Drug Conjugate Designed to Deliver Iodine-131 Shows Promise in Triple-Refractory Multiple Myeloma

September 11, 2020

Forty percent of patients with triple-refractory multiple myeloma achieved a response after receiving 60 millicurie (a unit of radioactivity) or greater of CLR 131.

Updated results from a phase 2 trial show that treatment with CLR 131 appears effective in inducing an overall response in patients with multiple myeloma whose disease is deemed triple-class refractory, according to a press release from Cellectar Biosciences.

The open-label phase 2 CLOVER-1 study is evaluating the safety and efficacy of CLR 131, a small-molecule phospholipid drug conjugate which is designed to provide targeted delivery of iodine-131 (radioisotope) directly to cancer cells, in the treatment of select B-cell malignancies.

Six out of 15 patients with triple-refractory multiple myeloma achieved a response after receiving 60 millicurie (a unit of radioactivity) of CLR 131. These patients were enrolled in part A of the CLOVER-1 study.

Triple-class refractory disease is resistant to treatment with immunomodulatory agents, proteasome inhibitors and anti-CD38 targeted drugs.

“We remain encouraged by the consistency of CLR 131’s efficacy and tolerability data in these extremely challenging to treat triple-class refractory multiple myeloma patients,” said Cellectar Biosciences’ chief medical officer Dr. John Friend in the release. “A 40% ORR (overall response rate) is a clinically meaningful outcome. For reference purposes, two recently approved drugs received a 25% and 31% ORR in triple-class refractory patients. We look forward to the further development of CLR 131, a first-in-class phospholipid radio conjugate that may provide a significant benefit to patients and treatment alternative for clinicians."


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