ADC Therapeutics, an oncology drug development company, has announced that the first patient has been dosed in a phase I trial to evaluate its lead antibody drug conjugate (ADC) ADCT-301 in acute myeloid leukemia (AML).

The two stage, phase I open-label trial will evaluate the tolerability, safety, pharmacokinetics and activity of ADCT-301 in patients with relapsed or refractory CD-25 positive AML. The initial dose escalation phase will recruit up to 30 patients at 10 clinical sites across the U.S. and will seek to determine the recommended dose of ADCT-301 for the second stage. The second stage, which will begin once an appropriate dose is identified, will be expanded into the U.K. and Europe with the recruitment of up to 30 additional patients.

ADCT-301 is composed of HuMax-TAC, a monoclonal antibody directed against CD25 (the alpha chain of the IL-2 receptor) conjugated to ADC Therapeutics’ highly potent proprietary pyrrolobenzodiazepine (PBD) dimer. In preclinical in vivo models, ADCT-301 exhibited strong dose-dependent anti-tumor activity against CD25-positive cell lines at single low doses.

Professor Martin Tallman, Principle Investigator of the trial and chief of the Leukemia Service at Memorial Sloan Kettering Cancer Center, New York, said, “Acute myeloid leukemia is the most common leukemia in the U.S. adult population and the prognosis is poor. Patients expressing CD25 on their leukemia cells have a particularly poor prognosis.

ADCT-301 has shown promise in in vivo studies and we believe that this important trial could help us to improve patient outcomes.”

ADC Therapeutics currently has two PBD-based ADCs in four clinical trials, with four other ADCs in late preclinical development and further ADCs in research.

ADC Therapeutics has its head office in Lausanne, Switzerland; its R&D laboratories in London, its clinical development team in New Jersey; and its manufacturing team based in San Francisco.