Item 8.01 Other Events. On September 15, 2024, MacroGenics, Inc. (the “ Company”) issued a press release announcing updated efficacy and safety data related to its Phase 2 TAMARACK clinical trial of vobramitamab duocarmazine in metastatic castration-resistant prostate cancer (the “ Press Release”). The Company included the updated efficacy and safety data in a poster presentation at the European Society for Medical Oncology (“ ESMO”) Congress, taking place in Barcelona, Spain from September 13-17, 2024. As announced in the Press Release, the Company also hosted an investor conference call on September 16, 2024 in which the Company presented a review of the TAMARACK Phase 2 data and also provided a general corporate update (the “ Post-ESMO Conference Call Presentation”). The full text of the Press Release is attached as Exhibit 99.1 to this Current Report on Form 8-K and is incorporated by reference herein. In addition, a copy of the Post-ESMO Conference Call Presentation is attached as Exhibit 99.2 to this Current Report on Form 8-K and is incorporated by reference herein.

Item 9.01 Financial Statements and Exhibits (d) Exhibits. Exhibit Number Description of Exhibit 99.1 Press Release, dated September 1 5, 2024. ──────────────────────────────────────────────────────────────────────────────────── 99.2 Post-ESMO Conference Call Presentation. 104 Cover Page Interactive Data File (formatted as Inline XBRL). SIGNATURE Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized. Date: September 16, 2024 MACROGENICS, INC. ────────────────────────────────────────────────────────────────────────────────────────────────── By: /s/ Jeffrey Peters