Amgen’s investigational therapy AMG 212 (pasotuxizumab) is safe, and showing therapeutic activity against metastatic castration-resistant prostate cancer (mCRPC) in a Phase 1 clinical trial, data show. This is the first study suggesting that Amgen’s BiTE immunotherapy, designed to bring together patients’ immune T-cells and cancer cells, “can be efficacious in solid tumors,” the researchers said. The findings were discussed at the recent 2019 American Society of Clinical Oncology (ASCO) Annual Meeting, in Chicago, in the poster “Phase 1 Study of Pasotuxizumab (BAY 2010112), a PSMA-targeting BiTE (Bispecific T Cell Engager) Immunotherapy for Metastatic Castration-Resistant Prostate Cancer (mCRPC).” The company’s proprietary BiTE technology platform builds antibodies that target two proteins at the same time — one in cancer cells and the other in immune cells. Specifically, AMG 212 targets the prostate-specific membrane antigen (PSMA) in prostate cancer cells and the CD3 protein at the surface of T-cells. This forms a bridge between T-cells and tumor cells, helping the T-cells kill the tumor. The safety and early anti-cancer activity of AMG 212 was evaluated in a Phase 1 trial (NCT01723475) in men with advanced mCRPC who had failed to respond to treatment with previous standard therapies. The study enrolled 16 adult men who received one of five doses of AMG 212, ranging between 5 and 80 µg per day, delivered by continuous intravenous infusion. The treatment showed significant anti-tumor activity in three patients, deemed as a decrease in prostate-specific antigen (PSA) levels by 50% or more. Two patients had long-lasting responses — 14 months in one man receiving the 40 µg dose, and 19.4 months in another receiving the 80 µg dose.