On April 28, 2025 Sutro Biopharma, Inc. (Sutro or the Company) (NASDAQ: STRO), an oncology company pioneering site-specific and novel-format antibody drug conjugates (ADCs), reported poster presentations at the upcoming 2025 American Association for Cancer Research (AACR) (Free AACR Whitepaper) Annual Meeting, taking place April 25-30 in Chicago, IL (Press release, Sutro Biopharma, APR 28, 2025, View Source [SID1234652257]). The presentations will cover preclinical activity and safety data for STRO-004, the Company’s novel exatecan Tissue Factor ADC, as well as showcase the unique advantages of Sutro’s XpressCF+ platform in enabling precise and efficient development of dual-payload ADCs.

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"We are excited to share our progress advancing our next-generation ADC pipeline at AACR (Free AACR Whitepaper)," said Jane Chung, Sutro’s Chief Executive Officer. "In preclinical studies, STRO-004 consistently demonstrated potent, dose-dependent anti-tumor activity and a favorable safety profile across all tested doses. Of note, STRO-004, after only a single dose, achieved promising overall response and disease control rates in Tissue Factor-positive patient-derived xenograft models spanning multiple cancer types. We look forward to continuing to investigate the full potential of STRO-004, as we complete IND-enabling studies and prepare to initiate a first-in-human trial later this year."

Ms. Chung continued: "Also, as presented at AACR (Free AACR Whitepaper), our XpressCF+ cell-free platform is uniquely capable of creating revolutionary dual-payload ADCs—differentiated by higher drug-to-antibody ratios, fully site-selective conjugation of two linker payloads and a validated, cell-free ADC manufacturing process. We are excited to showcase these and other key features of our platform, which enable our ADC candidates to overcome limitations of conventional ADCs and the challenges of targeting complex disease biology. These presentations further reinforce our technology leadership and our highly differentiated ADC candidates."

Poster Presentation Details:

Title: Preclinical activity and safety of STRO-004, a novel ADC targeting tissue factor for solid tumors
Abstract: #1572
Session: PO.ET02.01 – Antibody-Based Cancer Therapeutics 1
Date & Time: Monday, April 28, 2025, 9:00 a.m. – 12:00 p.m. CT
Presenter: Alice Yam, Ph.D., Vice President of Drug Discovery at Sutro Biopharma

Title: Enhancing Topo1i ADC efficacy: development of homogeneous dual-payload ADCs combining Topo1i with microtubule inhibitors or PARP inhibitors
Abstract: #2870
Session: PO.ET02.11 – Antibody-Based Cancer Therapeutics 2
Date & Time: Monday, April 28, 2025, 2:00 p.m. – 5:00 p.m. CT
Presenter: Gang Yin, Ph.D., Vice President of Platform Engineering & Process Research at Sutro Biopharma

The abstracts are currently available on AACR (Free AACR Whitepaper)’s website and the poster presentations will be accessible through the News & Events page of the Investor Relations section of the Company’s website at www.sutrobio.com.

On April 28, 2025 Agenus Inc. (Nasdaq: AGEN), a leader in immuno-oncology, reported that data from the investigator sponsored NEOASIS study were presented in an oral session at the American Association for Cancer Research (AACR) (Free AACR Whitepaper) Annual Meeting in Chicago, Illinois (Press release, Agenus, APR 28, 2025, View Source [SID1234652256]). This represents the third clinical study evaluating botensilimab and balstilimab (BOT/BAL) in the neoadjuvant setting, with outcomes reported in mismatch repair–proficient (pMMR/MSS) and mismatch repair–deficient (dMMR/MSI-H) solid tumors. These findings include the first reported outcomes with BOT/BAL outside colorectal cancer in the neoadjuvant setting.

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"These initial results from the NEOASIS study indicate that botensilimab and balstilimab can induce pathological responses in patients with a variety of solid tumors, including triple-negative breast cancer, after just two doses," said Myriam Chalabi, MD, of the Netherlands Cancer Institute. "The observed response rates—achieved without dose-limiting toxicities or surgical delays—are notable."

NEOASIS Phase 2 Neoadjuvant BOT/BAL in Early-Stage Solid Tumors (NCT06279130)

Study Design:

The safety run-in enrolled patients with non-metastatic solid tumors, divided into two cohorts of 10 patients each: dMMR/MSI-H and pMMR/MSS. Patients received a single dose of BOT (25 mg or 50 mg) combined with BAL (450 mg) on Day 1 and again on Day 22.

