[8-K] Perspective Therapeutics, Inc. Reports Material Event
Rhea-AI Filing Summary
Perspective Therapeutics reported updated interim results from its ongoing Phase 1/2a trial of [212Pb]VMT-α-NET in patients with advanced SSTR2-positive neuroendocrine tumors. As of the March 4, 2026 data cut-off, 64 patients had received at least one treatment across three dose cohorts.
The company highlighted a favorable safety profile with no dose-limiting toxicities, no Grade 4 or 5 adverse events, no treatment-related discontinuations, and no serious renal complications or clinically significant treatment-related myelosuppression. Grade 3 or higher treatment-emergent adverse events occurred in 23 patients, and one previously reported Grade 4 lymphopenia was revised to Grade 3.
Among two patients in Cohort 1 and 23 in Cohort 2, 18 of 25 patients (72%) were alive without progression, and 10 of 23 Cohort 2 patients (43%) had objective responses by investigator-assessed RECIST v1.1, with several showing deepening responses over time. Perspective plans further data updates in 2026 and continued regulatory engagement.
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Insights
Early trial data show encouraging activity and safety for [212Pb]VMT-α-NET, but results remain preliminary.
Perspective Therapeutics shared interim Phase 1/2a results for [212Pb]VMT-α-NET in advanced SSTR2-positive neuroendocrine tumors. The update covers 64 treated patients across three dose levels, focusing on safety in all patients and efficacy in 25 from Cohorts 1 and 2.
Safety looks favorable for an alpha-emitting radiopharmaceutical: there were no dose-limiting toxicities, no Grade 4 or 5 adverse events, no treatment-related discontinuations, and no serious renal complications or clinically significant treatment-related myelosuppression. Grade 3 or higher treatment-emergent adverse events occurred in 36% of patients, which is notable but manageable in this setting.
Efficacy signals are promising but still early. In the first half of Cohort 2 at the 5.0 mCi dose, 43% (10 of 23) achieved objective responses by investigator-assessed RECIST v1.1, and 72% (18 of 25) across Cohort 1 and early Cohort 2 remained alive without progression as of the March 4, 2026 cut-off. The company expects additional data from later Cohort 2 patients and Cohort 3 during 2026, which will be important to confirm durability, define the optimal dose, and support potential registration study planning.
8-K Event Classification
UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
WASHINGTON, D.C. 20549
FORM 8-K
CURRENT REPORT
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Indicate by check mark whether the registrant is an emerging growth company as defined in Rule 405 of the Securities Act of 1933 (§ 230.405 of this chapter) or Rule 12b-2 of the Securities Exchange Act of 1934 (§ 240.12b-2 of this chapter).
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Item 8.01 Other Events.
On April 18, 2026, Perspective Therapeutics, Inc. (the “Company”) posted to its website a poster regarding certain interim results from its Phase 1/2a clinical trial of [212Pb]VMT-α-NET for the treatment and diagnosis of patients with unresectable or metastatic somatostatin receptor subtype 2-expressing neuroendocrine tumors that is being presented as a poster presentation at the American Association for Cancer Research Annual Meeting 2026 (“AACR 2026”) taking place April 17-22, 2026 in San Diego, CA. A copy of the poster is filed as Exhibit 99.1 to this Current Report on Form 8-K and is incorporated by reference into this Item 8.01.
Additionally, on April 20, 2026, the Company issued a press release regarding the data on its Phase 1/2a clinical trial of [212Pb]VMT-α-NET that are being presented at AACR 2026. A copy of the press release is filed as Exhibit 99.2 to this Current Report on Form 8-K and is incorporated by reference into this Item 8.01.
On April 18, 2026, the Company updated its corporate presentation. A copy of the presentation is filed as Exhibit 99.3 to this Current Report on Form 8-K and is incorporated by reference into this Item 8.01.
Item 9.01 Financial Statements and Exhibits.
(d) Exhibits.
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AACR 2026 Poster. |
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Press release dated April 20, 2026. |
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Investor Presentation. |
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Cover Page Interactive Data File (embedded within the Inline XBRL document). |
SIGNATURES
Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.
