On May 21, 2026 Remix Therapeutics (Remix), Inc., a clinical-stage biotechnology company developing small molecule therapies to modulate RNA processing and address the underlying drivers of disease, reported positive results from its ongoing Phase 1/2 ARIA clinical trial evaluating REM-422, a first-in-class MYB mRNA degrader, in patients with recurrent or metastatic (R/M) adenoid cystic carcinoma (ACC). The data will be featured in an oral presentation at the American Society of Clinical Oncology (ASCO) (Free ASCO Whitepaper) Annual Meeting 2026, delivered by Renata Ferrarotto, MD, professor of thoracic/head and neck medical oncology at The University of Texas MD Anderson Cancer Center.

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Results from the Phase 1 dose-escalation cohort found anti-tumor activity in patients with R/M ACC across molecular subtypes and previous lines of therapy, including patients who received antibody-drug conjugates. In the recommended Phase 2 dose (RP2D) biomarker positive cohort, the overall response rate was 43% (3 out of 7 patients) with the duration of response exceeding one year and ongoing. The disease control rate was 100% with several patients approaching two years on treatment with dosing ongoing. REM-422 was generally well tolerated at the RP2D with no dose-limiting toxicities observed. The most common treatment-related adverse events were epistaxis, fatigue, and anemia, all of which were grade 1 or 2.

"Patients with ACC have long lacked effective therapeutic options, and REM-422 represents a novel first-in-class oral mRNA degrader targeting MYB. These data show encouraging anti-tumor activity across biomarker-selected patients, along with a favorable safety profile," said Dr. Ferrarotto. "Notably, tumor responses were durable and deepened over time suggesting potential for long-term benefit."

REM-422 is the first oral mRNA degrader of MYB demonstrating proof-of-concept in ACC. In this study, pharmacokinetic and pharmacodynamic analyses confirmed robust compound exposure in blood and target engagement with reductions in MYB mRNA and protein levels in tumor biopsies.

"These positive ARIA trial data, including a significant overall response rate coupled with meaningful durability, 100% disease control and a favorable safety profile, strongly support the potential of REM-422 for patients with ACC," said Pete Smith, PhD, Co-Founder and CEO of Remix. "We are working to complete enrollment in the Phase 2 portion of the trial and look forward to progressing the development of REM-422 for patients with ACC who have seen minimal therapeutic progress and have no approved treatment options."

About REM-422
REM-422 is a first-in-class, potent, selective, and oral small molecule mRNA degrader that induces the reduction of MYB mRNA and subsequent protein expression. REM-422 functions by facilitating the incorporation of a poison exon in the MYB mRNA transcript, leading to nonsense-mediated decay of the transcript. REM-422 is currently in Phase 1/2 clinical studies in both Adenoid Cystic Carcinoma (ACC) and Acute Myeloid Leukemia (AML) or high-risk myelodysplastic syndrome (HR-MDS). The U.S. Food and Drug Administration granted REM-422 Orphan Drug Designation for ACC and AML and Fast Track designation for ACC.

About the ARIA (A study of REM-422 In Adenoid cystic carcinoma) Clinical Trial
This Phase 1/2, open-label, non-randomized, multicenter study (NCT06118086) is investigating REM-422 in patients with recurrent, metastatic or unresectable Adenoid Cystic Carcinoma (ACC). The study includes a Dose Escalation Phase and a Dose Expansion Phase. The purpose of the Dose Escalation Phase is to determine the maximum tolerated dose and/or recommended Phase 2 dose (RP2D) of REM-422 in patients with recurrent, metastatic, or unresectable ACC. The purpose of Dose Expansion is to further evaluate the safety and anti-tumor activity of the REM-422 RP2D in biomarker positive patients.

About Adenoid Cystic Carcinoma
Adenoid cystic carcinoma (ACC) is a solid tumor that most commonly arises in the salivary glands characterized by frequent recurrent, perineural invasion and dysregulation of the MYB oncogene. Depending on the location of the tumor, symptoms may include numbness of the face, difficulties swallowing, changes in vision, or difficulty breathing, among others. Many therapeutic approaches, such as chemotherapy, kinase inhibitors, and immunotherapy have been studied in ACC with modest or disappointing results, and there remain no approved treatment options.

