After doctors stopped, GitLab co-founder kept going — now cancer-free
What's the deal? Sid SijbrandijDealroom has a profile for this one. Try Dealroom →, co-founder and executive chair of GitLab, has put his rare bone cancer into remission after exhausting standard treatments and assembling his own research team. When doctors told him in 2024 there was nothing left to do, the Dutch-born tech entrepreneur went "founder mode" on his disease — hiring scientists, running advanced diagnostics, and travelling to Germany for experimental radioligand therapy.
Why now? Sijbrandij is going public with his story. He'll speak at the OpenAI Forum on March 18 about how he used ChatGPT to analyse his cancer data and identify treatment options.
His experience comes as the biotech industry debates whether personalised medicine can ever scale beyond the wealthy. It currently costs roughly $1B to get a drug approved, Sijbrandij notes, but "only" $1M to dose a single patient with a personalised therapy. That gap keeps widening — which matters for research economics, but still puts these treatments far out of reach for most people.
What could go wrong? This approach required extraordinary resources and persistence. Sijbrandij describes "incredible struggle at every hospital" to access his own tissue samples.
Hospital institutional review boards proved harder to navigate than the FDA. Many experimental medicines his team discovered came from companies on the verge of bankruptcy. And some choices — like testing multiple drugs at lower doses in parallel — deviate from how oncologists typically deliver care.
The signal: Sijbrandij's case shows what's possible when frontier cancer tools meet Silicon Valley problem-solving. His team used single-cell sequencing, minimal residual disease tests, and AI analysis to identify a fibroblast marker called FAP that his tumour overexpressed. That led him to Richard Baum at CURANOSTICUM in Germany for radioligand therapy — a treatment using radioactive isotopes to target specific biomarkers.
The therapy shrank his tumour enough for surgery. He now has no evidence of disease.
The approach mirrors how Sijbrandij built GitLab: radical transparency, obsessive documentation, and what he calls "maximal diagnostics." His health notes have grown to over 1,000 pages for 2025 alone.
Whether this model can scale remains unclear. But Sijbrandij is using his remission to start a new AI coding company called Kilo CodeDealroom has a profile for this one. Try Dealroom → while building backup treatments in case his cancer returns. His full protocol is documented at sytse.com/cancer.
Sources:
Century of Bio
Sid Sijbrandij
OpenAI Forum Announcement
A.M. and B.S.
