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Date

Thursday, May 14, 2026 at 8:30 a.m. ET

Call participants

  • President and CEO — James Caruso
  • Chief Financial Officer — Chad Kolean
  • Chief Operating Officer — Jarrod Longcor
  • Investor Relations — Anne Marie Fields

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Takeaways

  • 12-Month CLOVER WaM Phase IIb Data -- Iopofosine I-131 achieved an overall response rate of 83.6% and a major response rate of 61.8% in patients with relapsed or refractory Waldenstrom's macroglobulinemia (WM), with a median duration of response of 17.8 months.
  • Progression-Free Survival (PFS) -- Median PFS for iopofosine was reported as 13.5 months in the Phase IIb study population.
  • Long-Term Response Durability -- More than 30% of responders maintained their response to iopofosine beyond 36 months.
  • Disease Control Rate -- Disease control rate remained stable at 98.2% for iopofosine in this patient population.
  • Patient Population Baseline -- Median of four prior therapy lines; refractory rates of 77% in BTKi-exposed, 75% in rituximab-exposed, 60% in chemotherapy-exposed, and 58% dual class (BTKi and rituximab) refractory.
  • Phase III Comparator Arm -- "the agency on the comparator arm is rituximab, cyclophosphamide, dexamethasone or RCD."
  • Control Arm PFS Expectation -- Literature cited median PFS for RCD or other salvage therapies in post-BTKi refractory patients was approximately 5.8 months.
  • Upcoming Milestones -- Planned initiation of randomized Phase III confirmatory trial for iopofosine in late Q4, enrollment of first patient triggers the first milestone for financing.
  • Financial Position -- Cash and equivalents stood at $8.3 million at quarter-end, excluding recent financing.
  • Oversubscribed Financing -- Announced $140 million financing structure: $35 million upfront and up to $105 million in three milestone-based tranches tied to clinical and regulatory milestones, all contingent on trading and volume thresholds.
  • Operating Expenses -- R&D expenses were $3 million (down from $3.4 million prior year), while G&A expenses were $2.8 million (down from $3 million prior year), driven by declines in follow-up activity and personnel costs.
  • Net Loss -- Net loss reported as $5.7 million, or $1.33 per share, improved from $6.6 million, or $4.30 per share, for the comparable period.
  • Pipeline Advancement -- First patients dosed in the Phase Ib CLR125 study for relapsed/refractory triple-negative breast cancer; the trial features multiple dose regimens and expansion cohort.

Summary

Cellectar Biosciences (CLRB +8.84%) presented pivotal 12-month Phase IIb clinical results for iopofosine, highlighting high response rates and prolonged durability in heavily pretreated WM patients, including those refractory to BTKi therapy. The company declared achievement of both primary and secondary study endpoints, supporting regulatory advancement toward an accelerated FDA approval and the initiation of a randomized Phase III confirmatory study. Additionally, leadership described the $140 million financing—split between an upfront payment and milestone-driven warrants—as a strategic capital infusion intended to support late-stage trial execution and potential commercialization. Plans for the CLR125 program in triple-negative breast cancer were further advanced by the dosing of initial patients in a dose-finding trial. The organization's strengthened cash position, efficient expense management, and exclusive milestone-based capital structure were emphasized as foundational to maintaining operational momentum.

  • The randomized Phase III trial for iopofosine will use RCD (rituximab, cyclophosphamide, dexamethasone) as its comparator, with patient enrollment powering based on historical PFS expectations outlined on the call.
  • "over 50% of patients in the study, who immediately came off BTKi before getting treatment with iopofosine," according to Longcor.
  • CFO Kolean stated the current cash runway is expected to fund operations into Q2 2027, prior to warrant exercises tied to development milestones.
  • Management detailed warrant structure: each warrant tranche exercisable only if CLRB stock trades above $3.45 with volume exceeding $500,000 per day for 20 consecutive days, ensuring tranches unlock alongside clinical/regulatory progress.
  • The NDA submission for iopofosine in WM is planned for early 2027, potentially enabling FDA approval in the second half of that year, subject to review timelines and milestones.

