# EDGAR Filing Document

**Accession Number:** 0001609492
**File Stem:** 0001609492-26-000004
**Filing Date:** 2026-5
**Character Count:** 42776
**Document Hash:** 605c477624fae78148f903a273a392db
**Contains OCR:** False
**Source Format:** 

## Filing Content

## Filing Summary
**0001609492-26-000004.hdr.sgml**: 20260505

**ACCESSION NUMBER**: 0001609492-26-000004

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

**PUBLIC DOCUMENT COUNT**: 2

**FILED AS OF DATE**: 20260505

**DATE AS OF CHANGE**: 20260505

**SUBJECT COMPANY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** Werewolf Therapeutics, Inc.
- **CENTRAL INDEX KEY:** 0001785530
- **STANDARD INDUSTRIAL CLASSIFICATION:** PHARMACEUTICAL PREPARATIONS [2834]
- **ORGANIZATION NAME:** 03 Life Sciences
- **EIN:** 823523180
- **STATE OF INCORPORATION:** DE
- **FISCAL YEAR END:** 1231

**FILING VALUES:**
- **FORM TYPE:** SCHEDULE 13D/A
- **SEC ACT:** 1934 Act
- **SEC FILE NUMBER:** 005-92515
- **FILM NUMBER:** 26945215

**BUSINESS ADDRESS:**
- **STREET 1:** 200 TALCOTT AVENUE
- **STREET 2:** 2ND FLOOR
- **CITY:** WATERTOWN
- **STATE:** MA
- **ZIP:** 02472
- **BUSINESS PHONE:** 617-952-0555

**MAIL ADDRESS:**
- **STREET 1:** 200 TALCOTT AVENUE
- **STREET 2:** 2ND FLOOR
- **CITY:** WATERTOWN
- **STATE:** MA
- **ZIP:** 02472
**FILED BY**: 

**COMPANY DATA:**
- **COMPANY CONFORMED NAME:** MPM BioVentures 2014, L.P.
- **CENTRAL INDEX KEY:** 0001609492

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

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

**BUSINESS ADDRESS:**
- **STREET 1:** C/O MPM BIOIMPACT
- **STREET 2:** 399 BOYLSTON STREET, SUITE 1100
- **CITY:** BOSTON
- **STATE:** MA
- **ZIP:** 02116
- **BUSINESS PHONE:** (617) 425-9200

**MAIL ADDRESS:**
- **STREET 1:** C/O MPM BIOIMPACT
- **STREET 2:** 399 BOYLSTON STREET, SUITE 1100
- **CITY:** BOSTON
- **STATE:** MA
- **ZIP:** 02116

## Ex-99.C

**Joint Filing Statement**

I, the undersigned, hereby express my agreement that the attached Schedule 13D (and any amendments thereto) relating to the beneficial ownership by the undersigned of the equity securities of Werewolf Therapeutics, Inc. is filed on behalf of each of the undersigned.

Date: May 5, 2026

**MPM BioVentures 2014, L.P.**

By: MPM BioVentures 2014 GP LLC,

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;its General Partner

By: MPM BioVentures 2014 LLC,

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Its Managing Member

By:

<u>/s/ Ansbert Gadicke</u>

Name: Ansbert Gadicke

Title: Managing Director

**MPM BioVentures 2014 (B), L.P.**

By: MPM BioVentures 2014 GP LLC,

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;its General Partner

By: MPM BioVentures 2014 LLC,

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Its Managing Member

By:

<u>/s/ Ansbert Gadicke</u>

Name: Ansbert Gadicke

Title: Managing Director

**MPM Asset Management Investors BV 2014 LLC**

By: MPM BioVentures 2014 LLC

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Its: Manager

By:

<u>/s/ Ansbert Gadicke</u>

Name: Ansbert Gadicke

Title: Managing Director

**MPM BioVentures 2014 GP, LLC**

By: MPM BioVentures 2014 LLC,

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Its Managing Member

By:

<u>/s/ Ansbert Gadicke</u>

Name: Ansbert Gadicke

Title: Managing Director

------

**MPM BioVentures 2014 LLC**

By:

