Cancer Vaccines for Dogs: what's proven, what's promising, and what failed.

Part of our complete guide to hemangiosarcoma in dogs.

Two families of cancer vaccine

A cancer vaccine trains the immune system to recognise cancer cells. The strategies differ in what they point the immune system at, and for dogs today there are two families in play:

• Shared-target vaccines pick one marker that many tumors carry, build a single product, and give it to any dog with that cancer type. Off-the-shelf.
• Whole-tumor (autologous) vaccines use the dog's own surgically removed tumor as the raw material, without choosing a target at all. Made from that one patient.

There is a third family, personalized neoantigen vaccines, which sequence the individual tumor and target only its unique mutations. That is a bigger story, and its own post at the end of this series. (If you want the full comparison now, we wrote a standalone guide to the three approaches.)

How to read a vaccine result

Before the scoreboard, one skill that will serve you for the rest of your dog's care: how to weigh a claim. Not all "it works" is equal.

• A randomized trial splits dogs into treated and untreated groups by chance, then compares them. This is the gold standard, because it is the only design that reliably separates the drug's effect from luck and from which dogs happened to be healthier.
• A single-arm study with "historical controls" gives every dog the treatment and compares them to survival numbers from the past. It is far weaker, because the past dogs may differ in a dozen ways. It is useful for a first look, not for proof.
• Peer-reviewed and published beats presented at a conference, which beats a company press release. Each step down means fewer outside experts have checked the work.

Here is why this matters, with a real example. A canine vaccine against the protein HER2, delivered by a modified bacterium, was tested in a small early study in bone cancer and looked encouraging against historical controls. It generated real excitement. Then a larger, properly randomized study of 118 dogs was run, and it found no significant survival benefit (Mason et al., Molecular Therapy, 2025; earlier phase I: Mason et al., 2016). Same vaccine, better study, opposite conclusion. That is not a scandal. It is how science is supposed to work, and it is exactly why the scoreboard below grades the evidence rather than the hype.

Shared-target vaccines

The EGFR/HER2 vaccine

The most talked-about shared-target vaccine for dogs comes out of Yale and is being commercialised by a spin-out. It is a simple peptide vaccine, given as an injection under the skin, that trains the immune system against two proteins, EGFR and HER2, that many aggressive tumors over-produce. Peer-reviewed work confirms the vaccine does what it is designed to do biologically: it induces antibodies and immune-cell responses against those proteins, with some tumor responses seen (Doyle et al., Translational Oncology, 2021).

What about survival in hemangiosarcoma specifically? Here we have to be careful. At veterinary oncology meetings in 2024 and 2026, the developers reported that dogs receiving surgery, chemotherapy, and the vaccine had a median survival of roughly 236 days, versus about 150 days for standard care, with around 30% alive past 500 days, and a benefit concentrated in earlier-stage disease. Those are encouraging numbers. They were also presented at conferences and have not yet been peer-reviewed or published, so they belong in the "promising, not proven" column, not the "established" one. The vaccine is reportedly offered at around a dozen US sites through the research program, often at no charge for the vaccine itself (you pay for administration and imaging). If it interests you, ask your oncologist about current availability.

More recently, the same group has described stacking that vaccine with Gilvetmab, a canine anti-PD-1 checkpoint drug (Part 4 explains how those release the immune system's brakes), on top of surgery and chemotherapy, reporting a median survival around 300 days in a small conference presentation. That is an encouraging direction, and it fits the pattern that combinations tend to outperform any single tool. But it is once again conference-only and not yet peer-reviewed, so treat the figure as a preview, not a proven result.

The external-vimentin vaccine (EVM)

A newer shared-target idea aims not at the tumor cells directly but at their blood supply. Hemangiosarcoma is a cancer of blood-vessel cells, and a vaccine developed in the Netherlands trains the immune system against vimentin, a protein exposed on the vessels that feed a tumor. In its first peer-reviewed test, 23 dogs with hemangiosarcoma received the vaccine alongside doxorubicin chemotherapy after splenectomy, and were compared to historical dogs given chemotherapy alone. The results were genuinely mixed, and worth reading precisely: median survival rose from 136 to 235 days, but that gap did not reach statistical significance; the share of dogs alive at one year, however, was 44% versus 14%, which did (Engbersen et al., International Journal of Molecular Sciences, 2025). No added toxicity was seen. So this is a promising, peer-reviewed early signal from a single-arm study against historical controls, a real step up from a conference talk, but still short of proof.

The frameshift vaccine (Calviri)

A different shared-target bet uses a class of oddities called frameshift neoantigens, badly garbled proteins that recur across many tumors. The largest effort here, from a company called Calviri, ran the biggest canine cancer trial ever attempted, but as a prevention vaccine in healthy dogs. That trial has finished, but its results have not been published, so whether it works is genuinely unknown (study design: Burton et al., Veterinary Immunology and Immunopathology, 2023). A separate treatment trial for hemangiosarcoma (nicknamed the SOCK study) is enrolling dogs now. For today, the honest status is: interesting idea, no results in hand.

