Shares of Cellectar Biosciences, Inc. (CLRB) jumped in pre-market trading after the company announced an oversubscribed financing of up to $140 million alongside positive 12-month follow-up results from its Phase 2b CLOVER-WaM study evaluating Iopofosine I 131 in relapsed or refractory Waldenström macroglobulinemia.
R/R Waldenström macroglobulinemia (WM), is a rare B-cell lymphoma with limited treatment options after BTK inhibitor therapy.
The financing includes $35 million upfront and $105 million in milestone-based securities, according to the company's securities purchase agreements with institutional investors and members of management.
Cellectar said the financing will support its planned confirmatory randomized pivotal trial of Iopofosine I 131 in WM, expected to begin in the fourth quarter of 2026, and will also fund preparation of a New Drug Application (NDA) for accelerated approval in the U.S.
12-Month CLOVER-WaM Data Show Durable, Deep Responses
Alongside the financing, Cellectar released mature 12-month follow-up data from its Phase 2b CLOVER-WaM study, which included all 55 patients with at least one year of follow-up as requested by the FDA.
Key efficacy results included:
- 83.6% Overall Response Rate (ORR)
- 61.8% Major Response Rate (MRR)- primary endpoint achieved
- 17.8 months median duration of responses (DoR)- secondary endpoint achieved
- 13.5 months median progression-free survival (PFS)
- 98.2% disease control rate (DCR)
- 14.5% Very Good Partial Response/Complete Response Rate (VGPR/CR)
Responses deepened over time, and durability continued to improve beyond 12 months, despite patients being among the most heavily pretreated WM populations studied to date. (median 4 prior lines; up to 15).Strong Activity in Post-BTKi Patients
In patients previously treated with Bruton tyrosine kinase inhibitors (BTKi), Iopofosine I 131 demonstrated:
-64.1% MRR
-18.2-month median DoR
-15.9-month median PFS
In BTKi-refractory patients:
-63.6% MRR
-14.8-month median PFS
These results compare favorably with published salvage therapy datasets and highlight the drug's potential in a population with no FDA-approved options after BTKi progression.
Safety Profile Remains Predictable and Manageable
The company reported:
-No significant bleeding events
-Low infection rates (<10%)
- Cytopenias were the most common adverse events
-Mostly low-grade non-hematologic toxicities (Grade <2)
Regulatory Pathway
Cellectar said the dataset meets key FDA expectations for accelerated approval, including:
-Use of surrogate endpoints (MRR+ DoR)
-Durable responses in a high-unmet-need population
- =12-month follow-up for all patients.
The company plans to initiate its confirmatory randomized trial in Q4 2026, with PFS as the primary endpoint.
CLRB has traded between $2.43 and $20.70 over the past year. The stock is currently trading at $4.20, up 50%.
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