uniQure and CSL Behring Announce Primary Endpoint Achieved in HOPE-B Pivotal Trial of Etranacogene Dezaparvovec Gene Therapy in Patients with Hemophilia B ~ Largest gene therapy study in hemophilia B achieved primary end

uniQure and CSL Behring Announce

Primary Endpoint Achieved in HOPE-B Pivotal Trial of Etranacogene Dezaparvovec Gene Therapy in Patients with Hemophilia B

~ Largest gene therapy study in hemophilia

B achieved primary endpoint of non-inferiority in annualized bleeding rate after stable Factor IX (FIX) expression, assessed at 18 months

following a single dose of etranacogene dezaparvovec ~

dezaparvovec also achieved secondary endpoint demonstrating statistical superiority in reduction of annualized bleeding rate

compared to baseline FIX prophylactic therapy ~

~ Stable and durable FIX levels with

mean FIX activity of 36.9 percent of normal in full study population at 18-months, compared to a mean of 39.0 percent of normal at 6 months

~ Manufacturing operations supporting

process validation of etranacogene dezaparvovec successfully completed by uniQure ~

Lexington, MA and Amsterdam, the Netherlands,

King of Prussia, PA , December 9, 2021 - CSL Behring, a global biotherapeutics leader, and uniQure

N.V. (NASDAQ: QURE), a leading gene therapy company advancing transformative therapies for patients with severe medical needs,

today announced that etranacogene dezaparvovec, an investigational adeno-associated virus five

(AAV5)-based gene therapy for the treatment of patients with severe to moderately severe hemophilia B, achieved the pre-specified primary

endpoint of non-inferiority in annualized bleeding rate (ABR) 18-months following administration compared to baseline Factor IX (FIX)

prophylactic therapy in the pivotal Phase III HOPE-B gene therapy trial. The study also successfully achieved a secondary endpoint demonstrating

statistical superiority in reduction of ABR compared to baseline FIX prophylactic therapy.

The primary endpoint in the pivotal study

was 52-week ABR after achievement of stable FIX expression compared with the six-month lead-in period, considering all bleeds regardless

of investigator adjudication as true bleeds. For this endpoint, ABR was measured from month seven to month 18 after infusion, ensuring

the observation period represented likely steady-state FIX transgene expression. Secondary endpoints included assessment of FIX activity

and statistical superiority of ABR after dosing.

"We are very pleased with these

top-line results from what is the largest and first pivotal trial of a gene therapy for patients with hemophilia B," stated Ricardo

Dolmetsch, Ph.D., president of research and development at uniQure. "The HOPE-B data not only achieved the pre-specified

primary endpoint of non-inferiority in annualized bleeding rate following 12 months or more of stable FIX expression, but also the secondary

endpoint of superiority in reduction of annualized bleeding, while continuing to demonstrate durability and stability in FIX levels and

other benefits to this point in the study."

"On behalf of uniQure, we extend

our heartfelt gratitude to all the HOPE-B clinical trial patients and their families, as well as the trial investigators," he continued.

"We now look forward to collaborating with CSL Behring on completing the regulatory submissions that we hope will advance etranacogene

dezaparvovec one step closer to reaching hemophilia B patients around the world."

uniQure led the multi-year clinical development

of etranacogene dezaparvovec prior to entering into a Commercialization and License Agreement with CSL Behring in June 2020 for exclusive

global rights to etranacogene dezaparvovec. Earlier this month, uniQure successfully completed manufacturing operations supporting process

validation of etranacogene dezaparvovec.

Etranacogene dezaparvovec has been granted Breakthrough

Therapy Designation by the United States Food and Drug Administration and access to Priority Medicine (PRIME) regulatory initiative by

the European Medicines Agency. CSL Behring plans to submit regulatory applications for marketing approval of etranacogene dezaparvovec

in the United States and European Union in the first half of 2022.

Top-line Data Results

A total of 54 patients received a single dose

of etranacogene dezaparvovec in the pivotal trial, with 53 patients completing at least 18 months of follow-up

ABR for all bleeds after stable FIX expression,

assessed at 18 months, was 1.51 compared with the ABR of 4.19 for the lead-in period of at least six months, achieving the primary non-inferiority

endpoint and a secondary superiority endpoint (p=0.0002) in the HOPE-B trial. ABR for investigator-adjudicated FIX-treated bleeds was

0.83 compared with lead-in ABR of 3.65 (p<0.0001).