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PERSPECTIVE THERAPEUTICS, INC. |
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Date: |
April 20, 2026 |
By: |
/s/ Johan (Thijs) Spoor |
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Johan (Thijs) Spoor |
-60 -40 -20 0 20 40 60 0 8 16 24 32 40 48 56 64 72 80 88 96 104 Percent change in sum of diameters from baseline 0 1 2 3 4 5 0 8 16 24 32 40 48 56 64 72 80 88 96 Study Week Creatinine (mg/dL) Safety Analysis Set Somatostatin receptor subtype 2 (SSTR2) is expressed in neuroendocrine tumors (NETs), and it is an important target for both diagnosis and therapy. [212Pb]VMT--NET is an alpha therapy agent targeting SSTR2-expressing NETs. Here, we report an update of the results of a prospective, open-label, Phase I/IIa clinical trial evaluating the safety, tolerability, pharmacokinetics, and efficacy of [212Pb]VMT--NET. Background [212Pb]VMT-a-NET in advanced SSTR2+ neuroendocrine tumors updated safety and efficacy results from dose-finding cohorts 1, 2 and 3 Thor Halfdanarson1, Richard Wahl2, Vineeth Sukrithan3, Brandon Mancini4, Seyed Mosallaie5, Savitha Balaraman6, Gregory Sibley7, Jason Starr 8, Lowell Anthony9, Chih-Yi Liao10, Samuel Mehr11, Jared Weiss12, Robert Ramirez 13, Lucia Baratto14, Wenjing Yang14, Alaa Hanna14, Stephen Keefe14, Markus Puhlmann14, Vikas Prasad2 1. Mayo Clinic Rochester, 2. Washington University School of Medicine, 3. Ohio State University, 4. BAMF, 5. Johns Hopkins, 6. Profound Clinical Research, 7. Virginia Cancer Specialists, 8. Mayo Jacksonville, 9. University of Kentucky, 10. University of Chicago, 11. Nebraska Cancer Specialists, 12. University of North Carolina, 13. Vanderbilt, 14. Perspective Therapeutics Baseline patient characteristics – All patients treated by 04-Mar-2026 DCO, n = 64 All patients treated as of data cutoff (DCO) 04-Mar-2026 Patient exposure and follow-up with [212Pb]VMT-α-NET Swimmer plot of disposition: Follow-up time and response status by patient Cohort 1 and first half of Cohort 2, n = 25 Spider plot of tumor change over time by patient Cohort 1 and first half of Cohort 2, n = 25 Conclusions: Treatment with [212Pb]VMT-α-NET continues to be well-tolerated among all patients treated, n = 64 No dose-limiting toxicities (DLTs) No grade 4 or 5 adverse events No dysphagia No treatment-related discontinuations No serious renal complications No clinically significant treatment-related myelosuppression Data cutoff 04-Mar-2026. Blood creatinine increase was reported as an AE in 11 subjects and were Gr 1 only. Four have recovered. Seven are ongoing. Data cutoff 04-Mar-2026. One patient had a non-evaluable post baseline scan (therefore not shown) Age [years] Median 62.5 Range 37-78 Sex [n, (%)] Female 25 (39.1) Male 39 (60.9) Race [n, (%)] White 59 (92.2) Black 1 (1.6) Asian 2 (3.1) Multiple 2 (3.1) ECOG Performance Status [n, (%)] 0 50 (78.1) 1 14 (21.9) Time from dx to enrollment [mos] Median, Range 38.4, 5-317 Tumor type [n, (%)] Gastroenteropancreatic (GEP)-NET 61 (95.3) Pancreatic GEP-NET 30 (46.9) Non-pancreatic GEP-NET 31 (48.4) Bronchial NET 2 (3.1) Pheochromocytoma/paraganglioma 1 (1.6) Grade [n, (%)] G1 13 (20.3) G2 43 (67.2) G3 8 (12.5) No. prior syst rx Median, Range 1, 0-2 Prior systemic therapies [n, (%)] Somatostatin Analogues 54 (84.4) Small molecule (e.g., sunitinib) 9 (14.1) Immunotherapy 2 (3.1) Chemotherapy 16 (25.0) Most common (≥ 15%) treatment-emergent adverse events (TEAEs) All patients treated, n = 64 16% 16% 16% 17% 17% 19% 19% 19% 19% 19% 25% 25% 25% 34% 34% 34% 36% 36% 42% 42% 42% 63% 63% 64% 64% 66% 66% 66% Hypertension Aspartate aminotransferase increased Blood alkaline phosphatase increased Alanine aminotransferase increased Abdominal pain Lymphocyte count decreased* Anemia