# Capstan Therapeutics

Source: https://onco.cc/companies/capstan-therapeutics/  
OnCo record `capstan-therapeutics` (Company). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Capstan built a way to create CAR T cells inside the patient's body by delivering messenger RNA in targeted lipid nanoparticles, avoiding the need to manufacture cells outside the body. AbbVie bought it in 2025 for $2.1 billion.

## Summary

Capstan Therapeutics developed in vivo CAR T therapy using targeted lipid nanoparticles (tLNP) that deliver RNA payloads such as mRNA to specific immune cells so that CAR T cells are generated inside the patient. Its lead candidate CPTX2309 (now ABBV-619) is an anti-CD19 in vivo CAR T in phase 1 for B cell-mediated autoimmune diseases; the platform is also applicable to oncology. SEC Form D filings show the company was incorporated in 2020 and sold roughly $63 million (2021), $76 million (2022) and $87 million of a $175 million offering (2024) in equity. AbbVie completed its acquisition of Capstan in August 2025 for cash consideration of $2.1 billion, accounted for as an asset acquisition, as disclosed in AbbVie's third-quarter 2025 Form 10-Q.

## Fields

- Kind: Company
- Last checked: 2026-09-10
- HQ: San Diego, CA
- Type: cell-therapy

## Notes

- capstantx.com redirects to an AbbVie page that returned HTTP 403 to automated fetches, so the EDGAR page is given as website. Lead indication is autoimmune rather than cancer; the Form D filings do not name series letters. Investor names not sourced.

## Sources

- Official website: https://www.sec.gov/edgar/browse/?CIK=0002015437
- AbbVie Q3 2025 Form 10-Q describing the acquisition: https://www.sec.gov/Archives/edgar/data/1551152/000155115225000049/abbv-20250930.htm
- AbbVie Q3 2025 results noting completion (8-K): https://www.sec.gov/Archives/edgar/data/1551152/000155115225000047/abbv-20250930xexhibit991.htm
- SEC EDGAR filings: https://www.sec.gov/edgar/browse/?CIK=0002015437

## Connected records

- fronts: [Cell Therapy](https://onco.cc/fronts/cell-therapy/)
- technologies: [In vivo CAR-T](https://onco.cc/technologies/in-vivo-car-t/)
- targets: [CD19](https://onco.cc/targets/cd19/)
- companies: [AbbVie (incl. ImmunoGen, Capstan)](https://onco.cc/companies/abbvie/)

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