Biotech · Veterinary oncology
Gamgee
A Y Combinator startup building personalised mRNA cancer vaccines for dogs, grown from one founder's attempt to save his own dog with ChatGPT and a university RNA lab. That dog, Rosie, died in mid 2026, and the company launched with a $4 million seed round led by Founders Fund.
A tumour, a chatbot, and a university lab
In 2024 Rosie, an eight year old Staffordshire bull terrier cross, was diagnosed with mast cell cancer, the most common skin cancer in dogs. Surgery, chemotherapy and immunotherapy slowed the disease without stopping it. Vets gave her months to live.
Her owner, Paul Conyngham, had no biology training but 17 years in machine learning. He paid about $3,000 to have Rosie's tumour DNA and healthy DNA sequenced at the University of New South Wales, then used ChatGPT and AlphaFold to sift the resulting mutations for neoantigens, the mutated proteins that sit only on cancer cells. According to reporting by Reason, he used Grok to help design the final mRNA construct.
He did not make the vaccine himself. Researchers at UNSW's RNA Institute, led by director Pall Thordarson, reviewed his data and built the physical mRNA construct in a university lab. Rosie received her first injection in Queensland in December 2025, with a booster the following month. The Y Combinator listing for the company Conyngham later founded calls it what is believed to be the first fully computationally designed mRNA cancer vaccine administered to a dog.
The problem
Cancer is the leading cause of death in adult dogs, and Gamgee cites about six million new canine cancer diagnoses a year in the United States. Owners who pursue specialist treatment can spend thousands of dollars on surgery, chemotherapy and radiation, often without a cure. Personalised neoantigen mRNA vaccines have been in human development for over a decade, most visibly at Moderna and Merck, but none of that work reaches dogs. Existing veterinary options, such as autologous tumour cell vaccines, use a patient's own tumour tissue but do not sequence its genome or target its specific mutations the way Rosie's case did.
Gamgee's bet is that the same steps that let a determined outsider build a one off vaccine can be industrialised into a repeatable service through any veterinary oncologist.
Founder
Conyngham previously co-founded Core Intelligence, described in his Y Combinator profile as building applied AI systems across startups and enterprise, and says he helped grow Australia's AI community through a group called DSAI. His academic background is in machine learning, data science, and electrical and computer systems engineering. Gamgee's Y Combinator page lists him as the company's only active founder and gives the team a size of two.
From one dog to a funded company
Rosie's story went viral in March 2026 after independent reporting, including by The Verge, and a social media post from Conyngham that OpenAI chief executive Sam Altman shared to his own followers, calling it an amazing story. An oncologist writing in The Conversation, Justin Stebbing, urged caution the same month, noting the case had no control group and that mast cell tumours behave unpredictably even without treatment.
According to Conyngham's own account of events in June 2026, relayed by the outlet 36Kr, a later surgery pushed Rosie's cancer out of remission, and within about four weeks the tumours had spread to her hindquarters and she was in enough pain that he chose to euthanise her. Gamgee's own launch material puts it more obliquely: it says Rosie entered remission, that her cancer returned following a later surgery, and writes about her in the past tense without stating what ultimately happened to her.
Five months after the original viral story, on August 17, 2026, Gamgee launched publicly with a $4 million seed round led by Founders Fund, alongside Celine Halioua of the canine longevity company Loyal, Steve Eidelman of Modern Animal, Dropbox co-founder Arash Ferdowsi, and Gokul Rajaram.
