# Tr1X
Tr1X, Inc. is a San Diego-based biotechnology company developing allogeneic (donor-derived, off-the-shelf) Type 1 regulatory T (Tr1) cell therapies for autoimmune and inflammatory diseases. It emerged from stealth with a $75 million Series A on January 17, 2024[1](https://www.prnewswire.com/news-releases/tr1x-inc-announces-75-million-series-a-financing-to-develop-best-in-class-universal-allogeneic-regulatory-t-treg-and-car-treg-cell-therapies-to-treat-and-potentially-cure-autoimmune-and-inflammatory-diseases-302036679.html) and is now clinical-stage, with two programs in Phase 1/2a trials as of early 2026[2](https://www.businesswire.com/news/home/20260204849494/en/Tr1X-Presents-First-Clinical-Data-Demonstrating-Proof-of-Safety-and-Proof-of-Mechanism-With-Allogeneic-Off-the-Shelf-Tr1-Regulatory-T-Cell-Therapy-TRX103).
| Key fact | Detail |
|---|---|
| Headquarters | San Diego, California[1](https://www.prnewswire.com/news-releases/tr1x-inc-announces-75-million-series-a-financing-to-develop-best-in-class-universal-allogeneic-regulatory-t-treg-and-car-treg-cell-therapies-to-treat-and-potentially-cure-autoimmune-and-inflammatory-diseases-302036679.html) |
| Sector | Cell therapy: regulatory T (Treg/Tr1) cells for autoimmunity[3](https://www.biopharmadive.com/news/tr1x-treg-cell-therapy-biotech-startup/704690/) |
| Emergence from stealth | January 17, 2024, with a $75 million Series A led by The Column Group[1](https://www.prnewswire.com/news-releases/tr1x-inc-announces-75-million-series-a-financing-to-develop-best-in-class-universal-allogeneic-regulatory-t-treg-and-car-treg-cell-therapies-to-treat-and-potentially-cure-autoimmune-and-inflammatory-diseases-302036679.html) |
| Lead candidate | TRX103, a polyclonal allogeneic Tr1 cell therapy in Phase 1/2a trials[2](https://www.businesswire.com/news/home/20260204849494/en/Tr1X-Presents-First-Clinical-Data-Demonstrating-Proof-of-Safety-and-Proof-of-Mechanism-With-Allogeneic-Off-the-Shelf-Tr1-Regulatory-T-Cell-Therapy-TRX103) |
| Second candidate | TRX319, a CD19 CAR-Tr1 therapy for progressive multiple sclerosis, IND cleared October 2025[4](https://www.biospace.com/press-releases/tr1x-announces-fda-clearance-of-ind-application-for-trx319-a-first-in-class-allogeneic-car-tr1-treg-cell-therapy-for-progressive-multiple-sclerosis-and-50-million-in-additional-financing) |
| Disclosed funding | At least $125 million ($75M Series A plus $50M extension)[1](https://www.prnewswire.com/news-releases/tr1x-inc-announces-75-million-series-a-financing-to-develop-best-in-class-universal-allogeneic-regulatory-t-treg-and-car-treg-cell-therapies-to-treat-and-potentially-cure-autoimmune-and-inflammatory-diseases-302036679.html) • [4](https://www.biospace.com/press-releases/tr1x-announces-fda-clearance-of-ind-application-for-trx319-a-first-in-class-allogeneic-car-tr1-treg-cell-therapy-for-progressive-multiple-sclerosis-and-50-million-in-additional-financing) |
| Status | Operating; latest record February 2026[2](https://www.businesswire.com/news/home/20260204849494/en/Tr1X-Presents-First-Clinical-Data-Demonstrating-Proof-of-Safety-and-Proof-of-Mechanism-With-Allogeneic-Off-the-Shelf-Tr1-Regulatory-T-Cell-Therapy-TRX103) |
## History and founding
Tr1X announced its emergence from stealth on January 17, 2024, alongside the $75 million Series A led by [The Column Group](https://www.edgepedia.org/the-column-group) with participation from NEVA SGR and Alexandria Venture Investments[1](https://www.prnewswire.com/news-releases/tr1x-inc-announces-75-million-series-a-financing-to-develop-best-in-class-universal-allogeneic-regulatory-t-treg-and-car-treg-cell-therapies-to-treat-and-potentially-cure-autoimmune-and-inflammatory-diseases-302036679.html). The launch was independently reported by BioPharma Dive, which described a San Diego startup advancing regulatory [T cell](https://www.edgepedia.org/t-cell) therapies for graft-versus-host disease, inflammatory bowel disease, and other disorders, with multiple clinical trials planned[3](https://www.biopharmadive.com/news/tr1x-treg-cell-therapy-biotech-startup/704690/).
