| Name | Relationship | Address | Signature | Signature date | CIK |
|---|---|---|---|---|---|
| MPM BioVentures 2014, L.P. | Former 10% Owner | C/O MPM BIOIMPACT LLC, 399 BOYLSTON STREET, SUITE 1100, BOSTON | /s/ Ansbert Gadicke, Managing Director of MPM BioVentures 2014 LLC, the manager of MPM Asset Management Investors BV2014 LLC | 2025-12-04 | 0001609492 |
| MPM BioVentures 2014 (B), L.P. | Former 10% Owner | C/O MPM BIOIMPACT, 399 BOYLSTON STREET, SUITE 1100, BOSTON | /s/ Ansbert Gadicke, Managing Director of MPM BioVentures 2014 LLC, the Managing Member of MPM BioVentures 2014 GP LLC, the GP of MPM BioVentures 2014, L.P. | 2025-12-04 | 0001609493 |
| MPM BioVentures 2014 LLC | Former 10% Owner | C/O MPM BIOIMPACT LLC, 399 BOYLSTON STREET, SUITE 1100, BOSTON | /s/ Ansbert Gadicke, Managing Director of MPM BioVentures 2014 LLC, the Managing Member of MPM BioVentures 2014 GP LLC | 2025-12-04 | 0001765021 |
| MPM BioVentures 2014 GP LLC | Former 10% Owner | C/O MPM BIOIMPACT LLC, 399 BOYLSTON STREET, SUITE 1100, BOSTON | /s/ Ansbert Gadicke, Managing Director of MPM BioVentures 2014 LLC | 2025-12-04 | 0001765091 |
| MPM Asset Management Investors BV2014 LLC | Former 10% Owner | C/O MPM BIOIMPACT LLC, 399 BOYLSTON STREET, SUITE 1100, BOSTON | /s/ Ansbert Gadicke, Managing Director of MPM BioVentures 2014 LLC, the Managing Member of MPM BioVentures 2014 GP LLC, the GP of MPM BioVentures 2014 (B), L.P. | 2025-12-04 | 0001609495 |
| Type | Sym | Class | Transaction | Value $ | Shares | Change % | * Price $ | Shares After | Date | Ownership | Footnotes |
|---|---|---|---|---|---|---|---|---|---|---|---|
| transaction | HOWL | Common Stock | Sale | -$52.8K | -59.3K | -1.19% | $0.89 | 4.92M | Dec 2, 2025 | See Footnotes | F1, F2, F3, F4, F5 |
| transaction | HOWL | Common Stock | Sale | -$49.8K | -57.2K | -1.16% | $0.87 | 4.87M | Dec 3, 2025 | See Footnotes | F1, F4, F6, F7, F8 |
| transaction | HOWL | Common Stock | Sale | -$80.7K | -83.2K | -1.71% | $0.97 | 4.78M | Dec 4, 2025 | See Footnotes | F1, F4, F9, F10, F11 |
MPM BioVentures 2014, L.P. is no longer subject to Section 16 filing requirements. Form 4 or Form 5 obligations may continue.
Buy Plan / Sale Plan: These are also open market purchases/sales of shares, but in this case the transaction is part of a trading plan. Rule 10b5-1 allows insiders to setup a trading plan to buy/sell stocks over a certain period of time. Since the purchases/sales are predetermined, this protects the insiders from violating insider trading law.
Transaction was made pursuant to a contract, instruction or written plan for the purchase or sale of equity securities of the issuer that is intended to satisfy the affirmative defense conditions of Rule 10b5-1(c).
| Id | Content |
|---|---|
| F1 | Transaction effected pursuant to a plan established pursuant to Rule 10b5-1 dated September 24, 2025. |
| F2 | The shares were sold as follows: 4,070 by MPM Asset Management LLC ("AM LLC"), 25,712 by MPM BioVentures 2014, L.P. ("BV 2014"), 1,715 by MPM BioVentures 2014(B), L.P. ("BV 2014(B)"), 884 by MPM Asset Management Investors BV2014 LLC ("AM BV2014"), 5,662 by MPM Oncology Innovations Fund, L.P. ("MPM OIF") and 21,234 by UBS Oncology Impact Fund L.P. ("UBS Oncology"). |
| F3 | The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $0.852 to $0.9246 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote. |
| F4 | MPM BioVentures 2014 GP LLC and MPM BioVentures 2014 LLC ("BV LLC") are the direct and indirect general partners of BV 2014 and BV 2014(B). BV LLC is the manager of AM BV2014. MPM Oncology Innovations Fund GP LLC ("MPM OIF GP") is the general partner of MPM OIF. MPM BioImpact LLC ("BioImpact") is the General Partner of Oncology Impact Fund (Cayman) Management L.P., the General Partner of UBS Oncology. Ansbert Gadicke is a member of AM LLC, a managing director of BV LLC, a manager of MPM OIF GP and the managing partner of BioImpact. Each Reporting Person disclaims beneficial ownership of the securities except to the extent of his or its pecuniary interest therein. |
| F5 | The shares are held as follows: 338,231 by AM LLC, 2,135,926 by BV 2014, 142,463 by BV 2014(B), 73,518 by AM BV2014, 468,282 by MPM OIF and 1,766,146 by UBS Oncology. |
| F6 | The shares were sold as follows: 3,929 by AM LLC, 24,821 by BV 2014, 1,656 by BV 2014(B), 854 by AM BV2014, 5,466 by MPM OIF and 20,499 by UBS Oncology. |
| F7 | The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $0.82 to $0.9256 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote. |
| F8 | The shares are held as follows: 334,302 by AM LLC, 2,111,105 by BV 2014, 140,807 by BV 2014(B), 72,664 by AM BV2014, 462,816 by MPM OIF and 1,745,647 by UBS Oncology. |
| F9 | The shares were sold as follows: 5,714 by AM LLC, 36,101 by BV 2014, 2,408 by BV 2014(B), 1,243 by AM BV2014, 7,950 by MPM OIF and 29,814 by UBS Oncology. |
| F10 | The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $0.92 to $1.0208 inclusive. The Reporting Person undertakes to provide to the Issuer, any security holder of the Issuer, or the staff of the Securities and Exchange Commission, upon request, full information regarding the number of shares sold at each separate price within the range set forth in this footnote. |
| F11 | The shares are held as follows: 328,588 by AM LLC, 2,075,004 by BV 2014, 138,399 by BV 2014(B), 71,421 by AM BV2014, 454,866 by MPM OIF and 1,715,833 by UBS Oncology. |
This filing is 1 of 2 identical filings due to limitations on number of Reporting Persons. See Form 4 filed by Ansbert Gadicke.