# Gritstone Oncology
Gritstone Oncology, Inc., later renamed Gritstone bio, Inc. (Nasdaq: GRTS), was a clinical-stage biotechnology company based in [Emeryville, California](https://www.edgepedia.org/emeryville-california), that developed next-generation vaccines against cancer and infectious disease, including the individualized neoantigen (a tumor-specific mutated protein that immune cells can target) cancer vaccine GRANITE and the off-the-shelf neoantigen vaccine SLATE. It filed for Chapter 11 bankruptcy on October 10, 2024; its common stock was canceled on April 4, 2025 and its main assets were sold for $21.25 million.[1](https://www.sec.gov/Archives/edgar/data/1656634/000119312524235637/d119736d8k.htm) • [2](https://www.sec.gov/Archives/edgar/data/1656634/000114036124023062/ny20020522x3_ars.pdf) • [3](https://elevenflo.com/blog/gritstone-bio-bankruptcy)
| Fact | Detail |
|---|---|
| Founded | 2015 (Series A announced October 20, 2015)[4](https://www.prnewswire.com/news-releases/gritstone-oncology-announces-102-million-series-a-financing-to-support-discovery-and-development-of-personalized-cancer-immunotherapies-300161742.html) |
| Headquarters | Emeryville, California, with operations in Boston and Pleasanton[3](https://elevenflo.com/blog/gritstone-bio-bankruptcy) |
| Founders | Drs. Tim Chan and Naiyer Rizvi (Memorial Sloan Kettering), Professor Jean-Charles Soria (Institut Gustave Roussy), Professor Graham Lord (King's College London), Dr. Mark Cobbold (Massachusetts General Hospital)[4](https://www.prnewswire.com/news-releases/gritstone-oncology-announces-102-million-series-a-financing-to-support-discovery-and-development-of-personalized-cancer-immunotherapies-300161742.html) |
| Sector | Oncology and infectious-disease vaccines[2](https://www.sec.gov/Archives/edgar/data/1656634/000114036124023062/ny20020522x3_ars.pdf) |
| Capital raised | $102M Series A (Oct 2015)[4](https://www.prnewswire.com/news-releases/gritstone-oncology-announces-102-million-series-a-financing-to-support-discovery-and-development-of-personalized-cancer-immunotherapies-300161742.html), $125M in private placements (Dec 2020)[5](https://www.globenewswire.com/news-release/2020/12/28/2150879/0/en/Gritstone-Oncology-Announces-Private-Placement-Financings-Totaling-125-Million.html) |
| Notable investors | Versant Ventures, The Column Group, Redmile Group, Avidity Partners, EcoR1 Capital, BVF Partners[5](https://www.globenewswire.com/news-release/2020/12/28/2150879/0/en/Gritstone-Oncology-Announces-Private-Placement-Financings-Totaling-125-Million.html) • [4](https://www.prnewswire.com/news-releases/gritstone-oncology-announces-102-million-series-a-financing-to-support-discovery-and-development-of-personalized-cancer-immunotherapies-300161742.html) |
| Outcome | Chapter 11 October 10, 2024; assets sold April 4, 2025; all common stock canceled[1](https://www.sec.gov/Archives/edgar/data/1656634/000119312524235637/d119736d8k.htm) • [3](https://elevenflo.com/blog/gritstone-bio-bankruptcy) |
## History and founding
The company launched in 2015 with a $102 million Series A announced on October 20, 2015, co-led by [Versant Ventures](https://www.edgepedia.org/versant-ventures) and [The Column Group](https://www.edgepedia.org/the-column-group), with Clarus Ventures.[4](https://www.prnewswire.com/news-releases/gritstone-oncology-announces-102-million-series-a-financing-to-support-discovery-and-development-of-personalized-cancer-immunotherapies-300161742.html) The financing was to support discovery and development of tumor-specific neoantigen (TSNA)-based immunotherapies, with an initial focus on lung cancer.[4](https://www.prnewswire.com/news-releases/gritstone-oncology-announces-102-million-series-a-financing-to-support-discovery-and-development-of-personalized-cancer-immunotherapies-300161742.html)
