Turnstone Biologics
Turnstone developed 'selected' tumour-infiltrating lymphocyte therapy, enriching the most cancer-reactive immune cells from a patient's tumour. It stopped its clinical programme in January 2025 and was bought by XOMA Royalty later that year.
Overview
Turnstone Biologics was a San Diego biotechnology company that pioneered selected tumour-infiltrating lymphocyte (Selected TIL) therapy, enriching TIL populations for tumour reactivity. Its lead programme TIDAL-01 was studied in solid tumours and clinical data were presented at the SITC TIL Symposium in November 2024. In January 2025 the company discontinued all TIDAL-01 studies and halted development, then began a strategic alternatives process. On 27 June 2025 Turnstone agreed to be acquired by XOMA Royalty Corporation for $0.34 in cash per share plus a contingent value right; the tender offer and merger completed on 11 August 2025 and the Nasdaq listing (TSBX) ended. The company website no longer resolves.
Funding
All startupsInvestors not recorded; see the round sources.
| Round | Year | Amount | Source |
|---|---|---|---|
| Acquisition · $0.34 in cash per share plus a contingent value right; agreement 27 June 2025, merger completed 11 August 2025 | 2025 | undisclosed | sec.gov |
Amounts only where the cited source states them. Rounds without a public source are not listed.
Notes
top- Former Nasdaq ticker TSBX. IPO (2023) not sourced.