Industry glossary

  • iopofosine I-131: Cellectar’s lead phospholipid drug conjugate (PDC) radiopharmaceutical designed for targeted cancer therapy.
  • CLOVER WaM: Phase IIb clinical study evaluating iopofosine I-131 in relapsed/refractory Waldenstrom's macroglobulinemia.
  • BTKi: Bruton tyrosine kinase inhibitor, a class of drugs for treating B-cell malignancies and WM.
  • RCD: Combination regimen of rituximab, cyclophosphamide, and dexamethasone, used in lymphoma salvage therapy.
  • RECIST: Response Evaluation Criteria In Solid Tumors, standardized measures for assessing tumor response in clinical trials.
  • TNBC: Triple-negative breast cancer, subtype characterized by lack of hormone receptor and HER2 protein expression.

Full Conference Call Transcript

Anne Marie Fields: Thank you, Vanessa. Good morning, and welcome to Cellectar Biosciences First Quarter 2026 Financial Results and Business Update Conference Call. Joining us today from Cellectar are Jim Caruso, President and CEO; who will provide an overview of the company's progress before turning the call over to Chad Cohen, CFO; for a financial review of the quarter. Following this, Jarrod Longcor, Chief Operating Officer; will give an update on the company's progress and plans for its promising clinical development pipeline of radiopharmaceuticals. Cellectar issued a press release earlier this morning detailing the content of today's call. A copy can be found on the Investor page of Cellectar's corporate website.

I want to remind callers that the information discussed on the call today is covered under the safe harbor provisions of the Private Securities Litigation Reform Act. I caution listeners that management will be making forward-looking statements. Actual results could differ materially from those stated or implied by our forward-looking statements due to risks and uncertainties associated with the business. These forward-looking statements are qualified in their entirety by the cautionary statements contained in today's press release and in the SEC filings. The content of this conference call contains time-sensitive information that is accurate only as of the date of this live broadcast, May 14, 2026.

The company undertakes no obligation to revise or update any forward-looking statements to reflect events or circumstances after the date of this conference call and webcast. As a reminder, this conference call and webcast are being recorded and archived. We will begin the call with prepared remarks and then open the line for your questions. Now let me turn the call over to Jim Caruso. Jim?

James Caruso: Thank you, Anne Marie, and thank you to all for joining us today. The first quarter of 2026 marked a transformational period for Cellectar. Defined by rigorous execution across our clinical, regulatory and financial strategies. We entered the year with momentum. And over the past quarter, that momentum has meaningfully accelerated. Earlier this month, we reported positive 12-month follow-on data from the Phase IIb CLOVER WaM study evaluating iopofosine I 131 in patients with relapsed or refractory Waldenstrom Macroglobulinemia or WM. These data demonstrated durable and consistent responses across one of the most heavily pretreated and refractory WM populations studied to date, including patients who were both exposed to and refractory to BTKi inhibitors.

Importantly, iopofosine met both the primary and secondary endpoints of the study. Reinforcing our confidence in its clinical profile and its potential to address a profound unmet need in WM, particularly for patients who have been previously prescribed to BTKi and are now searching for treatment answers with off-label salvage therapies. These results take on even greater significance when viewed in the broader disease context. WM is a rare and curable lymphoma affecting a prevalent patient population of approximately 60,000 to 80,000 patients in the U.S. and EU alone with a rapidly growing population of patients progressing after BTKi therapy with no FDA-approved therapies beyond BTKIs.

For these patients, therapeutic options are limited, outcomes are suboptimal and the need for new durable treatments is urgent. With the full 12-month data set now in hand, along with a deep and mature body of clinical evidence, we are advancing our plans to file for accelerated approval with the FDA and to initiate a randomized Phase III confirmatory trial. We believe iopofosine is well positioned to meet regulatory expectations and to become a foundational therapy in the WM treatment landscape. Running in parallel with this clinical momentum, we announced an oversubscribed financing of up to $140 million, led by high-quality long-term health care investors.

This capital materially strengthens our balance sheet and provides the resources necessary to advance iopofosine through our planned Phase III confirmatory study and potential commercialization as well as support the continued advancement of triple-negative breast cancer study as part of our broader radiopharmaceutical pipeline. Taken together, the strength of our iopofosine data and the successful financing represent a clear inflection point for Cellectar. They enable us to move forward decisively from a clinical validation to late-stage execution. With that overview, I'll now turn the call over to Chad to walk through our financial results.

