Chemomab-Scipher Merger Advances First-in-Class CCL24 Antibody Nebokitug Into AI-Guided Phase 2 RA Trial

Chemomab Therapeutics and Scipher Medicine Corporation have entered a definitive merger agreement to advance nebokitug, a first-in-class monoclonal antibody targeting the chemokine CCL24, into a phase 2 precision medicine trial in rheumatoid arthritis (RA). The combined company, which will operate as Scipher Medicine Corporation and trade on Nasdaq under "SCIP," is positioning nebokitug as a potential first precision medicine option for RA, a field that has not seen a novel mechanism approved by the FDA since 2012.

CCL24 was identified more than 15 years ago as a pro-inflammatory, pro-fibrotic cytokine implicated in RA pathology, and subsequent independent research has shown the chemokine is upregulated in RA patients regardless of disease onset, with higher expression correlating to greater disease severity.¹ Nebokitug neutralizes CCL24 activity, giving it what the companies describe as a dual mechanism addressing both inflammation and fibrosis, distinct from the largely inflammation-focused mechanisms of currently approved RA biologics.

What clinical data support the RA rationale?

Nebokitug's RA rationale draws on results from the phase 2 SPRING trial in primary sclerosing cholangitis, where the antibody met its primary safety endpoint and showed improvement across a range of immune and fibrosis-related secondary endpoints at 15 and 48 weeks, including dose-dependent downregulation of TGF-beta and other biomarkers relevant to RA.² The companies also point to five completed nebokitug clinical trials showing a consistent safety and tolerability profile.

Separately, Scipher's AI Network Medicine platform, which draws on genomic data and electronic medical records from more than 3 million rheumatology patients, independently ranked CCL24 as the top clinical-stage therapeutic target for RA efficacy. That convergence between preclinical mechanism, prior clinical data, and AI-derived target ranking is the core scientific argument behind the planned trial.

How will patients be selected for the phase 2 study?

The proposed phase 2 study will use standard 12-week FDA RA endpoints, but patient enrollment will be guided by PrismRA, Scipher's multi-omic blood test and the only RA treatment-response assay accepted for reimbursement by the Centers for Medicare and Medicaid Services. The approach reflects a broader push toward biomarker-guided trial design in immunology, similar to AI-driven patient selection strategies now being applied in oncology drug development. A topline readout from the RA phase 2 trial is expected in the first half of 2028.

What does the merger structure mean for the programs?

Under the agreement, pre-merger Scipher equity holders are expected to own approximately 68% of the combined company and pre-merger Chemomab equity holders approximately 32%, with Chemomab shareholders also receiving contingent value rights tied to nebokitug milestones. A concurrent $30 million private placement, led by Northpond Ventures with participation from Khosla Ventures and other investors, is expected to fund operations into the second half of 2028. The transaction has unanimous board approval from both companies and is expected to close in the fourth quarter of 2026, pending shareholder approval and other customary conditions.

Beyond RA, Chemomab has noted the potential to pursue a partner for a phase 3 trial of nebokitug in primary sclerosing cholangitis, an indication with no currently approved therapies.

References

1. Al-Jaberi, L., Simonds, M. M., & Brescia, A. M. C. (2023 Jul 5). CCL24, CXCL9 and CXCL10 are increased in synovial fluid in patients with juvenile idiopathic arthritis requiring advanced treatment. Rheumatology (Oxford, England). https://doi.org/10.1093/rheumatology/keac617
2. Bowlus CL, et al. (2025 Nov 19). Nebokitug, an Anti-chemokine (C-C Motif) Ligand 24 Monoclonal Antibody, in Patients With Primary Sclerosing Cholangitis: A Phase 2 Study. Am J Gastroenterol. https://pubmed.ncbi.nlm.nih.gov/41257532/