(Press release, Remix Therapeutics, MAY 21, 2026, View Source [SID1234665984])

On May 21, 2026 Autolus Therapeutics plc (Nasdaq: AUTL), a commercial-stage biopharmaceutical company developing, manufacturing and delivering next-generation programmed T cell therapies and candidates, reported the online publication of an abstract submitted to the American Society of Clinical Oncology (ASCO) (Free ASCO Whitepaper) Annual Meeting, to be held May 29 – June 2, 2026, in Chicago, Illinois.

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"Data to be presented at the upcoming ASCO (Free ASCO Whitepaper) Annual Meeting provides insight into the use of obe-cel in patients with B-ALL and extramedullary disease (EMD), which is typically associated with shorter median and long-term survival compared to marrow-only relapse. With an overall response rate of 59% and a median duration of response (mDOR) of 42.6 months for patients with EMD, obe-cel may be considered as a potential treatment option for this difficult to treat population of patients," said Matthias Will, MD, Autolus Chief Development Officer.

Abstract 6517
Title: The effect of obecabtagene autoleucel (obe-cel) on adult patients (pts) with relapsed/refractory B-cell acute lymphoblastic leukemia (R/R B-ALL) and extramedullary disease (EMD).
Session Type and Track: Rapid Oral Abstract: Hematologic Malignancies—Leukemia, Myelodysplastic Syndromes, and Allotransplant.
Session Date and Time: May 30, 2026; 1:15 – 2:45PM CDT
Session Room: E450a
Abstract Number: 6517
Presentation time: 2:27 – 2:33pm CDT
Presenting Author: Jae Park, MD, Director, Adult ALL Program | Acting Chief, Cellular Therapeutics, Memorial Sloan Kettering Cancer Center, New York, NY, USA

Summary: A post-hoc analysis of the Phase Ib/II FELIX study (NCT04404660) was conducted, evaluating the efficacy and safety of obe-cel in patients with relapsed or refractory (r/r) B-ALL, by EMD status at lymphodepletion (LD). Following LD, adults with r/r B-ALL received obe-cel using a tumor burden-guided dosing strategy to minimize toxicity. Obe-cel treatment demonstrated favorable response and safety outcomes in patients with and without EMD in the FELIX trial. Of 127 obe-cel infused patients, 27 (21%) had EMD at LD. Among responders, duration of response in patients with EMD was 42.6 months, and the overall remission rate was 59%. Overall, these findings suggest a positive benefit–risk profile for obe-cel, including for patients with adverse risk features, specifically EMD at LD.

(Press release, Autolus, MAY 21, 2026, View Source [SID1234665983])

On May 21, 2026 Aktis Oncology, Inc. (NASDAQ:AKTS) (Aktis or the Company), a clinical-stage oncology company focused on expanding the breakthrough potential of targeted radiopharmaceuticals to large populations, including those not addressed by existing platform technologies, reported first-in-human clinical imaging and dosimetry data for AKY-2519, a miniprotein radioconjugate targeting B7-H3 expressing tumors. The data from two separate assessments of AKY-2519 – a clinical imaging and dosimetry assessment in patients with mCRPC and a clinical imaging assessment in patients with various solid tumor types – demonstrated robust tumor uptake and limited normal tissue exposure. These findings, which supported the advancement of a broad clinical development program for AKY-2519, will be presented in two poster presentations at the upcoming 2026 ASCO (Free ASCO Whitepaper) Annual Meeting, being held May 29 – June 2, 2026, in Chicago.

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"We’re excited to report the first clinical imaging and dosimetry data for AKY-2519, which offer a potentially differentiated therapeutic option for patients with B7-H3 expressing tumors, including mCRPC, lung cancer, and colorectal cancer, among others," said Matthew Roden, Ph.D., President and Chief Executive Officer at Aktis. "These data informed the design of our ongoing Phase 1b clinical trial in patients with mCRPC and a second Phase 1b trial of AKY-2519 in various B7-H3 expressing tumor types, which we expect to initiate in the second half of this year. The broad development opportunity for AKY-2519, our second clinical-stage program for multiple tumor types, exemplifies our vision to bring targeted radiopharmaceuticals to large patient populations with significant unmet need."

