FDA Grants Orphan Drug Designation to DUNP19 for Osteosarcoma

The FDA has granted an orphan drug designation to DUNP19 for the treatment of osteosarcoma.

The FDA has granted an orphan drug designation (ODD) to DUNP19 for the treatment of osteosarcoma, according to an announcement from Radiopharm Theranostics.1

DUNP19, a dual-action, LRRC15-targeted monoclonal antibody, is a first-in-class therapy with dual-action tumor targeting designed to find, internalize, and destroy both cancer cells and cells in the tumor microenvironment. These cells, such as stromal and immune cells, comprise more than 50% of tumor masses.

“This is a very positive development for one of the latest additions to Radiopharm Theranostics’ portfolio of assets and demonstrates independent validation of the potential we saw in the DUNP19 technology,” Riccardo Canevari, chief executive officer and managing director of Radiopharm Theranostics, stated in a news release. “The resulting benefits of the ODD will allow us to continue the development work of DUNP19’s inventor, H. David Ulmert, MD, PhD, with an even greater level of confidence.”

LRRC15 is produced by cancer cells and cells in the surrounding tumor microenvironment, though it is not expressed by healthy cells. LRRC15 production is high in aggressive and treatment-resistant tumors.

Current treatment options for osteosarcoma include surgery and chemotherapy. Aggressive osteosarcoma has one of the highest expressions of LRRC15.

Radiopharm Theranostics is currently developing DUNP19 with the Cu64 and Lu177 isotopes, and the agents are under preclinical study.2

In April 2022, Radiopharm Theranostics entered an exclusive licensing agreement with the University of California Los Angeles (UCLA) Technology Development Group to develop DUNP19 as an antibody-drug conjugates within radiotherapy as part of its clinical development pipeline.3

“We are excited to have entered into the licensing agreement with UCLA and to have addedDUNP19, a breakthrough dual action monoclonal antibody, to our clinical development pipeline,” Canevari said in a press release in April. “DUNP19 has demonstrated promise for several indications, but its potential as first-in-class therapy for osteosarcoma is particularly exciting, considering the high unmet need in the children and adolescents who typically suffer this disease.”


  1. FDA grants orphan drug status to RAD’s DUNP19 for osteosarcoma. News release. Radiopharm Theranostics. September 9, 2022. Accessed September 9, 2022. https://bit.ly/3Rz0lbs
  2. Our pipeline. Radiopharm Theranostics. Accessed September 9, 2022. https://www.radiopharmtheranostics.com/our-pipeline
  3. Radiopharm licenses a dual action LRRC15-targeting monoclonal antibody. News release. Radiopharm Theranostics. April 4, 2022. Accessed September 9, 2022. https://bit.ly/3eF4hZS