Chad Kolean: Thank you, Jim, and good morning, everyone. I'll address our financial results for the period ended March 31, 2026, and the recently completed financing that allows us to accelerate our development of iopofosine I 131. We ended the first quarter with cash and cash equivalents of approximately $8.3 million compared to $13.2 million at the end of 2025. This does not include the results of the financing, which I will address in a moment. Our research and development expenses for the 3 months ended March 31, 2026, were approximately $3 million compared to approximately $3.4 million for the 3 months ended March 31, 2025.

R&D costs declined as the follow-up activities for patients of CLOVER WaM Phase IIb clinical study declined and preclinical product development was reduced. These reductions were partially offset by increased manufacturing spend for both iopofosine and CLR125. General and administrative expenses for the 3 months ended March 31, 2026, were $2.8 million compared to $3 million for the same period in 2025. The modest decrease in G&A was driven primarily by reduced personnel costs. Net loss for the 3 months ended March 31, 2026, was $5.7 million or $1.33 per share compared with $6.6 million or $4.30 per share during the 3 months ended March 31, 2025. Importantly, as Jim stated earlier.

Earlier this month, we completed an oversubscribed financing for up to $140 million, consisting of an upfront amount of $35 million and up to $105 million in milestone-based capital. As a result, we believe our current cash position enables us to fund planned operations, particularly the initiation of our confirmatory Phase III trial of iopofosine in patients with WM into the second quarter of 2027. The structure of the milestone-based warrants is designed to provide additional funding at key points in the development of iopofosine. Three tranches of warrants, one tied to each of three milestones were issued for each security the investors purchased upfront.

The first milestone is the initiation of the confirmatory study as demonstrated by the enrollment of the first patient in the study. The second milestone is the acceptance of an NDA submission by the FDA. And the third milestone is the approval of iopofosine by the FDA. Upon the attainment of each milestone, provided our common stock trades above $3.45 with volume exceeding $500,000 per day for 20 consecutive days, the company can call the warrants for cash. The warrants for each milestone represent potential additional funding of $35 million. So the aggregate potential for the 3 milestones is $105 million and when combined with the upfront of $35 million represents the $140 million of total potential funding.

The warrants are all exercisable upon approval of the transaction by the stockholders. Which will be part of our Annual Stockholders' Meeting agenda. Completion of this offering puts us in a position of financial strength and strategic flexibility, allowing the organization to remain focused on disciplined execution and value creation. Now I will turn the call over to Jarrod for an operational update, including plans for our promising pipeline of radiopharmaceuticals.

Jarrod Longcor: Thank you, Chad, and good morning, everyone. As Jim highlighted, the 12-month CLOVER-WaM results represent a significant milestone for iopofosine for patients living with WM. For some background, patients enrolled in the CLOVER-WaM had a median of four prior lines of therapy with refractory rates from 77% to 75% and 60% in BTKi, rituximab chemotherapy exposed patients, respectively. Additionally, 58% of patients exposed to both BTKi and rituximab were dual class refractory. Despite this being one of the most heavily pretreated and refractory WM patient populations to date, iopofosine produced robust and durable responses, underscoring the strength of the targeted phospholipid drug conjugate platform.

Notably, the primary and secondary endpoints were both achieved in the protocol study population (N=55) with an overall response rate of 83.6% and the primary endpoint of major response rate or MRR, improving to 61.8%. The secondary endpoint of duration of response, or DOR, achieved a median of 17.8 months. Importantly, greater than 30% of responders maintained their responses beyond 36 months. The median progression-free survival was 13.5 months and the (VGPR/CR) rate was 14.5%. The disease control rate remained stable at 98.2%. In addition, the data demonstrated consistent efficacy in both BTKi exposed and BTKi refractory patients. These results compare favorably with available therapies in the post-BTKi setting, where outcomes remain limited and durability is often modest.

Moreover, iopofosine's fixed dose regimen and manageable safety profile may also provide offer practical advantages for patients and providers. Importantly, these outcomes incorporate key elements that align with the previously described regulatory expectations for iopofosine's eligibility for accelerated approval. We were delighted to have the immediately post-BTKi subgroup analysis from the CLOVER WaM trial selected for presentation at the upcoming ASCO conference, which brings together the world's leading oncologists. The safety and efficacy of iopofosine observed to date in this subgroup are highly encouraging and underscore its potential to address a significant unmet need for patients who progressed after BTKi therapy.

