# EDGAR Filing Document

**Accession Number:** 0001612940
**File Stem:** 0001104659-25-080447
**Filing Date:** 2025-8
**Character Count:** 37298
**Document Hash:** e95e48b3da6614d6e98eb6092183d6d6
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001104659-25-080447.hdr.sgml**: 20250820

**ACCESSION NUMBER**: 0001104659-25-080447

**CONFORMED SUBMISSION TYPE**: SCHEDULE 13D/A

**PUBLIC DOCUMENT COUNT**: 4

**FILED AS OF DATE**: 20250820

**DATE AS OF CHANGE**: 20250820

**SUBJECT COMPANY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** ProQR Therapeutics N.V.
- **CENTRAL INDEX KEY:** 0001612940
- **STANDARD INDUSTRIAL CLASSIFICATION:** PHARMACEUTICAL PREPARATIONS [2834]
- **ORGANIZATION NAME:** 03 Life Sciences
- **EIN:** 000000000
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** SCHEDULE 13D/A
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 005-88671
- **FILM NUMBER:** 251233724

**BUSINESS ADDRESS:**
- **STREET 1:** ZERNIKEDREEF 9
- **CITY:** LEIDEN
- **STATE:** P7
- **ZIP:** 2333 CK
- **BUSINESS PHONE:** 31 88 166 7000

**MAIL ADDRESS:**
- **STREET 1:** ZERNIKEDREEF 9
- **CITY:** LEIDEN
- **STATE:** P7
- **ZIP:** 2333 CK

**FORMER COMPANY:**
- **FORMER CONFORMED NAME:** ProQR Therapeutics B.V.
- **DATE OF NAME CHANGE:** 20140708
**FILED BY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** VAN HERK INVESTMENTS B.V.
- **CENTRAL INDEX KEY:** 0001633120

**ORGANIZATION NAME:**
- **EIN:** 000000000
- **STATE OF INCORPORATION:** P7
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** SCHEDULE 13D/A

**BUSINESS ADDRESS:**
- **STREET 1:** LICHTENAUERLAAN 30
- **CITY:** ROTTERDAM
- **STATE:** P7
- **ZIP:** 3062ME
- **BUSINESS PHONE:** 0031102411555

**MAIL ADDRESS:**
- **STREET 1:** LICHTENAUERLAAN 30
- **CITY:** ROTTERDAM
- **STATE:** P7
- **ZIP:** 3062ME

## Exhibit 99.1

**Exhibit 99.1**

![](tm2523856d2_ex99-1img01.jpg)

---

| | |
|:---|:---|
| **By email** | Jan Willem de Groot |
| ProQR Therapeutics N.V. | Advocaat \| Partner |
| Attn. the Board | T +31 20 605 6962 |
| Zernikedreef 9 | M +31 6 1851 6628 |
| 2333CK LEIDEN | E j.w.de.groot@houthoff.com |
| THE NETHERLANDS | Postbus 75505 1070 AM Amsterdam |
|  | Gustav Mahlerplein 50 1082 MA Amsterdam |

---

Amsterdam, August 19, 2025 <br> Our ref: 3076380002/38683939.5

Dear members of the Board,

We write to you on behalf of Van Herk Investments B.V. ("**VHI**"), a shareholdwer of ProQR Therapeutics N.V. (the "**Company**") representing a shareholding of 11.6% in the Company. This letter serves as a follow-up to the letter sent by VHI to the board of the Company (the "**Board**") on 23 May 2025 (the "**Letter**").

In the Letter, which was delivered in advance of the annual general meeting of the Company (the "**AGM**") held on 3 June 2025, VHI formally expressed its serious concerns regarding, among other things, the proposed reappointments of Mr. James Shannon ("**Shannon**") and Mr. Daniel de Boer ("**De Boer**") and urged the Board to both adhere to the Company's own governance framework and to withdraw the relevant agenda items. VHI believed that it was not the only large shareholder to voice its concerns that the Board proposed the reappointment of Shannon in lieu of compliance with its own governance rules. At the time, VHI had hoped that such clear shareholder feedback would have compelled the Board to take actions consistent with proper corporate governance and address these concerns.

During the AGM, VHI again raised its concerns regarding the reappointments and requested clarification as to the rationale behind the proposed reappointments, particularly considering the Company's ongoing underperformance and clear failure to comply with the Dutch Corporate Governance Code ("**CGC**") and the Company's Board Rules ("**Board Rules**").