Akos Czibere, M.D., Ph.D., Chief Medical Officer at Aktis commented, "These first-in-human clinical imaging and dosimetry data suggest the potential of AKY-2519 to expand targeted radiopharmaceuticals to broader patient populations while also offering a potentially important new radiopharmaceutical option for the mCRPC patient population. The robust tumor uptake and retention and low normal tissue uptake consistently seen with AKY-2519 in these assessments gives us an initial understanding of its potential to kill cancer cells while minimizing normal-tissue radiation exposure. Moreover, the low predicted dose in salivary glands suggests AKY-2519’s unique potential as a B7-H3-targeted agent for mCRPC versus PSMA-targeting agents."

B7-H3 is highly expressed in mCRPC, lung, colorectal and various other solid tumor types, with limited expression in normal tissues. High tumor expression of B7-H3 has been shown to be associated with poor prognosis and lack of response to certain therapies in multiple tumor types. AKY-2519 is the second clinical-stage targeted miniprotein radioconjugate discovered and developed from Aktis’ proprietary platform. The program includes [64Cu]Cu-AKY-2519 for imaging with copper-64 (64Cu) and [225Ac]Ac-AKY-2519 for therapeutic use with actinium-225 (225Ac).

Aktis is currently enrolling patients in an mCRPC-dedicated Phase 1b trial of AKY-2519 in PLUVICTO-naïve and PLUVICTO-experienced patients, with preliminary data anticipated in 2027. The Company is on track to initiate a second Phase 1b trial of AKY-2519 in other B7-H3 expressing solid tumors in the second half of 2026. Aktis’ lead program, AKY-1189, a miniprotein radioconjugate targeting Nectin-4 expressing tumors, is currently being evaluated in a Phase 1b trial, with preliminary data expected in the first quarter of 2027.

About the AKY-2519 ASCO (Free ASCO Whitepaper) data presentations

Poster title: AKY-2519, a novel B7-H3–targeted radioconjugate, demonstrates a differentiated biodistribution profile with low normal tissue exposure and robust tumor doses in patients with mCRPC
Poster #: 234 / Abstract #: 3097 / Date & Time: Saturday, May 30, 1:30 – 4:30 p.m. CDT

Assessment background and methods

Conducted at the Nuclear Medicine Research Infrastructure (NuMeRI) at the University of Pretoria and Steve Biko Academic Hospital, South Africa, the assessment evaluated the biodistribution and dosimetry of AKY-2519, using [68Ga]Ga-AKY-2519 and low dose, non-therapeutic [177Lu]Lu-AKY-2519 as imaging surrogates in 16 patients with mCRPC. In the first part of the assessment, patients were given [68Ga]Ga-AKY-2519 and imaged using PET/CT at 30, 60, and 90 – 150 minutes to evaluate normal tissue distribution, tumor uptake and comparison with uptake of FDA-approved diagnostic PSMA-11. In the second part of the imaging assessment, patients were given low-dose, non-therapeutic [177Lu]Lu-AKY-2519 and imaged using SPECT/CT at 3, 24, and 144 hours to evaluate dosimetry (mean absorbed dose) and to estimate predicted [225Ac]Ac-AKY-2519 absorbed doses, at a therapeutic administration schedule of 8 MBq x4, in normal tissues and tumors.

Data highlights

Safety and tolerability

Administration of AKY-2519 was generally well tolerated, with no adverse events or infusion-related reactions reported with either [68Ga]Ga-AKY-2519 or [177Lu]Lu-AKY-2519.

Imaging and dosimetry results

Predicted absorbed doses of AKY-2519 in key normal tissues (bone marrow, liver, kidneys, salivary glands) were estimated to be favorable when compared to reference clinical benchmarks.
Notably, the predicted absorbed dose of AKY-2519 to the salivary glands was lower compared to approved radiopharmaceuticals.

Table 1. Predicted [225Ac]Ac-AKY-2519 absorbed doses in critical normal tissues

Normal Tissue
Mean Absorbed Dose Coefficient
(225Ac)
Predicted
Absorbed Dose at 8 MBq x 4

(n=12)a
GyRBE=5/MBq(SD)
GyRBE=5
Bone marrow 0.04 (0.02) 1.3
Liver 0.31 (0.10) 9.9
Kidneys 0.50 (0.17) 16
Salivary glands 0.13 (0.04) 4.2
a[177Lu]Lu-AKY-2519 was used as a surrogate for estimation of absorbed doses with [225Ac]Ac-AKY-2519. Of the 16 patients with [177Lu]Lu-AKY-2519 dosimetry data available, 12 had sufficient data for conversion to [225Ac]Ac-AKY-2519; RBE, relative biological effectiveness; SD, standard deviation.

