⚠️ Auto-extracted by Claude on 2026-05-14. PDF locally available at DOI lookup above (DOI: 10.1007/s11357-024-01484-7). Quantitative claims (dose, n, eligibility thresholds) are drawn directly from the PDF and should be verified against it. Trial results are not yet available — this is a protocol/design paper only.

TRIAD — Test of Rapamycin In Aging Dogs

TL;DR

TRIAD is a prospective, parallel-group, double-masked, randomized, placebo-controlled, multicenter trial of rapamycin (sirolimus) in 580 healthy middle-aged companion dogs (≥7 years, 20–55 kg), nested within the dog-aging-project cohort. Dogs receive 0.15 mg/kg rapamycin once weekly orally for 12 months, followed by a 24-month monitoring period (36 months total). Primary endpoint is survival (lifespan); secondary endpoints include functional measures of healthspan, cardiovascular function, and neurocognitive status. The authors describe it as “the first rigorous test of a pharmacologic intervention against biological aging with lifespan and healthspan metrics as endpoints to be performed outside of the laboratory in any species” ¹. Results are pending; at time of writing, 158 dogs had been enrolled and randomized.

Study design

Design: Prospective, parallel-group, double-masked, randomized, placebo-controlled, multicenter trial.

Sites: 19 sites at time of writing — 8 veterinary teaching hospitals (Texas A&M University, University of Georgia, Colorado State University, Iowa State University, University of Illinois, Tufts University, University of Wisconsin, and Washington State University) plus 11 non-academic specialty veterinary practices across the USA. Recruitment of additional sites was ongoing at time of publication.

Allocation: 1:1 rapamycin:placebo, stratified by clinical trial site and sex. Randomization uses permuted blocks (variable block sizes 1–8) generated by a commercial computer program. The randomization key is held by six individuals only, none involved in clinical screening or enrollment.

Masking: Dog owners, attending veterinarians, study monitors, and statisticians are all masked to treatment assignment. Unmasking is available only for veterinary emergencies, via the TRIAD Randomization Project Manager.

Treatment duration: 12 months of weekly oral dosing, followed by 24 months of monitoring only. Total study duration: 36 months per dog.

Status at time of writing (paper submitted August 2024): 252 dogs screened; 158 enrolled and randomized. 131 followed at specialty cardiology clinics; 27 at specialty neurology clinics.

Drug dosage and formulation

Dose: 0.15 mg/kg once weekly by mouth. The dose is calculated using the upper limit of the dog’s weight range group (six ranges: 20–25 kg, 25.1–30 kg, 30.1–35 kg, 35.1–40 kg, 40.1–45 kg, 45.1–55 kg), rounded to the nearest achievable dose from available tablet sizes (0.4, 1.2, and 2.4 mg). For dogs receiving rapamycin, actual doses delivered range 0.138–0.180 mg/kg.

Formulation: Delayed-release, enteric-coated tablet. Branded “RapaVet,” manufactured by TriviumVet (Waterford, Ireland) under WHO Good Manufacturing Practices and authorized by the FDA Center for Veterinary Medicine as an Investigational New Animal Drug. Placebo tablets are visually identical (inert, color- and size-matched). Both delivered in pre-assembled blister-pack dosing kits, each containing a 6-month supply.

Administration: Owner-administered at home on Wednesday mornings, with or without food. Owners are instructed to place the tablet(s) on the back of the dog’s tongue to discourage chewing and disruption of the enteric coating.

Rationale for once-weekly dosing: The target dose is below the immunosuppressive range used clinically in dogs. Once-weekly dosing is expected to minimize trough blood concentrations and thereby reduce risk of immunosuppression and glucoregulatory dysfunction while preserving longevity-promoting mTORC1 inhibition. Evidence from human studies (RAD001 trial) and a survey of off-label rapamycin use in 333 adults supports that once-weekly dosing reduces adverse events compared to daily dosing ¹.

Eligibility criteria

Inclusion: Client-owned, reproductively sterilized companion dogs, ≥7 years of age, 20–55 kg, typical health status for their age, receiving regular preventive veterinary care, and enrolled in the Dog Aging Project.

Key exclusions:

Active progressive or clinically significant systemic illness
Malignant neoplasia or heartworm infection
Systemic arterial hypertension (SBP ≥180 mmHg, or ≥160 mmHg with target-organ damage)
Trypanosoma cruzi seropositivity (>1:40 in high-risk regions of Texas)
Dementia or senility (validated questionnaire threshold)
Known rapamycin sensitivity
At cardiology sites: clinically significant cardiac disease, arrhythmia, or pulmonary arterial hypertension (detailed criteria in Tables 2 and 3 of the source paper)
At neurology sites: significant neurologic disease or sensory/mobility deficits preventing neurocognitive assessment
Current medications with known/suspected PK or PD interactions with rapamycin

Mild, stable age-related conditions (e.g., early, non-azotemic, non-proteinuric, non-hypertensive chronic kidney disease) for which rapamycin would not be expected to increase risk are allowed with all other criteria met.

