ranging EFD only)
“Dose-ranging embryonic and fetal development studies in rats and rabbits have been conducted with levacetylleucine.”
Species: carcinogenicity
Not conducted; carcinogenicity PMRs issued (lifetime use from early childhood)
“Rodent carcinogenicity studies have not been conducted with levacetylleucine. PMRs for carcinogenicity will be issued because levacetylleucine is likely to be administered for a lifetime beginning in infancy or early childhood.”
Surrogate used in
No surrogate used; studies used levacetylleucine itself
“There were no toxicologically significant findings in the 26-week rat and 39-week dog oral gavage toxicology studies conducted with levacetylleucine.”
Study lengthopen answer page →
Longest pivotal study
39 (39-week dog)
“Levacetylleucine (0, 100, 200, and 600 mg/kg/day) administered by oral gavage in dogs in a 39-week toxicity study followed by a 4-week treatment-free period was without adverse effects with NOAEL of 600 mg/kg/day.”
Pivotal GLP studies
26-week rat and 39-week dog oral gavage studies
“There were no toxicologically significant findings in the 26-week rat and 39-week dog oral gavage toxicology studies conducted with levacetylleucine.”
Route in tox
Oral gavage
“There were no toxicologically significant findings in the 26-week rat and 39-week dog oral gavage toxicology studies conducted with levacetylleucine.”
Skipped studiesopen answer page →
Genotoxicity
Negative in Ames, in vitro human lymphocyte chromosome aberration and in vivo rat bone marrow assays
“Levacetylleucine was non-mutagenic in vitro (in bacterial cells) and non-clastogenic in vitro (in cultured human peripheral lymphocytes) and in vivo (in bone marrow cells of the CD rats).”
Carcinogenicity
Not conducted; postmarketing requirement
“We are requiring juvenile toxicity, fertility, and early embryonic development, pre- and postnatal development, and carcinogenicity studies to be conducted postapproval.”
Reproductive & developmental
Dose-ranging rat EFD: resorptions, post-implantation loss and skeletal malformations at 600 mg/kg/day
“In pregnant rats, increases in resorptions, post-implantation loss, and skeletal malformation were seen due to exposure to levacetylleucine at doses of 600 mg/kg/day and at the human-equivalent dose of 97 mg/kg/day.”
Safety pharmacology
hERG inhibition <30% at 525 µM; IC50 not determinable (solubility-limited)
“At the highest feasible concentration of 525μM, levacetylleucine inhibited hERG tail currents by less than 30%, therefore, half-maximal inhibitory concentration (IC50) could not be determined, as the concentration response curve was limited by solubility.”
Genotox: Ames
Negative (non-mutagenic in bacterial cells)
“Levacetylleucine was non-mutagenic in vitro (in bacterial cells) and non-clastogenic in vitro (in cultured human peripheral lymphocytes) and in vivo (in bone marrow cells of the CD rats).”
Genotox: in vitro mammalian
Chromosome aberration in human peripheral lymphocytes: negative
“Levacetylleucine was non-mutagenic in vitro (in bacterial cells) and non-clastogenic in vitro (in cultured human peripheral lymphocytes) and in vivo (in bone marrow cells of the CD rats).”
Genotox: in vivo
Rat bone marrow micronucleus: negative
“Indeed, levacetylleucine was tested in male CD rats and did not induce micronucleus in bone marrow cells, indicating no mutagenic effects (the in vivo negative results confirmed the two in vitro results).”
Carcinogenicity model
Not conducted; 26-week rasH2 mouse study committed post-approval
“Consequently, the Applicant committed to realize the 26-week carcinogenicity study in rasH2 mice and submit the results when available.”
Carcinogenicity timing
26-week rasH2 mouse and 2-year rat required after approval (postmarketing requirement)
“A 26-week carcinogenicity study in the transgenic rasH2 mouse will be required as a PMR, along with a 2-year rat carcinogenicity study.”
hERG / QT
<30% hERG inhibition at 525 µM (solubility limit); IC50 not determinable
“At the highest feasible concentration of 525μM, levacetylleucine inhibited hERG tail currents by less than 30%, therefore, half-maximal inhibitory concentration (IC50) could not be determined, as the concentration response curve was limited by solubility.”
First doseopen answer page →
First-in-human starting dose
Not stated in public reviews
Why it's blank
The public FDA and EMA reviews of Aqneursa don't say how the first human dose was chosen. That rationale is in the IND, which is confidential, so it is missing for most approved products.
How it's usually set for small molecules outside oncology
Find the highest dose with no adverse effects (NOAEL) in each animal species, convert it to a human equivalent dose, usually by body surface area, pick the most appropriate species, then divide by a safety factor (default 10) to get the maximum recommended starting dose.
