Orphan drug designations are granted by the FDA to drugs and biologics that are developed for the treatment of rare diseases. According to a recent article in Biospace, Oncternal Therapeutics announced that the FDA has assigned orphan drug designation to cirmtuzumab for the treatment of chronic lymphocytic leukemia or small lymphocytic lymphoma. The FDA announcement also included cirmtuzumab for the treatment of mantle cell lymphoma (MCL).
FDA’s Orphan Drug Designation
Rare diseases are conditions affecting less than two hundred thousand individuals in the U.S. The FDA designation gives Oncternal certain benefits such as tax credits in connection with approved clinical trials. Also, if granted regulatory approval, the company would have the benefit of potential market exclusivity during which time Oncternal would have the sole rights to market cirmtuzumab.
About Cirmtuzumab, Antibodies, Proteins, and Epitopes
CIRM, San Diego and San Diego School of Medicine are conducting a Phase ½ clinical trial evaluating cirmtuzumab in combination with ibrutinib to treat MCL or CLL. Cirmtuzumab targets ROR1 (Receptor tyrosine kinase-like orphan receptor 1).
Cirmtuzumab is a monoclonal antibody which is a form of protein created in the lab. Antibodies, such as cirmtuzumab, can target certain cancers by transporting drugs, radioactive substances, or toxins to cancer cells. When cirmtuzumab binds to a protein it identifies a small area on the protein surface known as an epitope.
UC San Diego researchers found that focusing on a specific epitope bound to ROR1 is critical to targeting ROR1 tumors. This discovery led researchers to the development of this therapy which binds to the specific epitope of ROR1 on various cancers.
According to preclinical data, when cirmtuzumab binds to ROR1, tumor expansion and survival are inhibited and Wnt5a signaling is blocked.
Estimates are that there may be anywhere from thirteen thousand to twenty-one thousand people with MCL in the U.S. MCL is a form of non-Hodgkin’s lymphoma with a two to ten-year survival rate.
In comparison, CLL is one of the most common types of leukemia with estimates ranging up to 178,000 U.S. patients. Although the FDA has recently approved several therapies for CLL, it still remains incurable.
About the Company
Oncternal Therapeutics, a biopharmaceutical company, focuses on developing promising oncology therapies for biological pathways that are responsible for the generation and progression of cancers. In addition to its initial work on cirmtuzumab, the company is conducting a clinical trial (Phase 1) of paclitaxel combined with cirmtuzumab on-site at UC San Diego to treat HER2-negative metastatic breast cancer. A program is currently underway for the development of CAR-T therapy to target ROR1 to treat solid tumors and hematologic cancers.