Diarrhea Nausea Alopecia Fatigue 0% 20% 40% 60% 80% 100% Grade 3 Grade 2 Grade 1 No dose-limiting toxicities (DLTs) No grade 4 or 5 adverse events No treatment-related discontinuations No serious renal complications No dysphagia No clinically significant myelosuppression Serious adverse events were reported in five patients, none deemed related to the study medication. They were (1) pyrexia and vomiting, (2) decreased cardiac output, (3) foot fracture, (4) pancreatitis and (5) influenza like illness. Data cutoff 04-Mar-2026. Gr 3 AEs occurred in 23 pts in total (36%). Pts with TEAE 100%. Pts with G3 TEAE 23 (35.9%). The following additional Gr 3 AEs occurred in 1 pt each: vomiting, hypokalemia, presyn-cope, asthenia, cardiac failure, gamma-glutamyltranferase increased, alanine aminotransferase increased, pancreatitis, fatigue, abdominal pain, influenza like illness and hyperglycemia. Gr 3 AE of syncope was reported in two pts. Pts with vomiting all grades: 7 (10.9%) with 1 (1.6%) G3. *One subject was previously reported to have experienced grade 4 lymphopenia, but this was subsequently downgraded by the site to grade 3. Blood creatinine over time for all patients treated Data cutoff 4-Mar-2026 . Darker color segments of each bar represent the treatment period. Lighter color segments represent post-treatment follow-up. Greyed out segments represent heterogenous SSTR2 expression. Unconfirmed PR occurred on latest scan prior to data cutoff on week 60 and could not be confirmed yet. Two patients passed away from progression of disease. Data cutoff (DCO) 04-Mar-2026 Clinical activity continues to evolve as of 4-Mar-2026 18 of the 25 patients (72%) enrolled into Cohorts 1 and 2 (first half) continued progression free Tumor size continues to shrink after ESMO 2025 for 9 patients; new unconfirmed PR occurred on week 60 Investigator-assessed RECIST v1.1 objective responses were observed in 10 of 23 patients (43%) in the first half of Cohort 2 (9 confirmed, 1 unconfirmed) The two patients enrolled in cohort 1 at 2.5 mCi had stable disease for 2 years [212Pb]VMT-a-NET is an active and well-tolerated therapy for patients with advanced NETs Follow-up is ongoing for cohort 2 patients Treatment continues for paitnets enrolled in cohort 3 (6 mCi dose level) Study design Data cutoff 04-Mar-2026. *One patient in Cohort 2 received two doses of 5.0 mCi then two doses of 2.5 mCi. Cohort 1 2.5 mCi n = 2 (%) Cohort 2 1st half 5 mCi n = 23 (%) Cohort 2 2nd half 5 mCi n = 23 (%) Cohort 3 6 mCi n = 16 (%) All Patients Treated n = 64 (%) Exposure (doses) 1 -- 3 (13.0) 2 (8.7) 7 (43.8) 12 (18.8) 2 -- -- 1 (4.3) 1 (6.2) 2 (3.1) 3 -- -- 2 (8.7) 4 (25.0) 6 (9.4) 4 2 (100) 20 (87.0)* 18 (78.3) 4 (25.0) 44 (68.8) FoFollow upllow-u n 2 23 23 16 64 Median (wks) 96.4 60.1 46.1 15.6 45.2 Range (wks) 95-97 6-101 6-58 3-32 3-101 All pts treated, n = 64 Cohort 1 & first half of Cohort 2 n = 25 0 8 16 24 32 40 48 56 64 72 80 88 96 104 Week Week
Perspective Therapeutics Presents Updated Interim Data of [212Pb]VMT-α-NET in Its Ongoing Phase 1/2a Clinical Trial at the 2026 AACR Annual Meeting
SEATTLE, April 20, 2026 (GLOBE NEWSWIRE) – Perspective Therapeutics, Inc. (“Perspective” or the “Company) (NYSE AMERICAN: CATX), a radiopharmaceutical development company pioneering advanced treatments for cancers throughout the body, today announced updated interim results from its ongoing Phase 1/2a clinical trial of [212Pb]VMT-α-NET in patients with unresectable or metastatic somatostatin receptor type 2 (SSTR2) expressing neuroendocrine tumors (NETs) as part of a poster presentation at the American Association for Cancer Research (AACR) Annual Meeting 2026. [212Pb]VMT-α-NET is potentially the first-in-class 212Pb-radiopharmaceutical therapy targeting SSTR2.
