ProQR Announces Encouraging AX-0810 Phase 1 Safety and PK Data, Development Candidate Selections, and 2026 Outlook Initial AX-0810 data show no safety signals after 4 weeks of dosing and pharmacokinetics consistent with

ProQR Announces Encouraging AX-0810 Phase 1 Safety

and PK Data, Development Candidate Selections, and 2026 Outlook

LEIDEN, Netherlands & CAMBRIDGE, Mass., January 8,

2026 - ProQR Therapeutics N.V. (Nasdaq: PRQR) (ProQR), a clinical-stage company dedicated to changing lives through transformative

RNA therapies based on its proprietary Axiomer RNA editing technology platform, today announced encouraging initial safety and

PK data from the first cohort of healthy volunteers in its ongoing Phase 1 trial of AX-0810 and provided an update on broader pipeline

progress and anticipated 2026 milestones.

"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."

Daniel A. de Boer, Founder and Chief Executive Officer

of ProQR added, "In parallel to our work on AX-0810, we have delivered important pipeline progress in 2025, including the selection

of Development Candidates for AX-2402 in Rett syndrome and AX-2911 in MASH. Together with continued momentum from our strategic collaboration

with Lilly, which achieved $4.5 million in milestones in 2025, 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 and create long-term value for both patients and shareholders."

AX-0810 Phase 1 study - Early safety and

PK support continued dosing with target engagement readout on track for first half of 2026

AX-0810 is ProQR's lead investigational editing

oligonucleotide (EON) targeting NTCP, which is being developed for the treatment of cholestatic diseases, such as primary sclerosing

cholangitis and biliary atresia.

design overview: The ongoing Phase 1 study of AX-0810 is a single-center, randomized, double-blind, placebo-controlled, multiple

dose escalation study being conducted in healthy volunteers in the Netherlands. Up to 33 participants will be enrolled, including 24

receiving AX-0810 and 9 receiving placebo, across 3 dose cohorts. Participants receive 4 subcutaneous injections over 4 weeks followed

by a 12-week safety follow-up period. A Data Monitoring Committee reviews safety data prior to each dose escalation. The objectives of

the study are to evaluate the safety, tolerability and pharmacokinetics (PK) of AX-0810 and to confirm target engagement as measured

by biomarkers (EUCT number: 2025-521876-77-00).

safety and PK of AX-0810: Based on initial 4-week safety and PK data from participants dosed in Cohort 1 (3mg/kg), AX-0810

demonstrated a safety profile with no serious adverse events or clinically meaningful laboratory abnormalities observed to date. Preliminary

pharmacokinetic observations are in line with non-clinical data, supporting continued dosing per the study design.

milestone for AX-0810: ProQR remains on track to report target engagement data for healthy volunteer cohorts in the first

half of 2026. In parallel, activities are underway to include a patient cohort in this Phase 1 first-in-human trial following the healthy

Development Candidates selected for AX-2402 and

In addition to AX-0810, ProQR continues to advance

earlier-stage pipeline programs from its Axiomer RNA editing platform, with Development Candidates selected for pipeline programs AX-2402

AX-2402 for Rett Syndrome

is the Company's development program targeting MECP2 for Rett syndrome (R270X). ProQR selected a Development Candidate for

AX-2402 based on a robust preclinical profile supporting advancement to development activities, with the objective of initiating

a first-in-human clinical trial in the first half of 2027.

also announced non-clinical proof-of-concept data generated in a mouse model of Rett syndrome with the MECP2 R270X mutation. Treatment

with AX-2402 resulted in statistically significant and clinically relevant functional improvements. These effects included improvement

in cumulative Bird score, driven in part by robust improvements in hindlimb clasping score. Further details and analyses will be presented

at a later date. AX-2402 is supported by funding of up to $9.2M from the Rett Syndrome Research Trust (RSRT).

is the Company's development program targeting the PNPLA3 I148M mutation, a key genetic driver for metabolic liver disease,

including metabolic-associated steatohepatitis (MASH). Approximately 8 million individuals in the United States and European Union

are homozygous for the 148M variant. ProQR selected a Development Candidate for AX-2911 based on a robust preclinical proof-of-concept

profile demonstrating on-target RNA editing, favorable potency, and supportive in vitro and in vivo functional data.