“In general, one should consider using a safety factor of at least 10. The MRSD should be obtained by dividing the HED by the safety factor.”
This product's starting point
NOAEL / key findings: NOAEL exposure margins 2-3-fold in rats and 6-9-fold in dogs vs human AUC at MRHD (FDA integrated review, p. 88)
NOAEL / key findings
NOAEL exposure margins 2-3-fold in rats and 6-9-fold in dogs vs human AUC at MRHD
“Safety margins achieved at the no-observed-adverse-effect levels were 2- to 3-fold in rats and 6- to 9-fold in dogs compared to the steady-state AUCs in humans at the maximum recommended human dose (MRHD).”
Risksopen answer page →
Immune & cytokine safety
Not stated in public reviews
Not reported in the public reviews. Reviewers summarise selectively, so this usually means it wasn't discussed publicly, not that it wasn't studied.
Biodistribution & persistence
No distribution, milk or placental transfer studies conducted
“No studies of distribution, of excretion in milk and placental transfer with levacetylleucine have been carried out, as levacetylleucine is metabolized by deacetylation (a robust and ubiquitous mechanism), giving rise to a single metabolite, L-leucine, which is endogenously present in humans.”
Modality-specific risk
Embryo-fetal toxicity (malformations, embryo-fetal death)
“Embryofetal development toxicity, including malformations and embryofetal death, was observed based on dose-ranging embryofetal developmental toxicology studies that were conducted in rats and rabbits at 1.4- and 6-fold the MRHD based on body surface area.”
Anti-drug antibodies: animals
Not stated in public reviews
Not reported in the public reviews. Reviewers summarise selectively, so this usually means it wasn't discussed publicly, not that it wasn't studied.
Anti-drug antibodies: patients
No immunogenicity studies conducted
“No studies of immunogenicity and its impact on PK/PD, efficacy and safety were conducted.”
Label warnings
- Embryo-Fetal Toxicity
Embryo-fetal toxicity
US prescribing information, Warnings and PrecautionsDailyMed ↗
Tox packageopen answer page →
Before first-in-human
First-in-human: where
Not stated in public reviews
Not reported in the public reviews. Reviewers summarise selectively, so this usually means it wasn't discussed publicly, not that it wasn't studied.
Repeat-dose tox before first-in-human
Not stated in public reviews
Not reported in the public reviews. Reviewers summarise selectively, so this usually means it wasn't discussed publicly, not that it wasn't studied.
First-in-human starting dose
Not stated in public reviews
Why it's blank
The public FDA and EMA reviews of Aqneursa don't say how the first human dose was chosen. That rationale is in the IND, which is confidential, so it is missing for most approved products.
How it's usually set for small molecules outside oncology
Find the highest dose with no adverse effects (NOAEL) in each animal species, convert it to a human equivalent dose, usually by body surface area, pick the most appropriate species, then divide by a safety factor (default 10) to get the maximum recommended starting dose.
“In general, one should consider using a safety factor of at least 10. The MRSD should be obtained by dividing the HED by the safety factor.”
This product's starting point
NOAEL / key findings: NOAEL exposure margins 2-3-fold in rats and 6-9-fold in dogs vs human AUC at MRHD (FDA integrated review, p. 88)
Longest repeat-dose systemic studies
Longest repeat-dose study and recovery
39-week oral gavage dog study with 4-week treatment-free period
“Levacetylleucine (0, 100, 200, and 600 mg/kg/day) administered by oral gavage in dogs in a 39-week toxicity study followed by a 4-week treatment-free period was without adverse effects with NOAEL of 600 mg/kg/day.”
Pivotal GLP studies
26-week rat and 39-week dog oral gavage studies
“There were no toxicologically significant findings in the 26-week rat and 39-week dog oral gavage toxicology studies conducted with levacetylleucine.”
DART package
Species: DART
Rat and rabbit (dose-ranging EFD only)
“Dose-ranging embryonic and fetal development studies in rats and rabbits have been conducted with levacetylleucine.”
Reproductive & developmental
Dose-ranging rat EFD: resorptions, post-implantation loss and skeletal malformations at 600 mg/kg/day
“In pregnant rats, increases in resorptions, post-implantation loss, and skeletal malformation were seen due to exposure to levacetylleucine at doses of 600 mg/kg/day and at the human-equivalent dose of 97 mg/kg/day.”
PPND / ePPND: when
Rodent PPND not conducted before the NDA; required as a postmarketing requirement
“A rodent pre- and postnatal development toxicity study will be required as a PMR.”
Carcinogenicity
Species: carcinogenicity
Not conducted; carcinogenicity PMRs issued (lifetime use from early childhood)
“Rodent carcinogenicity studies have not been conducted with levacetylleucine. PMRs for carcinogenicity will be issued because levacetylleucine is likely to be administered for a lifetime beginning in infancy or early childhood.”