<u>/s/ Ansbert Gadicke</u>

Name: Ansbert Gadicke

Title: Managing Director

**MPM Asset Management LLC**

By:

<u>/s/ Ansbert Gadicke</u>

Name: Ansbert Gadicke

Title: Member

**MPM Oncology Innovations Fund LP**

By: MPM Oncology Innovations Fund GP LLC

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;its General Partner

By:

<u>/s/ Ansbert Gadicke</u>

Name: Ansbert Gadicke

Title: Manager

**MPM Oncology Innovations Fund GP LLC**

By:

<u>/s/ Ansbert Gadicke</u>

Name: Ansbert Gadicke

Title: Manager

**UBS Oncology Impact Fund, L.P.**

By: Oncology Impact Fund (Cayman) Management L.P.,

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;its General Partner

By: MPM BioImpact LLC,

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Its General Partner

By:

<u>/s/ Ansbert Gadicke</u>

Name: Ansbert Gadicke

Title: Managing Partner

------

**Oncology Impact Fund (Cayman) Management L.P.**

By: MPM BioImpact LLC,

&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;Its General Partner

By:

<u>/s/ Ansbert Gadicke</u>

Name: Ansbert Gadicke

Title: Managing Partner

**MPM BioImpact LLC**

By:

<u>/s/ Ansbert Gadicke</u>

Name: Ansbert Gadicke

Title: Managing Partner

By:

<u>/s/ Todd Foley</u>

Name: Todd Foley

By:

<u>/s/ Luke Evnin</u>

Name: Luke Evnin

By:

<u>/s/ Ansbert Gadicke</u>

Name: Ansbert Gadicke

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

## SCHEDULE 13D

### Under the Securities Exchange Act of 1934

**(Amendment No. 6)**

**WEREWOLF THERAPEUTICS, INC.**

*(Name of Issuer)*

**Common Stock**

*(Title of Class of Securities)*

**—**

*(CUSIP Number)*

**Ansbert Gadicke**<br>c/o MPM BioImpact LLC<br>339 Boylston Street, Suite 1100<br>Boston MA 02116<br>617-425-9200

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

**05/01/2026**

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

| **CUSIP No.** | **—** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**MPM BioVentures 2014, L.P.** | Name of reporting person<br>**MPM BioVentures 2014, L.P.** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**WC** | Source of funds (See Instructions)<br>**WC** | |
| 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>**DELAWARE** | Citizenship or place of organization<br>**DELAWARE** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**1131359.00** |
| 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>**1131359.00** |
| 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>**1131359.00** | Aggregate amount beneficially owned by each reporting person<br>**1131359.00** | |
| 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>**2.3%** | Percent of class represented by amount in Row (11)<br>**2.3%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**PN** | Type of Reporting Person (See Instructions)<br>**PN** | |

---

| **CUSIP No.** | **—** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**MPM BioVentures 2014 (B), L.P.** | Name of reporting person<br>**MPM BioVentures 2014 (B), L.P.** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**WC** | Source of funds (See Instructions)<br>**WC** | |
| 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>**DELAWARE** | Citizenship or place of organization<br>**DELAWARE** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**75458.00** |
| 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>**75458.00** |
| 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>**75458.00** | Aggregate amount beneficially owned by each reporting person<br>**75458.00** | |
| 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>**0.2%** | Percent of class represented by amount in Row (11)<br>**0.2%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**PN** | Type of Reporting Person (See Instructions)<br>**PN** | |

---

| **CUSIP No.** | **—** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**MPM Asset Management Investors BV2014 LLC** | Name of reporting person<br>**MPM Asset Management Investors BV2014 LLC** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**WC** | Source of funds (See Instructions)<br>**WC** | |
| 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>**DELAWARE** | Citizenship or place of organization<br>**DELAWARE** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**38939.00** |
| 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>**38939.00** |
| 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>**38939.00** | Aggregate amount beneficially owned by each reporting person<br>**38939.00** | |
| 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>**0.1%** | Percent of class represented by amount in Row (11)<br>**0.1%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**OO** | Type of Reporting Person (See Instructions)<br>**OO** | |

