# Walden Biosciences

> Walden Biosciences is a Cambridge, Massachusetts clinical-stage biotech building first-in-class, disease-modifying medicines that target the kidney directly instead of just delaying the slide toward dialysis. Founded in 2020 on the podocyte and suPAR research of renal scientist Jochen Reiser and colleagues, Walden pairs an antibody program (WAL0921, against soluble urokinase plasminogen activator receptor) with a small-molecule program (WAL0623, a dynamin stabilizer) to protect and restore the kidney's filtration cells. Backed by ARCH Venture Partners, UCB Ventures, Mass General Brigham Ventures and ATEM Capital, the company is advancing WAL0921 through a Phase 2 basket study across common and rare glomerular kidney diseases.

- **Founded:** 2020
- **Headquarters:** Cambridge, Massachusetts, United States
- **Founders:** Jochen Reiser (Scientific Co-Founder & Scientific Advisory Board Member)
- **Team size:** Approximately 22-25 employees
- **Products:** WAL0921, WAL0623
- **Notable:** Launched in October 2020 with $51M to pursue a novel, kidney-targeted approach to renal disease, Raised a $75M Series B in 2023, bringing total funding to roughly $126M, Reported positive topline Phase 1+ data for WAL0921 in 2024 - well tolerated with a rapid reduction in suPAR demonstrating proof-of-biology

## Products & services

- **WAL0921** — First-in-class, proprietary, humanized monoclonal antibody that binds soluble urokinase plasminogen activator receptor (suPAR) and inhibits its pro-inflammatory action on podocytes - the cause of podocyte dysfunction, proteinuria, and kidney disease progression. The lead program, currently in a Phase 2 basket study (WAL0921-02) across common and rare glomerular kidney diseases including FSGS, treatment-resistant minimal change disease, IgA nephropathy, and primary membranous nephropathy.
- **WAL0623** — First-in-class small molecule designed to stabilize and restore the function of dynamin, an enzyme that maintains the structure of the kidney's filtration apparatus and protects podocytes. IND-enabling studies were completed in 2024 with Phase 1 planned to follow.

## Achievements

- Launched in October 2020 with $51M to pursue a novel, kidney-targeted approach to renal disease
- Raised a $75M Series B in 2023, bringing total funding to roughly $126M
- Reported positive topline Phase 1+ data for WAL0921 in 2024 - well tolerated with a rapid reduction in suPAR demonstrating proof-of-biology
- Fully enrolled the first cohort of the WAL0921-02 Phase 2 basket study in chronic kidney diseases (2024)
- Completed IND-enabling studies for the dynamin-stabilizing small molecule WAL0623 (2024)
- Built on the breakthrough suPAR and podocyte science of co-founder Jochen Reiser

## Latest updates

- **2024-04** — Announced positive topline data from the Phase 1+ study of WAL0921, showing it was well tolerated and rapidly reduced suPAR (proof-of-biology).
- **2024-09** — Fully enrolled the first cohort of the Phase 2 basket study (WAL0921-02) of WAL0921 in chronic kidney diseases.
- **2025-01** — Highlighted 2024 accomplishments and 2025 priorities: advancing the Phase 2 basket study into rare glomerular kidney diseases and progressing the WAL0623 dynamin program toward Phase 1.
- **2025-09** — Announced key initiatives to advance the clinical pipeline and support the Phase 2 program for WAL0921 in rare kidney diseases, with interim data expected late 2025 into 2026.

## Links

- Website: https://waldenbiosciences.com
- LinkedIn: https://www.linkedin.com/company/waldenbiosciences
- Twitter/X: https://twitter.com/WaldenBio

---

Profile page: https://yespress.io/walden-biosciences
Published by YesPress — https://yespress.io
Last updated: 2026-06-10