Capital strengthens the advancement of EQ504 through key clinical milestones

Anticipated net proceeds, along with existing cash and cash equivalents, expected to extend cash runway into 2029

LA JOLLA, Calif., March 13, 2026 (GLOBE NEWSWIRE) -- Equillium, Inc. ("Equillium" or the "Company") (NASDAQ:EQ), a biotechnology innovator developing novel therapies to treat severe autoimmune and inflammatory disorders, today announced that it has entered into a definitive securities purchase agreement with RA Capital Management that will provide approximately $35 million in gross proceeds to Equillium.

Pursuant to the terms of the securities purchase agreement, the Company will issue approximately 18.9 million shares of its common stock (including shares of common stock underlying pre-funded warrants), representing a purchase price of $1.854 for each share of common stock (which represents the average closing price of the Company's common stock for the five trading days immediately prior to the financing) or $1.8539 for each pre-funded warrant sold in lieu of common stock at closing. Gross proceeds from the financing are expected to be $35 million, before deducting expenses.

Equillium intends to use the net proceeds from the PIPE to further advance clinical development of EQ504, working capital, and general corporate purposes.

"This financing strengthens our balance sheet and supports continued progress of EQ504 through its clinical development plan and is expected to fund company operations into 2029," said Bruce Steel, Chief Executive Officer of Equillium. "RA Capital Management's investment underscores confidence in our strategy and enables us to remain focused on disciplined execution of our upcoming EQ504 clinical objectives."

EQ504 is an investigational potent and selective aryl hydrocarbon receptor (AhR) modulator that we are developing to be administered orally. We have developed EQ504 to target the colon and believe that it represents a next-generation therapeutic to treat Ulcerative Colitis (UC) locally. We believe EQ504 has broad therapeutic potential in UC as a potential standalone oral therapy or in combination with other therapeutic approaches.

LifeSci Capital is acting as Equillium's financial advisor.

The offer and sale of the foregoing securities to be issued in the PIPE financing are being made in a transaction not involving a public offering and have not been registered under the Securities Act of 1933, as amended (the "Securities Act"), or any applicable state securities laws. Accordingly, the securities may not be offered or sold in the United States except pursuant to an effective registration statement or an applicable exemption from the registration requirements of the Securities Act and such state securities laws. RA Capital Management has been granted customary resale Form S-3 registration rights for the shares of common stock issued to (or that are exercisable by) them in connection with the financing.

This press release shall not constitute an offer to sell or the solicitation of an offer to buy any securities, nor shall there be any sale of these securities in any state or other jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such state or other jurisdiction.

About Equillium

Equillium is a biotechnology innovator developing novel therapies to treat severe autoimmune and inflammatory disorders. The company's lead therapeutic candidate is EQ504, a potent and selective aryl hydrocarbon receptor modulator designed with a multi-modal, non-immunosuppressive mechanism of action to be complementary to other inflammation and immunology agents. EQ504 is an investigational therapeutic program with potential for targeted, local delivery via enteric coating for the treatment of ulcerative colitis and other gastrointestinal diseases or inhaled formulations for the treatment of inflammatory lung diseases.

For more information, visit www.equilliumbio.com.

Forward Looking Statements

Statements contained in this press release regarding matters that are not historical facts are "forward-looking statements" within the meaning of the Private Securities Litigation Reform Act of 1995. Forward-looking statements may be identified by the use of words such as "anticipate", "believe", "could", "continue", "expect", "estimate", "may", "plan", "outlook", "future", "potential" and "project" and other similar expressions that predict or indicate future events or trends or that are not statements of historical matters.

These statements include, but are not limited to, statements regarding the completion of the proposed private placement; Equillium's intent to develop EQ504 as an orally delivered, colon-targeted treatment; Equillium's belief that EQ504 is a next generation therapeutic; the broad therapeutic potential of EQ504 to treat ulcerative colitis, including as a mono and/or combination therapy; Equillium's expectation that the net proceeds from the initial closing will extend its cash runway into 2029; Equillium's expected use of the net proceeds from the private placement; and other statements that are not historical facts. Because such statements are subject to risks and uncertainties, many of which are outside of Equillium's control, actual results may differ materially from those expressed or implied by such forward-looking statements. Risks that contribute to the uncertain nature of the forward-looking statements include: risks and uncertainties related to market conditions; volatility in the trading price of Equillium's common stock; Equillium's ability to initiate or progress clinical trials on the anticipated timelines, if at all; the potential for results from clinical trials to differ from nonclinical, early clinical, preliminary or expected results; reliance on the clinical results from third-party product candidates and/or approved drugs to support advancement and the potential of Equillium's product candidates; implementation of Equillium's strategic plans for its business and product candidates; the sufficiency of Equillium's capital resources and need for additional capital to achieve its goals; and other risks and uncertainties described more fully under the heading "Risk Factors" in Equillium's Quarterly Report on form 10-Q for the quarter ended September 30, 2025 filed with the Securities and Exchange Commission (SEC), and elsewhere in Equillium's filings and reports, which may be accessed for free by visiting the SEC's website and on Equillium's website under the heading "Investors." Investors should take such risks into account and should not rely on forward-looking statements when making investment decisions. All forward-looking statements contained in this press release speak only as of the date on which they were made. Equillium undertakes no obligation to update such statements to reflect events that occur or circumstances that exist after the date on which they were made, except as required by law.

Corporate Contact

PJ Kelleher

LifeSci Advisors, LLC

+1-617-430-7579

pkelleher@lifesciadvisors.com

Equillium Announces $35 Million Financing with RA Capital Management