Primary endpoint — lifespan

The primary efficacy outcome is survival time from randomization, assessed at 3 years. Analysis uses Kaplan–Meier curves and a Cox proportional hazards model adjusting for age and randomization strata. Null hypothesis: rapamycin has no effect on survival. Alternative: rapamycin increases mean lifespan.

Power: with 580 dogs (290/arm), the trial has >80% power to detect a 6% difference in mean total lifespan and >80% power to detect an 11% difference in survival within the 3-year study timeframe, based on mortality data from 855 dogs within the eligible age/weight range (α=0.0066, β=0.29 Gompertz parameters).

Planned interim analyses: Two superiority interim analyses using O’Brien–Fleming boundaries:

First interim at 200 randomized dogs who have completed 3-year period or died (significance threshold 0.0052)
Second interim at 400 dogs (threshold 0.0141)
Final analysis at 580 dogs (threshold 0.0451, maintaining overall α=0.05)

Secondary endpoints — healthspan

Secondary endpoints test whether rapamycin delays or reduces the incidence of age-related diseases and conditions:

Cancer diagnoses
Infectious disease diagnoses
Cataract formation
Multimorbidity (≥2 concurrent age-related diagnoses)
Physical function (gait speed, mobility assessments, thigh circumference — frailty markers)
Cardiovascular health (echocardiography, ECG, blood pressure at specialty cardiology sites)
Neurocognitive health (CAnine DEMentia Scale [CADES], owner survey instruments, at-home cognitive tasks, sustained gaze test at specialty neurology sites)

Exploratory endpoints

Clinical pathology (CBC, serum biochemistry, urinalysis), blood inflammatory markers (CRP, IL-2, IL-6, IL-8, TNFα), lipoprotein profile, metabolomics (plasma), epigenomics (PBMCs), fecal microbiome, and hair toxicology. Blood rapamycin levels and mTOR activity (phosphorylation of downstream targets in PBMCs) measured at visits 2 and 3 to confirm pharmacodynamic engagement.

Rationale — why rapamycin in dogs

From mouse ITP data to dogs

Rapamycin extends lifespan in multiple laboratory species including yeast, C. elegans, Drosophila, and mice. In mice, lifelong rapamycin administration extends lifespan ²; middle-age initiation appears equally or comparably effective ³. Transient treatment at middle age is sufficient to increase lifespan ⁴. In the NIA Interventions Testing Program (ITP), rapamycin is one of the most robustly validated longevity compounds in mice, with effects replicated across multiple sites and genetic backgrounds ².

Dogs represent the next translational step: a co-housed-exposome mammal with naturally occurring aging pathologies, a lifespan ~7–9× shorter than humans, and pharmacological responsiveness to rapamycin demonstrated in the pilot Urfer et al. 2017 RCT ⁵.

Pilot RCT (Urfer 2017)

A double-masked, placebo-controlled RCT of rapamycin in n=24 middle-aged companion dogs over 10 weeks (0.05 or 0.1 mg/kg three times weekly) found a statistically significant increase in fractional shortening (an echocardiographic index of left ventricular systolic performance) in rapamycin-treated compared to placebo-treated dogs ⁵. No significant difference in adverse events between groups. This pilot established safety and a cardiac pharmacodynamic signal at non-immunosuppressive doses, providing the proximate justification for TRIAD’s dosing rationale.

Dimension	Status
Pathway conserved in humans?	yes — mTOR is identical; once-weekly dosing rationale extrapolated from human rapalog trials
Phenotype conserved in humans?	partial — cardiac and cognitive aging endpoints share phenomenology; lifespan endpoint not directly testable in humans
Replicated in humans?	in-progress — TRIAD is the powered lifespan trial; human aging rapamycin trials (Mannick mTORC1 immune-aging, Kaeberlein longevity survey) are ongoing/completed for healthspan endpoints

NIH funding

TRIAD is supported by NIA grant UI9AG057377 to the Dog Aging Project (Aec, KEC, VF, GA, BGB, BB, AD, AF, KKF, ANG, SNH, MI, KI, SAK, RLM, JOP, SMS, AR, DELP, MK). The grant supports the DAP’s full infrastructure including TRIAD as a nested cohort. Note: public announcements referenced a ~$7M NIH expansion grant for TRIAD in 2025 — the paper’s funding section lists grant UI9AG057377 as the primary NIA source; a separate TRIAD-specific award amount is not stated in the protocol paper. needs-citation-verification (grant award amount and any supplemental TRIAD-specific award)