Unfortunately, the concerns expressed by shareholders during the AGM were not meaningfully addressed by the Board in advance of the AGM, and the Board has since reverted back to its status quo by failing to offer any meaningful justification for the decisions taken. This lack of engagement leads VHI to believe the Board remains unwilling to adhere to its own governance framework or to engage constructively with its shareholders regarding their well-founded concerns in a way that results in necessary change.

Houthoff is de handelsnaam van Houthoff Coöperatief U.A., statutair gevestigd te Amsterdam (KvK Amsterdam nr. 34216182). De algemene voorwaarden van Houthoff, waarin een beperking van aansprakelijkheid, de toepasselijkheid van Nederlands recht en de exclusieve bevoegdheid van de rechtbank te Amsterdam zijn bedongen, zijn op alle opdrachten van toepassing. De algemene voorwaarden worden op verzoek toegezonden, maar zijn eveneens te vinden op www.houthoff.com

Houthoff is the trade name of Houthoff Coöperatief U.A. with registered office in Amsterdam (Chamber of Commerce Amsterdam no. 34216182). Houthoff's general terms and conditions, which stipulate a limitation of liability, the applicability of Dutch law and the exclusive jurisdiction of the District Court of Amsterdam, the Netherlands, are applicable to all services performed. A copy of the general terms and conditions is available on request or at www.houthoff.com

![](tm2523856d2_ex99-1img01.jpg)

In the view of VHI, the following issues constitute well-founded reasons to doubt the soundness of the Company's governance and policies as driven by the Board:

The reappointment of Shannon contradicts the explicit assurance given at the 2024 AGM that his term would not be extended beyond 2026. The reappointment not only undermines the credibility of the Board's communications with shareholders but also raises questions about the Board's integrity and accountability.

Shannon's reappointment extends his cumulative tenure to thirteen years, in direct contravention of the Board Rules and the CGC, which limit such terms to ten years. The Board has failed to provide specific and sufficient justification for exceeding a cumulative term of eight years, as required by the CGC.

Several non-executive directors have served since 2012–2014, and the Company has failed to present any credible plan for leadership transition or Board rotation. The longstanding composition can fairly be believed to have contributed to a lack of renewal in governance practices and insufficient oversight, which in turn has contributed to the Company's underperformance.

Since its IPO, the Company has undergone three major strategic reorientations, none of which has delivered the results promised by the Board and Company management. The Company's public record makes clear that key partnerships have stagnated, business development deals have not materialized, and clinical progress remains slow.

- Despite this dismal track record, the same leadership remains in place. The Board's inaction in addressing these issues demonstrates an unwillingness to critically assess its own performance or to take corrective action.

Further, despite the lacking performance, the Board has continued to award maximum short and long term incentive bonuses to senior management. VHI sees no credible basis for such awards under the current compensation scheme, given the disappointing short and long-term development of the Company and the lack of individual performance by the Executive Directors that would justify such bonuses. This raises serious concerns about the effectiveness and independence of the compensation committee, particularly given that it is chaired by a dependent Board member.

These issues, taken together, reflect a pattern of ineffectual and non-compliant governance.

VHI therefore calls on the Board to immediately take the following steps, in order to restore stakeholder confidence in its governance practices and to avoid further (legal) action:

- The Board publicly announces that Shannon and De Boer will only serve their current terms until the 2026 AGM, at which point their potential reappointments will be considered in consultation with shareholders.

2/3

![](tm2523856d2_ex99-1img01.jpg)

The Board publicly provides a clear explanation of the rationale for the reappointment of De Boer, including how this reappointment aligns with the Company and its stakeholders' long-term interests. In this context, VHI is open to consider the possibility of an extension for De Boer beyond 2026, provided that his performance and adherence to governance expectations over the coming period give sufficient reason to do so.

- The Board publicly commits to presenting a structured and transparent plan for board rotation in advance of the 2026 AGM.

- The Board publicly commits to future compliance with the Board Rules, the CGC and the highest standards of Dutch and U.S. corporate governance generally.

Should the Board fail to take these steps, VHI reserves all rights to take further steps to protect its interests in the Company. For the avoidance of doubt, this letter serves as a letter of objection (*bezwarenbrief*) as prescribed by Article 2:349, section 1, of the Dutch Civil Code.

