FDA Grants Fast Track Designation to CLR 131 for Diffuse Large B-cell Lymphoma

July 9, 2019
Katie Kosko

CLR 131, a targeted, molecular radiotherapy, showed a 33% overall response rate in patients with diffuse large B-cell lymphoma.

The Food and Drug Administration (FDA) granted Fast Track Designation to CLR 131 for relapsed or refractory diffuse large B-cell lymphoma (DLBCL).

The targeted, molecular radiotherapy is being studied in 3 clinical trials for various types of hematologic malignancies. An interim assessment from the phase II CLOVER-1 study last year showed a 33% overall response rate in the DLBCL cohort. In addition to DLBCL, CLOVER-1 involves patients with other types of relapsed or refractory B-cell lymphomas, such as multiple myeloma, chronic lymphocytic leukemia/small lymphocytic lymphoma, lymphoplasmacytic lymphoma, marginal zone lymphoma, and mantle cell lymphoma.

“We are pleased to receive FDA’s Fast Track Designation for CLR 131. This designation supports our efforts to more rapidly provide a new therapeutic option for patients with relapsed or refractory DLBCL, a disease that typically has a very poor prognosis and low rates of survival,” James Caruso, president and CEO of Cellectar Biosciences, Inc., the maker of the therapy, said in a press release. “Patients prior to the interim assessment received a single 25.0 mCi/m2 dose of CLR 131. Dosing in the phase II CLOVER-1 study has increased, and patients are now receiving 37.50 mCi/m2 fractionated in two administrations of CLR 131.”

Clinical benefit response is the primary endpoint in the CLOVER-1 study. Additional endpoints include the following: overall response rate, progression free survival, and median overall survival. The trial is taking place throughout 10 leading cancer centers in the United States and will enroll up to 80 patients.

Two phase I trials— 1 in relapsed/refractory multiple myeloma and another in pediatric solid tumors and lymphoma—are also underway to study CLR 131, which is a small-molecule, targeted phospholipid drug conjugate that delivers cytotoxic radiation directly to cancer cells to help limit exposure to healthy cells.

In 2014, CLR 131 was granted Orphan Drug designation for the treatment of multiple myeloma and in May received Fast Track Designation for fourth line or later treatment of relapsed or refractory multiple myeloma. In 2018, the therapy was granted Orphan Drug and Rare Pediatric Disease designation for the treatment of neuroblastoma, rhabdomyosarcoma, Ewing’s sarcoma and osteosarcoma.

“We are optimistic that CLR 131 has the potential to provide a meaningful treatment option for these patients and look forward to additional data in 2019,” Caruso said.