Project summary:

We conducted a first in human trial evaluating the own-developed PSMAxCD3 bispecific antibody CC-1 in patients with metastatic prostate carcinoma (NCT04104607) evaluating intravenous (IV) and subcutaneous (SC) application. In part IV, cytokine release syndrome (CRS, max. 2°) was the most frequently observed toxicity. A profound decline of PSA levels was documented in all but one of the heavily pretreated patients that received the target dose. After enrolment of 5 patients in the SC part, the most frequently observed toxicity was injection site reactions (max. 2°) and CRS, (max. 1°). The so far highest dose level of 3.4mg as weekly application was reached without DLT. Again, rapid decline of PSA levels was documented at dose levels ≥ 1.7 mg. Enrollment of further patients is ongoing. Based on the favorable results, we plan to conduct a basket trial including patients with mPC and other patients with PSMA expressing tumors identified by PSMA-PET imaging and/or IHC, for which NCT funding has been applied for.