Co-founders Drs. Tim Chan and Naiyer Rizvi pioneered the neoantigen work for lung cancer patients at [Memorial Sloan Kettering Cancer Center](https://www.edgepedia.org/memorial-sloan-kettering-cancer-center); the other co-founders were Professor Jean-Charles Soria of the Institut Gustave Roussy in Paris, Professor Graham Lord of King's College London, and Dr. Mark Cobbold of Massachusetts General Hospital, an expert in antigenic-peptide binding and recognition by T cells.[4](https://www.prnewswire.com/news-releases/gritstone-oncology-announces-102-million-series-a-financing-to-support-discovery-and-development-of-personalized-cancer-immunotherapies-300161742.html)
## Products and technology
Gritstone's oncology programs centered on tumor-specific neoantigens.[2](https://www.sec.gov/Archives/edgar/data/1656634/000114036124023062/ny20020522x3_ars.pdf) Its GRANITE program produced individualized neoantigen vaccines: the company sequenced a patient's tumor biopsy in-house and applied its proprietary EDGE platform to identify which mutations formed tumor-specific neoantigens most likely to be presented on the patient's tumor.[2](https://www.sec.gov/Archives/edgar/data/1656634/000114036124023062/ny20020522x3_ars.pdf) The selected antigens were delivered by intramuscular injection, and GRANITE received FDA Fast Track designation for microsatellite-stable colorectal cancer (MSS-CRC), a form of the disease with limited immunotherapy options.[2](https://www.sec.gov/Archives/edgar/data/1656634/000114036124023062/ny20020522x3_ars.pdf) A second program, SLATE, applied the same antigen-selection logic to off-the-shelf vaccines built from shared mutations rather than an individual's tumor.[2](https://www.sec.gov/Archives/edgar/data/1656634/000114036124023062/ny20020522x3_ars.pdf) The company also applied its vaccine technology to infectious disease, including a BARDA-backed COVID-19 study under its CORAL program.[3](https://elevenflo.com/blog/gritstone-bio-bankruptcy)
## Funding by the numbers
- **Series A, October 20, 2015:** $102.0 million, co-led by Versant Ventures and The Column Group.[4](https://www.prnewswire.com/news-releases/gritstone-oncology-announces-102-million-series-a-financing-to-support-discovery-and-development-of-personalized-cancer-immunotherapies-300161742.html)
- **December 2020 PIPEs:** a $110 million PIPE closed December 28, 2020, plus a newly executed $15 million PIPE, for $125 million gross, at $3.71 per share, supported by Redmile Group, Avidity Partners, EcoR1 Capital, BVF Partners L.P., and Versant Ventures.[5](https://www.globenewswire.com/news-release/2020/12/28/2150879/0/en/Gritstone-Oncology-Announces-Private-Placement-Financings-Totaling-125-Million.html)
## Clinical programs and traction
The Phase 1/2 trial of GRANITE in MSS-CRC produced the company's most cited data. In the cohort, 6 of 11 evaluable patients (55%) achieved a molecular response, defined as at least a 30% reduction in circulating tumor DNA (ctDNA) from baseline.[2](https://www.sec.gov/Archives/edgar/data/1656634/000114036124023062/ny20020522x3_ars.pdf) As of August 31, 2022, median overall survival among molecular responders had not yet been reached, compared with 7.8 months in evaluable MSS-CRC patients who did not exhibit a molecular response; the interim results were published in [Nature Medicine](https://www.edgepedia.org/nature-medicine) in August 2022.[2](https://www.sec.gov/Archives/edgar/data/1656634/000114036124023062/ny20020522x3_ars.pdf)
A registrational-intent Phase 2/3 trial in newly diagnosed metastatic MSS-CRC enrolled its first patient in January 2022 and completed Phase 2 enrollment in August 2023, with molecular response as the Phase 2 primary endpoint.[2](https://www.sec.gov/Archives/edgar/data/1656634/000114036124023062/ny20020522x3_ars.pdf) Phase 2 colorectal cancer data fell short of the pivotal path management had discussed.[3](https://elevenflo.com/blog/gritstone-bio-bankruptcy) The kept sources do not report final results for the CORAL SARS-CoV-2 program, which was delayed.[3](https://elevenflo.com/blog/gritstone-bio-bankruptcy)