---

| **CUSIP No.** | **—** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**UBS Oncology Impact Fund L.P.** | Name of reporting person<br>**UBS Oncology Impact Fund L.P.** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**WC** | Source of funds (See Instructions)<br>**WC** | |
| 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>**CAYMAN ISLANDS** | Citizenship or place of organization<br>**CAYMAN ISLANDS** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**936031.00** |
| 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>**936031.00** |
| 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>**936031.00** | Aggregate amount beneficially owned by each reporting person<br>**936031.00** | |
| 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>**1.9%** | Percent of class represented by amount in Row (11)<br>**1.9%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**PN** | Type of Reporting Person (See Instructions)<br>**PN** | |

---

| **CUSIP No.** | **—** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**MPM BioVentures 2014 GP LLC** | Name of reporting person<br>**MPM BioVentures 2014 GP LLC** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**WC** | Source of funds (See Instructions)<br>**WC** | |
| 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>**DELAWARE** | Citizenship or place of organization<br>**DELAWARE** | |
| 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>**1206817.00** |
| 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>**1206817.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**1206817.00** | Aggregate amount beneficially owned by each reporting person<br>**1206817.00** | |
| 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>**2.5%** | Percent of class represented by amount in Row (11)<br>**2.5%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**OO** | Type of Reporting Person (See Instructions)<br>**OO** | |

---

| **CUSIP No.** | **—** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**MPM BioVentures 2014 LLC** | Name of reporting person<br>**MPM BioVentures 2014 LLC** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**WC** | Source of funds (See Instructions)<br>**WC** | |
| 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>**DELAWARE** | Citizenship or place of organization<br>**DELAWARE** | |
| 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>**1245756.00** |
| 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>**1245756.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**1245756.00** | Aggregate amount beneficially owned by each reporting person<br>**1245756.00** | |
| 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>**2.6%** | Percent of class represented by amount in Row (11)<br>**2.6%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**OO** | Type of Reporting Person (See Instructions)<br>**OO** | |

---

| **CUSIP No.** | **—** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Oncology Impact Fund (Cayman) Management L.P.** | Name of reporting person<br>**Oncology Impact Fund (Cayman) Management L.P.** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**WC** | Source of funds (See Instructions)<br>**WC** | |
| 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>**CAYMAN ISLANDS** | Citizenship or place of organization<br>**CAYMAN ISLANDS** | |
| 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>**936031.00** |
| 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>**936031.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**936031.00** | Aggregate amount beneficially owned by each reporting person<br>**936031.00** | |
| 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>**1.9%** | Percent of class represented by amount in Row (11)<br>**1.9%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**PN** | Type of Reporting Person (See Instructions)<br>**PN** | |

---

| **CUSIP No.** | **—** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**MPM BioImpact LLC** | Name of reporting person<br>**MPM BioImpact LLC** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**WC** | Source of funds (See Instructions)<br>**WC** | |
| 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>**DELAWARE** | Citizenship or place of organization<br>**DELAWARE** | |
| 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>**936031.00** |
| 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>**936031.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**936031.00** | Aggregate amount beneficially owned by each reporting person<br>**936031.00** | |
| 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>**1.9%** | Percent of class represented by amount in Row (11)<br>**1.9%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**OO** | Type of Reporting Person (See Instructions)<br>**OO** | |

---

| **CUSIP No.** | **—** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**ANSBERT GADICKE** | Name of reporting person<br>**ANSBERT GADICKE** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**WC** | Source of funds (See Instructions)<br>**WC** | |
| 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>**X1** | Citizenship or place of organization<br>**X1** | |
| 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>**2608501.00** |
| 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>**2608501.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**2608501.00** | Aggregate amount beneficially owned by each reporting person<br>**2608501.00** | |
| 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>**5.4%** | Percent of class represented by amount in Row (11)<br>**5.4%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**IN** | Type of Reporting Person (See Instructions)<br>**IN** | |