Whole-tumor (autologous) vaccines

Autologous vaccines (Torigen / VimClera)

Instead of choosing a target, an autologous vaccine takes the dog's own removed tumor and processes it into a vaccine, so everything unique about that tumor is included. In the US this is available today as a kit your veterinarian can use, at a relatively modest cost. It has real peer-reviewed data in hemangiosarcoma, and that data is worth reading honestly: in dogs with metastatic (advanced) splenic HSA, the vaccine produced a median survival of about 142 days, with roughly 12.5% alive at one year (Lucroy et al., BMC Veterinary Research, 2020). The catch: the numbers came from a small group, and they were similar to chemotherapy, not better. Both beat surgery alone. So this is a reasonable option for a dog who cannot tolerate chemotherapy, rather than a proven upgrade over it.

ELIAS (whole tumor plus a T-cell transfer)

A more elaborate autologous approach, from ELIAS Animal Health, makes a vaccine from the dog's tumor and then grows the dog's own immune cells outside the body and infuses them back. In bone cancer, it earned full USDA approval in 2025, becoming the first approved product of its kind. But its striking survival numbers come from bone cancer, and there is no hemangiosarcoma data yet. It is a proven approach in one cancer that has not been tested in this one. We will come back to one fascinating detail from its data (about chemotherapy dosing) in Part 4.

Other whole-tumor and shared-antigen vaccines exist in research, including a GD3 vaccine studied mostly in melanoma, but none has published survival data in hemangiosarcoma (Milner et al., 2006). Newer entrants are earlier still: Ardent Animal Health is running a trial that pairs an autologous vaccine with a small-molecule checkpoint blocker (aimed at a target called CD200), and scattered single-case reports describe tumor regressions with TLR-agonist immune stimulants. Both are too preliminary, no published results and single cases respectively, to place on the scoreboard yet.

A word on immune stimulants (Immunocidin)

You may also hear about Immunocidin, which is not a targeted vaccine at all but a non-specific immune stimulant made from a mycobacterial cell-wall fraction (it is USDA-licensed for canine mammary tumors and used off-label elsewhere). It is worth knowing what happened when it was actually tested here: in an 18-dog pilot in splenic hemangiosarcoma, adding Immunocidin to doxorubicin gave a median survival of about 147 days, with no improvement over chemotherapy alone and somewhat more gastrointestinal side effects (Musser et al., PLoS One, 2022). A single dog whose tumor regressed on immune stimulation sometimes gets passed around; one dog is a story, not evidence, and this small controlled pilot is the number that counts.

The scoreboard

Here it is in one place, graded by the strongest evidence available for each approach in hemangiosarcoma (or the nearest cancer where HSA data does not exist yet).

Two takeaways that actually matter

1. Available and proven are not the same thing. Notice that some vaccines you can get today sit in the "promising" or "modest" columns, while the one rigorous negative result came from a vaccine that is not sold. Access reflects business and regulatory decisions as much as evidence. A treatment being purchasable does not mean it is proven, and a treatment being unavailable does not mean it failed.

2. Combinations beat any single vaccine. Across the whole field, the pattern is the same one seen in human oncology: no single vaccine cures on its own, and the better results come from combining approaches, a vaccine plus a checkpoint drug, or immunotherapy paired thoughtfully with chemotherapy. There is even early evidence that less chemotherapy, given at the right moment, may help immunotherapy work better than the standard full course. That idea is worth its own discussion, and it gets one in Part 4.

What this means for your dog

• Ask where a claim sits on this scoreboard. When you hear about a vaccine, the useful questions are: is it randomized or single-arm? Published or a conference talk? Tested in hemangiosarcoma or a different cancer?
• An autologous vaccine is a reasonable option if chemo is off the table, with the honest expectation that it performs about like chemo, not better.
• The EGFR/HER2 vaccine is a legitimate thing to ask about, framed as promising and still-unproven, and it is one of the few actually available now.
• If a vaccine or personalized approach is a possibility, protect the tumor sample at surgery. Several of these need tissue. We wrote a guide on preserving a tumor sample.

Every one of these is a conversation for you and a licensed veterinary oncologist who knows your dog's case and timeline.

A note on sources

This series was prompted by a public educational webinar from the Canine Cancer Alliance, a nonprofit that funds canine cancer research; the conference-reported figures for the EGFR/HER2 vaccine were shared there. Peer-reviewed claims are cited to their original studies by DOI. Where a result is early, unpublished, or conference-only, we say so, because with this cancer the difference is everything.

Sources

1. Mason et al., Mol Ther, 2025 (118 dogs). PubMed · DOI
2. Mason et al., Clin Cancer Res, 2016 (18 dogs). PubMed · DOI
3. Doyle et al., Transl Oncol, 2021. PubMed · DOI
4. Engbersen et al., Int J Mol Sci, 2025 (23 dogs). PubMed · DOI
5. Burton et al., Vet Immunol Immunopathol, 2023. PubMed · DOI
6. Lucroy et al., BMC Vet Res, 2020. PubMed · DOI
7. Milner et al., Vet Immunol Immunopathol, 2006. PubMed · DOI
8. Musser et al., PLoS One, 2022 (18 dogs). PubMed · DOI