Arsenal Biosciences (ArsenalBio) is reducing its workforce by 99 employees as part of a strategic transition toward the development of in vivo CAR-T therapies. The company said the move represents a significant change in research and development priorities and will leave a smaller core team focused on advancing the new strategy.
A company spokesperson confirmed that the layoffs affect the majority of employees across teams, functions and locations. The reduction follows a previous workforce cut in September 2025, when ArsenalBio reduced its staff by 50%. After that restructuring, the company had 127 employees.
Company Redirects Resources Toward In Vivo CAR-T Development
ArsenalBio announced that it is redirecting its efforts to the field of in vivo CAR-T therapy. As part of the restructuring, development of the company’s ex vivo clinical assets has been halted.
The company said it will retain a core group of employees to advance its in vivo CAR-T plans while also evaluating strategic opportunities for its existing technologies and assets.
“We plan to apply our foundational understanding of T cell biology and compositions to in vivo, where we believe our technology will advance the field and help patients win,” ArsenalBio Chief Executive Officer Ken Drazan, M.D., said in the company’s announcement.
The company stated that it is seeking strategic alternatives for its current assets and technology portfolio as it proceeds with the transition.
Pipeline Restructuring Accompanies Strategic Change
The strategic shift is accompanied by changes to ArsenalBio’s development pipeline. AB-2100, an autologous integrated circuit cell therapy being studied in recurrent clear-cell renal cell carcinoma, is no longer listed in the company’s pipeline.
ArsenalBio had previously focused resources on a phase 1/2 trial of AB-2100 following its 2025 workforce reduction. According to the information provided, topline data from the program had been expected earlier this year, though no results have been disclosed.
AB-1015, which had been in a Phase 1 study, has also been removed from the company’s pipeline listing. Both AB-2100 and AB-1015 remain categorized as active but not recruiting on ClinicalTrials.gov.
The most advanced candidate currently listed by ArsenalBio is AB-3028, an early clinical-stage program for prostate cancer. The company is also developing AB-7000, a preclinical candidate for an undisclosed indication.
Financing and Collaboration Agreements Remain Part of Company History
In September 2024, ArsenalBio announced a $325 million financing intended to support the advancement of its programmable cell therapy programs through clinical development.
The company also entered a multi-program discovery collaboration with Bristol Myers Squibb in late 2020 to advance programmable cell therapies for cancer indications. The agreement included a $70 million upfront payment and additional milestone opportunities. One milestone payment was made in January 2025 after Bristol Myers Squibb exercised an exclusive option to license one program.
ArsenalBio previously raised $325 million with backing from Bristol Myers Squibb and Regeneron and also maintained a partnership with Roche’s Genentech. As part of its latest restructuring, the company said it is exploring strategic opportunities for its technologies and assets while concentrating future development efforts on in vivo CAR-T therapies.
ArsenalBio is making a major strategic shift toward in vivo CAR-T therapies, cutting 99 employees as the biotechnology company redirects resources toward a new generation of cell therapies. ArsenalBio confirmed that the layoffs affect the majority of its workforce across teams, functions, and locations.
ArsenalBio Shifts Focus to In Vivo CAR-T
ArsenalBio said its new strategy will build on years of investment in T-cell biology, synthetic biology, computational technologies, and cell engineering. The company plans to apply these capabilities to in vivo CAR-T therapies targeting a broader range of diseases, including blood cancers and autoimmune conditions.
Unlike traditional ex vivo CAR-T approaches, in vivo CAR-T therapies aim to engineer a patient’s T cells directly inside the body. ArsenalBio believes this approach could potentially make cell therapy more accessible and scalable.
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
- Editorial Team
