Exhibit 99.1
Jade Biosciences Announces Proposed Underwritten Public Offering
San Francisco and Vancouver, British Columbia – June 3, 2026 – Jade Biosciences, Inc. (“Jade” or the “Company”)
(Nasdaq: JBIO), a clinical-stage biotechnology company focused on developing best-in-class therapies for autoimmune diseases, today announced that it intends to offer
and sell, subject to market and other conditions, shares of its common stock or, in lieu of common stock to certain investors that so choose, pre-funded warrants to purchase shares of its common stock, in a
proposed underwritten public offering. All of the shares of common stock and pre-funded warrants to be sold in the proposed offering are being offered by Jade. In addition, Jade intends to grant the
underwriters a 30-day option to purchase up to an additional 15% of the securities offered in the public offering, at the public offering price, less underwriting discounts and commissions. There can be no
assurance as to whether or when the proposed public offering may be completed, or as to the actual size or terms of the proposed offering.
Jade intends
to use the net proceeds from the proposed offering, together with its existing cash, cash equivalents, and investments, to fund clinical trials, preclinical studies, and manufacturing in support of its programs, as well as for additional research
and development activities, capital expenditures, working capital and other general corporate purposes.
Jefferies, TD Cowen and UBS Investment Bank are
acting as joint book-running managers for the proposed offering. LifeSci Capital is also acting as a book-running manager for the proposed offering. BTIG is acting as a lead manager for the proposed offering.
The securities described above are being offered by Jade pursuant to a shelf registration statement on Form S-3,
including a base prospectus, that was previously filed with the Securities and Exchange Commission (“SEC”) and was declared effective on May 15, 2026. A preliminary prospectus supplement and accompanying prospectus relating to this
offering will be filed with the SEC. Copies of the prospectus supplement for this offering may be obtained, when available, by contacting Jefferies LLC, Attention: Equity Syndicate Prospectus Department, 520 Madison Avenue, New York, NY 10022, by
telephone at (877) 821-7388, or by email at Prospectus_Department@Jefferies.com; TD Securities (USA) LLC, c/o Broadridge Financial Solutions, 1155 Long Island Avenue, Edgewood, NY 11717 or by email at
TDManualrequest@broadridge.com; and UBS Securities LLC, Attention: Prospectus Department, 11 Madison Avenue, New York, NY 10010, or by email at ol-prospectus-request@ubs.com. Electronic copies of the
preliminary prospectus supplement and accompanying prospectus will also be available on the website of the SEC at http://www.sec.gov.
This press release
shall not constitute an offer to sell or the solicitation of an offer to buy these securities, 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 the
registration or qualification under the securities laws of any such state or jurisdiction.
About Jade Biosciences, Inc.
Jade Biosciences is a clinical-stage biotechnology company focused on developing
best-in-class therapies that address critical unmet needs in autoimmune diseases. Jade’s lead candidate, JADE101, targets the cytokine APRIL, and is currently
being evaluated for the treatment of immunoglobulin A nephropathy. Jade’s pipeline also includes JADE201, an afucosylated anti-BAFF-R monoclonal antibody, as well as JADE301, an undisclosed antibody
program. Jade was launched based on assets licensed from Paragon Therapeutics, an antibody discovery engine founded by Fairmount.