AKY-2519 demonstrated robust tumor uptake and retention in tumors for at least 6 days after administration.
Predicted absorbed doses of AKY-2519 to prospectively selected tumors, including involved prostate and seminal vesicles and nodal and bony metastases, were within expected therapeutic ranges for approved radiopharmaceuticals.
The combined findings of predicted absorbed doses in tumors and normal tissues suggest a wide therapeutic index and a favorable profile for AKY-2519 compared to approved radiopharmaceuticals.

Table 2. Estimated tumor absorbed doses of [225Ac]Ac-AKY-2519 in mCRPC lesions

Lesion Location Evaluable
Patients Mean Absorbed Dose Coefficienta(225Ac)
Mean Absorbed Dose Coefficient with PVC (225Ac)
Predicted
Absorbed Dose at 8 MBq x 4
Predicted Absorbed Dosebat 8 MBq x 4 with PVC
GyRBE=5/MBq(SD)
GyRBE=5/MBq(SD)
GyRBE=5
GyRBE=5
Involved prostate ± seminal vesicles 8 2.6 (1.2) N/Ac 83 (39) N/Ac
Nodal metastases 5 4.4 (2.8) 8.4 (4.2) 141 (88) 268 (134)
Bony metastases 6 1.5 (0.8) 3.8 (1.8) 48 (25) 121 (57)
aWhere multiple regions of interest (ROIs) of the same category were available in a single patient (nodal or bony metastasis), the highest value was utilized. bProjected absorbed dose estimates are calculated based on the corresponding raw dose coefficient for the ROI. cPartial volume correction (PVC) was not applied for ROI analysis of involved prostate due to spillover activity from adjacent bladder. SD, standard deviation

AKY-2519 and PSMA-11 comparison

Distribution of tumor uptake appears comparable between [68Ga]Ga-AKY-2519 and [68Ga]Ga-PSMA-11 at the standard 60 minutes measurement time point, with tumor uptake with [68Ga]Ga-AKY-2519 increasing over time.

Poster Presentation 2: First-in-Human PET/CT imaging with [69Ga]Ga-AKY-2519, a B7-H3 Targeted Miniprotein Conjugate, to demonstrate tumor uptake and normal tissue exposure across various advanced solid tumors
Poster #: 235 / Abstract #: 3098 / Date & Time: Saturday, May 30, 1:30 – 4:30 p.m. CDT

Assessment background and methods

Conducted by the Department of Nuclear Medicine, University of Duisburg-Essen and German Cancer Consortium (DKTK), Universitätsklinikum Essen (University Hospital Essen), Essen, Germany, the assessment evaluated the biodistribution and tumor uptake of [68Ga]Ga-AKY-2519 in patients with advanced or metastatic disease in a variety of solid tumors, including prostate, lung, colorectal, and other tumor types (n=18). Following intravenous administration of [68Ga]Ga-AKY-2519 patients were imaged with PET/CT and SUV (standardized uptake value) measurements were taken to assess tumor uptake and normal tissue distribution at 15, 60 and 120 minutes.

Data highlights

Safety and tolerability

Administration of [68Ga]Ga-AKY-2519 was generally well tolerated, with no adverse events or infusion-related reactions reported.

Imaging results

Robust uptake of [68Ga]Ga-AKY-2519 as measured by SUVmax was observed across multiple tumor types, including prostate, non-small cell lung cancer (NSCLC), small cell lung cancer (SCLC), and rectal cancer at various time points out to 120 minutes with representative patients showing:
Prostate cancer: SUVmax = 33.9-37.4;
NSCLC: SUVmax = 17.5-21.5;
SCLC: SUVmax = 15.4; and
Rectal cancer: SUVmax = 15.3.
In prostate cancer, high [68Ga]Ga-AKY-2519 tumor uptake was consistently observed across metastatic disease sites with the most intense uptake observed in bone and visceral metastases.

