YolTech Announces Interim Clinical Data from Investigator-Initiated Trials of YOLT-203 in Primary Hyperoxaluria Type 1 to be Presented at the American Society of Nephrology (ASN) Kidney Week 2026

Single administration of YOLT-203 demonstrated durable urinary oxalate reduction in pediatric and adult primary hyperoxaluria type 1 (PH1) patients

Up to 61.8% reduction in urinary oxalate was observed across dose cohorts in pediatric and adult PH1 patients after one year of follow-up

Kidney function remained stable through one year of follow-up

SHANGHAI – October 22, 2026 - YolTech Therapeutics, a late clinical-stage biotechnology company pioneering next generation in vivo gene-editing therapies, today announced positive interim efficacy data from two ongoing investigator-initiated trials (IIT) evaluating YOLT-203 in patients with primary hyperoxaluria type 1 (PH1). These data will be presented as a poster presentation at the American Society of Nephrology (ASN) Kidney Week 2026, taking place October 21-25, 2026, in Denver, Colorado, USA.

YOLT-203 is being evaluated in two ongoing open-label, single-dose escalation IITs designed to assess safety, tolerability, pharmacodynamics, and efficacy in patients with genetically confirmed PH1. The primary efficacy endpoint is change in 24-hour urinary oxalate excretion (24h-UOx), with the percent change in the 24-hour urinary oxalate: creatinine ratio (24h-UOx:UCr) and change in estimated glomerular filtration rate (eGFR) also being evaluated.

Interim data from the two ongoing IITs (NCT06511349; NCT06892301) include 11 treated patients, comprising both pediatric and adult participants ranging from 2 to 59 years of age. As of November 2025, 11 participants had received a single dose of YOLT-203, including two patients in the 0.3 mg/kg cohort, eight patients in the 0.45 mg/kg cohort, and one patient in the 35 mg fixed-dose cohort. All participants completed at least 24 weeks of follow-up and five patients completed 52 weeks of follow-up. Across all dose cohorts, YOLT-203 demonstrated durable reduction in urinary oxalate excretion through up to 52 weeks of follow-up while maintaining stable kidney function.

Key Data from the Evaluable Patient Population Include:

·        A single administration of YOLT-203 demonstrated durable reduction in urinary oxalate excretion of up to 61.8% at one year of follow-up across pediatric and adult patients, while kidney function remained stable throughout the follow-up period.

·        At Week 24, mean reductions in 24h-UOx from baseline reached 31.1%, 53.0% and 59.0% in the 0.3 mg/kg, 0.45 mg/kg, and 35 mg dose cohorts, respectively. 

·        Reduction in the 24h-UOx:UCr were consistent with 24h-UOx, reaching 52.6% and 56.6% at Week 24 in the 0.45 mg/kg and 35 mg cohorts, respectively. 

·        Durable reduction in 24h-UOx:UCr were maintained through Week 52, with decreases of 37.7% and 58.9% in the 0.3 mg/kg and 0.45 mg/kg cohorts, respectively.

·        Among patients with one year of follow-up, reduction in 24-UOx was maintained at 42.9% in the 0.3 mg/kg cohort and 61.8% in the 0.45 mg/kg cohort at Week 52.

·        Kidney function remained stable throughout follow-up, with mean eGFR changes of +2.2 mL/min/1.73m2 at Week 24 and -0.1 mL/min/1.73m2 at Week 52 versus baseline.

“Primary hyperoxaluria type 1 is a devastating genetic disease that can lead to lifelong kidney complications,” said Yuxuan Wu, Ph.D., Co-Founder and Chief Executive Officer of YolTech Therapeutics. “These data provide encouraging evidence that support the potential of YOLT-203 as a one-time gene editing therapy for PH1, which attacks the disease at its source. The durability we are seeing at one year from a single dose is meaningful, as it speaks directly to the promise of our in vivo gene editing platform and reinforces our conviction that YOLT-203 has the potential to fundamentally change how PH1 is treated.”

"These early data have begun to show that a one-time intervention can produce sustained, clinically meaningful changes in the underlying biology driving PH1,” said Matthew Breeggemann, MD, Director of UCSF's Kidney Stone Prevention Clinic. “For a disease where current management is largely focused on symptom control and dialysis or transplantation in advanced cases, YOLT-203 could represent a completely new type of treatment we might be able to offer patients someday soon."

Presentation Details:

Title: YOLT-203, an In Vivo Gene-Editing Therapy for Primary Hyperoxaluria Type 1: Interim Efficacy Results from Two Investigator-Initiated Trials

Session: Integrative Genomics and Multi-Omics in Noncystic Genetic Kidney Disease

Abstract: TH-PO0143

Presentation Time: October 22, 2026, 10:00 am to 12:00 pm MDT

Location: Exhibit Hall A, Convention Center
Author: Matthew Clarence Breeggemann, MD, Director of UCSF's Kidney Stone Prevention Clinic

The abstract is available on the ASN Kidney Week 2026 website here.

About YOLT-203

YOLT-203 is a clinical-stage in vivo gene-editing therapy designed as a durable one-time treatment for primary hyperoxaluria type 1 (PH1). The therapy uses YolTech’s proprietary YolCas12HF CRISPR/Cas system and lipid nanoparticle (LNP) delivery to inactivate the HAO1 gene in hepatocytes, reducing glycolate oxidase activity and downstream oxalate production. YOLT-203 is currently being evaluated in two investigator-initiated trials (NCT06511349; NCT06892301) and has received RMAT, Orphan Drug, and Rare Pediatric Disease designations from the U.S. Food and Drug Administration, as well as Orphan Drug Designation from the European Medicines Agency.

About Primary Hyperoxaluria Type 1

Primary hyperoxaluria type 1 (PH1) is the most common and severe form of primary hyperoxaluria, a rare autosomal recessive disorder caused by mutations in the AGXT gene. These mutations impair hepatic glyoxylate metabolism, resulting in excessive oxalate production and the formation of calcium oxalate crystals that can cause recurrent kidney stones, nephrocalcinosis, and progressive kidney damage. As kidney function declines, oxalate may accumulate in other organs and potentially require intensive dialysis and organ transplantation.

About YolTech Therapeutics

YolTech Therapeutics is a clinical-stage biotechnology company, pioneering next-generation in vivo gene editing therapies for patients with serious genetic, cardiometabolic, and autoimmune diseases. The company has built a fully integrated platform that combines HEPDONE™, its proprietary gene editing technologies, with AI-enabled discovery capabilities and targeted lipid nanoparticle (LNP) delivery systems designed to enable precise, one-time treatments with the potential for lifelong benefits. YolTech is advancing a broad portfolio of wholly owned and partnered programs spanning rare genetic diseases, cardiovascular and metabolic disorders, and autoimmune diseases, with multiple assets in clinical development. Founded on the vision of redefining genetic medicine through precision in vivo editing, YolTech is committed to developing transformative therapies that address the underlying cause of disease and improve outcomes for patients worldwide. For more information, visit www.yoltx.com.

Contacts:

Investor Contact:

Matthew Ventimiglia, FTI, yoltech@fticonsulting.com

Media Contact:

Tony Plohoros, 6 Degrees, tplohoros@6degreespr.com