AbbVie wasn’t part of the first wave of cell therapies developed for cancer, but it is positioning itself to contend in the next one, which is expanding to therapies made by engineering immune cells inside a patient’s body and the application of these cells to autoimmune disease. The pharmaceutical giant is committing up to $2.1 billion to acquire Capstan Therapeutics, a cell therapy startup whose in vivo therapies are based on research from biotechnology pioneers at the University of Pennsylvania.
No financial breakdown was provided for the cash sum. But the deal announced Monday brings AbbVie a lead Capstan program that recently began a Phase 1 test in autoimmune disease as well as CellSeeker, the platform technology that produced it.
The first cell therapies to reach patients were CAR T-therapies, which are made by harvesting a patient’s own T cells and engineering them in a lab to go after a particular cancer target. After those cells are multiplied, they’re infused back into the patient. The entire process can take weeks, though many companies are working on ways to make it faster and more efficient. In vivo engineering of a patient’s immune cells would avoid this expensive, multi-step manufacturing process altogether.
The approach of San Diego-based Capstan uses messenger RNA to reprogram immune cells to go after disease-driving cells. The mRNA is encapsulated in a lipid nanoparticle. While viral vectors are a widely used delivery vehicle for genetic medicines, they are typically one-time treatments. These engineered viruses prompt the body to produce antibodies against them, so subsequent doses would be rendered ineffective. By contrast, a lipid nanoparticle does not prompt that immune response, making redosing possible. That’s important for bringing cell therapy to immunology, where treatment of chronic disease typically requires redosing.
Immunology and inflammation is already a strength of AbbVie, but the company has been looking to expand its prospects in this area as its blockbuster antibody drug Humira loses market share to biosimilar competition. The company is offsetting some of the revenue declines with Skyrizi, an antibody drug, and Rinvoq, an oral small molecule. Both products are expanding their labels to multiple immunology indications. Capstan brings a new modality to AbbVie’s immunology pipeline.
The most advanced Capstan program is CPTX2309, which is being developed as a treatment for B cell-mediated autoimmune disorders. The therapy is intended to deplete pathogenic memory B cells, enabling the immune system to repopulate with naïve B cells that don’t remember attacking healthy tissue. This approach could “reset” the immune system, potentially preventing disease progression or even leading to clinical remission.
In preclinical research presented at the recent annual meeting of the American Society of Cell & Gene Therapy, Capstan reported its CAR T-therapy led to in vivo engineering of immune cells followed by depletion of B cells in blood and tissues. Furthermore, the therapy did not require lymphodepletion, which is suppression of the immune system. This preconditioning helps ensure the engineered cells are taken up by the body. It’s a required step of ex vivo CAR T-therapies for cancer.
A Phase 1 test of CPTX2309 is underway enrolling healthy volunteers. While the main goals are to assess safety and efficacy, the trial could also show signs of how the therapy is working. Secondary study goals include measuring levels of components of CPTX2309 and levels of circulating B cells.
William Blair analyst Matt Phipps spoke with AbbVie management, who said a preliminary look at data from the Phase 1 study show “patients achieving rapid and robust B-cell depletion, which provides some clinical validation of CPTX2309,” he wrote in a note sent to investors. While this program is still in early clinical development, William Blair believes the acquisition demonstrates AbbVie’s strategic effort to strengthen its immunology franchise with novel, disease-modifying approaches.
“Given the stage of development, this asset clearly comes with clinical risk, but given the potential of in vivo CAR-T, which does not require lymphodepletion and has potential for greater manufacturing scalability, it offers significant long-term upside if successful,” Phipps said.
Capstan’s co-founders include Carl June, a professor of immunotherapy at Penn who developed Kymriah, which under Novartis became the first FDA-approved CAR T-therapy. Drew Weissman, a Penn professor in vaccine research and an expert in mRNA, is another Capstan co-founder. The startup launched in 2022, revealing $165 million raised to date. Capstan last raised money in 2024, a $175 million Series B round of funding. Besides its lead program for B cell-mediated autoimmune disease, Capstan’s pipeline includes preclinical in vivo CAR T-programs in development for plasma cell disorders and fibrotic disorders.
Other companies in various stages of development with CAR T-therapies for autoimmune disease include Kyverna Therapeutics and Autolus Therapeutics, albeit with therapies that are made ex vivo. Clinical-stage startup Umoja Biopharma has technology for in vivo CAR T-therapies. Last year, AbbVie licensed an Umoja in vivo CAR T-program in development for blood cancers. Umoja has another in vivo CAR T-program for autoimmune diseases in development under a partnership with Iaso Biotherapeutics.
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