Table 3. Uptake of [68Ga]Ga-AKY-2519 (120 min post infusion) in multiple metastatic disease sites
from patients with prostate cancer (n=7)

Bone Metastases Lymph Node Metastases Visceral Metastases
Median SUVmax 40.4 13.8 31.0
Median SUVpeak 25.0 6.5 22.2
Median SUVmean 16.1 5.1 18.7
SUV, standard uptake value

PET/CT imaging 120 min after [68Ga]Ga-AKY-2519 injection showed low uptake in critical normal tissues.

Table 4. Uptake of [68Ga]Ga-AKY-2519 (120 min post infusion) in normal tissues of patients with solid tumors (n=18)

Adrenal
Glands Bone
Marrow Kidneys Liver Salivary
Glands Spleen

Median (IQR) SUVmax 17.5
(15.9—19.8) 4.1
(3.3—5.1) 6.7
(6.3—8.7) 22.9
(20.9—30.8) 7.3
(6.4—11.4) 9.2
(7.6—10.4)

Conference call and webcast information
Aktis will host a live conference call and webcast on Wednesday, May 27, 2026, at 8 a.m. ET to discuss the AKY-2519 imaging and dosimetry data with leading clinical investigators, Oliver Sartor, M.D., LCMC Health, Director, Transformational Prostate Cancer Research Center (New Orleans, LA), and Timothy A. Yap, MBBS, Ph.D., Vice President and Head of Clinical Development, Therapeutics Discovery Division; Professor, Department of Investigational Cancer Therapeutics (Phase I Program), University of Texas MD Anderson Cancer Center. To access the conference call, please register here. Registrants will receive the dial-in number and unique PIN. A live webcast of the call will also be available under "Events" in the Investors section of the Aktis Oncology website at investors.aktisoncology.com. The archived webcast will be available for 90 days following the call.

(Press release, Aktis Oncology, MAY 21, 2026, View Source [SID1234665982])

On May 21, 2026 Pliant Therapeutics, Inc. (Nasdaq: PLRX) reported a presentation at the upcoming 2026 American Society of Clinical Oncology (ASCO) (Free ASCO Whitepaper) Annual Meeting taking place in Chicago, Illinois from May 29 to June 2, 2026.

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Poster Presentation

Title: Cohort Expansion of a Phase I Study of PLN-101095, a First-in-Class Dual αvβ8 /αvβ1 Integrin Inhibitor, in Combination with Pembrolizumab in Patients with Advanced Solid Tumors Refractory to Immune Checkpoint Inhibitors

Presenter: Timothy A. Yap, MBBS, Ph.D., University of Texas, M.D. Anderson Cancer Center
Session: Developmental Therapeutics – Immunotherapy
Date: Saturday, May 30, 2026, 1:30 – 4:30 p.m. Central Time
Location: Hall A, Poster 467b

FORTIFY – PLN-101095 Phase 1b Indication Expansion Trial

PLN-101095 is currently being evaluated in Phase 1a/1b open-label, dose-escalation and indication expansion trial (NCT06270706) to evaluate the safety, tolerability, pharmacokinetics, and preliminary evidence of antitumor activity of PLN-101095 when administered orally in combination with pembrolizumab, in patients with immune checkpoint inhibitor (ICI)-refractory advanced or metastatic solid tumors. Pliant is currently enrolling patients in FORTIFY, a Phase 1b open-label, indication expansion trial enrolling three cohorts of patients with non-small cell lung cancer (NSCLC), tumors with high tumor mutational burden or clear cell renal cell carcinoma. Patients will be treated for 14 days with PLN-101095 dosed at 1,000 mg twice daily as monotherapy, after which pembrolizumab will be added as combination therapy.

(Press release, Pliant Therapeutics, MAY 21, 2026, View Source [SID1234665981])

On May 21, 2026 Perspective Therapeutics, Inc. ("Perspective" or the "Company") (NYSE AMERICAN: CATX), a radiopharmaceutical development company pioneering advanced treatments for cancers throughout the body, reported that updates on all three of its advancing clinical programs, [²¹²Pb]VMT-α-NET, [²¹²Pb]VMT01, and [²¹²Pb]PSV359, will be presented at the 2026 American Society of Clinical Oncology (ASCO) (Free ASCO Whitepaper) Annual Meeting taking place from May 29 to June 2, 2026 in Chicago, IL.

