Climb Bio Reports Fourth Quarter and Year-End 2024 Financial Results and Provides Business Updates Received Clearance from the U.S. Food and Drug Administration (FDA) for Clinical Trials of Budoprutug in Primary Membrano

Climb Bio Reports Fourth Quarter and Year-End 2024 Financial

Results and Provides Business Updates

Received Clearance from the U.S. Food and Drug Administration (FDA) for Clinical Trials of

Budoprutug in Primary Membranous Nephropathy (pMN), Immune Thrombocytopenia (ITP), and Systemic Lupus Erythematosus (SLE)

Studies to Support Process Optimization through Cell Line Switch for Budoprutug and Filed Additional Patent Applications to Further Strengthen Intellectual Property Position

Expanded Pipeline to Include CLYM116, an Anti-APRIL (A PRoliferation-Inducing Ligand) Monoclonal Antibody for Treatment of IgA Nephropathy

Appointed Perrin Wilson, Ph.D. as Chief Business Officer

Ended 2024 in a Strong Financial Position, with Cash Runway Expected Through 2027

WELLESLEY HILLS, MASS., (GLOBE NEWSWIRE) March 25, 2025 Climb Bio, Inc. (Nasdaq: CLYM), a clinical stage biotechnology company developing

therapeutics for patients with immune-mediated diseases, today reported financial results for the quarter and year ended December 31, 2024, provided a business update, and reiterated anticipated program milestones.

2024 was a transformational year for Climb Bio, as we rebranded the company and embarked on our mission to bring more inspired medicines to patients

living with immune-mediated diseases, said Aoife Brennan, President and CEO of Climb Bio. Our momentum continues in 2025, which marks a critical year of execution across our portfolio. Our cornerstone asset, budoprutug, a potentially best-in-class anti-CD19 monoclonal antibody, is being developed for three initial indications: pMN, ITP, and SLE, each of which represents a significant opportunity where we

believe budoprutug is differentiated and uniquely positioned to deliver meaningful outcomes for patients. With regulatory clearance from the FDA now in place for clinical trials in all three indications, we have begun initiating clinical trials and

expect to begin dosing patients later this year.

Dr. Brennan continued, Additionally, we recently

in-licensed a second asset, CLYM116, a potential best-in-class anti-APRIL monoclonal antibody currently in Investigational New

Drug (IND)-enabling studies for the treatment of IgAN and other B-cell mediated diseases. We remain focused on progressing this program towards the clinic and expect to share initial preclinical data in the

second half of 2025. With two highly differentiated assets in our pipeline, a strong balance sheet, and a deeply experienced team, we are well positioned to execute on our goals and advance new treatment options for the approximately 50 million

people in the U.S. living with immune-mediated diseases.

Portfolio Overview and Anticipated Key Milestones

Fourth Quarter and Full Year 2024 Financial Results

About Climb Bio, Inc.

Climb Bio, Inc. is a clinical-stage biotechnology company developing therapeutics for patients with immune-mediated diseases. The Company s pipeline

includes, budoprutug, an anti-CD19 monoclonal antibody that has demonstrated B-cell depletion and has potential to treat a broad range of B-cell mediated diseases, and

CLYM116, an anti-APRIL monoclonal antibody currently in IND-enabling studies for IgA nephropathy. For more information, please visit climbbio.com.

Forward-Looking Statements

This press release contains

forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995, including without limitation statements regarding: future expectations, plans and prospects for Climb Bio; expectations regarding the

therapeutic benefits, clinical potential and clinical development of budoprutug and CLYM116; the trial design for the planned clinical trials of budoprutug; the anticipated timelines for initiating clinical trials of budoprutug for primary

membranous nephropathy, immune thrombocytopenia and systemic lupus erythematosus; plans to optimize the administration of budoprutug; the anticipated benefits of Climb Bio s license agreement with Mabworks; the sufficiency of Climb Bio s

cash resources for the period anticipated; and other statements containing the words anticipate, believe, continue, could, estimate, expect, intend, may,

plan, potential, predict, project, should, target, would, will, working and similar expressions. Forward-looking statements are based on

management s current expectations of future events and are subject to a number of risks and uncertainties that could cause actual results to differ materially and adversely from those set forth in, or implied by, such forward-looking

statements. Climb Bio may not actually achieve the plans, intentions or expectations disclosed in these forward-looking statements, and you should not place undue reliance on these forward-looking statements. These risks and uncertainties include,

but are not limited to, important risks and uncertainties associated with: the ability of Climb Bio to timely and successfully achieve or recognize the anticipated benefits of its acquisition of Tenet Medicines, Inc. and its license agreement with

Mabworks; changes in applicable laws or regulation; the possibility that Climb Bio may be adversely affected by other economic, business and/or competitive factors; Climb Bio s ability to advance budoprutug and CLYM116 on the timelines expected

or at all and to obtain and maintain necessary approvals from the U.S. Food and Drug Administration and other regulatory authorities; obtaining and maintaining the necessary approvals from investigational review boards at clinical trial sites and

independent data safety monitoring boards; replicating in clinical trials positive results found in early-stage clinical trials; competing successfully with other companies that are seeking to develop treatments for primary membranous nephropathy,

immune thrombocytopenia, systemic lupus erythematosus, IgA nephropathy and other immune-mediated diseases; maintaining or protecting intellectual property rights related to budoprutug, CLYM116 and/or its other product candidates; managing expenses;

and raising the substantial additional capital needed, on the timeline necessary, to continue development of budoprutug, CLYM116 and any other product candidates Climb Bio may develop. For a discussion of other risks and uncertainties, and other

important factors, any of which could cause Climb Bio s actual results to differ materially from those contained in the forward-looking statements, see the Risk Factors section, as well as discussions of potential risks,

uncertainties and other important factors, in Climb Bio s most recent filings with the U.S. Securities and Exchange Commission. In addition, the forward-looking statements included in this press release represent Climb Bio s views as of

the date hereof and should not be relied upon as representing Climb Bio s views as of any date subsequent to the date hereof. Climb Bio anticipates that subsequent events and developments will cause Climb Bio s views to change. However,

while Climb Bio may elect to update these forward-looking statements at some point in the future, Climb Bio specifically disclaims any obligation to do so, except as required by law.

Condensed Consolidated Balance Sheets

Condensed Consolidated Statements of Operations

(In thousands, except per share amounts)