The Conversation (0)
Preclinical data for CLYM116, anti-APRIL monoclonal antibody, highlight favorable pharmacokinetic and pharmacodynamic profile, supporting development for IgA nephropathy (IgAN)
Long-term follow-up clinical data for budoprutug, anti-CD19 monoclonal antibody, support potential for therapeutic benefit in primary membranous nephropathy (pMN)
Climb Bio, Inc. (Nasdaq: CLYM), a clinical stage biotechnology company developing therapeutics for patients with immune-mediated diseases, today announced the upcoming presentation of CLYM116 preclinical data and published budoprutug pMN Phase 1b long-term outcome data at the 2025 American Society of Nephrology (ASN) Kidney Week, which will be held in Houston, TX November 6-9, 2025.
Climb Bio will present additional preclinical data characterizing CLYM116, a novel ‘sweeper' anti-APRIL monoclonal antibody, which is being developed to treat IgAN. In preclinical models, CLYM116 promoted APRIL degradation and demonstrated enhanced antibody recycling, leading to deep and durable reduction of IgA. On September 29, 2025, Climb Bio held an R&D Spotlight Webcast focused on CLYM116 to review initial preclinical data and the development opportunity in IgAN.
The company also published an abstract providing new clinical data from its budoprutug program, a novel anti-CD19 monoclonal antibody in development for B-cell mediated diseases. Long-term follow-up clinical data from the previously conducted Phase 1b trial (NCT04652570) in pMN demonstrated long-term control of proteinuria for up to three years after initial dosing in four patients who received up to four doses of budoprutug. Additionally, in three of these patients, no further immunosuppressive treatment was required. In the study, no clinically significant treatment-related adverse events were observed. These results, along with other available data, support further investigation of budoprutug as a potential disease-modifying therapy for pMN and other B-cell-mediated diseases.
The abstracts are now available on the ASN Kidney Week conference website .
Presentation Details
Title: Development and Characterization of CLYM116, a Novel Fc-Engineered Anti-APRIL Monoclonal Antibody (mAb) with pH-Dependent Binding for IgAN
Poster Number: SA-PO0253
Session: Pharmacology PO2000
Date / Time: November 8, 2025, 10:00 AM to 12:00 PM
Published Abstract
Title : Long-Term Remission of Proteinuria in Primary Membranous Nephropathy After Four Doses of Budoprutug, a Novel Anti-CD19 Monoclonal Antibody
Abstract Number: 4350370
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 being developed for IgA nephropathy. For more information, please visit climbbio.com .
About Budoprutug
Budoprutug is a clinical-stage, anti-CD19 monoclonal antibody being developed by Climb Bio to address a broad range of B-cell mediated, immune-driven diseases. Designed with enhanced effector function and low picomolar affinity, budoprutug targets and depletes CD19-expressing B cells, including plasmablasts that are key sources of pathogenic autoantibodies. Climb Bio is evaluating budoprutug in multiple clinical trials across three lead indications—primary membranous nephropathy (pMN), immune thrombocytopenia (ITP), and systemic lupus erythematosus (SLE)—which represent distinct mechanistic subtypes of immune-mediated disease. Early clinical data suggest budoprutug may offer durable B-cell depletion, rapid reductions in autoantibodies, and clinical remission in pMN. A subcutaneous formulation is also in development to enable broader patient access and potential home-based dosing. Budoprutug has been granted orphan drug designation by the FDA for the treatment of pMN.
About CLYM116
CLYM116 is a preclinical-stage monoclonal antibody targeting APRIL (A PRoliferation-Inducing Ligand), a key driver of pathogenic B-cell activity in autoimmune diseases. CLYM116 employs a novel pH-dependent bind-and-release mechanism to potently block APRIL signaling, promote lysosomal degradation of APRIL, and recycle the antibody to extend its half-life. This differentiated design offers the potential for rapid, deep, and durable inhibition of APRIL with a favorable safety profile and less frequent dosing. CLYM116 is being advanced for the treatment of IgA nephropathy (IgAN) and may also have broader utility across other B-cell mediated diseases where APRIL plays a critical role.
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; expectations regarding the timing of submitting an investigational new drug application or clinical trial application submission for CLYM116; the anticipated timelines for initiating a clinical trial of CLYM116; the anticipated timelines for announcing data from Climb Bio's ongoing and planned clinical trials; 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 technology transfer and exclusive license agreement with Beijing Mabworks Biotech Co., Ltd.; 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 or preclinical studies; 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; changes in applicable laws or regulation; the possibility that Climb Bio may be adversely affected by other economic, business and/or competitive factors; 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.
Investors and Media
Carlo Tanzi, Ph.D.
Kendall Investor Relations
ctanzi@kendallir.com