ProQR also announced new non-clinical functional proof-of-concept

data for AX-2911, showing >80% reduction in hepatic fat content in a humanized PNPLA3-148M mouse model fed a Western diet,

outperforming a clinical-stage PNPLA3-directed antisense therapy that achieved an approximately 36% reduction in a head to head

comparison in vivo. These results support AX-2911 as a differentiated, disease-modifying approach for MASH. Additional details and analyses

will be presented at a later date.

Strategic Collaboration Progress

ProQR's collaboration with Eli Lilly and Company

(Lilly) continued to progress in 2025, resulting in $4.5 million in milestones achieved during the year. The collaboration reflects

external validation of ProQR's Axiomer RNA editing platform and provides non-dilutive capital.

Corporate Outlook for 2026

AX-0810 is a first-in-class investigational RNA editing

oligonucleotide (EON) that harnesses the body's endogenous ADAR enzymes to selectively modulate NTCP function. Through this novel

mechanism, AX-0810 aims to reduce toxic bile acid accumulation in the liver and improve outcomes in cholestatic diseases, which are characterized

by inflammation, fibrosis, and progressive liver failure. By targeting a key pathogenic process that drives disease progression, AX-0810

has the potential to be disease-modifying. AX-0810 is the first program from ProQR's Axiomer RNA editing pipeline to enter

clinical development and is being evaluated in a Phase 1 trial in healthy volunteers focused on safety, pharmacokinetics, and biomarkers

of target engagement to inform future studies in patients.

ProQR is pioneering a next-generation RNA base editing technology

called Axiomer , which could potentially yield a new class of medicines for diverse types of diseases. Axiomer

"Editing Oligonucleotides", or EONs, mediate single nucleotide changes to RNA in a highly specific and targeted way using

molecular machinery that is present in human cells called ADAR (Adenosine Deaminase Acting on RNA). Axiomer EONs are

designed to recruit and direct endogenously expressed ADARs to change an Adenosine (A) to an Inosine (I) in the RNA -

an Inosine is translated as a Guanosine (G) - correcting an RNA with a disease-causing mutation back to a normal (wild type)

RNA, modulating protein expression, or altering a protein so that it will have a new function that helps prevent or treat disease.

ProQR Therapeutics is dedicated to changing lives through the creation

of transformative RNA therapies. ProQR is pioneering a next-generation RNA technology called Axiomer , which uses a

cell's own editing machinery called ADAR to make specific single nucleotide edits in RNA to reverse a mutation or modulate protein

expression and could potentially yield a new class of medicines for both rare and prevalent diseases with unmet need. Based on our unique

proprietary RNA repair platform technologies we are growing our pipeline with patients and loved ones in mind.

about ProQR at www.proqr.com.

Forward Looking Statements

This press release contains forward-looking statements. All statements

other than statements of historical fact are forward-looking statements, which are often indicated by terms such as "continue,"

"anticipate," "believe," "could," "estimate," "expect," "goal," "intend,"

"look forward to", "may," "plan," "potential," "predict," "project," "should,"

"will," "would" and similar expressions. Such forward-looking statements include, but are not limited to, statements

regarding our business, technology, strategy, preclinical and clinical model data, our initial pipeline targets and the upcoming strategic

priorities and milestones related thereto, the continued advancement of our lead development pipeline programs, including ongoing and

planned clinical trials, expectations regarding regulatory feedback and the potential registrational pathway for AX-0810 in NTCP for

cholestatic diseases, the preliminary clinical data from the first cohort of the initial phase 1 study, the anticipated timing of target

engagement data for our Phase 1 clinical trial for our lead program, AX-0810, in H1 2026, and clinical updates across multiple programs

in 2026, our Axiomer platform, including the continued development and advancement of our Axiomer platform, the therapeutic

potential of our Axiomer RNA editing oligonucleotides and product candidates, the timing, progress and results of our preclinical studies

and other development activities, including the release of data related thereto, our patent estate, including our anticipated strength

and our continued investment in it, as well as the timing of our clinical development, the potential of our technologies and product

candidates, the collaboration with Lilly and the intended benefits thereof, including timing for data updates, potential milestones,

exercise of an option to expand targets and the receipt of an opt-in payment, our ability to selectively form new partnerships and enter

into future collaborations, and our financial position and cash-runway. Forward-looking statements are based on management's beliefs

and assumptions and on (preliminary) information available to management only as of the date of this press release. Our actual results

could differ materially from those expressed or implied by these forward-looking statements for many reasons, including, without limitation,

the risks, uncertainties and other factors in our filings made with the Securities and Exchange Commission, including certain sections