The development of highly-potent antibody products (e.g., bispecific antibodies, antibody-cytokine fusions) represents a novel development in pharmaceutical biotechnology, with distinctive requirements in terms of pharmaceutical quality and industrial manufacturing processes. Indeed, while it is common to administer conventional antibody products in IgG format at doses of 100 mg or higher, highly-potent antibody derivatives are often used at doses in the single-digit milligram range or lower. In this article, we describe the design, construction, implementation and authorization process for a new GMP facility, dedicated to the production of antibody-cytokine fusion proteins and bispecific antibodies. The facility was designed capitalizing on the availability of single-use systems for several procedures, both at the upstream and downstream level. The requirement of Annex I to Regulation (EU) 2024/568 of a physical separation of sample processing before and after the last viral removal step was implemented by means of a nanofiltration system, passing through the wall of dedicated laboratories. A stringent design for personnel and material flow was implemented to minimize the risk of cross-contamination and accidental exposure. The experience presented in this article may be of interest to companies that wish to construct similar facilities for their own antibody-based products.