The company's science rests on the work of [Maria Grazia Roncarolo](https://www.edgepedia.org/maria-grazia-roncarolo), Tr1X's Scientific Founder and the discoverer of Tr1 cells, which the company describes as the primary basis of its technology[1](https://www.prnewswire.com/news-releases/tr1x-inc-announces-75-million-series-a-financing-to-develop-best-in-class-universal-allogeneic-regulatory-t-treg-and-car-treg-cell-therapies-to-treat-and-potentially-cure-autoimmune-and-inflammatory-diseases-302036679.html). At launch, the company appointed William Lis as Chief Executive Officer; BioSpace reported that Lis had more than 25 years in biotech, including time as interim CEO of Jasper Therapeutics (2019 to 2022) and CEO of Portola Pharmaceuticals (2008 to 2018)[5](https://www.biospace.com/cell-therapy-startup-tr1x-emerges-from-stealth-with-75m-series-a).[9](https://www.globenewswire.com/news-release/2018/06/04/1516585/28021/en/Portola-Pharmaceuticals-Announces-Retirement-of-CEO-Bill-Lis-in-2018.html) Lis said the team had closed the Series A and an extension in 18 months[1](https://www.prnewswire.com/news-releases/tr1x-inc-announces-75-million-series-a-financing-to-develop-best-in-class-universal-allogeneic-regulatory-t-treg-and-car-treg-cell-therapies-to-treat-and-potentially-cure-autoimmune-and-inflammatory-diseases-302036679.html).
By October 2025, David de Vries was identified as co-founder and CEO in the company's press materials, a role he still held when the first clinical data were announced in February 2026[4](https://www.biospace.com/press-releases/tr1x-announces-fda-clearance-of-ind-application-for-trx319-a-first-in-class-allogeneic-car-tr1-treg-cell-therapy-for-progressive-multiple-sclerosis-and-50-million-in-additional-financing) • [2](https://www.businesswire.com/news/home/20260204849494/en/Tr1X-Presents-First-Clinical-Data-Demonstrating-Proof-of-Safety-and-Proof-of-Mechanism-With-Allogeneic-Off-the-Shelf-Tr1-Regulatory-T-Cell-Therapy-TRX103). The record does not state when or why the leadership transition from Lis occurred.
## Platform and pipeline: TRX103 and TRX319
Tr1X's proprietary technology converts CD4+ T cells isolated from healthy donors into Treg-like cells that function and profile similarly to naturally occurring Tr1 cells, using a GMP-grade closed-loop system the company says enables commercial-scale production[1](https://www.prnewswire.com/news-releases/tr1x-inc-announces-75-million-series-a-financing-to-develop-best-in-class-universal-allogeneic-regulatory-t-treg-and-car-treg-cell-therapies-to-treat-and-potentially-cure-autoimmune-and-inflammatory-diseases-302036679.html). Tr1 cells are a subset of regulatory T cells (Tregs) whose functions include dampening local inflammation and downregulating the inflammasome, a protein complex that mediates inflammatory responses[6](https://medcitynews.com/2024/01/cell-therapy-startup-with-stanford-roots-unveils-75m-to-seek-inflammation-cures/). Using abundant donor-derived CD4+ T cells rather than scarcer natural Tregs is the stated rationale for an off-the-shelf product[6](https://medcitynews.com/2024/01/cell-therapy-startup-with-stanford-roots-unveils-75m-to-seek-inflammation-cures/).
**TRX103** is the lead program: a polyclonal, allogeneic Tr1 cell therapy generated from reprogrammed healthy-donor cells. It is being evaluated across multiple Phase 1/2a studies, including prevention of graft-versus-host disease (GvHD) in patients with hematologic malignancies undergoing HLA-mismatched (donor and recipient immune-type proteins don't match) hematopoietic stem cell transplantation, refractory inflammatory bowel disease, and noninfectious uveitis[2](https://www.businesswire.com/news/home/20260204849494/en/Tr1X-Presents-First-Clinical-Data-Demonstrating-Proof-of-Safety-and-Proof-of-Mechanism-With-Allogeneic-Off-the-Shelf-Tr1-Regulatory-T-Cell-Therapy-TRX103). Per the company's website, TRX103 has received FDA Fast Track Designation for refractory moderate-to-severe [Crohn's disease](https://www.edgepedia.org/crohns-disease)[7](https://tr1x.bio/programs/).
