X0306 4 2021-01-20 0 0001708493 Harpoon Therapeutics, Inc. HARP 0001609492 MPM BioVentures 2014, L.P. C/O MPM CAPITAL 450 KENDALL STREET CAMBRIDGE MA 02142 0 0 1 0 0001263048 MPM ASSET MANAGEMENT LLC C/O MPM CAPITAL 450 KENDALL STREET CAMBRIDGE MA 02142 0 0 1 0 0001609493 MPM BioVentures 2014 (B), L.P. C/O MPM CAPITAL 450 KENDALL STREET CAMBRIDGE MA 02142 0 0 1 0 0001609495 MPM Asset Management Investors BV2014 LLC C/O MPM CAPITAL 450 KENDALL STREET CAMBRIDGE MA 02142 0 0 1 0 0001765021 MPM BioVentures 2014 LLC C/O MPM CAPITAL 450 KENDALL STREET CAMBRIDGE MA 02142 0 0 1 0 0001765091 MPM BioVentures 2014 GP LLC C/O MPM CAPITAL 450 KENDALL STREET CAMBRIDGE MA 02142 0 0 1 0 0001473930 Foley Todd C/O MPM CAPITAL 450 KENDALL STREET CAMBRIDGE MA 02142 0 0 1 0 0001134655 GADICKE ANSBERT C/O MPM CAPITAL 450 KENDALL STREET CAMBRIDGE MA 02142 0 0 1 0 0001134657 EVNIN LUKE C/O MPM CAPITAL 450 KENDALL STREET CAMBRIDGE MA 02142 0 0 1 0 Common Stock 2021-01-20 4 S 0 15694 23.95 D 4508731 I See Footnote Common Stock 2021-01-20 4 S 0 2000 24.71 D 4506731 I See Footnote Common Stock 2021-01-20 4 J 0 101646 D 4405085 I See Footnote Common Stock 2021-01-21 4 S 0 20979 22.11 D 4384106 I See Footnote Common Stock 2021-01-21 4 S 0 4887 22.61 D 4379219 I See Footnote Common Stock 2021-01-21 4 S 0 200 23.77 D 4379019 I See Footnote Common Stock 2021-01-22 4 S 0 24695 21.72 D 4354324 I See Footnote Common Stock 3898422 I See Footnote Transaction effected pursuant to a plan established pursuant to Rule 10b5-1 on 12/21/2020. The shares were sold as follows: 15,145 by MPM BioVentures 2014, L.P. ("BV 2014") and 549 by MPM Asset Management Investors BV2014 LLC ("AM BV2014"). The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $23.58 to $24.52 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. The shares are held as follows: 3,794,906 by BV 2014, 254,116 by MPM BioVentures 2014(B), L.P. ("BV 2014(B)"), 137,646 by MPM Asset Management Investors BV2014 LLC ("AM BV2014") and 322,063 by MPM Asset Management LLC ("AM LLC"). 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). Luke Evnin, Ansbert Gadicke and Todd Foley are the members of BV LLC and Luke Evnin and Anbert Gadicke are the members of AM LLC. Each Reporting Person disclaims beneficial ownership of the securities except to the extent of his or its pecuniary interest therein. The shares were sold as follows: 1,930 by BV 2014 and 70 by AM BV2014. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $24.60 to $24.84 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. The shares are held as follows: 3,792,976 by BV 2014, 254,116 by BV 2014(B), 137,576 by AM BV2014 and 322,063 by AM LLC. MPM BioVentures 2014 GP LLC and BV LLC are the direct and indirect general partners of BV 2014 and BV 2014(B). Luke Evnin, Ansbert Gadicke and Todd Foley are the members of BV LLC and Luke Evnin and Anbert Gadicke are the members of AM LLC. Represents a pro rata in-kind distribution from BV 2014(B) to its limited partners for no consideration. The shares are held as follows: 3,792,976 by BV 2014, 152,470 by BV 2014(B), 137,576 by AM BV2014 and 322,063 by AM LLC. MPM BioVentures 2014 GP LLC and BV LLC are the direct and indirect general partners of BV 2014 and BV 2014(B). Luke Evnin, Ansbert Gadicke and Todd Foley are the members of BV LLC and Luke Evnin and Anbert Gadicke are the members of AM LLC. The shares were sold as follows: 20,245 by BV 2014 and 734 by AM BV2014. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $21.36 to $22.33 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. The shares are held as follows: 3,772,731 by BV 2014, 152,470 by BV 2014(B), 136,842 by AM BV2014 and 322,063 by AM LLC. MPM BioVentures 2014 GP LLC and BV LLC are the direct and indirect general partners of BV 2014 and BV 2014(B). Luke Evnin, Ansbert Gadicke and Todd Foley are the members of BV LLC and Luke Evnin and Anbert Gadicke are the members of AM LLC. The shares were sold as follows: 4,716 by BV 2014 and 171 by AM BV2014. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $22.36 to $23.25 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. The shares are held as follows: 3,768,015 by BV 2014, 152,470 by BV 2014(B), 136,671 by AM BV2014 and 322,063 by AM LLC. MPM BioVentures 2014 GP LLC and BV LLC are the direct and indirect general partners of BV 2014 and BV 2014(B). Luke Evnin, Ansbert Gadicke and Todd Foley are the members of BV LLC and Luke Evnin and Anbert Gadicke are the members of AM LLC. The shares were sold as follows: 193 by BV 2014 and 7 by AM BV2014. The shares are held as follows: 3,767,822 by BV 2014, 152,470 by BV 2014(B), 136,664 by AM BV2014 and 322,063 by AM LLC. MPM BioVentures 2014 GP LLC and BV LLC are the direct and indirect general partners of BV 2014 and BV 2014(B). Luke Evnin, Ansbert Gadicke and Todd Foley are the members of BV LLC and Luke Evnin and Anbert Gadicke are the members of AM LLC. The shares were sold as follows: 23,831 by BV 2014 and 864 by AM BV2014. The price reported in Column 4 is a weighted average price. These shares were sold in multiple transactions at prices ranging from $21.48 to $22.35 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. The shares are held as follows: 3,743,991 by BV 2014, 152,470 by BV 2014(B), 135,800 by AM BV2014 and 322,063 by AM LLC. MPM BioVentures 2014 GP LLC and BV LLC are the direct and indirect general partners of BV 2014 and BV 2014(B). Luke Evnin, Ansbert Gadicke and Todd Foley are the members of BV LLC and Luke Evnin and Anbert Gadicke are the members of AM LLC. The reported securities are held in the account of UBS Oncology Impact Fund L.P. ("UBS Oncology"). MPM Oncology Impact Management GP LLC ("Oncology GP LLC") is the General Partner of MPM Oncology Impact Management LP, the General Partner of Oncology Impact Fund (Cayman) Management L.P., the General Partner of UBS Oncology. Ansbert Gadicke is the Managing Member of Oncology GP LLC. /s/ Ansbert Gadicke, 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. 2021-01-22 /s/ Ansbert Gadicke, managing member of MPM Asset Management 2021-01-22 /s/ Ansbert Gadicke, managing director of MPM BioVentures 2014 LLC, the managing member of MPM BioVentures 2014 GP LLC, the general partner of MPM BioVentures 2014 (B), L.P. 2021-01-22 /s/ Ansbert Gadicke, managing director of MPM BioVentures 2014 LLC, the manager of MPM Asset Management Investors BV2014 LLC 2021-01-22 /s/ Ansbert Gadicke, managing director of MPM BioVentures 2014 LLC 2021-01-22 /s/ Ansbert Gadicke, managing director of MPM BioVentures 2014 LLC, the managing member of MPM BioVentures 2014 GP LLC 2021-01-22 /s/ Todd Foley 2021-01-22 /s/ Ansbert Gadicke 2021-01-22 /s/ Luke Evnin 2021-01-22