Estuary Biotherapeutics Launches with $93M for ADPKD Gene Therapies
Estuary Biotherapeutics launched with $93 million in Series A funding to develop one-time gene therapies for autosomal dominant polycystic kidney disease.
Estuary Biotherapeutics has officially launched with a $93 million Series A financing round to develop genetic medicines for autosomal dominant polycystic kidney disease. The California-based company, forged in 2022, is built on foundational research from Yale School of Medicine professors and scientific co-founders Stefan Somlo and Michael Caplan.
Wayne Sackett, Estuary’s co-founder and CEO, stated that patients "are still awaiting a therapy that can transform the course of their disease." The company believes its technology will yield the first treatment capable of halting or reversing ADPKD, moving beyond current options that only slow progression.
Science builds on Yale discoveries to target ADPKD at its genetic source
The company’s approach leverages landmark discoveries from its scientific founders. Somlo’s lab published a study showing that reactivating polycystins in mice could shrink cysts and reverse kidney inflammation and scarring. Separately, Caplan's lab determined that only a small fragment of the full polycystin protein is needed to suppress the disease.
Estuary is advancing two lead programs targeting the main genetic drivers of ADPKD. Both are designed as one-time, locally administered treatments.
| Program | Target | Design |
|---|---|---|
| EST-201 | PKD2 gene | Delivers a functional, full-length version of the gene |
| EST-101 | PKD1 gene | Provides only the most useful fragments of the protein |
Caplan's findings suggest this helpful genetic material can be packaged and delivered to kidneys using standard viral vectors for gene therapy.
Lead programs designed for one-time kidney delivery with clinical timelines set
The company has outlined clear development timelines for its lead candidates. Estuary expects EST-201 to enter human testing in 2027. The follow-on candidate, EST-101, is projected to begin clinical trials in 2028.
Sackett emphasized that the current focus is on solving "the most crucial remaining barrier to kidney gene therapy: delivery."
Leadership and advisors bring deep biotech and gene therapy experience
The $93 million Series A round was led by RA Capital Management and included participation from Deep Track Capital, 4BIO Capital, and Alphabet's GV venture arm, among others. The company's management team is stocked with former Biogen leaders, including Jeremy Duffield, Kiley Keelin, and Uptal Patel.
Estuary’s board includes Sackett, RA Capital Managing Director Emily Minkow, and 4BIO partner Owen Smith. A fourth co-founder, Xavier Anguela, brings gene therapy expertise from roles at Eli Lilly, Spark Therapeutics, and AskBio. The company is also advised by key industry figures: Frank Czerwiec, who led the clinical development of the current standard therapy tolvaptan, and Jeff Marrazzo, co-founder and former CEO of Spark Therapeutics.
Estuary expects EST-201 to enter human testing in 2027 and EST-101 in 2028.
