Geron Corporation (Nasdaq:GERN) today announced the initiation of GRABM-B ( GRN1005 Against Brain Metastases – Breast cancer), a Phase 2 clinical trial to evaluate GRN1005 in patients with brain metastases arising from breast cancer. GRN1005 is the company's lead LRP-directed peptide-drug conjugate (LRP-directed PDC) that consists of the cytotoxic drug, paclitaxel, linked to a peptide (Angiopep-2) that targets the LRP receptor to cross the blood-brain barrier (BBB) and to target tumors in the brain. “There is a need for effective drugs for patients with cancer metastases in the brain,” said Stephen M. Kelsey, M.D., Geron's Executive Vice President, Head of R&D and Chief Medical Officer. "We have been encouraged by the preliminary evidence of anti-tumor activity against brain metastases observed in the Phase 1 clinical trial of GRN1005, and we hope to confirm these results in the GRABM-B Phase 2 study in patients with brain metastases from breast cancer." Phase 2 Clinical Trial Design (GRABM-B) The purpose of the Phase 2 study is to assess the efficacy, safety and tolerability of GRN1005 in patients with brain metastases from breast cancer. The trial is designed to include 100 patients with HER2 positive or HER2 negative metastatic breast cancer (MBC) disease, who will be assessed in two separate cohorts of 50 patients each. Approximately half of the patients in each cohort will have received prior Whole Brain Radiation Therapy. GRN1005 will be evaluated as a single agent in patients with HER2 negative metastatic breast cancer. For patients with HER2 positive disease, GRN1005 will be assessed in combination with trastuzumab (Herceptin®), which is the standard-of-care therapy for HER2 positive extra-cranial MBC disease. GRN1005 will be administered at a dose of 650 mg/m 2 by intravenous (IV) infusion every three weeks. The primary efficacy endpoint for the trial is intra-cranial response rate. Important secondary endpoints include duration of intra-cranial response, three month intra-cranial progression-free survival and six month overall survival. Rationale for the Study Cancer in the brain, particularly metastases, currently represents a significant unmet medical need, because drugs that might be effective against these tumor types are not able to efficiently cross the blood-brain barrier and enter the tumor. Preclinical and Phase 1 data indicate that GRN1005 transports paclitaxel into tumors inside the brain through LRP1-mediated transport. GRN1005 also has activity against tumors outside the brain.