VHI reserves all rights.

![](tm2523856d2_ex99-1img02.jpg)

3/3

### UNITED STATES SECURITIES AND EXCHANGE COMMISSION
**Washington, D.C. 20549**

## SCHEDULE 13D

### Under the Securities Exchange Act of 1934

**(Amendment No. 1)**

**ProQR Therapeutics N.V.**

*(Name of Issuer)*

**Ordinary Shares, nominal value Euro 0.04 per share**

*(Title of Class of Securities)*

**N71542109**

*(CUSIP Number)*

**Van Herk Investments B.V.**<br>Lichtenauerlaan 30<br>Rotterdam P7 3062 ME<br>31-10-241-1555

*(Name, Address and Telephone Number of Person Authorized to Receive Notices and Communications)*

**08/19/2025**

*(Date of Event Which Requires Filing of this Statement)*

| **CUSIP No.** | **N71542109** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Van Herk Investments B.V.** | Name of reporting person<br>**Van Herk Investments B.V.** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**BK** | Source of funds (See Instructions)<br>**BK** | |
| 5 | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | |
| 6 | Citizenship or place of organization<br>**P7** | Citizenship or place of organization<br>**P7** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**12202190.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 8 | Shared Voting Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 9 | Sole Dispositive Power<br>**12202190.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 10 | Shared Dispositive Power<br>**0.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**12202190.00** | Aggregate amount beneficially owned by each reporting person<br>**12202190.00** | |
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | |
| 13 | Percent of class represented by amount in Row (11)<br>**11.6%** | Percent of class represented by amount in Row (11)<br>**11.6%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**CO** | Type of Reporting Person (See Instructions)<br>**CO** | |

---

**Comment for Reporting Person:** * Based on 105,344,052 ordinary shares, nominal value Euro 0.04 per share, of ProQR Therapeutics N.V. (the "Issuer") issued and outstanding as of June 30, 2025, as reported in the Issuer's Form 6-K filed with the SEC on August 7, 2025.

| **CUSIP No.** | **N71542109** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Van Herk Investments THI B.V.** | Name of reporting person<br>**Van Herk Investments THI B.V.** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**BK** | Source of funds (See Instructions)<br>**BK** | |
| 5 | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | |
| 6 | Citizenship or place of organization<br>**P7** | Citizenship or place of organization<br>**P7** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 8 | Shared Voting Power<br>**12202190.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 9 | Sole Dispositive Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 10 | Shared Dispositive Power<br>**12202190.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**12202190.00** | Aggregate amount beneficially owned by each reporting person<br>**12202190.00** | |
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | |
| 13 | Percent of class represented by amount in Row (11)<br>**11.6%** | Percent of class represented by amount in Row (11)<br>**11.6%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**CO** | Type of Reporting Person (See Instructions)<br>**CO** | |

---

**Comment for Reporting Person:** Based on 105,344,052 ordinary shares, nominal value Euro 0.04 per share, of the Issuer issued and outstanding as of June 30, 2025, as reported in the Issuer's Form 6-K filed with the SEC on August 7, 2025.

| **CUSIP No.** | **N71542109** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Van Herk Private Equity Investments B.V.** | Name of reporting person<br>**Van Herk Private Equity Investments B.V.** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**BK** | Source of funds (See Instructions)<br>**BK** | |
| 5 | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | |
| 6 | Citizenship or place of organization<br>**P7** | Citizenship or place of organization<br>**P7** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 8 | Shared Voting Power<br>**12202190.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 9 | Sole Dispositive Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 10 | Shared Dispositive Power<br>**12202190.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**12202190.00** | Aggregate amount beneficially owned by each reporting person<br>**12202190.00** | |
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | |
| 13 | Percent of class represented by amount in Row (11)<br>**11.6%** | Percent of class represented by amount in Row (11)<br>**11.6%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**CO** | Type of Reporting Person (See Instructions)<br>**CO** | |

