Myeloma patients who had relapsed after receiving both a proteasome inhibitor (like Velcade) and immunomodulator (like Revlimid) participated in a Phase I study of a new drug called CLR 131 and experienced an average 22 month overall survival.  

While no head-to-head treatment comparisons have been performed, a 2016 article in the journal Bone Marrow Transplantation showed that these these types of patients refractory to both proteasome inhibitors and immunomodulatory drugs typically achieve achieve a 9-12 month overall survival, even on the newer approved drugs. 

It is clear that we need additional types of drugs for myeloma patients. 

CLR 131 is a phospholipid drug conjugate (PDC) that delivers a radioactive, toxic compound directly and selectively to cancer cells. CLR 131 is being tested for patients with multiple myeloma, lymphoma, head and neck cancers, and pediatric cancers. 

“The median overall survival of 22 months in this heavily pretreated patient population is very encouraging. These are patients with limited therapeutic options and, unfortunately, face poor prognoses,” said James Caruso, president and chief executive officer of Cellectar Biosciences. “The convenience afforded by CLR 131 delivered in only one or two doses as currently administered in our ongoing hematology studies makes it a far less intrusive regimen than other treatments that must be administered at regular dosing intervals. We believe extending median overall survival with a more patient-friendly dosing regimen provides both a distinctive product profile and the potential to provide beneficial patient outcomes even in later lines of therapy.”

Radiotherapy has been used as a cancer therapy for more than 40 years. The goal of targeted radiotherapy is selective delivery (directed to tumor) of effective doses of radioactive isotopes (amount of radiation) that destroy tumor tissue, limit the effect on surrounding normal tissue, do not accumulate in and damage vital organs (especially bone marrow, liver and kidneys), and that can be rapidly eliminated from the body.

Participants in the Phase I study were divided into four groups with different doses of the drug. Phase I studies typically test for dosing and safety. Patients in the highest dosing group had the best response to treatment with all experiencing either a partial reduction of disease or disease stabilization. Investigators are now studying whether this higher dose should be split to be given a week apart. 

“The convenience afforded by CLR 131 delivered in only one or two doses as currently administered in our ongoing hematology studies makes it a far less intrusive regimen than other treatments that must be administered at regular dosing intervals,” Caruso said. “We believe extending [the study] with a more patient-friendly dosing regimen provides both a distinctive product profile and the potential to provide beneficial patient outcomes even in later lines of therapy.”

A new Phase II study is open testing CLR 131 with dexamethasone and is open at over 10 centers for relapsed myeloma and lymphoma. 

To learn more about this study, click here. 

CLR 131 Phase II Study