On the 6th January 2020, CLR 131, an investigational small-molecule radio-therapeutic, was granted Orphan Drug Designation by the U.S. Food and Drug Administration (FDA) in lymphoplasmacytic lymphoma.1 CLR 131 is a phospholipid drug conjugate that selectively kills cancer cells by delivering cytotoxic radiation.
The Orphan Drug designation was based on the positive results from a multicenter phase II clinical trial (NCT02952508) CLOVER-1, which is evaluating the efficacy and safety of CLR 131 in select relapsed or refractory (R/R) B cell hematologic malignancies. Recently, released summary data from 20 heavily pre-treated patients, including 10 patients with R/R multiple myeloma (MM), and 10 with R/R B-cell lymphoma, who received a single dose of CLR 131, demonstrated a 30% overall response rate (ORR), with an average progression-free survival of 4.5 months, and an acceptable safety profile.2
In 2019, CLR 131 was granted Fast Track designation for the treatment of patients with R/R diffuse large B-cell lymphoma (DLBCL) based on an interim assessment of CLOVER-1 where patients with R/R DLBCL demonstrated an ORR of 33%.3 CLR 131 has also received Orphan Drug designation for the treatment of MM, neuroblastoma, rhabdomyosarcoma, Ewing’s sarcoma, and osteosarcoma. Additionally, CLR 131 is currently being evaluated in phase I studies in pediatric solid tumors and lymphoma, as well as MM.4