---

**Comment for Reporting Person:** * Based on 105,344,052 ordinary shares, nominal value Euro 0.04 per share, of the Issuer issued and outstanding as of June 30, 2025, as reported in the Issuer's Form 6-K filed with the SEC on August 7, 2025

| **CUSIP No.** | **N71542109** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Stichting Administratiekantoor Penulata** | Name of reporting person<br>**Stichting Administratiekantoor Penulata** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**BK** | Source of funds (See Instructions)<br>**BK** | |
| 5 | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | |
| 6 | Citizenship or place of organization<br>**P7** | Citizenship or place of organization<br>**P7** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 8 | Shared Voting Power<br>**12202190.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 9 | Sole Dispositive Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 10 | Shared Dispositive Power<br>**12202190.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**12202190.00** | Aggregate amount beneficially owned by each reporting person<br>**12202190.00** | |
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | |
| 13 | Percent of class represented by amount in Row (11)<br>**11.6%** | Percent of class represented by amount in Row (11)<br>**11.6%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**OO** | Type of Reporting Person (See Instructions)<br>**OO** | |

---

**Comment for Reporting Person:** * Based on 105,344,052 ordinary shares, nominal value Euro 0.04 per share, of the Issuer issued and outstanding as of June 30, 2025, as reported in the Issuer's Form 6-K filed with the SEC on August 7, 2025.

| **CUSIP No.** | **N71542109** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Van Herk Management Services B.V.** | Name of reporting person<br>**Van Herk Management Services B.V.** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**BK** | Source of funds (See Instructions)<br>**BK** | |
| 5 | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | |
| 6 | Citizenship or place of organization<br>**P7** | Citizenship or place of organization<br>**P7** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 8 | Shared Voting Power<br>**12202190.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 9 | Sole Dispositive Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 10 | Shared Dispositive Power<br>**12202190.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**12202190.00** | Aggregate amount beneficially owned by each reporting person<br>**12202190.00** | |
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | |
| 13 | Percent of class represented by amount in Row (11)<br>**11.6%** | Percent of class represented by amount in Row (11)<br>**11.6%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**CO** | Type of Reporting Person (See Instructions)<br>**CO** | |

---

**Comment for Reporting Person:** * Based on 105,344,052 ordinary shares, nominal value Euro 0.04 per share, of the Issuer issued and outstanding as of June 30, 2025, as reported in the Issuer's Form 6-K filed with the SEC on August 7, 2025.

| **CUSIP No.** | **N71542109** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Onroerend Goed Beheer- en Beleggingsmaatschappij A. van Herk B.V.** | Name of reporting person<br>**Onroerend Goed Beheer- en Beleggingsmaatschappij A. van Herk B.V.** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**BK** | Source of funds (See Instructions)<br>**BK** | |
| 5 | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | |
| 6 | Citizenship or place of organization<br>**P7** | Citizenship or place of organization<br>**P7** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 8 | Shared Voting Power<br>**12202190.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 9 | Sole Dispositive Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 10 | Shared Dispositive Power<br>**12202190.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**12202190.00** | Aggregate amount beneficially owned by each reporting person<br>**12202190.00** | |
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | |
| 13 | Percent of class represented by amount in Row (11)<br>**11.6%** | Percent of class represented by amount in Row (11)<br>**11.6%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**CO** | Type of Reporting Person (See Instructions)<br>**CO** | |

---

**Comment for Reporting Person:** * Based on 105,344,052 ordinary shares, nominal value Euro 0.04 per share, of the Issuer issued and outstanding as of June 30, 2025, as reported in the Issuer's Form 6-K filed with the SEC on August 7, 2025.

| **CUSIP No.** | **N71542109** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**A. van Herk Holding B.V.** | Name of reporting person<br>**A. van Herk Holding B.V.** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**BK** | Source of funds (See Instructions)<br>**BK** | |
| 5 | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | |
| 6 | Citizenship or place of organization<br>**P7** | Citizenship or place of organization<br>**P7** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 8 | Shared Voting Power<br>**12202190.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 9 | Sole Dispositive Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 10 | Shared Dispositive Power<br>**12202190.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**12202190.00** | Aggregate amount beneficially owned by each reporting person<br>**12202190.00** | |
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | |
| 13 | Percent of class represented by amount in Row (11)<br>**11.6%** | Percent of class represented by amount in Row (11)<br>**11.6%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**CO** | Type of Reporting Person (See Instructions)<br>**CO** | |

---

**Comment for Reporting Person:** * Based on 105,344,052 ordinary shares, nominal value Euro 0.04 per share, of the Issuer issued and outstanding as of June 30, 2025, as reported in the Issuer's Form 6-K filed with the SEC on August 7, 2025.

