Atinvicitinib: what the FDA reviewed for dog products
1 Freedom of Information summary from the FDA Center for Veterinary Medicine for products containing Atinvicitinib, as typed records: every value below is followed by the verbatim passage it was taken from. Species as stated by each summary: Dogs.
Products
- Numelvi™ (NADA/ANADA 141-596)
Numelvi™ NADA 141-596, Original approval, February 25, 2026; sponsor Intervet, Inc.; species: Dogs; foi_id 18155; FDA PDF
Indication
Control of pruritus associated with allergic dermatitis in dogs 6 months of age and older
Dose regimen
0.8 to 1.2 mg/kg (0.36 to 0.54 mg/lb), Oral, once daily, with food
Numelvi™ should be administered orally, once daily, with food, at a dose of 0.36 to 0.54 mg atinvicitinib/lb (0.8 to 1.2 mg atinvicitinib/kg) body weight.
Pharmacokinetics
| Parameter | Value | Conditions | Quote |
|---|---|---|---|
| bioavailability | 45.5% | geometric mean, based on AUClast; single oral 1.2 mg/kg vs intravenous 0.3 mg/kg, fed state | Following a single oral (1.2 mg/kg) or intravenous (0.3 mg/kg) administration of atinvicitinib in the fed state, the geometric mean oral bioavailability based on area under the curve from the time of dosing to the last quantifiable plasma concentration (AUClast) was 45.5%. |
| clearance | 1,074 mL/h/kg | mean systemic clearance after intravenous administration (0.3 mg/kg, fed) | The mean systemic clearance following intravenous administration was 1,074 mL/h/kg |
| half-life | 1.1 hour | geometric mean terminal half-life after intravenous administration (0.3 mg/kg, fed); text hyphenation artifact 'half- life' preserved | with a geometric mean terminal half- life of 1.1 hour. The mean volume of distribution was 1,651 mL/kg (n=8). |
| cmax | 280% higher (fed vs fasted) | single oral 1.2 mg/kg, fed compared with fasted state, n=16; AUClast was 120% higher | Following a single oral administration of atinvicitinib at 1.2 mg/kg, the maximum plasma concentration (Cmax) and AUClast were 280% and 120% higher, respectively, in the fed state as compared to the fasted state (n=16). |
| protein binding | 82.3% bound | fortified canine plasma at 1,802 ng/ml (5 μM) | Atinvicitinib has moderate protein binding with 82.3% bound in fortified canine plasma at concentrations of 1,802 ng/ml (5 μM). |
| cmax | 196 ng/mL (CV 49%) | geometric mean; 1.2 mg/kg once daily, Day 182 of the margin-of-safety study (Table III.2); table flattened: parameter then value | Cmax (ng/mL) 196 (49%) Tmax *(h) 2 (range: 1-6) AUClast (h*ng/mL) 861 (27%) AUCinf (h*ng/mL) 909 (24%) t1/2 (h) 2.2 (25%) |
| auc | 861 h*ng/mL (CV 27%) | AUClast, geometric mean; 1.2 mg/kg once daily, Day 182 (Table III.2); AUCinf 909 h*ng/mL | Cmax (ng/mL) 196 (49%) Tmax *(h) 2 (range: 1-6) AUClast (h*ng/mL) 861 (27%) AUCinf (h*ng/mL) 909 (24%) t1/2 (h) 2.2 (25%) |
| half-life | 2.2 h (CV 25%) | geometric mean t1/2; 1.2 mg/kg once daily oral, Day 182 (Table III.2); median Tmax 2 h (range 1-6) | Cmax (ng/mL) 196 (49%) Tmax *(h) 2 (range: 1-6) AUClast (h*ng/mL) 861 (27%) AUCinf (h*ng/mL) 909 (24%) t1/2 (h) 2.2 (25%) |
Target-animal safety
dose multiples 0X, 1X, 3X, 5X; duration 183 to 184 consecutive days, once daily, fed state; animals 32 (16 male, 16 female).
