Imago BioSciences, Inc. Announces Proposed Initial Public Offering of Common Stock

Imago BioSciences, Inc. ("Imago"), a clinical stage biopharmaceutical company discovering new medicines for the treatment of myeloproliferative neoplasms (MPNs), today announced that it has commenced an underwritten initial public offering of up to 7,000,000 shares of its common stock. All of the shares to be sold in the offering will be offered by Imago. In addition, Imago expects to grant the underwriters for the offering a 30-day option to purchase up to an additional 1,050,000 shares of common stock at the public offering price, less underwriting discounts and commissions. The offering is subject to market and other conditions, and there can be no assurance as to whether or when the offering may be completed, or as to the actual size or terms of the offering.

Imago currently expects to use the net proceeds from this offering to fund the clinical development of bomedemstat for essential thrombocythemia through the completion of both the ongoing Phase 2 clinical trial and the planned Phase 3 clinical trial, clinical development of bomedemstat for myelofibrosis through the completion of both the ongoing and planned Phase 2 clinical trials, cGMP process development for bomedemstat, development of bomedemstat for additional indications, and for the development of additional pipeline candidates, internal research, and any remaining amounts for working capital and general corporate purposes.

Jefferies, Cowen, Stifel and Guggenheim Securities are acting as joint book-running managers for the offering.

A registration statement relating to the securities has been filed with the Securities and Exchange Commission, but has not yet become effective. These securities may not be sold, nor may offers be accepted, prior to the time the registration statement becomes effective. This press release shall not constitute an offer to sell or the solicitation of an offer to buy, nor shall there be any sale of, these securities in any state or jurisdiction in which such offer, solicitation, or sale would be unlawful prior to registration or qualification of these securities under the securities laws of any such state or jurisdiction.

In addition to the shares being sold in the initial public offering, Imago has agreed to sell an additional $20 million of its common stock in a concurrent private placement at the public offering price per share to Pfizer Inc. The sale of these shares of common stock will not be registered under the Securities Act of 1933, as amended, and will be subject to a 180-day lock-up agreement. The concurrent private placement is also scheduled to close concurrent with the initial public offering, subject to satisfaction of customary closing conditions. The closing of Imago's initial public offering is not conditioned upon the closing of the concurrent private placement, but the closing of the concurrent private placement is conditioned upon the closing of the initial public offering.

The offering of these securities is being made only by means of a prospectus, copies of which may be obtained from: Jefferies LLC, 520 Madison Avenue, 2nd Floor, New York, NY 10022, or by email at [email protected] or by phone at 877-821-7388; or Cowen and Company, LLC, c/o Broadridge Financial Solutions, Attn: Prospectus Department, 1155 Long Island Avenue, Edgewood, NY 11717, by telephone at (833) 297-2926 or by email at [email protected]; or Stifel, Nicolaus & Company, Incorporated, Attention: Syndicate, One Montgomery Street, Suite 3700, San Francisco, CA 94104, or by telephone at (415) 364-2720, or by email at [email protected]; or Guggenheim Securities, LLC, Attention: Equity Syndicate Department, 330 Madison Avenue, 8th Floor, New York, NY 10017, by telephone at (212) 518-9544 or by email at [email protected].

Imago has applied to list its common stock on The Nasdaq Global Select Market under the symbol "IMGO."