## Status and outcome
The end came quickly. On February 29, 2024, Gritstone bio announced an approximately 40% reduction of its workforce.[6](https://ir.gritstonebio.com/news-releases/news-release-details/gritstone-bio-announces-workforce-reduction) The company's First Day Declaration in bankruptcy described about $40 million of cash, cash equivalents and marketable securities as of August 31, 2024, but not enough capital to support its programs through commercialization.[3](https://elevenflo.com/blog/gritstone-bio-bankruptcy) • [1](https://www.sec.gov/Archives/edgar/data/1656634/000119312524235637/d119736d8k.htm)
On October 10, 2024, Gritstone bio filed a voluntary Chapter 11 petition in the US Bankruptcy Court for the District of Delaware, case number 24-12305, styled In re Gritstone bio, Inc.; the company expected Nasdaq delisting and did not intend to appeal.[1](https://www.sec.gov/Archives/edgar/data/1656634/000119312524235637/d119736d8k.htm) By the plan effective date of April 4, 2025, Seattle Project Corp. had bought the main asset package for $21.25 million, Hercules, and Future Solution Investments had taken narrower asset packages through credit bids, and all outstanding common stock and other equity interests were canceled.[3](https://elevenflo.com/blog/gritstone-bio-bankruptcy)
## Recent developments
Records that describe Gritstone as active based on a December 2020 financing are outdated. After completing Phase 2 enrollment of its pivotal-intent colorectal trial in August 2023, the company cut 40% of its workforce in February 2024, reported Phase 2 data that fell short of a pivotal path, entered Chapter 11 on October 10, 2024, and ceased to exist as a public company when its stock was canceled on April 4, 2025.[2](https://www.sec.gov/Archives/edgar/data/1656634/000114036124023062/ny20020522x3_ars.pdf) • [6](https://ir.gritstonebio.com/news-releases/news-release-details/gritstone-bio-announces-workforce-reduction) • [1](https://www.sec.gov/Archives/edgar/data/1656634/000119312524235637/d119736d8k.htm) • [3](https://elevenflo.com/blog/gritstone-bio-bankruptcy)
## References
1. [Gritstone bio, Inc. Form 8-K — Chapter 11 filing (October 10, 2024)](https://www.sec.gov/Archives/edgar/data/1656634/000119312524235637/d119736d8k.htm)
2. [Gritstone bio, Inc. Annual Report to Stockholders 2024](https://www.sec.gov/Archives/edgar/data/1656634/000114036124023062/ny20020522x3_ars.pdf)
3. [Gritstone bio: $21.25M Sale and Hybrid Emergence (ElevenFlo)](https://elevenflo.com/blog/gritstone-bio-bankruptcy)
4. [Gritstone Oncology Announces $102 Million Series A Financing (company press release)](https://www.prnewswire.com/news-releases/gritstone-oncology-announces-102-million-series-a-financing-to-support-discovery-and-development-of-personalized-cancer-immunotherapies-300161742.html)
5. [Gritstone Oncology Announces Private Placement Financings Totaling $125 Million (company press release)](https://www.globenewswire.com/news-release/2020/12/28/2150879/0/en/Gritstone-Oncology-Announces-Private-Placement-Financings-Totaling-125-Million.html)
6. [Gritstone bio Announces Workforce Reduction (company press release)](https://ir.gritstonebio.com/news-releases/news-release-details/gritstone-bio-announces-workforce-reduction)
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*Initially written Sep 17, 2026 · Edited: Oct 11, 2026; Oct 15, 2026; Oct 21, 2026; Oct 25, 2026*
*Copyright 2026 EdgeChat AI, a subsidiary of Biostate AI.*
License: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license