​​Paula Videira and team​

In 2024, the European Union recorded an estimated 2.7 million new cancer cases. A significant obstacle in detection is that many aggressive tumours, such as pancreatic and triple-negative breast cancers, often lack reliable or well-defined biomarkers. Identification is further complicated by the nature of glycans, short sugar chains that form a "coat" on our cells. While these sugars are a normal part of cellular structure, cancer cells express abnormal, truncated versions known as tumour-associated glycan antigens. Videira and her collaborators set out to create an antibody that could accurately distinguish these malignant features while sparing healthy tissue.

The team developed the L2A5 antibody, which targets the sialyl Tn (STn) antigen, a small structure that is present on the surface of approximately 80% of cancer cells but missing in healthy cells. What sets L2A5 apart from earlier antibodies is its ability to recognise cancer cells with greater precision. Previous anti-glycan tools often did not bind strongly enough with cancer cells or reacted with healthy tissue by mistake. L2A5 features distinctive sequence patterns in its binding regions that allow it to recognise several closely related cancer markers simultaneously. Because of its high precision, the L2A5 sequence can be adapted into different formats, including antibody-drug conjugates (ADCs) that deliver medicine directly into tumours or CAR-T cell therapies that "train" a patient's own immune system to hunt STn-positive cells.

Solving the puzzle, one piece at a time

Videira became interested in glycobiology during her master’s and PhD studies, and became drawn to a central question: why do cancer cells display shortened, abnormal glycans that healthy cells usually hide? This puzzle, together with personal experiences of cancer within her team, helped guide the group’s direction. The team advanced L2A5 step-by-step. Videira recalls, “There was no single ‘eureka’ moment. It was a buildup. Each experiment gave us more confidence.”

Early studies showed that L2A5 bound firmly to tumour tissue while sparing healthy cells, an encouraging pattern that set the direction for further work. Later sequence analysis confirmed that the antibody’s binding regions were unique, demonstrating that L2A5 was genuinely new and forming the scientific basis for patenting.

In 2019, the patent was filed. In that same year, Videira and her colleagues co‑founded CellmAbs and the patent was licensed from NOVA to CellmAbs. They worked with external patent attorneys to refine claims and plan the next development steps. Filing the patent set the pathway for future commercial decisions, and in 2024, CellmAbs and NOVA entered a patent assignment and licensing agreement with a pharmaceutical company, which took over L2A5 for further development.

L2A5 was the result of close collaboration between NOVA University Lisbon, the Instituto Português de Oncologia Francisco Gentil and Helmholtz‑Zentrum Dresden‑Rossendorf. As Videira notes, “Ours was never a one-discipline story...Each partner brought crucial expertise, and without that collaboration, the technology would not be what it is today.”

About the inventor

Paula Videira is a glycobiology researcher and full professor at the NOVA School of Science and Technology in Lisbon | NOVA FCT and director of UCIBIO research unit. She has worked at NOVA since 2008, advancing through academic ranks while building a leading research programme in glycobiology as leader of the Glycoimmunology Research Group. Her academic path began with a biochemistry degree in Coimbra, followed by master’s and doctoral studies in biotechnology. Her long‑standing interest in glycans, once considered an overlooked biological domain, has shaped her career and focus on cancer‑linked sugar structures.