Description of Business	6 Months Ended
Jun. 30, 2026
Organization, Consolidation and Presentation of Financial Statements [Abstract]
Description of Business	Description of Business Allogene Therapeutics, Inc. (the Company or Allogene) was incorporated on November 30, 2017 in the State of Delaware and is headquartered in South San Francisco, California. Allogene is a clinical stage immuno-oncology company pioneering the development of genetically engineered allogeneic T cell product candidates for the treatment of cancer and autoimmune diseases. The Company is developing a pipeline of off-the-shelf T cell product candidates that are designed to target and kill cancer cells in patients or eliminate pathogenic autoreactive cells in patients with autoimmune disorders. The Company’s engineered T cells are allogeneic, meaning they are derived from healthy donors for intended use in any patient, rather than from an individual patient for that patient’s use, as in the case of autologous T cells. The Company believes this key difference will enable it to deliver readily available treatments faster, more reliably, at greater scale, and to more patients. Public Offerings In November 2019, the Company entered into a sales agreement with TD Securities (USA) LLC (f/k/a Cowen and Company, LLC) (TD Cowen), as amended on November 2, 2022 and November 2, 2023, under which the Company may from time to time issue and sell shares of its common stock through TD Cowen in at-the-market (ATM) offerings. The aggregate compensation payable to TD Cowen as the Company’s sales agent equals up to 3.0% of the gross sales price of the shares sold through TD Cowen pursuant to the sales agreement. Although the sales agreement does not specify an aggregate dollar limit on sales, sales under the agreement may be made only pursuant to an effective registration statement and an applicable prospectus supplement. On June 22, 2026, the Company filed a prospectus supplement under its effective shelf registration statement relating to the offer and sale of shares of its common stock having an aggregate offering price of up to $135.0 million pursuant to the sales agreement. During the six months ended June 30, 2026, the Company sold an aggregate of 12,476,533 shares of common stock in ATM offerings resulting in net proceeds of $20.7 million. No shares were sold pursuant to the June 2026 prospectus supplement through June 30, 2026. As of June 30, 2026, shares of common stock having an aggregate offering price of up to $135.0 million remained available for sale under the June 2026 prospectus supplement, subject to market conditions, the terms and conditions of the sales agreement and applicable law. On April 14, 2026, the Company entered into an underwriting agreement with Goldman Sachs & Co. LLC, Jefferies LLC and TD Securities (USA) LLC, as representatives of the several underwriters named therein (Underwriters), relating to the issuance and sale in a public offering of shares of the Company’s common stock (April 2026 Public Offering). On April 16, 2026, the Company closed the April 2026 Public Offering in which it sold 100,200,000 shares of its common stock at a public offering price of $2.00 per share, including 12,700,000 additional shares sold pursuant to the Underwriters’ partial exercise of their option to purchase additional shares. The aggregate gross proceeds were $200.4 million and the aggregate net proceeds were approximately $187.9 million, after deducting underwriting discounts and commissions and offering expenses payable by the Company. Need for Additional Capital The Company has sustained operating losses and expects to continue to generate operating losses for the foreseeable future. The Company’s ultimate success depends on the outcome of its research and development activities as well as the ability to commercialize the Company’s product candidates. The Company had cash, cash equivalents and investments of $423.6 million as of June 30, 2026. Since inception through June 30, 2026, the Company has incurred cumulative net losses of $2,096.0 million. Management expects to incur additional losses in the future to fund its operations and conduct product research and development and recognizes the need to raise additional capital to fully implement its business plan. The Company may raise additional capital through the issuance of equity securities, debt financings, collaborations or other sources to further implement its business plan. If additional financing is not available at adequate levels, the Company may need to reevaluate its operating plan and may be required to delay the development of its product candidates. The Company expects that its cash, cash equivalents and investments as of June 30, 2026 will be sufficient to fund its operations for at least the next 12 months from the date the accompanying unaudited condensed financial statements are filed with the SEC.

Allogene Therapeutics, Inc. (the Company or Allogene) was incorporated on November 30, 2017 in the State of Delaware and is headquartered in South San Francisco, California. Allogene is a clinical stage immuno-oncology company pioneering the development of genetically engineered allogeneic T cell product candidates for the treatment of cancer and autoimmune diseases. The Company is developing a pipeline of off-the-shelf T cell product candidates that are designed to target and kill cancer cells in patients or eliminate pathogenic autoreactive cells in patients with autoimmune disorders. The Company’s engineered T cells are allogeneic, meaning they are derived from healthy donors for intended use in any patient, rather than from an individual patient for that patient’s use, as in the case of autologous T cells. The Company believes this key difference will enable it to deliver readily available treatments faster, more reliably, at greater scale, and to more patients.

In November 2019, the Company entered into a sales agreement with TD Securities (USA) LLC (f/k/a Cowen and Company, LLC) (TD Cowen), as amended on November 2, 2022 and November 2, 2023, under which the Company may from time to time issue and sell shares of its common stock through TD Cowen in at-the-market (ATM) offerings. The aggregate compensation payable to TD Cowen as the Company’s sales agent equals up to 3.0% of the gross sales price of the shares sold through TD Cowen pursuant to the sales agreement. Although the sales agreement does not specify an aggregate dollar limit on sales, sales under the agreement may be made only pursuant to an effective registration statement and an applicable prospectus supplement.

On June 22, 2026, the Company filed a prospectus supplement under its effective shelf registration statement relating to the offer and sale of shares of its common stock having an aggregate offering price of up to $135.0 million pursuant to the sales agreement. During the six months ended June 30, 2026, the Company sold an aggregate of 12,476,533 shares of common stock in ATM offerings resulting in net proceeds of $20.7 million. No shares were sold pursuant to the June 2026 prospectus supplement through June 30, 2026. As of June 30, 2026, shares of common stock having an aggregate offering price of up to $135.0 million remained available for sale under the June 2026 prospectus supplement, subject to market conditions, the terms and conditions of the sales agreement and applicable law.

On April 14, 2026, the Company entered into an underwriting agreement with Goldman Sachs & Co. LLC, Jefferies LLC and TD Securities (USA) LLC, as representatives of the several underwriters named therein (Underwriters), relating to the issuance and sale in a public offering of shares of the Company’s common stock (April 2026 Public Offering). On April 16, 2026, the Company closed the April 2026 Public Offering in which it sold 100,200,000 shares of its common stock at a public offering price of $2.00 per share, including 12,700,000 additional shares sold pursuant to the Underwriters’ partial exercise of their option to purchase additional shares. The aggregate gross proceeds were $200.4 million and the aggregate net proceeds were approximately $187.9 million, after deducting underwriting discounts and commissions and offering expenses payable by the Company.

The Company has sustained operating losses and expects to continue to generate operating losses for the foreseeable future. The Company’s ultimate success depends on the outcome of its research and development activities as well as the ability to commercialize the Company’s product candidates.

The Company had cash, cash equivalents and investments of $423.6 million as of June 30, 2026. Since inception through June 30, 2026, the Company has incurred cumulative net losses of $2,096.0 million. Management expects to incur additional losses in the future to fund its operations and conduct product research and development and recognizes the need to raise additional capital to fully implement its business plan.