---

| **CUSIP No.** | **—** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**LUKE EVNIN** | Name of reporting person<br>**LUKE EVNIN** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**WC** | Source of funds (See Instructions)<br>**WC** | |
| 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>**X1** | Citizenship or place of organization<br>**X1** | |
| 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>**1672470.00** |
| 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>**1672470.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**1672470.00** | Aggregate amount beneficially owned by each reporting person<br>**1672470.00** | |
| 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>**3.4%** | Percent of class represented by amount in Row (11)<br>**3.4%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**IN** | Type of Reporting Person (See Instructions)<br>**IN** | |

---

| **CUSIP No.** | **—** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**Todd Foley** | Name of reporting person<br>**Todd Foley** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**WC** | Source of funds (See Instructions)<br>**WC** | |
| 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>**X1** | Citizenship or place of organization<br>**X1** | |
| 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>**1245756.00** |
| 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>**1245756.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**1245756.00** | Aggregate amount beneficially owned by each reporting person<br>**1245756.00** | |
| 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>**2.6%** | Percent of class represented by amount in Row (11)<br>**2.6%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**IN** | Type of Reporting Person (See Instructions)<br>**IN** | |

---

| **CUSIP No.** | **—** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**MPM ASSET MANAGEMENT LLC** | Name of reporting person<br>**MPM ASSET MANAGEMENT LLC** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**WC** | Source of funds (See Instructions)<br>**WC** | |
| 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>**DELAWARE** | Citizenship or place of organization<br>**DELAWARE** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**179188.00** |
| 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>**179188.00** |
| 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>**179188.00** | Aggregate amount beneficially owned by each reporting person<br>**179188.00** | |
| 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>**0.4%** | Percent of class represented by amount in Row (11)<br>**0.4%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**OO** | Type of Reporting Person (See Instructions)<br>**OO** | |

---

| **CUSIP No.** | **—** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**MPM ONCOLOGY INNOVATIONS FUND LP** | Name of reporting person<br>**MPM ONCOLOGY INNOVATIONS FUND LP** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**WC** | Source of funds (See Instructions)<br>**WC** | |
| 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>**DELAWARE** | Citizenship or place of organization<br>**DELAWARE** | |
| Number of Shares<br>Beneficially Owned by<br>Each Reporting Person With: | 7 | Sole Voting Power<br>**247526.00** |
| 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>**247526.00** |
| 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>**247526.00** | Aggregate amount beneficially owned by each reporting person<br>**247526.00** | |
| 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>**0.5%** | Percent of class represented by amount in Row (11)<br>**0.5%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**PN** | Type of Reporting Person (See Instructions)<br>**PN** | |

---

| **CUSIP No.** | **—** |

---

| | | | |
|:--|:--|:--|:--|
| 1 | Name of reporting person<br>**MPM Oncology Innovations Fund GP LLC** | Name of reporting person<br>**MPM Oncology Innovations Fund GP LLC** | |
| 2 | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | Check the appropriate box if a member of a Group (See Instructions)<br>[ ] (a)<br>[x] (b) | |
| 3 | SEC use only | SEC use only | |
| 4 | Source of funds (See Instructions)<br>**WC** | Source of funds (See Instructions)<br>**WC** | |
| 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>**DELAWARE** | Citizenship or place of organization<br>**DELAWARE** | |
| 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>**247526.00** |
| 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>**247526.00** |
| 11 | Aggregate amount beneficially owned by each reporting person<br>**247526.00** | Aggregate amount beneficially owned by each reporting person<br>**247526.00** | |
| 12 | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[x] | Check if the aggregate amount in Row (11) excludes certain shares (See Instructions)<br>[x] | |
| 13 | Percent of class represented by amount in Row (11)<br>**0.5%** | Percent of class represented by amount in Row (11)<br>**0.5%** | |
| 14 | Type of Reporting Person (See Instructions)<br>**OO** | Type of Reporting Person (See Instructions)<br>**OO** | |