Data from the HOPE-B pivotal trial showed that

patients continued to demonstrate durable, sustained increases in FIX activity at 18 months post-infusion with a mean FIX activity of

36.9 percent of normal as measured by a one-stage APTT-based clotting assay, compared to mean FIX activity of 39.0 percent of normal at

six months post-infusion.

Etranacogene dezaparvovec was generally well-tolerated

with over 80% of adverse events considered mild. One death resulting from urosepsis and cardiogenic shock in a 77-year-old patient at

65-weeks following dosing was considered unrelated to treatment by investigators and the company sponsor. A serious adverse event of hepatocellular

carcinoma (HCC) was identified in one patient. Independent molecular characterization and vector integration analysis of the HCC and adjacent

tissue supported the conclusion by the investigator and company sponsor that the HCC was unrelated to treatment with etranacogene dezaparvovec.

No inhibitors to FIX were reported.

"These encouraging results illustrate the

potential that gene therapy has to be a long-term treatment option for patients living with hemophilia B and we look forward to sharing

more detailed data with the medical community in the near future," stated Brahm Goldstein, MD, MCR, Vice President, Research and

Development, Hematology at CSL Behring. "This milestone advances our efforts towards expected regulatory submissions in first half

HOPE-B Pivotal Trial Design

The pivotal Phase III HOPE-B trial is a

multinational, open-label, single-arm study to evaluate the safety and efficacy of etranacogene dezaparvovec. Fifty-four adult

hemophilia B patients classified as severe or moderately severe (defined as less than or equal to 2% of normal FIX activity) and

requiring prophylactic FIX replacement therapy were enrolled in a prospective, six-month observational period during which time they

continued to use their current standard of care therapy to establish a baseline annualized bleeding rate. No prophylactic

immunosuppression was provided to patients upon entering the study. After the six-month lead-in period, patients received a single

intravenous administration of etranacogene dezaparvovec at the 2x10^13 gc/kg dose. Patients were not excluded from the trial based

on pre-existing neutralizing antibodies (NAbs) to AAV5. Forty-three percent of patients in the study had pre-existing NAbs to AAV5

up to a maximum observed pre-dosing titer of over 3,200.

uniQure is delivering on the promise

of gene therapy - single treatments with potentially curative results. We are leveraging our modular and validated technology platform

to rapidly advance a pipeline of proprietary gene therapies to treat patients with hemophilia

B, Huntington's disease, Fabry disease, spinocerebellar ataxia Type 3 temporal lobe epilepsy, Alzheimer's, Parkinson's and

ALS. www.uniQure.com

is a global biotherapeutics leader driven by our promise to save lives. Focused on serving patients' needs by using the latest

technologies, we discover, develop and deliver innovative therapies for people living with conditions in the immunology, hematology,

cardiovascular and metabolic, respiratory, and transplant therapeutic areas. We use three strategic scientific platforms of plasma fractionation,

recombinant protein technology, and cell and gene therapy to support continued innovation and continually refine ways in which products

can address unmet medical needs and help patients lead full lives.

CSL Behring operates one of the world's

largest plasma collection networks, CSL Plasma. Our parent company, CSL

Limited (ASX:CSL; USOTC:CSLLY), headquartered in Melbourne, Australia, employs more than 25,000 people, and delivers its lifesaving

therapies to people in more than 100 countries. For inspiring stories about the promise of biotechnology, visit CSLBehring.com/Vita

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

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

"will," "would" and similar expressions. Forward-looking statements are based on management's beliefs and assumptions

and on information available to management only as of the date of this press release. These forward-looking statements include, but are

not limited to, whether CSL Behring will submit a BLA for etranacogene dezaparvovec in the first half of 2022, whether etranacogene dezaparvovec

will reach hemophilia B patients around the world, and whether etranacogene dezaparvovec has the potential to provide well-tolerated,

long-term clinical benefits, and whether AAV5-based gene therapies can provide clinical benefit to patients with pre-existing neutralizing

antibodies. Our actual results could differ materially from those anticipated in these forward-looking statements for many reasons, including,

without limitation, risks associated with the impact of the ongoing COVID-19 pandemic on our Company and the wider economy and health

care system, our Commercialization and License Agreement with CSL Behring, our and our collaborators' clinical development activities,