Estuary launches with $103M for kidney disease gene therapies

Estuary Biotherapeutics announced its launch with $103 million in total committed financing which will support the company’s two lead gene therapy programs, EST-201 and EST-101, through clinical proof of concept.

Estuary’s lead programs are designed to target the most common genetic subtypes of ADPKD, an inherited, lifelong, progressive disease characterized by the growth of cysts in both kidneys. Over time, these cysts enlarge, displacing functioning tissue until the organs fail, requiring dialysis or transplant. While other ADPKD therapies target pathways downstream of the causal biology, EST-201 and EST-101 are designed to address the underlying genetic root cause directly, using a potentially one-time, locally delivered AAV to transduce individual kidney epithelial cells, with the goal of restoring polycystin protein levels across the entire nephron

EST-201 is a full-length PKD2 gene therapy delivered through AAV, which will be evaluated in patients with ADPKD with a PKD2 mutation and is anticipated to enter the clinic in 2027. EST-101is a gene therapy delivering a PC1-derived functional region via the same AAV as EST-201. EST-101 will be evaluated in patients with ADPKD with a PKD1 mutation and is anticipated to enter the clinic in 2028.

The $93 million Series A was led by RA Capital Management and included participation from Deep Track Capital, Biogen New Ventures, UPMC Enterprises, Pivotal bioVenture Partners, the National Kidney Foundation Innovation Fund and a family office connected to an individual living with autosomal dominant polycystic kidney disease. 4BIO Capital and GV, which co-led the company’s $10 million seed financing, also participated in the Series A.