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2026 ASCO (Free ASCO Whitepaper) Poster Presentation Highlights and Details

[212Pb]VMT-α-NET for Neuroendocrine Tumors – Updated Phase 1/2a data show:

Clinical profile being reported is consistent with previously disclosed findings at the American Association for Cancer Research (AACR) (Free AACR Whitepaper) Annual Meeting 2026 (AACR 2026)
Deepening of response continues to be observed since the AACR (Free AACR Whitepaper) 2026 and the European Society for Medical Oncology Congress 2025 (ESMO 2025) presentations
The ASCO (Free ASCO Whitepaper) data cut-off date of April 17, 2026 represents an additional ~6 weeks of follow-up since the prior update at AACR (Free AACR Whitepaper) 2026 in April 2026 and ~31 weeks since ESMO (Free ESMO Whitepaper) 2025 in October 2025

[²¹²Pb]VMT01 for Melanoma – 3.0 mCi monotherapy (n=7) and nivolumab combination (n=6) cohorts are ongoing in the Phase 1/2a study in positive melanocortin 1 receptor (MC1R)-targeted, heavily pre-treated melanoma.

As of the March 25, 2026 data cut-off date:
One new response was observed early in the 3.0 mCi monotherapy cohort, in addition to a previously reported response, for a total of two responders out of seven treated patients
Six patients (86%) experienced stable disease or partial response out of the seven patients in the 3.0 mCi monotherapy cohort; four patients completed all three treatments with 24 weeks or more of follow-up since their first treatment, and two remain on treatment and in study
[²¹²Pb]VMT01 was well-tolerated with no dose limiting toxicities (DLTs), no discontinuations due to adverse events, and no Grade 4 or Grade 5 treatment emergent adverse events (TEAEs)
Eight (30%) patients out of a total of 27 patients treated experienced Grade 3 TEAEs
[²¹²Pb]PSV359 for Solid Tumors – Treatments in Cohort 3 (6.0 mCi) initiated in May 2026 in the Phase 1/2a study in solid tumors that express fibroblast activation protein alpha (FAP-α).

[212Pb]PSV359 was well-tolerated with no DLTs, and TEAEs at Grades 1 and 2 only, as of the data cut-off date of December 24, 2025

Presenter Abstract Title Presentation Details
Thorvardur Halfdanarson,
Mayo Clinic Comprehensive Cancer Center

Cohort-level safety and efficacy results for [212Pb]VMT-α-NET in advanced somatostatin receptor subtype 2 (SSTR2+)–expressing neuroendocrine tumors (NETs): Cohorts 1–3 Abstract Number: 4173
Session Title: Gastrointestinal Cancer—Gastroesophageal, Pancreatic, and Hepatobiliary
Date and Time: May 30, 2026, 9:00 am – 12:00 pm CDT
Zachary Morris, University of Wisconsin School of Medicine and Public Health A phase I/IIa, first-in-human, multicenter, monotherapy and combination-therapy with nivolumab, dose-finding of [212Pb]VMT01 melanocortin-1-receptor-targeted, image-guided, alpha-particle therapy in subjects with previously treated unresectable or metastatic melanoma

Abstract Number: 9525
Session Title: Melanoma/Skin Cancers
Date and Time: May 31, 2026, 9:00 a.m. – 12:00 p.m. CDT

Samuel Mehr, Nebraska Cancer Specialists

A phase I/IIa, image-guided, alpha-particle therapy study of [203Pb]Pb-PSV359 and [212Pb]Pb-PSV359 in patients with solid tumors that are known to be fibroblast activation protein (FAP)-positive

Abstract Number: e15146
Session Type: Publication Only

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).

Interim analysis with a data cut-off date of March 4, 2026 was recently reported at AACR (Free AACR Whitepaper) 2026 in April 2026, including efficacy data on half of the patients in Cohort 2 and both patients in Cohort 1. Initial efficacy data for the remaining patients in Cohort 2 and eight patients in Cohort 3 are pending, and submissions for presentations at additional medical conferences during 2026 are planned.

