At the Early Clinical Trial Unit in Dresden, Germany, a new weapon against advanced cancers that have resisted standard treatment is showing real promise. IMA401, a bispecific T-cell engager, has demonstrated its ability to shrink tumors by doing something clever: it acts as a biological bridge, linking cancer cells directly to the body's T lymphocytes—the immune system's frontline soldiers—and activating them to destroy the disease.
The drug works through an elegant molecular strategy. IMA401 simultaneously binds to two targets: MAGEA4/8, a tumor antigen found inside cancer cells, and CD3, a molecule on the surface of immune T cells. This dual binding redirects T lymphocytes specifically to tumor locations and activates them to attack, a significant advance because it allows doctors to target tumor markers that exist within cancer cells rather than only on their surface.
In a Phase Ia/Ib first-in-human trial led by Prof. Martin Wermke at NCT/UCC Dresden, 61 patients with advanced tumors that had stopped responding to standard treatments received IMA401 as an infusion. Some patients received it alone; others in combination with Pembrolizumab, an already approved immunotherapy drug. The primary goals were establishing safety and finding the optimal dose for future development.
Overall, the treatment was well tolerated. The most common side effects were expected consequences of immune activation. Cytokine release syndrome—the body's natural response to immune stimulation—occurred in 38% of patients and was typically mild, mainly causing fever. Temporary blood count changes appeared in about a third of patients, including reversible lymphopenia in 33% and neutropenia in 31%. These adverse events were manageable and reversible.
The trial showed responses across several tumor types, including lung cancer, melanoma, and neuroendocrine tumors. Head and neck cancer patients showed particularly encouraging results. Among 14 patients treated at the optimal dose range, four experienced significant tumor shrinkage—a 29% response rate in a population with extremely limited options. Remarkably, three of those four responses were still ongoing when researchers conducted their analysis, with a median response duration of 8.8 months.
"The results of the study represent a significant advancement for our patients, for whom otherwise only very limited chemotherapy options are available in this situation," said Wermke. He emphasized that IMA401's good tolerability opens doors to combination strategies that were previously too risky. Already, researchers are planning the next phase: testing IMA401 combined with a different T-cell engager targeting another tumor marker in lung cancer patients, with hopes this combination will prove even more effective.
The findings reflect a broader shift in cancer immunotherapy toward smarter targeting. By using internal tumor markers rather than relying solely on surface proteins, IMA401 expands the universe of cancers that could theoretically be attacked this way. The full results will be presented May 31, 2026, at the American Society of Clinical Oncology annual meeting in Chicago and published simultaneously in Nature Medicine, giving the global oncology community detailed access to Dresden's breakthrough work.