| **CUSIP No.** | **N71542109** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Stichting Administratiekantoor Abchrys** | Name of reporting person<br>**Stichting Administratiekantoor Abchrys** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**BK** | Source of funds (See Instructions)<br>**BK** | |
| 5 | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | |
| 6 | Citizenship or place of organization<br>**P7** | Citizenship or place of organization<br>**P7** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 8 | Shared Voting Power<br>**12202190.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 9 | Sole Dispositive Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 10 | Shared Dispositive Power<br>**12202190.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**12202190.00** | Aggregate amount beneficially owned by each reporting person<br>**12202190.00** | |
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | |
| 13 | Percent of class represented by amount in Row (11)<br>**11.6%** | Percent of class represented by amount in Row (11)<br>**11.6%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**OO** | Type of Reporting Person (See Instructions)<br>**OO** | |

---

**Comment for Reporting Person:** * Based on 105,344,052 ordinary shares, nominal value Euro 0.04 per share, of the Issuer issued and outstanding as of June 30, 2025, as reported in the Issuer's Form 6-K filed with the SEC on August 7, 2025.

| **CUSIP No.** | **N71542109** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Adrianus van Herk** | Name of reporting person<br>**Adrianus van Herk** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[x] (a)<br>[ ] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**BK** | Source of funds (See Instructions)<br>**BK** | |
| 5 | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | Check if disclosure of legal proceedings is required pursuant to Items 2(d) or 2(e)<br>[ ] | |
| 6 | Citizenship or place of organization<br>**P7** | Citizenship or place of organization<br>**P7** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 8 | Shared Voting Power<br>**12202190.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 9 | Sole Dispositive Power<br>**0.00** |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 10 | Shared Dispositive Power<br>**12202190.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**12202190.00** | Aggregate amount beneficially owned by each reporting person<br>**12202190.00** | |
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[ ] | |
| 13 | Percent of class represented by amount in Row (11)<br>**11.6%** | Percent of class represented by amount in Row (11)<br>**11.6%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**IN** | Type of Reporting Person (See Instructions)<br>**IN** | |

---

**Comment for Reporting Person:** * Based on 105,344,052 ordinary shares, nominal value Euro 0.04 per share, of the Issuer issued and outstanding as of June 30, 2025, as reported in the Issuer's Form 6-K filed with the SEC on May 8, 2025.

**Item 1. Security and Issuer**

**(a) Title of Class of Securities:**
Ordinary Shares, nominal value Euro 0.04 per share

**(b) Name of Issuer:**
ProQR Therapeutics N.V.

**(c) Address of Issuer's Principal Executive Offices:**
Zernikedreef 9, Leiden, P7, 2333 CK

This Schedule 13D/A (this "Amendment") amends the Schedule 13D (the "Original Schedule 13D") filed on May 28, 2025. Items 1, 4, 5 and 7 of the Original Schedule 13D are hereby amended and supplemented to the extent hereinafter expressly set forth in this Amendment. Except as amended hereby, the original disclosure set forth in the Original Schedule 13D shall remain unchanged. All capitalized terms used and not expressly defined herein have the respective meanings ascribed to such terms in the Original Schedule 13D.

**Item 4. Purpose of Transaction**

Item 4 of the Schedule 13D is amended by adding the following:

On August 19, 2025, VHI sent a follow-up letter (the "Follow-Up Letter") to the Issuer's board of directors reiterating VHI's position that the Issuer had failed to fulfil its corporate governance duties towards the Issuer's stakeholders by failing to withdraw agenda items proposing the reappointment to the board of directors of Mr. James Shannon ("Shannon") and Mr. Daniel de Boer ("De Boer") at the Issuer's June 3, 2025 annual general meeting ("AGM"), contrary to the Dutch Corporate Governance Code (the "CGC"), the Issuer's Board Rules and the prior request to withdraw such agenda items from VHI in its initial May 23, 2025 letter to the Issuer's board of directors.

In the Follow-Up Letter, VHI further called on the board of directors of the Issuer to publicly:

- announce that Shannon and De Boer will only serve their current terms until the 2026 AGM, at which point their potential reappointments will be considered in consultation with shareholders;

- provide a clear explanation of the rationale for the reappointment of De Boer, including how this reappointment aligns with the Issuer and its stakeholders' long-term interests;

- commit to presenting a structured and transparent plan for board rotation in advance of the 2026 AGM; and

- commit to future compliance with the Board Rules, the CGC and the highest standards of Dutch and U.S. corporate governance generally.

