The capital will fund clinical proof-of-concept testing for the biotechnology company’s lead gene therapy candidates, EST-101 and EST-201, whilst advancing its platform for direct kidney delivery.
The total comprises a $93m Series A round led by RA Capital Management, alongside Biogen New Ventures, Deep Track Capital, the National Kidney Foundation Innovation Fund, Pivotal bioVenture Partners, UPMC Enterprises, and a family office linked to an autosomal dominant polycystic kidney disease (ADPKD) patient.
Estuary previously completed a $10m seed financing co-led by 4BIO Capital and GV, both of which also took part in the Series A financing.
ADPKD is an inherited, progressive disorder where fluid-filled cysts expand in both kidneys, displacing healthy tissue over time and causing organ failure that requires dialysis or transplantation.
Rather than targeting downstream biological pathways, Estuary seeks to treat the underlying genetic defect.
The company uses a locally administered adeno-associated virus (AAV) to transduce epithelial cells and restore polycystin levels across the nephron, aiming to avoid safety and delivery issues linked to systemic AAV administration.
Estuary co-founder and CEO Wayne Sackett said: “ADPKD is one of the world’s most common genetic diseases, yet patients are still awaiting a therapy that can transform the course of their disease.
“We paired our scientific co-founders’ landmark breakthroughs in disease biology with a dedicated and passionate team focused on solving the most crucial remaining barrier to kidney gene therapy: delivery.
“By pioneering fit-for-purpose local administration and an efficient global development strategy, our team is moving with urgency to bring these important medicines into the clinic.”
EST-101, an AAV-delivered therapy targeting the PC1 functional region in ADPKD patients with PKD1 mutations, is projected to enter clinical testing in 2028.
EST-201, a full-length PKD2 gene therapy delivered via AAV for individuals with PKD2 mutations, is scheduled to enter the clinic in 2027.