---

**Item 1. Security and Issuer**

**(a) Title of Class of Securities:**
Common Stock

**(b) Name of Issuer:**
WEREWOLF THERAPEUTICS, INC.

**(c) Address of Issuer's Principal Executive Offices:**
200 TALCOTT AVENUE, 2ND FLOOR, WATERTOWN, MA, 02472

Explanatory Note:  This Amendment No. 6 to Schedule 13D ("Amendment No. 6") is being filed as an amendment to the initial statement on Schedule 13D relating to the common stock (the "Common Stock"), of Werewolf Therapeutics Inc. (the 'Issuer'), as filed with the Securities and Exchange Commission (the "SEC") on May 14, 2021 and as amended by Amendment No. 1 filed November 4, 2025, Amendment No. 2 filed November 17, 2025, Amendment No. 3 filed December 3, 2025, Amendment No. 4 filed December 29, 2025 and Amendment No. 5 filed January 16, 2026 (as amended, the "Original Schedule 13D").   This Schedule 13D/A is being filed by the Filing Persons to report the open market sales of the Issuer's Common Stock by certain Filing Persons.

Items 5 and 7 of the Original Schedule 13D are hereby amended and supplemented to the extent hereinafter expressly set forth and, except as amended and supplemented hereby, the Original Schedule 13D remains in full force and effect.  All capitalized terms used in this Amendment No. 6 but not defined herein shall have the meanings ascribed thereto in the Original Schedule 13D.

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

**(a)**
See rows (11) and (13) of the Filing Persons Owner Profile of this Amendment No. 6 for the aggregate number of Common Stock and percentages of the shares of Common Stock beneficially owned by the Filing Person.

The Common Stock is held as follows:

*	 1,131,359 shares are held directly by BV 2014;
*	 75,458 shares are held directly by BV 2014(B);
*	 38,939 shares are held directly by AM BV2014 LLC;
*	 247,526 shares are held directly by MPM OIF;
*       179,188 shares by AM LLC; and
*	 936,031 shares are held directly by UBS Oncology.

BV 2014 GP and BV 2014 LLC are the direct and indirect general partners of BV 2014 and BV 2014(B) and, accordingly, may be deemed to beneficially own the shares held by BV 2014 and BV 2014(B).

BV 2014 LLC is the managing member of AM BV2014 LLC and, accordingly, may be deemed to beneficially own the shares held by AM BV2014 LLC.

MPM OIF GP is the general Partner of MPM OIF and, accordingly, may be deemed to beneficially own the shares held by MPM OIF.

BioImpact and Oncology Cayman are the direct and indirect general partners of UBS Oncology and, accordingly, may be deemed to beneficially own the shares held by UBS Oncology.

Drs. Gadicke and Evnin and Mr. Foley are the managing directors of BV 2014 LLC and, accordingly, may be deemed to beneficially own the shares held by BV 2014, BV 2014(B) and AM BV2014 LLC.

Drs. Gadicke and Evnin are the members of AM LLC and managers of MPM OIF GP and, accordingly, may be deemed to beneficially own the shares held by AM LLC and MPM OIF.

Dr. Gadicke is the managing partner of BioImpact and, accordingly may be deemed to beneficially own the shares held by UBS Oncology.

Calculation of the percentage of the shares of Common Stock beneficially owned is based upon 48,596,817 shares of Common Stock outstanding as of March 20, 2026, as reported in the Issuer's Form 10-K filed with the SEC on March 27, 2026.

**(b)**
See rows (7) through (10) of the Filing Persons Owner Profile of this Amendment No. 6 for the number of shares as to which there is sole power to vote or to direct the vote, sole power to dispose or to direct the disposition, or shared power to dispose or to direct the disposition.

