| Name | Relationship | Address | Signature | Signature date | CIK |
|---|---|---|---|---|---|
| MPM BioVentures 2014, L.P. | 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 | 2025-12-01 | 0001609492 |
| MPM BioVentures 2014 (B), L.P. | 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. | 2025-12-01 | 0001609493 |
| MPM BioVentures 2014 LLC | 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 | 2025-12-01 | 0001765021 |
| MPM BioVentures 2014 GP LLC | 10%+ Owner | C/O MPM BIOIMPACT LLC, 399 BOYLSTON STREET, SUITE 1100, BOSTON | /s/ Ansbert Gadicke, Managing Director of MPM BioVentures 2014 LLC | 2025-12-01 | 0001765091 |
| MPM Asset Management Investors BV2014 LLC | 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. | 2025-12-01 | 0001609495 |
| Type | Sym | Class | Transaction | Value $ | Shares | Change % | * Price $ | Shares After | Date | Ownership | Footnotes |
|---|---|---|---|---|---|---|---|---|---|---|---|
| transaction | HOWL | Common Stock | Sale | -$59.5K | -60.7K | -1.18% | $0.98 | 5.07M | Nov 26, 2025 | See Footnotes | F1, F2, F3, F4, F5 |
| transaction | HOWL | Common Stock | Sale | -$20.1K | -20.3K | -0.4% | $0.99 | 5.04M | Nov 28, 2025 | See Footnotes | F1, F4, F6, F7, F8 |
| transaction | HOWL | Common Stock | Sale | -$57.3K | -60.9K | -1.21% | $0.94 | 4.98M | Dec 1, 2025 | See Footnotes | F1, F4, F9, F10, F11 |
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: 4,170 by MPM Asset Management LLC ("AM LLC"), 26,343 by MPM BioVentures 2014, L.P. ("BV 2014"), 1,757 by MPM BioVentures 2014(B), L.P. ("BV 2014(B)"), 907 by MPM Asset Management Investors BV2014 LLC ("AM BV2014"), 5,801 by MPM Oncology Innovations Fund, L.P. ("MPM OIF") and 21,755 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 $0.9328 to $1.01 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: 347,875 by AM LLC, 2,196,856 by BV 2014, 146,527 by BV 2014(B), 75,615 by AM BV2014, 481,700 by MPM OIF and 1,816,464 by UBS Oncology |
| F6 | The shares were sold as follows: 1,392 by AM LLC, 8,795 by BV 2014, 587 by BV 2014(B), 303 by AM BV2014, 1,937 by MPM OIF and 7,263 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 $0.9681 to $1.01 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: 346,483 by AM LLC, 2,188,061 by BV 2014, 145,940 by BV 2014(B), 75,312 by AM BV2014, 479,763 by MPM OIF and 1,809,201 by UBS Oncology |
| F9 | The shares were sold as follows: 4,182 by AM LLC, 26,423 by BV 2014, 1,762 by BV 2014(B), 910 by AM BV2014, 5,819 by MPM OIF and 21,821 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 $0.905 to $1.00 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: 342,301 by AM LLC, 2,161,638 by BV 2014, 144,178 by BV 2014(B), 74,402 by AM BV2014, 473,944 by MPM OIF and 1,787,380 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.