MDX-2001-101 study protocol: a phase I/IIa, multicenter, first-in-human, open-label clinical trial evaluating MDX2001 monotherapy in patients with advanced solid tumors.

MDX2001 is a tetraspecific T-cell engager-expander antibody engineered to recognize four distinct antigens: cellular mesenchymal-epithelial transition factor (c-MET) and trophoblast antigen 2 (TROP2) to direct T cells to tumor cells, CD3 to activate T cells, and CD28 to enhance T-cell survival and proliferation. MDX2001 has demonstrated potent antitumor activity in nonclinical studies over a wide range of tumor types. Here, we present the protocol design for study MDX-2001-101, a multicenter, open-label, phase I/IIa clinical trial designed to evaluate the safety, tolerability, and antitumor effects of MDX2001 in patients with advanced solid tumors. The study comprises a phase Ia dose escalation guided by a Bayesian optimal interval design with a targeted maximum tolerated dose toxicity rate of 30%, a phase Ib dose expansion, and a phase IIa indication expansion.