A copy of the Follow-Up Letter is filed as an exhibit herewith and is incorporated herein by reference.

The Reporting Persons acquired the Ordinary Shares reported herein for investment purposes in the ordinary course of business. The Reporting Persons intend to review their investment in the Issuer on a continuing basis. Depending on various factors including, without limitation, the Issuer's financial position and investment strategy, the price levels of the Ordinary Shares, conditions in the securities markets and general economic and industry conditions, the Reporting Persons may in the future take such actions with respect to their investment in the Issuer as they deem appropriate including, without limitation, engaging in communications with management and the board of directors of the Issuer, engaging in discussions with stockholders of the Issuer or other third parties about the Issuer and the Reporting Persons' investment, including potential business combinations or dispositions involving the Issuer or certain of its businesses, making recommendations or proposals to the Issuer concerning changes to the capitalization, ownership structure, board structure (including board composition), potential business combinations or dispositions involving the Issuer or certain of its businesses, or suggestions for improving the Issuer's financial and/or operational performance, purchasing additional Ordinary Shares, selling some or all of their Ordinary Shares, engaging in short selling of or any hedging or similar transaction with respect to the Ordinary Shares, including swaps and other derivative instruments, or changing their intention with respect to any and all matters referred to in Item 4.

**Item 5. Interest in Securities of the Issuer**

**(a)**
The information previously provided in response to Item 5 is hereby amended and restated by replacing the text thereof in its entirety with the following:

The information set forth in or incorporated by reference in Items 2, 3, 4 and 6 and on the cover pages of this Schedule 13D is incorporated by reference in its entirety into this Item 5.

**(b)**
The information set forth in or incorporated by reference in Items 2, 3, 4 and 6 and on the cover pages of this Schedule 13D is incorporated by reference in its entirety into this Item 5.

**(c)**
Except as set forth in this Schedule 13D, no transactions in Ordinary Shares of the Issuer have been effected during the past sixty days by any of the Reporting Persons.

### SIGNATURE

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

**Reporting Person:** Van Herk Investments B.V.

**Signature:** /s/ Erik G.A. Esveld

**Name/Title:** Erik G.A. Esveld/Attorney-In-Fact*

**Date:** 08/20/2025

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

**Reporting Person:** Van Herk Investments THI B.V.

**Signature:** /s/ Erik G.A. Esveld

**Name/Title:** Erik G.A. Esveld/Attorney-In-Fact*

**Date:** 08/20/2025

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

**Reporting Person:** Van Herk Private Equity Investments B.V.

**Signature:** /s/ Erik G.A. Esveld

**Name/Title:** Erik G.A. Esveld/Attorney-In-Fact*

**Date:** 08/20/2025

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

**Reporting Person:** Stichting Administratiekantoor Penulata

**Signature:** /s/ Erik G.A. Esveld

**Name/Title:** Erik G.A. Esveld/Attorney-In-Fact*

**Date:** 08/20/2025

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

**Reporting Person:** Van Herk Management Services B.V.

**Signature:** /s/ Erik G.A. Esveld

**Name/Title:** Erik G.A. Esveld/Attorney-In-Fact*

**Date:** 08/20/2025

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

**Reporting Person:** Onroerend Goed Beheer- en Beleggingsmaatschappij A. van Herk B.V.

**Signature:** /s/ Erik G.A. Esveld

**Name/Title:** Erik G.A. Esveld/Attorney-In-Fact*

**Date:** 08/20/2025

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

**Reporting Person:** A. van Herk Holding B.V.

**Signature:** /s/ Erik G.A. Esveld

**Name/Title:** Erik G.A. Esveld/Attorney-In-Fact*

**Date:** 08/20/2025

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

**Reporting Person:** Stichting Administratiekantoor Abchrys

**Signature:** /s/ Erik G.A. Esveld

**Name/Title:** Erik G.A. Esveld/Attorney-In-Fact*

**Date:** 08/20/2025

After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct.

**Reporting Person:** Adrianus van Herk

**Signature:** /s/ Erik G.A. Esveld

**Name/Title:** Erik G.A. Esveld/Attorney-In-Fact*

**Date:** 08/20/2025