Cellectar Biosciences has not secured FDA approval in the past two years, but iopofosine I 131 holds Breakthrough Therapy designation and is under FDA review with a potential Pediatric Review Voucher upon approval.

Investors, BD teams, and analysts tracking CLRB; patients with certain cancers (e.g., Waldenström macroglobulinemia) and pediatric rare diseases; and competitors in the radiopharmaceutical space.

What should teams watch next?

Key PDUFA dates for iopofosine I 131 in 2026, initiation of the CLR 125 Phase 1b TNBC study, and any FDA advisory committee meetings or regulatory updates.

Cellectar Biosciences (CLRB) FDA Approvals & PDUFA Dates 2026

Cellectar Biosciences (CLRB) FDA Approvals, PDUFA Dates & Drug Alerts 2026

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Cellectar Biosciences (CLRB) has not received FDA approval in the past two years but has drugs under review, including iopofosine I 131 with Breakthrough Therapy designation. The company is eligible for a Pediatric Review Voucher upon approval, and key PDUFA dates in 2026 will be critical for investors and BD teams.

Dr. Elena Rossi PhD Pharmaceutical Sciences · EMA Regulatory Affairs Editor

Reviewed by Dr. Sarah Chen Pharmaceutical Sciences Editor

Thursday, June 4, 2026 5 min read Updated Jun 4, 2026 Your watchlist

Executive Summary

Cellectar has not secured an FDA approval in the past two years, but its lead candidate iopofosine I 131 is under active review with Breakthrough Therapy designation, raising the stakes for upcoming regulatory decisions.

A Pediatric Review Voucher (PRV) is contingent on FDA approval of iopofosine I 131 — an asset that could be monetized or leveraged to accelerate other programs across the industry.

Critical 2026 catalysts include the PDUFA target action date for iopofosine I 131 and the initiation of the CLR 125 Phase 1b study in triple-negative breast cancer (TNBC) in the first quarter.

Regulatory	high
Commercial	high
Competitive	medium
Investment	high

Regulatory

high

Commercial

high

Competitive

medium

Investment

high

Cellectar Biosciences (CLRB) FDA Approvals, PDUFA Dates & Drug Alerts 2026

Key Takeaways

Cellectar has not secured an FDA approval in the past two years, but its lead candidate iopofosine I 131 is under active review with Breakthrough Therapy designation, raising the stakes for upcoming regulatory decisions.
A Pediatric Review Voucher (PRV) is contingent on FDA approval of iopofosine I 131 — an asset that could be monetized or leveraged to accelerate other programs across the industry.
Critical 2026 catalysts include the PDUFA target action date for iopofosine I 131 and the initiation of the CLR 125 Phase 1b study in triple-negative breast cancer (TNBC) in the first quarter.

What is the current status of the Cellectar Biosciences, Inc pipeline?

Cellectar is advancing its drug pipeline using its proprietary Phospholipid Drug Conjugate (PDC) delivery platform, with a primary focus on iopofosine I 131, a radiopharmaceutical designed to deliver iodine-131 directly to cancer cells. As of mid-2026, the company has not received any FDA approvals in the past two years, but iopofosine I 131 is under review with Breakthrough Therapy designation from the FDA — a status that signals the agency's commitment to expediting development and review for serious conditions (MarketBeat). The drug is being investigated in a global, open-label pivotal cohort in patients with relapsed or refractory Waldenström macroglobulinemia who have received at least two prior lines of therapy, including those who failed Bruton tyrosine kinase inhibitors (Cellectar Q1 2026 press release).

Beyond Waldenström macroglobulinemia, Cellectar is expanding into solid tumors. The company anticipates dosing the first patients in the CLR 125 Phase 1b study in triple-negative breast cancer (TNBC) in the first quarter of 2026. This expansion could open up a much larger addressable market if the data are positive.

Why does the Pediatric Review Voucher matter for BD teams?

One of the most attractive strategic assets tied to a potential approval of iopofosine I 131 is the Pediatric Review Voucher (PRV). Under the FDA's program, Cellectar is eligible to receive a PRV upon approval of the drug, which can be redeemed for priority review of a subsequent drug application or sold to another company. The voucher eligibility is explicitly stated in the company's filings (Cellectar Q1 2026 press release). For BD teams, this voucher represents a liquid, high-value asset that can either accelerate internal programs or be monetized to inject capital into Cellectar's balance sheet. Investors should note that the voucher is only received upon FDA approval, tying its value directly to the regulatory outcome.

What upcoming PDUFA dates should investors monitor?

For investors and analysts, the single most important catalyst in 2026 is the PDUFA target action date for iopofosine I 131. The company has confirmed that iopofosine is under active review with a user fee goal date that will fall in 2026 (Cellectar Q1 2026 press release). Given the Breakthrough Therapy designation, the review process may also include advisory committee meetings. These meetings can generate volatility and provide early signals about the FDA's thinking ahead of the final decision.

Also worth watching is the broader radiopharmaceutical regulatory environment. The FDA's novel drug approval list for 2026 includes several radioisotope-based therapies, signaling continued agency engagement with the modality (FDA Novel Drug Approvals 2026). A positive precedent for other radiopharmaceuticals could work in Cellectar's favor, though each program is evaluated on its own data.

How does Cellectar compare to competitors in the radiopharmaceutical space?

The radiopharmaceutical competitive landscape is dominated by large players such as Novartis with Pluvicto and Lantheus with Pylarify. However, Cellectar's PDC platform offers a differentiated delivery mechanism that aims to reduce off-target toxicity and improve the therapeutic index. The company remains firmly in the small-cap category and lacks commercial infrastructure, making a successful approval and subsequent partnership or out-licensing a likely path. For analysts, the key comparison points will be progression-free survival and overall survival data from the pivotal Waldenström macroglobulinemia cohort versus standard of care, as well as the safety profile relative to other targeted radiotherapies. The initiation of the TNBC study is a step toward competing in the large solid tumor market, but data from that study will take several years to mature.