Corporate Action (Form 8-K)

On September 17, 2025, Vor Biopharma Inc. (the "Company") filed a Certificate of Amendment to its Amended and Restated Certificate of Incorporation with the Secretary of State of the State of Delaware to effect a reverse stock split at a ratio of 1-for-20(the "Charter Amendment"). The Charter Amendment was authorized by the stockholders of the Company at the Company's Special Meeting of Stockholders held on August 25, 2025.

Pursuant to the Charter Amendment, effective at 5:00 p.m. Eastern Time on September 18, 2025 (the "Effective Time"), every 20 shares of the Company's issued and outstanding common stock will be automatically converted into one issued and outstanding share of common stock, without any change in the par value per share. As a result of the reverse stock split, proportionate adjustments will be made to the per share exercise price and the number of shares issuable upon the exercise or vesting of all stock options and warrants outstanding at the Effective Time, which will result in a proportional decrease in the number of shares of the Company's common stock reserved for issuance upon exercise of such stock options and warrants, and a proportional increase in the exercise price of all such stock options and warrants. In addition, the number of shares reserved for issuance under the Company's 2015 Stock Incentive Plan, Amended and Restated 2021 Equity Incentive Plan, 2021 Employee Stock Purchase Plan and 2023 Inducement Plan immediately prior to the Effective Time will be reduced proportionately.

No fractional shares will be issued as a result of the reverse stock split. Stockholders of record who would otherwise be entitled to receive a fractional share will receive a cash payment in lieu thereof. The reverse stock split will affect all stockholders proportionately and will not affect any stockholder's percentage ownership of the Company's common stock (except to the extent that the reverse stock split results in any stockholder owning only a fractional share).

The Company's common stock will begin trading on The Nasdaq Global Select Market on a split-adjusted basis when the market opens on September 19, 2025. The new CUSIP number for the Company's common stock following the reverse stock split will be 929033207.

As of September 16, 2025, there were 136,822,693 shares of common stock outstanding. Immediately following the reverse stock split, there will be approximately 6,841,134 shares of common stock outstanding (subject to adjustment due to the effect of cashing out fractional shares as described above).

A copy of the Charter Amendment is filed with this report as Exhibit 3.1.

The information contained in Item 3.03 of this Current Report on Form 8-Kis hereby incorporated by reference.

The Company has registration statements on Form S-3(File No. 333-268798, 333-284380and 333-285969)and registration statements on Form S-8(File No. 333-252908, 333-263540, 333-270789, 333-274275, 333-278117and 333-285971)on file with the Securities and Exchange Commission (the "Commission"). Commission regulations permit the Company to incorporate by reference future filings made with the Commission pursuant to Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act, prior to the termination of the offerings covered by registration statements filed on Form S-3or Form S-8.The information incorporated by reference is considered to be part of the prospectus included within each of those registration statements. Information in this Item 8.01 of this Current Report on Form 8-Kis therefore intended to be automatically incorporated by reference into each of the active registration statements listed above, thereby amending them. Pursuant to Rule 416(b) under the Securities Act, the amount of undistributed shares of Common Stock deemed to be covered by the effective registration statements of the Company described above are proportionately reduced as of the Effective Time to give effect to the Reverse Stock Split.