Carcinogenicity model
Not conducted; 26-week rasH2 mouse study committed post-approval
“Consequently, the Applicant committed to realize the 26-week carcinogenicity study in rasH2 mice and submit the results when available.”
Carcinogenicity timing
26-week rasH2 mouse and 2-year rat required after approval (postmarketing requirement)
“A 26-week carcinogenicity study in the transgenic rasH2 mouse will be required as a PMR, along with a 2-year rat carcinogenicity study.”
Safety marginopen answer page →
Safety margin at NOAEL
NOAEL 2-3x (rat) and 6-9x (dog) human steady-state AUC at MRHD
“Safety margins achieved at the no-observed-adverse-effect levels were 2- to 3-fold in rats and 6- to 9-fold in dogs compared to the steady-state AUCs in humans at the maximum recommended human dose (MRHD).”
NOAEL / key findings
NOAEL exposure margins 2-3-fold in rats and 6-9-fold in dogs vs human AUC at MRHD
“Safety margins achieved at the no-observed-adverse-effect levels were 2- to 3-fold in rats and 6- to 9-fold in dogs compared to the steady-state AUCs in humans at the maximum recommended human dose (MRHD).”
Efficacy evidenceopen answer page →
Efficacy evidence
Published data: Npc1-/- CHO cells, NPC patient fibroblasts and Npc1-/- mice
“The supportive nonclinical mechanistic data that contributed to CE include in vitro and in vivo data in (1) wildtype and NPC1-deficient Chinese hamster ovary (CHO) (Npc1-/- CHO) cells; (2) fibroblasts derived from patients with NPC; and (3) Npc1-/- mice”
Why that model
Not stated in public reviews
Not reported in the public reviews. Reviewers summarise selectively, so this usually means it wasn't discussed publicly, not that it wasn't studied.
Reviewer's view of the efficacy data
Proof-of-concept only; plausible mechanistic support for confirmatory evidence, not direct support for clinical endpoint
“It is concluded that the pharmacology parameters evaluated in nonclinical models are primarily proof-of-concept that suggest plausible mechanistic support for the overall package of CE of effectiveness for levacetylleucine in patients with NPC.”
Flexibilityopen answer page →
Flexibility accepted
CarcinogenicityAccepted with a conditionBeyond the letter
No carcinogenicity studies before approval; 26-week rasH2 mouse and 2-year rat required postmarketing
Why: Lifelong use from infancy and leucine tumour-promotion concern make studies necessary; deferred to PMR
“Carcinogenicity studies with levacetylleucine have not been conducted.”
“A 26-week carcinogenicity study in the transgenic rasH2 mouse will be required as a PMR, along with a 2-year rat carcinogenicity study.”
Juvenile toxAccepted with a conditionBeyond the letter
No juvenile animal toxicity study despite paediatric use from infancy
Why: Clinical safety and efficacy data adequate to support paediatric approval, but data limited; juvenile study required as PMR · Human data
“A juvenile toxicity study with levacetylleucine has not been conducted.”
“While the current clinical safety and efficacy data appear to be adequate to support approval in pediatric patients, the available data are limited; therefore, a juvenile toxicity study will be required as a PMR.”
DARTAccepted with a conditionBeyond the letter
No fertility/early embryonic development or pre- and postnatal development studies
Why: Absence stated in labeling; fertility studies required as PMRs to support risk communication
“Information was described in the impairment of fertility subsection of labeling (Table 89; Section 13.1) to indicate that studies of fertility and early embryonic development and pre-and postnatal toxicology were not conducted with the drug.”
“Rodent male and female fertility and early embryonic development toxicity studies will be required as PMRs to support risk communication to patients and caregivers.”
DARTAccepted with a conditionBeyond the letter
Only dose-range-finding rat and rabbit EFD studies submitted; definitive EFD reports outstanding
Why: Final reports required as PMR; EFD Warning and Precaution with contraception advice in labeling
“However, final study reports for EFD toxicity studies in rats and rabbits have not been submitted.”
“Submission of final study reports for EFD toxicity studies in rats and rabbits will be required as a postmarketing requirement (PMR).”
GenotoxicityAcceptedBeyond the letter
In vivo micronucleus assay lacked toxicokinetic data, a deviation from OECD 474 and ICH S2
Why: Rats exposed to the maximum ethically acceptable dose (2000 mg/kg/day) in toxicology studies · Pharmacology or kinetics
“Although there is a deviation from OECD guideline 474 and ICH guideline S2 on genotoxicity study due to the absence of specific toxicokinetic in vivo data in the micronucleus assay, it is known that the rats were exposed to the maximum ethically acceptable dose toxicology studies (2000 mg/kg/day).”
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