Relationship to Loyal LOY-001/003 — a contrast

TRIAD targets the mTOR kinase (rapamycin = mTORC1 inhibitor) — a downstream node of the IGF-1/GH/IIS signaling axis. Loyal Inc.’s LOY-001 and LOY-003 target the upstream GH/IGF-1 axis directly (API not publicly disclosed, but suspected to reduce circulating IGF-1 levels in large breeds) ⁶. Both are nutrient-sensing axis interventions but via distinct molecular points of intervention:

Program	Target	Molecular level	Population	Regulatory status
TRIAD (rapamycin)	mTORC1	Downstream kinase	Medium-to-large dogs ≥7 yr, 20–55 kg	Investigational New Animal Drug (INAD)
LOY-001 (Loyal)	GH/IGF-1 axis (suspected)	Upstream ligand/receptor	Large/giant breeds >40 lb	FDA RXE complete Nov 2023
LOY-003 (Loyal)	GH/IGF-1 axis (suspected)	Upstream ligand/receptor	Large/giant breeds (daily alt to LOY-001)	Earlier stage

The two programs provide complementary, non-redundant tests of the somatotropic-axis-vs-aging hypothesis in the same species. A positive TRIAD result would validate mTOR inhibition specifically; a positive LOY-001/003 result would validate IGF-1 reduction specifically. Both positive would be strong evidence for the nutrient-sensing axis as a causal driver of canine aging rate, with distinct mechanistic separation. See canis-lupus-familiaris § Active aging research programs for further context.

Cross-reference: mtor-inhibitors, insulin-igf1, deregulated-nutrient-sensing.

Limitations and pending questions

No results yet. TRIAD is an ongoing trial. This page summarizes the protocol/design paper only. All efficacy and safety claims are pre-specified hypotheses, not observed outcomes. long-term-unknown
Owner-administered intermittent dosing introduces compliance variability. Compliance is monitored via monthly owner surveys, paper medication logs, and tablet residual counts at veterinary visits — but cannot be directly verified for each weekly dose. Compliance variability is tracked in the ITT and per-protocol analyses.
PK in dogs may differ from mouse rapamycin PK. The dose rationale is extrapolated from the Urfer 2017 cardiac pilot and human rapalog data; full rapamycin PK characterization in companion dogs across the dose range is not available. Blood rapamycin levels will be measured in a subset to confirm systemic exposure.
Breed and genetic heterogeneity. Unlike laboratory mice on inbred backgrounds, TRIAD dogs are genetically diverse across breeds and mixed-breed animals. Breed-to-breed variation in rapamycin response (PK, PD, susceptibility to adverse effects) is unknown and cannot be fully controlled.
Cardiovascular endpoint non-replication. The Urfer 2017 pilot fractional-shortening improvement was not replicated in a subsequent 17-dog study at lower dose/longer duration ⁷. TRIAD was designed to resolve this uncertainty at scale.
NCT registration number not confirmed from PDF. The trial is stated to be preregistered; the NCT number is not printed in the protocol paper body. needs-nct-id-confirmation

🧬 Aging Wiki

Explorer

Test of Rapamycin in Aging Dogs (TRIAD): study design and rationale for a prospective, parallel-group, double-masked, randomized, placebo-controlled, multicenter trial of rapamycin in healthy middle-aged dogs from the Dog Aging Project

TRIAD — Test of Rapamycin In Aging Dogs

TL;DR

Study design

Drug dosage and formulation

Eligibility criteria

Primary endpoint — lifespan

Secondary endpoints — healthspan

Exploratory endpoints

Rationale — why rapamycin in dogs

From mouse ITP data to dogs

Pilot RCT (Urfer 2017)

NIH funding

Relationship to Loyal LOY-001/003 — a contrast

Limitations and pending questions

See also

Graph View

Table of Contents

Backlinks

🧬 Aging Wiki

Explorer

Test of Rapamycin in Aging Dogs (TRIAD): study design and rationale for a prospective, parallel-group, double-masked, randomized, placebo-controlled, multicenter trial of rapamycin in healthy middle-aged dogs from the Dog Aging Project

TRIAD — Test of Rapamycin In Aging Dogs

TL;DR

Study design

Drug dosage and formulation

Eligibility criteria

Primary endpoint — lifespan

Secondary endpoints — healthspan

Exploratory endpoints

Rationale — why rapamycin in dogs

From mouse ITP data to dogs

Pilot RCT (Urfer 2017)

NIH funding

Relationship to Loyal LOY-001/003 — a contrast

Limitations and pending questions

See also

Footnotes

Graph View

Table of Contents

Backlinks