Cellectar Announces Overall Survival Exceeding 19 Months in Phase 1b Trial with CLR 131 in Relapsed/Refractory Multiple Myeloma MADISON, Wis. (

Cellectar Announces Overall Survival

Exceeding 19 Months in Phase 1b Trial with CLR 131 in Relapsed/Refractory Multiple Myeloma

MADISON, Wis. (October 2, 2018) - Cellectar Biosciences

(Nasdaq: CLRB), a clinical-stage biopharmaceutical company focused on the discovery, development and commercialization of drugs

for the treatment of cancer, today updates interim overall survival (OS) data from the company's ongoing Phase 1b clinical

trial evaluating CLR 131 for the treatment of relapsed/refractory (R/R) multiple myeloma (MM).

The results to date show that OS is currently at 19.4 months.

Cellectar continues to monitor these patients and intends to update OS results as data become available. All 15 patients from the

Phase 1b, single-dose cohorts were heavily pretreated, receiving an average of 5 previous lines of multidrug therapy including

anti CD38, immunomodulating drugs and proteasome inhibitors. All patients were relapsed or refractory to at least one proteasome

inhibitor and IMiD. Most patients presented with advanced stage 2 or 3 disease and 67% had previously received at least 1 stem

"We are extremely pleased to announce that CLR 131 has

achieved OS of 19.4 months in our Phase 1b trial in R/R MM. We view this outcome as impressive considering all patients were heavily

pretreated and presented with high tumor burden," said James Caruso, president and chief executive officer of Cellectar Biosciences.

"Most drugs currently approved for third-line or later R/R MM average approximately 12 months of survival, including several

recent approvals. We believe extending OS to beyond 19 months with a more patient-friendly dosing regimen provides both a unique

product profile and potential for beneficial patient outcomes."

The objective of this

multicenter, open-label, Phase 1b dose-escalation study is the characterization of safety and tolerability of CLR 131 administered

as a single-dose, 30-minute infusion in patients with R/R MM. Patients received doses of 12.5 mCi/m2 up to 31.25 mCi/m2.

All doses were deemed safe and well tolerated by an independent data monitoring committee.

Data from a fifth cohort,

released in August, evaluated a split or fractionated dose of 31.25 mCi/m2 for tolerability and safety. The dosing

schedule provided higher average drug exposure but lower peak serum levels than non-fractionated dosing potentially reducing adverse

events and improving efficacy. The independent Data Monitoring Committee (DMC) determined the fractionated dose used in Cohort

5 to be safe and well tolerated and recommended advancement to a higher dose cohort.

Cellectar's product candidates are built upon a patented delivery

and retention platform that utilizes optimized phospholipid ether-drug conjugates (PDCs ) to target cancer cells. The PDC

platform selectively delivers diverse oncologic payloads to cancerous cells and cancer stem cells, including hematologic cancers

and solid tumors. This selective delivery allows the payloads' therapeutic window to be modified, which may maintain or enhance

drug potency while reducing the number and severity of adverse events. This platform takes advantage of a metabolic pathway utilized

by all tumor cell types in all cell cycle stages. Compared with other targeted delivery platforms, the PDC platform's mechanism

of entry does not rely upon specific cell surface epitopes or antigens. In addition, PDCs can be conjugated to molecules in numerous

ways, thereby increasing the types of molecules selectively delivered. Cellectar believes the PDC platform holds potential for

the discovery and development of the next generation of cancer-targeting agents.

CLR 131 is Cellectar's

investigational radioiodinated PDC therapy that exploits the tumor-targeting properties of the company's proprietary phospholipid

ether (PLE) and PLE analogs to selectively deliver radiation to malignant tumor cells, thus minimizing radiation exposure to normal

tissues. CLR 131 is in a Phase 2 clinical study in R/R MM and a range of B-cell malignancies and a Phase 1b clinical study

in patients with R/R MM exploring fractionated dosing. The objective of the multicenter,

open-label, Phase 1b dose-escalation study is the characterization of safety and tolerability of CLR 131 in patients with R/R MM.

Patients in Cohorts 1-4 received single doses of CLR 131 ranging from 12.5 mCi/m2 to 31.25 mCi/m2. All study

doses have been deemed safe and well tolerated by an independent Data Monitoring Committee. The company is currently initiating

a Phase 1 study with CLR 131 in pediatric solid tumors and lymphoma, and is planning a second Phase 1 study in combination with

external beam radiation for head and neck cancer.

About Cellectar Biosciences, Inc.

Cellectar Biosciences is focused on the discovery, development

and commercialization of drugs for the treatment of cancer. The company plans to develop proprietary drugs independently and through

research and development (R&D) collaborations. The core drug development strategy is to leverage our PDC platform to develop

therapeutics that specifically target treatment to cancer cells. Through R&D collaborations, the company's strategy is

to generate near-term capital, supplement internal resources, gain access to novel molecules or payloads, accelerate product candidate

development and broaden our proprietary and partnered product pipelines.

The company's lead PDC therapeutic, CLR 131, is in a Phase 1

clinical study in patients with R/R MM and a Phase 2 clinical study in R/R MM and a range of B-cell malignancies. The company is

currently initiating a Phase 1 study with CLR 131 in pediatric solid tumors and lymphoma, and is planning a second Phase 1 study

in combination with external beam radiation for head and neck cancer. The company's product pipeline also includes two preclinical

PDC chemotherapeutic programs (CLR 1700 and 1900) and partnered assets include PDCs from multiple R&D collaborations.

For more information please visit www.cellectar.com.

Forward-Looking Statement Disclaimer

This news release contains forward-looking statements. You can

identify these statements by our use of words such as "may," "expect," "believe," "anticipate,"

"intend," "could," "estimate," "continue," "plans," or their negatives or cognates.

These statements are only estimates and predictions and are subject to known and unknown risks and uncertainties that may cause

actual future experience and results to differ materially from the statements made. These statements are based on our current beliefs

and expectations as to such future outcomes. Drug discovery and development involve a high degree of risk. Factors that might cause

such a material difference include, among others, uncertainties related to the ability to raise additional capital, uncertainties

related to the disruptions at our sole source supplier of CLR 131, the ability to attract and retain partners for our technologies,

the identification of lead compounds, the successful preclinical development thereof, the completion of clinical trials, the FDA

review process and other government regulation, the volatile market for priority review vouchers, our pharmaceutical collaborators'

ability to successfully develop and commercialize drug candidates, competition from other pharmaceutical companies, product pricing

and third-party reimbursement. A complete description of risks and uncertainties related to our business is contained in our periodic

reports filed with the Securities and Exchange Commission including our Form 10-K for the year ended December 31, 2017 and

our Form 10-Q for the quarterly period ended June 30, 2018. These forward-looking statements are made only as of the date hereof,

and we disclaim any obligation to update any such forward-looking statements.

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