Open Enrollment Approved for Phase IIb Trial of Immunotherapy in Osteosarcoma

OS Therapies has announced that the Data Safety & Monitoring Committee (DSMC) approved open enrollment for AOST-2121: an open label Phase IIb Trial of OST-HER2 (Listeria monocytogenes) in Recurred, Resected Osteosarcoma (OS). OS is a deadly and debilitating cancer of the bone that usually occurs in adolescence and young adults. Standard treatment includes surgery and chemotherapy. For patients with initially metastatic or recurrence after chemotherapy, there is a significantly poorer prognosis.

OST-HER2 is a Lm vector-based off-the-shelf Immunotherapy intended to prevent metastasis, delay recurrence, and increase overall survival. The FDA had requested a safety roll-out staggering the first three patients by three weeks - safety data from these patients has given the safety committee the ability to open the trial nationally to the remaining patients.

"The Osteosarcoma Community has been anxiously awaiting the clinical trial of this very promising technology ever since it was provisionally approved for dogs by the USDA – we just want to try it on our kids," said Miriam Cohen, Chair of the Osteosarcoma Collaborative, an OS patient advocacy organization that has supported the trial.

The OST-HER2 Lm vector platform technology has been administered to over 450 cancer patients in ongoing and completed clinical trials. AOST-2121 is a Phase IIB clinical trial intended to prevent metastasis and improve overall survival in Osteosarcoma. OST-HER2 has received Rare Disease Designation (RDD), Fast-Track and Orphan Designations by the FDA and EMA. OST hopes to seek a Break-Through Designation (BTD) based on data from this Phase IIb clinical trial.  OST31-164 has previously received USDA provisional approval for treatment of Osteosarcoma in canines. In a completed Phase III study in canines (n=180), data demonstrated a clear separation of treated and untreated canine patients (p=.0007) in overall survival and disease progression.