Objective: To evaluate the safety of Numelvi™ when orally administered once daily at 1, 3, and 5X the maximum labeled dose (1.2 mg/kg/day), in the fed state, to 6- month-old Beagle dogs for 183 to 184 consecutive days. Study Animals: The study included 32 6-month-old beagle dogs (16 male and 16 female) weighing between 4.3 and 9.0 kg
| Finding | Quote |
|---|---|
| One 5X dog developed generalized demodicosis (attributed to Numelvi-induced immunosuppression) and was euthanized on Day 175 | One serious adverse reaction occurred in one 5X group dog who developed generalized demodicosis resulting in euthanasia on Day 175. |
| One 3X dog developed a single interdigital cyst | One dog in the 3X group developed a single interdigital cyst. |
| No Numelvi-related effects on clinical pathology | Clinical Pathology: There were no Numelvi™ related effects on clinical pathology. |
| Decreased mean testes weight in treated males | Male dogs in the Numelvi™ treatment groups had decreased mean testes weight compared to the control dogs. |
| Overall conclusion: demodicosis with secondary dermal inflammation, interdigital furunculosis, lower mean testes weight | Numelvi™ was associated with generalized demodicosis with secondary dermal inflammation, interdigital furunculosis, and lower mean testes weight. |
Effectiveness
Masked, randomized, placebo-controlled, multi-site field study (GCP); 1:1 Numelvi 0.8-1.2 mg/kg orally once daily vs placebo for 7 days, optional continuation to Day 28; 289 enrolled, 288 treated (144/144); n = 125 Numelvi, 125 placebo (effectiveness analysis); primary endpoint: Treatment success on Day 7: at least 50% reduction from baseline in owner-assessed PVAS pruritus score on at least 5 of the first 7 days; result: Treatment success 31/125 (estimated proportion 0.23) Numelvi vs 10/125 (0.07) placebo; p=0.0128 (Table II.3)
Two hundred fifty dogs (125 Numelvi™, 125 placebo) were included in the effectiveness analysis. Primary Effectiveness at Day 7: The proportion of dogs that were treatment successes in the Numelvi™ group was significantly different from (p=0.0128) and greater than the placebo group.
Adverse reactions
| Term | Treated | Control | Quote |
|---|---|---|---|
| Vomiting or nausea | 10 (6.9%) | 6 (4.2%) | Vomiting or nausea 10 (6.9%) 6 (4.2%) |
| Otitis externa | 9 (6.3%) | 8 (5.6%) | Otitis externa 9 (6.3%) 8 (5.6%) |
| Hematuria (without urinary tract infection) | 7 (4.9%) | 6 (4.2%) | Hematuria (without urinary tract infection) 7 (4.9%) 6 (4.2%) |
| Anorexia | 6 (4.2%) | 5 (3.5%) | Anorexia 6 (4.2%) 5 (3.5%) |
| Bacterial skin infection | 6 (4.2%) | 10 (6.9%) | Bacterial skin infection 6 (4.2%) 10 (6.9%) |
| Diarrhea | 6 (4.2%) | 15 (10.4%) | Diarrhea 6 (4.2%) 15 (10.4%) |
Extraction notes: Adverse reaction rows quoted from flattened Table II.6 (through Day 28): term, Numelvi n (%) of N=144, placebo n (%) of N=144. Day-182 PK values come from the 6-month margin-of-safety study (Table III.2, 1.2 mg/kg), other PK from single-dose Dosage Characterization text. Summary also contains a vaccine response study (3X, 84 days, 20 dogs; adequate titers, no adverse effects) and a pilot 42-day TAS study (40 dogs, non-final formulation) not captured here. Design quote spans a line-break hyphenation artifact ('6- month-old') preserved verbatim.
Reproduce: foi_structured_search(query="Atinvicitinib") and foi_summary_get(foi_id=...) in dog-geroscience-mcp; dataset foi-summaries-dog (config structured).