On June 13, 2023 Cellectar Biosciences, Inc. (NASDAQ: CLRB), a late-stage biopharmaceutical company focused on the discovery, development and commercialization of targeted treatments for cancer, reported an update for its iopofosine I 131 clinical program and guidance related to its Waldenstrom’s macroglobulinemia (WM) CLOVER-WaM pivotal trial, as well as preclinical advancements to its proprietary phospholipid ether drug conjugate platform (Press release, Cellectar Biosciences, JUN 13, 2023, View Source [SID1234632651]).

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WM CLOVER-WaM pivotal trial

The company now expects to release top-line data from the WM CLOVER-WaM trial in the second half of 2023 and assuming NDA approval, remains on target for a 2024 product launch. Cellectar experienced delays with trial start-up activities, such as site contracting and country regulatory responses, which slowed the initial pace of site initiations resulting in lower-than-expected patient enrollment. The company now has all 49 sites up and running and patient enrollment rates have accelerated. As has been previously reported, and in agreement with the FDA, WM CLOVER-WaM is a single arm, open label trial with a target enrollment of 50 patients.

"Although we are disappointed with the delay in the study’s completion, our ongoing commercial preparations have compressed timelines and support a 2024 launch. Trial activations at high patient volume sites over recent quarters have increased the enrollment trend giving us confidence in our ability to complete the WM CLOVER-WaM study in the second half of 2023," said Dr. Andrei Shustov, Cellectar’s senior vice president, medical. "Iopofosine I 131 demonstrated a 100% overall response rate, an 83.3% major response rate and a 16.7% complete response rate in our Phase 2a study of six WM relapsed/refractory patients. In addition to these impressive response rates, iopofosine I 131’s fixed, short-duration therapy removes the need for the indefinite or prolonged maintenance treatment that is currently required for other therapies."

Phase 1b study in pediatric high-grade gliomas

With the support of a $2 million grant from the National Institute of Health’s National Cancer Institute (NCI) the company plans to initiate a Phase 1b study in pediatric high-grade gliomas (pHGGs) in the third quarter of 2023. The study objective is to identify the recommended iopofosine I 131 Phase 2 dose in pHGG patients. The NCI grant was in part driven by the Phase 1a trial data demonstrating a near tripling of the progression free survival typically observed in relapsed/refractory patients.

Central nervous system lymphoma

Iopofosine I 131’s ability to cross the blood-brain barrier and recently demonstrated activity in central nervous system lymphoma (CNSL) provides further rationale for treatment of WM patients with CNSL involvement, also known as Bing-Neel syndrome.

Based upon achieving a complete response in a CNSL patient treated as part of its Phase 2a trial, the company expanded the CNSL cohort to further evaluate iopofosine I 131 in this indication. Currently, there are no approved therapies available to CNSL patients.

Multiple myeloma

Iopofosine I 131 has been evaluated in over 125 multiple myeloma patients including triple class refractory, quad/penta refractory, high-risk and post-BCMA patients with response rates ranging from 40 to 62%. The company’s recently published post BCMA response rate of 50% prompted expansion of this cohort in our ongoing Phase 2a trial.

The company’s COO, Jarrod Longcor, will deliver an oral presentation of iopofosine I 131 in multiple myeloma at the Society of Nuclear Medicine and Molecular Imaging Annual Conference. The presentation is on June 26th (#P1243, Using targeted radiotherapy in highly refractory multiple myeloma).

Phospholipid ether cancer targeting platform

Development of the company’s phospholipid ether cancer targeting platform continues to demonstrate its broad utility to provide targeted intracellular delivery of multiple cancer treatment modalities. Preclinical data recently presented at several conferences demonstrate the broad utility of the platform, including:

· multiple alpha-emitter radiotherapeutic programs targeting solid tumors;
· the activity of multiple cytotoxic small molecule payloads in triple negative breast cancer mouse models including eradication of the tumors with no subsequent regrowth;
· the successful delivery, uptake, and gene knockdown in a mouse model of pancreatic cancer with siRNA-phospholipid ether when given intravenously; and,
· the conjugation and use of peptides against intracellular targets where small molecules may not be effective.

James Caruso, president and CEO of Cellectar said, "The company’s priority remains the near-term completion of our WM pivotal study. Iopofosine I 131’s Fast Track Designation allows for a six-month FDA review of our submission. In parallel, we continue to advance the clinical development of iopofosine I 131 for both adult and pediatric indications while efficiently executing on potentially value-creating research to best understand the wide-ranging capacity of our proprietary delivery platform."