Program selection
Licensing human molecules for companion animals
Which human drugs are the best candidates to develop for dogs and cats, judged against this review's evidence on where dog biology matches human.
How we pick candidates
- Demonstrated safety and efficacy in humans
- Comparative biology in companion animals
- Unmet need in animals
Route 1 · Approved, mechanism unclaimed in dogs or cats
Approved in humans. No companion-animal product works this mechanism.
Route 2 · Shelved for a verified non-clinical reason
Stopped for supply, portfolio or corporate reasons.
Held back · Human pipeline, not yet approved
Phase 2 and Phase 3 assets, still active. No approval yet.
Curious case of BTK inhibitors
| Molecule | Canine study | Human |
|---|---|---|
| Ibrutinib | 2010, pet dogs with spontaneous B-cell lymphoma | Approved 2013 |
| Acalabrutinib | 2016, 20 dogs, 25% response, median PFS 22.5 days | Approved 2017 |
| Rilzabrutinib | 2020, open trial in canine pemphigus foliaceus | Phase 3 missed its endpoint |
The paper that introduced ibrutinib stated: "PCI-32765 induced objective clinical responses in dogs with spontaneous B-cell non-Hodgkin lymphoma. These findings support Btk inhibition as a therapeutic approach for the treatment of human diseases associated with activation of the BCR pathway." Human trials had already started, so technically the dogs did not launch the program.
The acalabrutinib trial: "Preclinical Evaluation of the Novel BTK Inhibitor Acalabrutinib in Canine Models of B-Cell Non-Hodgkin Lymphoma." It ran a year before human approval and reported doses, tolerability and efficacy "comparable with that observed in ibrutinib-treated DLBCL patients."
These were pet dogs with naturally occurring lymphoma, in trials designed to inform human development. Untreated survival is about six weeks, which is why the model reads out fast.
Three of this review's 22 veterinary-first pairs are BTK inhibitors. No companion-animal BTK product exists.
Why no dog drug came of it
No paper gives a reason. These are the obstacles the literature does record.
The trial was never aimed at a dog drug. It was designed to inform human development, and the authors argue the case for the model, not for a product.
The dogs were the hardest cases. Two-thirds were chemotherapy-refractory, where "survival in these relapsed patients is often as short as 28 days". A 22.5-day median PFS sits against that.
The dose may have been too low. "Because acalabrutinib was well-tolerated, higher doses may be better suited to use in follow up studies."
Nobody could tell which dogs would respond. In humans, ABC/GCB subtype and MYD88, CD79, CARD11 and TNFAIP3 mutations predict ibrutinib response. The authors were "currently pursuing additional studies to determine whether such molecular differences exist" in dogs.
The field moved to combinations. Work from 2021 and 2025 pairs BTK with PI3K inhibition in canine DLBCL rather than pushing BTK alone.
Canine DLBCL is not human DLBCL. The same drivers recur — TRAF3, SETD2, POT1, TP53, FBXW7 — at different frequencies, confirmed by whole-genome sequencing. Whether that explains the weaker BTK response has not been tested.
Then there is the ceiling. Only four cancer drugs have ever been approved for dogs: Palladia, Stelfonta, Tanovea and Laverdia, the last of which took four annual renewals of a conditional approval before reaching full approval in January 2026.
Every candidate
54 candidates, ranked. The 75 pipeline assets are in the table too — switch "Show" to see them. Click a row for the evidence behind it.
Rank combines three things: how well dog and human findings agreed in that condition area, how little the companion-animal market is already crowded, and how large the mechanism is in human medicine.
Human market scale is hand-curated per mechanism class, with a source for each, because no per-molecule figure could be sourced to this site's standard. It says how big the mechanism is **in people**. It is not a measure of the companion-animal opportunity.
Prevalence, market size and willingness to pay for dogs and cats are absent from this analysis entirely, and are probably the largest determinant of what a program is worth. Seven molecules have no established market figure; they are ranked on the legs that could be established and can never outrank a molecule with all three.
| Rank | Molecule | Target | Human indication | Condition area | Route | Human stage | Companion-animal programs |
|---|
How the list was cut
What this cannot tell you
- No prevalence, market size, or willingness to pay. Probably the largest driver of value, and we do not have it.
- "Not found" describes the checks above. The supplied list covers branded programs, not the formulary.
- Patent status is recorded only where we searched.
- Target-animal safety is not systematically checked.
- Molecules within an area are not ranked against each other.
- Formulation, route, and dosing are not assessed.