We believe these findings further support the potential for iopofosine to emerge as a differentiated therapeutic option in the post-BTKi setting and as early as the second line of treatment in WM. With the strength and maturity of the total data set, we are advancing with a randomized controlled Phase III confirmatory study, evaluating progression-free survival as the primary endpoint. We anticipate initiating the study in the late fourth quarter of 2026. Beyond iopofosine, we were delighted to advance our broader pipeline with the recent dosing of the first patients in the Phase Ib trial of CLR125, our OJ emitting radio conjugate in relapsed/refractory triple-negative breast cancer or TNBC.

TNBC is an aggressive subtype of breast cancer characterized by the absence of estrogen receptors, progesterone receptors and HER2 protein expression. This lack of common therapeutic targets make TNBC particularly challenging to treat with limited options beyond chemotherapy. TNBC tends to grow and spread more quickly than other breast cancer types and disproportionately affects younger women and those of African descent. In the U.S., approximately 12% of breast cancer diagnoses are triple-negative breast cancer. CLR125 with its demonstrated selective tumor uptake, promising activity in preclinical models of TNBC gives us confidence in its potential to be an effective treatment for TNBC. The Phase Ib clinical trial is an open-label dose-finding study in patients with relapsed/refractory TNBC.

It will evaluate three dose levels and dosing regimens of CLR125. 32.75 millicuries administered over four cycles or 62.5 millicuries per meter squared over three cycles or 95 millicuries per meter squared over 2 cycles, with approximately 15 patients enrolled per treatment arm with an expansion arm of an additional 15 patients for the recommended Phase II dose. The study utilizes dosimetry assessments to characterize tumor uptake and distribution, which supports the prediction of safety and therapeutic activity. Clinical endpoints include safety, tolerability as well as preliminary efficacy measures, including tumor response per RECIST criteria and progression-free survival.

The study is well underway and our first patients already treated, and we look forward to sharing biodistribution, dosimetry and early clinical efficacy insights as the year progresses. Overall, 2026 is shaping up to be a year of substantial execution and progress across the organization, and we remain focused on advancing each program with scientific rigor and regulatory discipline. With that overview of our clinical progress and plans moving forward, I'll turn the call back to Jim for closing remarks.

James Caruso: All right. Thank you, Jarrod. As we look ahead, Cellectar enters the next phase of 2026 with clarity of purpose, strong momentum and the financial resources to execute. The combination of compelling 12-month iopofosine data and a significantly strengthened balance sheet positions us to advance with the initiation of our Phase III confirmatory study and subsequent accelerated approval application. The WM patient community remains at the heart of our commitment. We continue to hear from and remain motivated by individuals and families affected by WM, particularly those patients with limited treatment options or those that are no longer treatment seekers because of poor or no remaining treatment options.

The product profile presented by iopofosine reinforce our belief that this therapy has the potential to be truly meaningful and potentially life-changing for these patients in need. At the same time, we remain disciplined towards of capital, focused on creating long-term shareholder value by advancing differentiated assets, engaging constructively with regulators and executing against clearly defined milestones. I want to take this opportunity to thank the entire Cellectar team for their continued dedication and sense of urgency. And I thank our investors for their continued support and conviction. We are committed to delivering on both our mission for patients and our responsibility to shareholders. With that, operator, we are happy to open the call for questions.

Operator: [Operator Instructions] And we have our first question from Kevin DeGeeter with Ladenburg Thalmann.

Kevin DeGeeter: My first question is on CLOVER WaM and specifically for the BTK experienced patients. did most patients go directly from a BTK inhibitor to study drug in CLOVER WaM or for the patients that did get lines of therapy between a BTK and coming on study drug, what were the most common therapies they received immediately prior to study drug?

James Caruso: Kevin, this is Jim. First of all, thank you for your participation in the call today. And your question is spot on. It's significant on a number of different levels, and I'll ask Jarrod Longcor to address it.

