ProQR's RNA Editing Platform Shows Clinical Promise and Pipeline Depth

LEIDEN, Netherlands & CAMBRIDGE, Mass. – January 08, 2026 – ProQR Therapeutics has unveiled a trio of significant advancements, bolstering its position in the competitive field of RNA therapies. The company announced encouraging initial safety and pharmacokinetic data from the first human trial of its lead candidate, AX-0810, and revealed the selection of two new development candidates for Rett syndrome and metabolic liver disease, underscoring the versatility of its proprietary Axiomer™ RNA editing platform.

These developments, combined with substantial milestone payments from a strategic collaboration with Eli Lilly, paint a picture of a company executing on a multi-pronged strategy to translate its novel science into tangible clinical progress. The initial human data provides the first clinical validation for ProQR's unique approach, which uses the body's own machinery to edit RNA and treat disease.

“The initial human data from AX-0810 mark an important early milestone for ProQR, providing safety and pharmacokinetic observations in healthy volunteers,” said Cristina Lopez Lopez, MD, PhD, Chief Medical Officer of ProQR. “These data support continued dosing and position us well for the upcoming target engagement readout in the first half of 2026.”

A Crucial First Step into the Clinic

At the forefront of ProQR's progress is AX-0810, a first-in-class investigational therapy for cholestatic diseases such as primary sclerosing cholangitis (PSC) and biliary atresia. These conditions are characterized by the toxic accumulation of bile acids in the liver, leading to inflammation, fibrosis, and eventual liver failure. AX-0810 is an “Editing Oligonucleotide” (EON) designed to harness the body’s endogenous ADAR enzymes to edit the RNA that codes for NTCP, a key protein responsible for transporting bile acids into liver cells. By modulating NTCP function, the therapy aims to reduce this toxic buildup and modify the course of the disease.

The ongoing Phase 1 study (EUCT number: 2025-521876-77-00) is a randomized, double-blind, placebo-controlled trial in healthy volunteers in the Netherlands. The initial data from the first cohort, who received four subcutaneous injections of AX-0810 at a 3mg/kg dose over four weeks, showed no serious adverse events or clinically meaningful laboratory abnormalities. Furthermore, the drug's behavior in the body, its pharmacokinetics, was in line with predictions from extensive non-clinical studies.

With this positive safety profile, ProQR is cleared to continue dosing and dose escalation. The next major catalyst for the program will be target engagement data, expected in the first half of 2026. This readout will be critical, as it will measure key biomarkers—such as serum bile acid levels—to confirm that AX-0810 is having its intended biological effect in humans. Success here would provide strong proof-of-concept for the Axiomer platform and pave the way for initiating a cohort of patients with cholestatic disease within the same Phase 1 trial.

The Power of a Versatile Platform

Beyond its lead program, ProQR demonstrated the broad potential of its Axiomer platform by selecting two new development candidates, each targeting distinct and challenging diseases with high unmet needs.

First is AX-2402 for Rett syndrome, a severe neurodevelopmental disorder. This candidate targets a specific mutation, MECP2 R270X, aiming to correct the faulty RNA and restore protein function. In preclinical studies using a mouse model of the disease, treatment with AX-2402 led to statistically significant and clinically relevant functional improvements, including a better cumulative Bird score, a key measure of disease severity in these models. The program's promise is further validated by up to $9.2 million in funding from the Rett Syndrome Research Trust (RSRT), signaling strong external confidence. ProQR aims to advance AX-2402 into a first-in-human trial in the first half of 2027.

Second, the company selected AX-2911 for metabolic-associated steatohepatitis (MASH), a prevalent and progressive form of fatty liver disease. This candidate targets the PNPLA3 I148M gene variant, a major genetic driver of MASH that is present in millions of individuals in the US and EU. In a humanized mouse model, AX-2911 demonstrated a greater than 80% reduction in hepatic fat content. In a head-to-head comparison within the study, this result significantly outperformed a clinical-stage antisense therapy, which achieved an approximately 36% reduction. This suggests AX-2911 could be a highly differentiated and potent disease-modifying approach in the crowded and competitive MASH landscape.

Daniel A. de Boer, Founder and Chief Executive Officer of ProQR, commented on the broader progress: “These advances underscore the strength and versatility of our Axiomer platform. As we enter 2026, we remain focused on executing on our priorities and advancing innovative RNA editing therapies on our Axiomer platform to address high unmet-need patient populations.”

Strategic Partnerships and Financial Stability

Underpinning this ambitious research and development effort is a robust financial and strategic foundation. ProQR's collaboration with pharmaceutical giant Eli Lilly and Company continued to bear fruit in 2025, yielding $4.5 million in milestone payments. This partnership not only provides crucial non-dilutive capital but also serves as a powerful external endorsement of the Axiomer platform's potential.

The influx of capital from the Lilly collaboration, combined with disciplined financial management, has fortified ProQR's balance sheet. The company reports a cash runway extending into mid-2027, a strong position that allows it to confidently pursue its clinical and preclinical milestones without immediate financial pressures.

This strategic approach—leveraging a core proprietary technology platform to build an internal pipeline while simultaneously securing high-value partnerships—is a well-regarded blueprint for success in the capital-intensive biotechnology industry. The company's 2026 outlook includes continued execution on the Lilly partnership, which could bring further data updates and milestone income, alongside evaluating new potential partnerships to maximize the value of its platform.

With its lead program now validated in early human studies, a pipeline expanding into new, high-value indications, and a secure financial footing, ProQR has set the stage for a transformative period. The upcoming target engagement data for AX-0810 will be a closely watched event, serving as the next major test for a technology that aims to create a new class of medicines. The successful execution of its 2026 goals could significantly de-risk the Axiomer platform and accelerate its journey toward addressing diseases that currently have few, if any, effective treatments.