Highlights from the recently presented AACR (Free AACR Whitepaper) analysis included the following:

As of the data cut-off date of March 4, 2026:

Safety findings based on 64 patients who received at least one treatment:

The 64 patients in this safety analysis comprised two patients in Cohort 1 (2.5 mCi), 46 patients in Cohort 2 (5.0 mCi), and 16 patients in Cohort 3 (6.0 mCi).
There were no reports of DLTs, treatment-related discontinuations, serious renal complications, dysphagia, or clinically significant treatment-related myelosuppression.
Grade 3 or higher treatment-emergent adverse events were reported in 23 patients (36%). One of these patients, who was enrolled in Cohort 3, experienced a transient lymphocyte count decrease on the cusp of Grades 3 and 4. This event was subsequently determined by the site to be a Grade 3 event. This event was transient and resolved without medical intervention. The patient completed the full course of [212Pb]VMT-α-NET treatment of four treatments without interruption and remains on study. Otherwise, no Grade 4 or Grade 5 events have occurred.
No additional patients experienced serious adverse events (SAEs) since the most recent data update at the 2026 ASCO (Free ASCO Whitepaper) Gastrointestinal Cancers Symposium in January 2026 (ASCO-GI 2026), with none of the five SAEs deemed related to the study medication.

Anti-tumor activity based on both patients in Cohort 1 and 23 patients in Cohort 2:

Updated efficacy analysis in the same 25 patients from ASCO (Free ASCO Whitepaper)-GI 2026 and ESMO (Free ESMO Whitepaper) 2025 was presented with an additional ~12 weeks and ~25 weeks of follow-up, respectively.
18 of the 25 patients (72%) were without progression and remained alive, including both patients in Cohort 1.
Ten (43%) patients in Cohort 2 were observed to have response according to investigator-assessed RECIST v1.1. Nine of those responses were previously reported at ASCO (Free ASCO Whitepaper)-GI 2026, including one initial response reported at ASCO (Free ASCO Whitepaper)-GI 2026 that has since been confirmed. Since then, one more patient experienced an initial response in their most recent tumor assessment. As the patient remains on study, the patient is expected to receive a subsequent tumor assessment.
Eight (50%) of the 16 patients in Cohort 2 whose tumors all express SSTR2 were observed to have response according to investigator-assessed RECIST v1.1.
Nine patients were observed to have deepening of best response since initial tumor assessments on these patients were reported at ESMO (Free ESMO Whitepaper) in October 2025.

About [212Pb]VMT01
Perspective designed [212Pb]VMT01 to target and deliver 212Pb to tumor sites expressing MC1R, a protein that can be overexpressed in metastatic melanoma tumors.1 The Company is conducting a multi-center, open-label dose escalation, dose expansion study (clinicaltrials.gov identifier NCT05655312) in patients with histologically confirmed melanoma and MC1R-positive imaging scans. In September 2024, the Company announced that the U.S. Food and Drug Administration (FDA) granted Fast Track Designation for the development of [212Pb]VMT01 for the diagnosis and treatment of patients with unresectable or metastatic melanoma and who have demonstrated MC1R tumor expression. The FDA’s Fast Track Designation is one of several approaches utilized by the FDA to expedite development and review of potential medicines for serious conditions and that fulfill unmet medical needs.2

About PSV359
PSV359 was designed to target and deliver 212Pb to tumor sites expressing FAP-α, associated with multiple highly prevalent solid tumors, with patients in need of additional treatment options. The targeting moiety may also be radiolabeled with 203Pb or 68Ga (known as PSV377) to detect FAP-α expression in individual patients. Preclinical imaging and therapy as well as human imaging results suggest Perspective’s proprietary targeting ligand has improved levels of target engagement and uptake in tumors, as well as reduced retention in healthy tissues, which may result in a desirable therapeutic index.

Perspective is conducting a multi-center, open-label, dose-finding and dose-expansion study (clinicaltrials.gov identifier NCT06710756) of [212Pb]PSV359 in patients with advanced solid tumors that express FAP-α as determined by imaging with [203Pb]PSV359. The primary objective of the dose finding phase of the study is to assess the safety and tolerability of various doses of [212Pb]PSV359 in order to determine the recommended Phase 2 dose to be used in the expansion phase of the study, where anti-tumor activities may be an additional primary outcome measure.

(Press release, Perspective Therapeutics, MAY 21, 2026, View Source [SID1234665980])