What is proven, and what is still claimed
| Evidence | What the record shows | Source type |
|---|---|---|
| Rosie's tumour response | Independent and company accounts agree several of Rosie's tumours shrank 50 to 75 percent after her first injection, with immune cell infiltration seen in responsive lesions. One tumour did not respond, prompting a second, differently targeted vaccine Rosie did not receive before her relapse. | Independent |
| Whether the vaccine caused the improvement | The Verge and The Conversation both note the treatment was given without a control group and alongside prior surgery, chemotherapy and immunotherapy, so its specific contribution cannot be isolated. Conyngham has declined to call it a cure. | Differs from company framing |
| Rosie's outcome | Gamgee's launch release says Rosie's cancer returned after a later surgery and writes about her in the past tense without confirming her death. Conyngham's own June 2026 account, as reported by 36Kr, and a KuCoin news item both describe Rosie being euthanised after the cancer spread. | Company account less direct than founder's statements |
| Clinical trial | Company and press materials describe a trial in eastern Australia, run with UNSW, the University of Queensland and the Garvan Institute, with a target of about 30 dogs. No listing for this study was found in a public trial registry. | Company-stated |
| Regulatory pathway | The company says it is working with regulators toward a USDA pathway for a patient-specific veterinary biologic. Animal vaccines fall under USDA rather than FDA jurisdiction, which independent reporting confirms is correct. No filing status was found in a public database. | Company-stated |
| Peer-reviewed publication | No paper describing Rosie's case or Gamgee's platform was found in PubMed searches. | Not found |
| SEC filings | No Form D or other SEC filing under "Gamgee" or "Gamgee Technologies" was found on EDGAR. A 2013 to 2014 Form D filer also named "Gamgee, Inc." (CIK 0001562526, Palo Alto, California) is a different, unrelated company that predates this startup's 2026 founding by more than a decade. | Not found |
| Target cost and timeline | Gamgee's pitch states a goal of a 48 hour vaccine design and a $2,000 end-to-end cost, against the roughly one year and $20,000 the manual process for Rosie took. Its vet-facing site states an indicative four weeks from biopsy to vaccine, based on a single case. | Company-stated |
Read plainly: the biology behind personalised neoantigen mRNA vaccines is not new, and human trials of the same basic approach have produced randomised evidence in melanoma. What is unproven is whether Conyngham's do-it-yourself version, now being turned into a company, can be repeated safely and consistently across dogs. Rosie's case is one uncontrolled outcome, not a validated result, and it ended in relapse and, by the founder's own account, euthanasia.
What to watch
- Results from the Australian trial, targeted at up to 30 dogs, the first attempt to test the approach beyond a single case.
- Whether Gamgee registers its study in a public trial database and publishes Rosie's tumour grade, a detail several outlets note was never made public.
- Progress on a USDA pathway for a patient-specific veterinary biologic.
- Whether a Form D appears for the $4 million seed round.
In their words
“My dog Rosie was given months to live. Chemo and immunotherapy failed. I used ChatGPT and computational genomics to design a personalized mRNA cancer vaccine for her tumour. Several of her tumours shrank.”
Paul Conyngham, founder and CEO, X post announcing Gamgee, August 11, 2026 · Company-stated
“I should not have been the only person who could do this. A background in machine learning and months of obsessive research should not be the price of admission.”
Paul Conyngham, Gamgee website story page · Company-stated
“We cannot be sure how much of Rosie's improvement is due to the vaccine, how long it will last, or whether the same approach would help other dogs.”
Justin Stebbing, oncologist, The Conversation, March 20, 2026 · Independent
“Paul's love for Rosie led him to cross disciplines, teach himself entirely new fields, and push forward where most people would have stopped. That kind of determination is rare, and it's what we look for in founders.”
Amin Mirzadegan, Partner, Founders Fund, Gamgee launch release, August 17, 2026 · Company release
“This study is designed to test whether this personalized approach can be delivered safely, and done consistently, in a clinical setting.”
Pall Thordarson, Director, UNSW RNA Institute, Gamgee launch release, August 17, 2026 · Company release
“For a startup built around a single dog whose improvement cannot be clearly attributed to the treatment at the core of its pitch, that's a grand ambition.”
Robert Hart, The Verge, August 12, 2026 · Independent
“I lost my dog because we weren't fast enough at developing the next mRNA cancer vaccine.”
Paul Conyngham, as quoted by 36Kr, referencing his August 2026 statement · Independent
Related companies
Sources
- CompanyGamgee homepage
- CompanyRosie's Cancer Vaccine: The Original Dog mRNA Case
- CompanyGamgee for Veterinary Oncologists
- CompanyGamgee: Curing cancer, starting with dogs, company profile and launch post
- CompanyOne Dog's Legacy Becomes GAMGEE
- IndependentOf course the ChatGPT dog cancer vaccine spawned a startup
- IndependentA man used AI to help make a cancer vaccine for his dog, an oncologist urges caution
- IndependentRosie's Cancer Came Back After Her AI-Designed Vaccine, and Her Owner Just Raised $4 Million
- IndependentOne Dog's Cancer Vaccine Just Became a Real Company
- IndependentAI Dog Cancer Vaccine Story Now a Full-Blown Startup
- IndependentChatGPT Helped Design a Dog Cancer Vaccine, Now It's a Startup
- IndependentFounders Fund backs Gamgee's $4M seed for AI-designed dog cancer vaccines
- Independent3 Months After Dog Rosie Passed Away, Her Medical Records Spawned an AI Medical Startup
- IndependentAI-powered dog cancer vaccine startup Gamgee secures $4M in seed funding
- Public recordEDGAR company search, "Gamgee"
Profile researched and written by Healthcare Discovery. Last updated September 29, 2026.