**TRX319** is an allogeneic, off-the-shelf CAR-Tr1 Treg cell therapy designed to pair CD19-targeted B-cell control with active anti-inflammatory signaling and T-cell regulation. The FDA cleared its Investigational New Drug (IND) application for progressive multiple sclerosis in October 2025, and a multicenter, open-label, dose-escalation Phase 1/2a study with safety and tolerability as primary objectives was slated to enter the clinic in early 2026[4](https://www.biospace.com/press-releases/tr1x-announces-fda-clearance-of-ind-application-for-trx319-a-first-in-class-allogeneic-car-tr1-treg-cell-therapy-for-progressive-multiple-sclerosis-and-50-million-in-additional-financing). The company's website says TRX319 also holds Fast Track Designation for primary or secondary progressive multiple sclerosis[7](https://tr1x.bio/programs/).
Beyond the clinic, the company has described pipeline plans for inflammatory bowel disease, type 1 diabetes, and multiple B-cell mediated autoimmune diseases[1](https://www.prnewswire.com/news-releases/tr1x-inc-announces-75-million-series-a-financing-to-develop-best-in-class-universal-allogeneic-regulatory-t-treg-and-car-treg-cell-therapies-to-treat-and-potentially-cure-autoimmune-and-inflammatory-diseases-302036679.html).
## Clinical evidence and manufacturing
In February 2026, Tr1X presented the first clinical data from its ongoing Phase 1 study of TRX103, in patients with hematologic malignancies undergoing HLA-mismatched transplantation, at the 2026 ASTCT/CIBMTR Tandem Meetings. Across all evaluated dose levels, the company reported TRX103 was well tolerated, with no dose-limiting toxicities and no serious adverse events related to the product. All patients achieved successful engraftment and full donor chimerism following transplantation, with dose-dependent persistence and induction of Tr1 and FOXP3+ regulatory T cells[2](https://www.businesswire.com/news/home/20260204849494/en/Tr1X-Presents-First-Clinical-Data-Demonstrating-Proof-of-Safety-and-Proof-of-Mechanism-With-Allogeneic-Off-the-Shelf-Tr1-Regulatory-T-Cell-Therapy-TRX103).
On manufacturing, the company states TRX103 is produced in a fully closed, end-to-end process capable of yielding billions of cells per production run at a fraction of the cost of autologous cell therapies[2](https://www.businesswire.com/news/home/20260204849494/en/Tr1X-Presents-First-Clinical-Data-Demonstrating-Proof-of-Safety-and-Proof-of-Mechanism-With-Allogeneic-Off-the-Shelf-Tr1-Regulatory-T-Cell-Therapy-TRX103). These manufacturing and data statements are the company's own and were reported in its press release[2](https://www.businesswire.com/news/home/20260204849494/en/Tr1X-Presents-First-Clinical-Data-Demonstrating-Proof-of-Safety-and-Proof-of-Mechanism-With-Allogeneic-Off-the-Shelf-Tr1-Regulatory-T-Cell-Therapy-TRX103).
## Funding and investors
Tr1X's disclosed financing totals at least $125 million across two events:
- **$75 million Series A (January 2024)**, led by The Column Group with participation from NEVA SGR and Alexandria Venture Investments, announced at the company's emergence from stealth[1](https://www.prnewswire.com/news-releases/tr1x-inc-announces-75-million-series-a-financing-to-develop-best-in-class-universal-allogeneic-regulatory-t-treg-and-car-treg-cell-therapies-to-treat-and-potentially-cure-autoimmune-and-inflammatory-diseases-302036679.html). At that time, Lis said the raise should fund the company through 2025, by which point Tr1X aimed to complete clinical-grade manufacturing runs and obtain an initial TRX103 clinical data readout[8](https://endpoints.news/graphite-bio-co-founder-debuts-treg-cell-therapy-startup-with-75m-aims-to-trick-immune-system-into-resetting/).
- **$50 million additional financing (October 2025)**, announced with the TRX319 IND clearance and extending the company's cash runway into 2027[4](https://www.biospace.com/press-releases/tr1x-announces-fda-clearance-of-ind-application-for-trx319-a-first-in-class-allogeneic-car-tr1-treg-cell-therapy-for-progressive-multiple-sclerosis-and-50-million-in-additional-financing).