Interim results with a data cut-off date of March 4, 2026 formed the basis of the AACR update. The presentation includes safety data from 64 patients across three dose cohorts who have received at least one treatment of [212Pb]VMT-α-NET, and efficacy analysis from two patients in Cohort 1 (2.5 mCi) and 23 patients in Cohort 2 (5.0 mCi). Efficacy analysis with earlier data cut-off dates for the same patients were previously presented at the 2026 ASCO Gastrointestinal Cancers Symposium in January 2026 (ASCO-GI 2026) and the European Society for Medical Oncology Congress 2025 (ESMO 2025) in October 2025.
“Updated analyses continue to support the compelling overall clinical profile of [212Pb]VMT-α-NET as a treatment for GEP-NETs at the Cohort 2 dose level of 5 mCi per dose or up to 20 mCi cumulatively,” said Markus Puhlmann, Chief Medical Officer of Perspective. “We are particularly encouraged by continued learning on the time to onset of best response, durability of response, as well as emerging long-term safety of [212Pb]VMT-α-NET. Meanwhile, we are enhancing our robust clinical package and adding optionality with additional dose cohorts, as well as looking beyond GEP-NETs.”
As of the data cut-off date of March 4, 2026:
Safety findings based on 64 patients who received at least one treatment:
Anti-tumor activity based on both patients in Cohort 1 and 23 patients in Cohort 2:
About [212Pb]VMT-α-NET
Perspective designed [212Pb]VMT-α-NET to target and deliver 212Pb to tumor sites expressing somatostatin receptor type 2 (SSTR2). The Company is conducting a multi-center, open-label, dose-escalation, dose-expansion study (clinicaltrials.gov identifier NCT05636618) of [212Pb]VMT-α-NET in patients with unresectable or metastatic SSTR2-positive neuroendocrine tumors who have not received prior radiopharmaceutical therapies (RPT).
About Perspective Therapeutics, Inc.
Perspective Therapeutics, Inc. is a radiopharmaceutical development company pioneering advanced treatments for cancers throughout the body. The Company has proprietary technology that utilizes the alpha-emitting isotope 212Pb to deliver powerful radiation specifically to cancer cells via specialized targeting moieties. The Company is also developing complementary imaging diagnostics that incorporate the same targeting moieties, which provides the opportunity to personalize treatment and optimize patient outcomes. This "theranostic" approach enables the ability to see the specific tumor and then treat it to potentially improve efficacy and minimize toxicity.
The Company's neuroendocrine tumor (VMT-α-NET), melanoma (VMT01), and solid tumor (PSV359) programs are in Phase 1/2a imaging and therapy trials in the U.S. The Company is growing its regional network of drug product candidate finishing facilities, enabled by its proprietary 212Pb generator, to deliver patient-ready product candidates for clinical trials and commercial operations.
For more information, please visit the Company's website at www.perspectivetherapeutics.com.
Safe Harbor Statement
This press release contains forward-looking statements within the meaning of the United States Private Securities Litigation Reform Act of 1995. Statements in this press release that are not statements of historical fact are forward-looking statements. Words such as "may," "will," "should," "expect," "plan," "anticipate," "could," "intend," "target," "project," "estimate," "believe," "predict," "potential," or "continue" or the negative of these terms or other similar expressions are intended to identify forward-looking statements, though not all forward-looking statements contain these identifying words. Forward-looking statements in this press release include statements concerning, among other things, the Company’s clinical development plans and the expected timing for the release of additional data from its clinical programs; the Company’s expectations regarding its interactions with regulatory agencies and the expected timing thereof; and other statements that are not historical fact.
