ProQR Therapeutics N.V. Press Release

ProQR spins out Amylon Therapeutics as a privately-held company focused on central nervous system (CNS) therapeutics

LEIDEN, the Netherlands,

September 12 2017 ProQR Therapeutics N.V. (Nasdaq: PRQR), today announced that the company has spun out Amylon Therapeutics (Amylon), a privately-held company focused on the development of therapies for central nervous system (CNS)

disorders, with seed funding from a group of institutional and private investors. As part of the transaction, ProQR has granted an exclusive license to Amylon to develop therapeutics for beta amyloid related disorders. Amylon will use the license

and proceeds to continue research and development of therapies for CNS disorders, with an initial focus on a RNA-based treatment for a rare genetic disease that leads to strokes at mid-adulthood, called Hereditary Cerebral Hemorrhage with Amyloidosis of the Dutch type (HCHWA-D). A future beta amyloid related indication could include cerebral amyloid

angiopathy (CAA). ProQR retains majority ownership in Amylon and is entitled to future milestones and royalties from the products developed by Amylon on the terms and conditions set forth in the license.

Amylon will be led by Thomas de Vlaam as founding CEO, who holds a bachelor s degree in international medicine and global health. Thomas joined ProQR in

2015 to incubate the CNS activities, with the goal of spinning it out into a new company. On behalf of ProQR, Dinko Valerio, the Chairman of the Supervisory board of ProQR, will join the Supervisory board of Amylon and Gerard Platenburg, Chief

Innovation Officer of ProQR, will join the scientific advisory board of Amylon.

Since its inception in 2012, ProQR has invested significantly in

discovering and developing innovative RNA therapies for severe genetic rare diseases. This has led to an extensive pipeline of discovery development programs that are harbored in separate business units with dedicated teams of specialists focused on

cystic fibrosis, eye diseases, skin diseases and CNS diseases.

As part of our corporate strategy to bring as many of our programs to patients as

possible, we built ProQR as a group of focused business units that enable us to attract external funding directly into the individual development programs or ultimately spin programs out as we have now done with Amylon, said Daniel de Boer,

Chief Executive Officer of ProQR. Through spinning out Amylon, we position the beta amyloid program for optimal success with a dedicated team and the funding to develop treatments for patients suffering from these

devastating brain diseases. Through our involvement in the Supervisory board and scientific advisory board of Amylon we will continue to assist Thomas and his team in building success.

The unmet need of patients living with beta amyloid related disorders is very significant and to date no disease modifying treatments are

available, said Thomas Wisniewski, Director of the Alzheimer s Disease Research Center in New York. The technology that Amylon is developing for these patients is built on a solid scientific rationale and holds great promise for

The scientific advisory board at Amylon will consist of the following members:

ProQR Therapeutics is dedicated to

changing lives through the creation of transformative RNA medicines for the treatment of severe genetic rare diseases such as cystic fibrosis, Leber s congenital amaurosis 10 and dystrophic epidermolysis bullosa. Based on our unique

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

Amylon Therapeutics is a privately-owned

company targeting CNS disorders through an ultra genetics approach in which developing treatments for rare genetic disorders can serve as a possible gateway to global indications. It is using its technology for beta-amyloid related disorders to

initially target a rare disease called HCHWA-D, with potential expansion into more prevalent indications such as CAA and Alzheimer s disease. Amylon is led by a combination of ambitious entrepreneurs and

experienced biotech veterans. Amylon is a spin-off from NASDAQ listed ProQR Therapeutics.

Hereditary Cerebral Hemorrhage with Amyloidosis of the Dutch type

(HCHWA-D) is the genetic subtype of cerebral amyloid angiopathy (CAA), in which a point mutation leads to the accelerated onset of disease. The condition is characterized by a progressive loss of intellectual

function (dementia), stroke, and other neurological problems starting in mid-adulthood. Most affected individuals die within a decade after signs and symptoms first appear, and after onset the quality of life

diminishes quickly and severely. There is currently no intervention available nor in development to battle the cause and/or symptoms of HCHWA-D.

Cerebral amyloid angiopathy (CAA) is the

leading cause of hemorrhagic (bleeding) stroke in the elderly. The disease is caused by the aggregation and deposition of the toxic peptide Amyloid Beta in the blood vessels in the brain. These vascular amyloid deposits ultimately cause irreparable

damage to the vessel walls and lead to hemorrhagic stroke. There are currently no effective prevention or treatment strategies for CAA.

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, statements

regarding Amylon Therapeutics, our license with Amylon, including the future milestones and royalty terms contained therein, the product candidates of Amylon, including the clinical development and therapeutic potential thereof, and other programs

in our product candidate pipeline. Our actual results could differ materially from those anticipated in these forward-looking statements for many reasons, including, without limitation, risks associated with our ability to maintain our ownership

interest in Amylon and or license with Amylon, Amylon s ability to continue development of its product candidates and obtain additional funding for their advancement, clinical development activities, including that positive results observed in

prior and ongoing studies may not be replicated in later trials or guarantee approval of any product candidate by regulatory authorities, manufacturing processes and facilities, regulatory oversight, product commercialization, intellectual property

claims, and the risks, uncertainties and other factors in our filings made with the Securities and Exchange Commission, including certain sections of our annual report filed on Form 20-F. Given these risks,

uncertainties and other factors, you should not place undue reliance on these forward-looking statements, and we assume no obligation to update these forward-looking statements, even if new information becomes available in the future, except as

ProQR Therapeutics N.V.:

T: +31 6 2970 4513 (NL)

T: + 1 213 261 8891 (US)