CX-2029

P1/2, N=133, Completed, CytomX Therapeutics | Active, not recruiting --> Completed

Except for an antibody drug conjugate (CX-2029), this is the first-in-class trial of an unmodified human antibody other than the murine P1a trial conducted in the 1990s. AEs are mild as observed within the level of previous healthy volunteer's trial. Efficacy observed in all erythroid parameters including hematocrit, hemoglobin and other parameter shown symptoms seen in iron deficiency anemia. This antibody can specifically suppress erythrocyte differentiation by inhibiting iron influx in the target erythroid lineage, which cells are highly expressed TfR1, without any significant AE on other normal organs with low expression level of TfR.

The Probody therapeutic platform enables targeting CD71, a previously undruggable ADC target, at tolerable doses associated with clinical activity.

Secondary endpoints include duration of response, progression-free survival, overall survival, safety, and pharmacokinetics. Tumor specimens are required during screening (optional at 3-5 days following the first infusion) for assessment of CD71 parameters and possible correlation with response.

The observed safety profile for CX-2029 effectively reduces on-target toxicity for this previously undruggable target, supporting the PROBODY platform. Evidence of anti-tumor activity was observed. Dose escalation continues.