**(c)**
The Reporting Persons sold the following Common Stock in the open market in the last 60 days:

Date of     Price Range    Ave. Price    Sold by       Sold by      Sold By        Sold by       Sold by      Sold by
 Sale                                                    BV 2014        BV        AM BV2014   MPM OIF    AM LLC        UBS
                                                                              2014(B)         LLC                                               Oncology
04/27/26    $0.818-$0.8788      $0.85   36,488       2,434         1,256             7,983          5,779         30,188
04/28/26    $0.673-$0.82          $0.73   64,541       4,305         2,222           14,121        10,223         53,400
04/29/26    $0.68-$0.75            $0.69   38,259       2,552         1,317             8,371          6,060         31,654
04/30/26    $0.688-$0.7458      $0.72  113,821      7,592         3,918           24,903        18,028         94,172
05/01/26   $0.7011-$0.74         $0.73   39,501       2,635         1,360             8,642          6,256         32,682
05/04/26    $0.69-$0.7497        $0.72   32,455       2,164         1,117             7,098          5,139         26,843
05/05/26    $0.6616-$0.7253    $0.69     4,640          310            160             1,015             735           3,840

### 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:** MPM BioVentures 2014, L.P.

**Signature:** /s/ Ansbert Gadicke

**Name/Title:** Managing Director of MPM BioVentures 2014 LLC, the Managing Member of MPM BioVentures 2014 GP LLC, the General Partner of MPM BioVentures 2014, L.P.

**Date:** 05/05/2026

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:** MPM BioVentures 2014 (B), L.P.

**Signature:** /s/ Ansbert Gadicke

**Name/Title:** Managing Director of MPM BioVentures 2014 LLC, Managing Member of MPM BioVentures 2014 GP LLC, the General Partner of MPM BioVentures 2014 (B), L.P.

**Date:** 05/05/2026

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:** MPM Asset Management Investors BV2014 LLC

**Signature:** /s/ Ansbert Gadicke

**Name/Title:** Managing Director of MPM BioVentures 2014 LLC, the manager of MPM Asset Management Investors BV2014 LLC

**Date:** 05/05/2026

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:** UBS Oncology Impact Fund L.P.

**Signature:** /s/ Ansbert Gadicke

**Name/Title:** Managing Partner of MPM BioImpact LLC, the GP of Oncology Impact Fund (Cayman) Management L.P., the GP of UBS Oncology Impact Fund L.P.

**Date:** 05/05/2026

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:** MPM BioVentures 2014 GP LLC

**Signature:** /s/ Ansbert Gadicke

**Name/Title:** Managing Director of MPM BioVentures 2014 LLC, the Managing Member of MPM BioVentures 2014 GP LLC

**Date:** 05/05/2026

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:** MPM BioVentures 2014 LLC

**Signature:** /s/ Ansbert Gadicke

**Name/Title:** Managing Director

**Date:** 05/05/2026

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:** Oncology Impact Fund (Cayman) Management L.P.

**Signature:** /s/ Ansbert Gadicke

**Name/Title:** Managing Partner of MPM BioImpact LLC, the General Partner of Oncology Impact Fund (Cayman) Management L.P.

**Date:** 05/05/2026

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:** MPM BioImpact LLC

**Signature:** /s/ Ansbert Gadicke

**Name/Title:** Managing Partner

**Date:** 05/05/2026

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:** ANSBERT GADICKE

**Signature:** /s/ Ansbert Gadicke

**Name/Title:** Ansbert Gadicke

**Date:** 05/05/2026

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:** LUKE EVNIN

**Signature:** /s/ Luke Evnin

**Name/Title:** Luke Evnin

**Date:** 05/05/2026

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:** Todd Foley

**Signature:** /s/ Todd Foley

**Name/Title:** Todd Foley

**Date:** 05/05/2026

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:** MPM ASSET MANAGEMENT LLC

**Signature:** /s/ Ansbert Gadicke

**Name/Title:** Member

**Date:** 05/05/2026

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:** MPM ONCOLOGY INNOVATIONS FUND LP

**Signature:** /s/ Ansbert Gadicke

**Name/Title:** Manager of MPM Oncology Innovations Fund GP LLC, the General Partner of MPM Oncology Innovations Fund, L.P.

**Date:** 05/05/2026

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:** MPM Oncology Innovations Fund GP LLC

**Signature:** /s/ Ansbert Gadicke

**Name/Title:** Manager

**Date:** 05/05/2026