The Company may not actually achieve the plans, intentions, or expectations disclosed in the forward-looking statements, and you should not place undue reliance on the forward-looking statements. These forward-looking statements involve risks and uncertainties that could cause the Company's actual results to differ materially from the results described in or implied by the forward-looking statements. Known risk factors include that the Company’s clinical trials may be more costly or take longer to complete than anticipated, or may never be completed, or may not generate results that warrant future development of the tested product candidate; the Company may elect to change its strategy regarding its product candidates and clinical development activities; economic and market conditions may worsen; and risks related to the sufficiency of the Company’s cash resources for its future operating expenses and capital expenditures. A more complete discussion of the risks and uncertainties facing the Company appears under the heading “Risk Factors” in the Company’s most recent Annual Report on Form 10-K filed with the Securities and Exchange Commission (the “SEC”), in the Company’s other filings with the SEC, and in the Company’s future reports to be filed with the SEC and available at www.sec.gov. Forward-looking statements contained in this news release are made as of this date. Unless required to do so by law, we undertake no obligation to publicly update or revise any forward-looking statements, whether as a result of new information, future events, or otherwise.
Media and Investor Relations Contact:
Annie J. Cheng, CFA
ir@perspectivetherapeutics.com
Redefining Oncology Treatment with Next-Generation Radiopharmaceuticals
Why Radiotherapy, Why Perspective: Realizing the Untapped Value Across Oncology
Rapidly Advancing Best-in-Class Next Generation Radiopharmaceuticals
Proprietary Radioligand Platform Optimizes Therapeutic Index
Proprietary Pb-Based Chelator Designed for Broader and Safer Use
Lead-212: Optimal Isotope with Advantages Over Beta and Other Alpha Emitters
Imaging Optimizes Targeted Delivery to Tumor
Solid Tumors are an Attractive Market for Radiopharmaceuticals
End-to-End Manufacturing with Clinical Supply Secured and Commercial Scale Underway
Advancing a Diverse Wholly Owned 212Pb-Based Oncology Portfolio
SSTR2+ Neuroendocrine Tumors is a Large, Growing Market with Significant Unmet Need
VMT-⍺-NET: Potential First-in-Class 212Pb-Radioligand Therapy Targeting SSTR2
Ongoing Phase 1/2a to Establish Broad Therapeutic Window For VMT-⍺-NET in NETs
Compelling Anti-tumor Activity with Sustained or Deepening Responses
VMT-⍺-NET: Durable Disease Control Across All Doses
Best-in-class Safety Profile1
VMT-α-NET’s Compelling Profile Supports Potential Registration Study at Current Dose Level
Checkpoint Inhibitors Transformed Care of Melanoma but Leave Many Patients Behind
VMT01: Potential First-in-Class 212Pb Therapy Targeting MC1R for Melanoma
Ongoing Phase 1/2a Open-Label Trial For VMT01 in Melanoma
Preliminary Anti-tumor Activity Observed at Lower Dose of VMT01
Treatment Emergent Adverse Events (All Grades, Occurring in ≥ 2 Patients)
VMT01 is Well-tolerated with Initial Anti-tumor Activity Supporting Further Development
FAP-ɑ is an Attractive Cancer Target with Broad Solid Tumor Potential
PSV359: Potential First-in-Class 212Pb Therapy Targeting FAP-ɑ for Solid Tumors
Ongoing Open-label Phase 1/2a Trial For PSV359 in Advanced Solid Tumors
PSV359 has Improved Tumor Retention, Highlighting its Potential as a Therapeutic Agent
Strong IP Portfolio Covering All Aspects of Radiopharmaceutical Value Chain
Phase 1/2 Data Expected Across All 3 Clinical Programs in 2026
Abbreviations
APPENDIX
NETs Trials
VMT-⍺-NET: Baseline Patient Characteristics in AACR 2026 Data Analysis
Patient Exposure and Follow-up with [212Pb]VMT-α-NET in AACR 2026 Data Analysis
Patient with Confirmed PR After [212Pb]VMT-α-NET Treatment
Blood Creatinine During Follow-up for All Patients Treated (n=64)
Refractory Metastatic Melanoma Trials
ICI Combo Rationale: Strong Synergy with [212Pb]VMT01 in Melanoma
Daily production at regional sites ensures supply of ready-to-administer product
Perspective’s proprietary chelator has been optimized for lead-based RPTs
Construct designed for better clinical outcome
Construct designed for better clinical outcome