The company also reports grant support from the California Institute for Regenerative Medicine (CIRM)[2](https://www.businesswire.com/news/home/20260204849494/en/Tr1X-Presents-First-Clinical-Data-Demonstrating-Proof-of-Safety-and-Proof-of-Mechanism-With-Allogeneic-Off-the-Shelf-Tr1-Regulatory-T-Cell-Therapy-TRX103).
## Recent developments
January 2024 brought the Series A and public launch[1](https://www.prnewswire.com/news-releases/tr1x-inc-announces-75-million-series-a-financing-to-develop-best-in-class-universal-allogeneic-regulatory-t-treg-and-car-treg-cell-therapies-to-treat-and-potentially-cure-autoimmune-and-inflammatory-diseases-302036679.html); TRX103 entered Phase 1/2a trials[2](https://www.businesswire.com/news/home/20260204849494/en/Tr1X-Presents-First-Clinical-Data-Demonstrating-Proof-of-Safety-and-Proof-of-Mechanism-With-Allogeneic-Off-the-Shelf-Tr1-Regulatory-T-Cell-Therapy-TRX103); October 2025 brought the TRX319 IND clearance, the $50 million extension, and David de Vries as co-founder and CEO[4](https://www.biospace.com/press-releases/tr1x-announces-fda-clearance-of-ind-application-for-trx319-a-first-in-class-allogeneic-car-tr1-treg-cell-therapy-for-progressive-multiple-sclerosis-and-50-million-in-additional-financing); and February 2026 brought the first human data for TRX103[2](https://www.businesswire.com/news/home/20260204849494/en/Tr1X-Presents-First-Clinical-Data-Demonstrating-Proof-of-Safety-and-Proof-of-Mechanism-With-Allogeneic-Off-the-Shelf-Tr1-Regulatory-T-Cell-Therapy-TRX103). The company was operating as of its latest record, February 2026; nothing in the record covers mid-to-late 2026.
## References
1. Tr1X, Inc. Announces $75 Million Series A Financing, PR Newswire, January 17, 2024. https://www.prnewswire.com/news-releases/tr1x-inc-announces-75-million-series-a-financing-to-develop-best-in-class-universal-allogeneic-regulatory-t-treg-and-car-treg-cell-therapies-to-treat-and-potentially-cure-autoimmune-and-inflammatory-diseases-302036679.html
2. Tr1X Presents First Clinical Data Demonstrating Proof of Safety and Proof of Mechanism With Allogeneic Off-the-Shelf Tr1 Regulatory T Cell Therapy TRX103, Business Wire, February 2026. https://www.businesswire.com/news/home/20260204849494/en/Tr1X-Presents-First-Clinical-Data-Demonstrating-Proof-of-Safety-and-Proof-of-Mechanism-With-Allogeneic-Off-the-Shelf-Tr1-Regulatory-T-Cell-Therapy-TRX103
3. Tr1x, a new biotech, joins 'Treg' chase with $75M fundraise, BioPharma Dive, January 2024. https://www.biopharmadive.com/news/tr1x-treg-cell-therapy-biotech-startup/704690/
4. Tr1X Announces FDA Clearance of IND Application for TRX319 ... and $50 Million in Additional Financing, BioSpace (GlobeNewswire), October 14, 2025. https://www.biospace.com/press-releases/tr1x-announces-fda-clearance-of-ind-application-for-trx319-a-first-in-class-allogeneic-car-tr1-treg-cell-therapy-for-progressive-multiple-sclerosis-and-50-million-in-additional-financing
5. Cell Therapy Startup Tr1X Emerges from Stealth with $75M Series A, BioSpace, January 2024. https://www.biospace.com/cell-therapy-startup-tr1x-emerges-from-stealth-with-75m-series-a
6. Cell Therapy Startup With Stanford Roots Unveils $75M to Seek Inflammation Cures, MedCity News, January 2024. https://medcitynews.com/2024/01/cell-therapy-startup-with-stanford-roots-unveils-75m-to-seek-inflammation-cures/
7. Programs, Tr1X Bio (company website). https://tr1x.bio/programs/
8. Graphite Bio co-founder debuts Treg cell therapy startup with $75M, Endpoints News, January 2024. https://endpoints.news/graphite-bio-co-founder-debuts-treg-cell-therapy-startup-with-75m-aims-to-trick-immune-system-into-resetting/
9. Portola Pharmaceuticals Announces Retirement of CEO Bill Lis in 2018 (globenewswire.com). https://www.globenewswire.com/news-release/2018/06/04/1516585/28021/en/Portola-Pharmaceuticals-Announces-Retirement-of-CEO-Bill-Lis-in-2018.html
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