Rallybio Announces Reverse Stock Split of Common Stock in Connection with the Proposed Merger with Avenzo (Form 8-K)

Rallybio Announces Reverse Stock Split of Common Stock in Connection with the Proposed Merger with Avenzo

EAST BERLIN, Conn., November 10, 2026 - Rallybio Corporation (Nasdaq: RLYB) today announced that it will effect a one-for-two reverse stock split of its issued and outstanding common stock in connection with the transactions contemplated by the Agreement and Plan of Merger and Reorganization, dated as of May 31, 2026, among Rallybio, Avenzo Therapeutics, Inc. ("Avenzo") and Farmington Merger Sub, Inc., a wholly owned subsidiary of Rallybio (the "Merger Agreement"). At Rallybio's Annual Meeting of Stockholders held on November 4, 2026, stockholders approved an amendment to Rallybio's Amended and Restated Certificate of Incorporation to effect a reverse stock split at a ratio ranging from one-for-two to one-for-nine, inclusive, with the final ratio to be mutually determined by Rallybio and Avenzo. On November 8, 2026, Rallybio's Board of Directors, with Avenzo's mutual agreement, approved a one-for-two reverse stock split of Rallybio's issued and outstanding common stock. The reverse stock split is expected to become effective at 12:01 a.m., Eastern Time, on November 20, 2026, prior to the anticipated completion of the merger contemplated by the Merger Agreement (the "Merger"). Following the satisfaction of applicable Nasdaq approvals and the closing of the Merger, Rallybio plans to change its name to Avenzo Therapeutics, Inc. and to trade on the Nasdaq Capital Market under the new trading symbol "AVZO" and the new CUSIP number 053928 107.

At the effective time of the reverse stock split, every two issued and outstanding shares of Rallybio's common stock will automatically be combined into one share of common stock. The reverse stock split will reduce the number of issued and outstanding shares of Rallybio's common stock from approximately 5.6 million to approximately 2.8 million (prior to giving effect to the closing of the Merger). The reverse stock split will not change the authorized number of shares of Rallybio's common stock.

The par value of Rallybio's common stock will remain unchanged at $0.0001 per share after the reverse stock split. The reverse stock split will affect all stockholders uniformly and, by itself, will not alter any stockholder's percentage interest in Rallybio's equity, except to the extent that the reverse stock split results in some stockholders receiving cash in lieu of any fractional shares as described below.

Proportionate adjustments will be made to the number of shares underlying outstanding pre-funded warrants, equity awards and, where applicable, their exercise prices, and to the number of shares reserved for issuance under Rallybio's equity incentive plans, in each case in accordance with the terms of the applicable pre-funded warrants, awards and plans.

No fractional shares will be issued in connection with the reverse stock split. Stockholders who would otherwise be entitled to receive a fractional share will instead receive a cash payment equal to the fair market value of that fractional share based on the closing price of Rallybio's common stock on the effective date of the reverse stock split.

Computershare Trust Company, N.A. ("Computershare") is acting as the exchange agent and transfer agent for the reverse stock split. Stockholders holding their shares electronically in book-entry form are not required to take any action to receive post-split shares. Computershare will provide instructions to stockholders holding physical certificates regarding the process for exchanging their pre-split stock certificates for the appropriate number of post-split shares in book-entry form and receiving payment in lieu of any fractional shares. Stockholders holding shares through a bank, broker or other nominee will have their positions adjusted to reflect the reverse stock split and will receive payment in lieu of any fractional shares in accordance with their respective bank's, broker's or nominee's procedures. Additional information regarding the reverse stock split can be found in Rallybio's proxy statement/prospectus, included in its registration statement on Form S-4, which was declared effective by the Securities and Exchange Commission on October 15, 2026 (the "Proxy Statement/Prospectus").

About Avenzo Therapeutics

Avenzo Therapeutics is a clinical-stage biotechnology company focused on developing next-generation oncology therapies for patients. The company's pipeline includes potentially differentiated small molecules and bispecific antibody-drug conjugates (ADCs). Avenzo's small molecule inhibitors, AVZO-021 and AVZO-023, are novel, highly potent and selective inhibitors of CDK2 and CDK4, respectively, which are key enzymes involved in cell cycle regulation. AVZO-021 is being evaluated in a Phase 1/2 study as monotherapy in advanced solid tumors and in combination with fulvestrant in HR+/HER2- metastatic breast cancer. AVZO-021 and AVZO-023 are being evaluated in the Phase 1/2 ORION-1 study in HR+/HER2- metastatic breast cancer, where AVZO-023 is administered in combination with endocrine therapy, with or without AVZO-021. Avenzo's first ADC drug candidate, AVZO-1418, is a potentially differentiated EGFR/HER3 bispecific ADC that is being studied in the AVENTINE-1 Phase 1/2 study for the treatment of advanced solid tumors. Avenzo's second ADC drug candidate, AVZO-103, is a potentially differentiated Nectin4/TROP2 bispecific ADC that is being studied in the BEACON-1 Phase 1/2 study for the treatment of advanced solid tumors.

About Rallybio

Rallybio (Nasdaq: RLYB) is a clinical-stage biotechnology company with a mission to develop and commercialize life-transforming therapies for patients with severe and rare diseases. Rallybio has built a pipeline of promising product candidates aimed at addressing diseases with unmet medical need in areas of complement dysregulation and hematology.