Jarrod Longcor: Kevin, briefly, I don't have the number -- the exact number in my head at the moment, but I can say that it was over 50% of patients in the study, who immediately came off BTKi before getting treatment with iopofosine. Most common -- in addition to that as the most common sort of transition, the other would be coming directly off of rituximab either monotherapy or in combination with chemotherapy.

Kevin DeGeeter: Really helpful. And then with regard to the Phase III program, thanks for the additional color. Can you comment on what the likely comparator arm for the Phase III program will be or at least -- or I think the question I'm ultimately interested is how one might think about potential range of PFS for the control arm population in a potential Phase III population?

James Caruso: Excellent question, Kevin. We've had -- we've engaged our friends at the FDA a number of different times on this. So we've settled in and are aligned on the comparator arm in the study. I could have Jarrod talk to that and provide some additional color.

Jarrod Longcor: Yes. So it is a great question. So what we believe the -- or what we've aligned on with the agency on the comparator arm is rituximab, cyclophosphamide, dexamethasone or RCD. It is commonly used in a post-BTKi patient population that tends to have significant adverse events associated with any of the other treatments and provides a comparable sort of outcome to some of the other treatment scenarios. So it makes a good choice.

I will say since you sort of asked the question about how to think about these compounds and how they might behave because obviously, in the literature, what you will find is that RCD, the last time it was significantly sort of challenged or experienced in various studies was pre-BTKi being in the marketplace. And so what you best bet is to look at an article that came out from a group, I'll call it Anna Frustaci out of Italy, where they demonstrated that with any rituximab combination and essentially any salvage therapy, progression-free survival in those patients varied anywhere from about 5.8 to 8.1 months in a post-BTKi exposed patient population and refractory for the earlier numbers.

So the 5.8 was a refractory patient population, which in our case, with the pivotal study or the confirmatory study that we're designing, which is essentially an immediate post-BTKi patient population following the frontline therapy. What we expect to see is the vast majority of those patients to be refractory to the BTKis' when they enter into the clinical study.

James Caruso: And the refractory to BTKi population in that salvage therapy, including these RCD combinations were approximately 5.8 months, correct?

Jarrod Longcor: Correct.

James Caruso: And out of the Phase II CLOVER WaM, our progression-free survival with iopofosine.

Jarrod Longcor: It was over 15 months.

James Caruso: In that same patient population. I think the other element there, Kevin, if you could take a moment and just talk to the powering of the study, the 100 in each arm and based on that differential, your level of confidence relative to how the study was powered.

Jarrod Longcor: Yes. So to Jim's point on the powering, what we did was we assumed for the comparator arm, essentially a hazard ratio that corresponds to an 8-month progression-free survival. And for the iopofosine arm, we used a hazard ratio that assumed no greater than a 12-month progression-free survival. So obviously, as Jim just said, our expectation is really that the -- with the vast majority of the patients being BTKi refractory, we're going to see something likely closer to 6 months of progression-free survival of the per arm.

And if the patients behave as they did in the CLOVER WaM study, we would expect something closer to 15 months in the iopofosine arm, thereby essentially overpowering the study by a number of patients in order to ensure success.

Kevin DeGeeter: Makes a lot of sense. And if I could just sneak in one more. I think just one of the questions that might be on investors' minds is just how you're thinking about the potential timing for an NDA submission under accelerated approval for WM.

James Caruso: It's pretty straightforward from our perspective. I mean, we're planning to initiate the study, as Jarrod had cited at the very back end of this year. Once we have the study up and running, enrolling patients, and that may be a couple of 2, 3 months. At that point, we would submit our new drug application. Please keep in mind that in May of last year, we received our breakthrough designation, which essentially obligates the FDA to -- for a 6-month window prior to regulatory action. So if you initiate at the very back end of this year, wait a couple of 2 or 3 months and then have the FDA action within 6 months of that submission.

You're in the second half of 2027 with a potential approval.

Operator: [Operator Instructions] There are no further questions at this time. I will now turn the call over to Jim Caruso for final remarks.

James Caruso: All right. Thank you, operator. I appreciate your assistance today. And certainly, thank you to all conference participants for both your time and continued interest in Cellectar. Have a good day.

Operator: And thank you, ladies and gentlemen. This concludes today's conference call. Thank you for your participation. You may now disconnect.