Results:

dMMR/MSI-H Cohort (9 colorectal, 1 duodenal cancer):
Pathological response rate: 90%
Major pathological response (MPR): 80%
Pathological complete response (pCR): 70%
pMMR/MSS Cohort (6 triple-negative breast cancer, 2 ER+ breast cancer, 1 merkel cell carcinoma, 1 sarcoma):
Pathological response rate: 80%
Major pathological response (MPR): 70%
Pathological complete response (pCR): 20%
Triple-negative breast cancer subgroup (n=6): 63% achieved MPR
No dose-limiting toxicities were observed at either dose level, and all patients proceeded to surgery on schedule. Enrollment in the efficacy phase of the study continues.

"The NEOASIS study data reinforces earlier evidence of profound clinical activity with the BOT/BAL combination in the neoadjuvant treatment of solid tumors, including those traditionally resistant to immunotherapy," said Steven O’Day, MD, Chief Medical Officer at Agenus. "These findings substantiate the importance of this immunotherapy in early treatment settings and highlight the broad potential utility of this combination."

Presentation Details:

Title: Neoadjuvant botensilimab plus balstilimab in MMR proficient and deficient early-stage cancers: First results of the pan-cancer NEOASIS study (NCT06279130)
Presenter:Myriam Chalabi, MD, Netherlands Cancer Institute
Session:Aiming for Cure: Adjuvant and Neoadjuvant Approaches
Date and Time:April 28, 2025; 2:30 PM – 4:30 PM CT
Abstract Number:CT130
Visit View Source for more information.

About Botensilimab (BOT)

Botensilimab is a human Fc enhanced CTLA-4 blocking antibody designed to boost both innate and adaptive anti-tumor immune responses. Its novel design leverages mechanisms of action to extend immunotherapy benefits to "cold" tumors which generally respond poorly to standard of care or are refractory to conventional PD-1/CTLA-4 therapies and investigational therapies. Botensilimab augments immune responses across a wide range of tumor types by priming and activating T cells, downregulating intratumoral regulatory T cells, activating myeloid cells and inducing long-term memory responses.

Botensilimab alone, or in combination with Agenus’ investigational PD-1 antibody, balstilimab, has shown clinical responses across nine metastatic, late-line cancers. Approximately 1,100 patients have been treated across the botensilimab/balstilimab program in phase 1 and phase 2 clinical trials. For more information about botensilimab trials, visit www.clinicaltrials.gov.

About Balstilimab (BAL)

Balstilimab is a novel, fully human monoclonal immunoglobulin G4 (IgG4) designed to block PD-1 (programmed cell death protein 1) from interacting with its ligands PD-L1 and PD-L2. It has been evaluated in >900 patients to date and has demonstrated clinical activity and a favorable tolerability profile in several tumor types.

On April 28, 2025 The Management Board of 4SC AG ("4SC") (Frankfurt Stock Exchange, Prime Standard: VSC; ISIN: DE000A14KL72) reported by the European Medicines Agency (EMA) that, based on the review of the final data and the company’s responses to the Day-180 Assessment Report, 4SC has been invited to an oral discussion before the Committee for Medicinal Products for Human Use (CHMP) at its meeting in late May (Press release, 4SC, APR 28, 2025, View Source [SID1234652255]). Following this meeting, the CHMP is expected to issue a decision on whether to issue a positive or negative recommendation on the company’s Marketing Authorization Application (MAA) for resminostat (Kinselby) in the EU.

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Information and explanations of the issuer regarding this announcement:

Future-oriented information
This release contains certain forward-looking statements that involve risks and uncertainties and reflect 4SC’s assessment as of the date hereof. Such forward-looking statements are neither promises nor guarantees, but are subject to numerous risks and uncertainties, many of which are beyond 4SC’s control, which could cause actual results to differ materially from those contemplated by such forward-looking statements. 4SC expressly disclaims any obligation to update or revise any forward-looking statements to reflect changed expectations or new events, conditions, or circumstances on which any such statements are based.

On April 28, 2025 Actinium Pharmaceuticals, Inc. (NYSE AMERICAN: ATNM) (Actinium or the Company), a pioneer in the development of targeted radiotherapies, reported preclinical results with ATNM-400 in prostate cancer models presented at the American Association for Cancer Research (AACR) (Free AACR Whitepaper) Annual Meeting (Press release, Actinium Pharmaceuticals, APR 28, 2025, View Source [SID1234652253]). ATNM-400 is a novel, non-PSMA targeting, first in class targeted radiotherapy utilizing the Actinium-225 (Ac-225) radioisotope that Actinium is evaluating in prostate cancer models prior to and following treatment with Pluvicto. Pluvicto (Lu-177-PSMA-617) is a prostate-specific membrane antigen (PSMA) directed radiotherapy radiolabeled with the beta-particle emitter, Lutetitium-177 (Lu-177) is approved for patients with metastatic castration-resistant prostate cancer. Pluvicto is marketed and sold by Novartis and generated sales of $1.39 billion in 2024.

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In vivo studies demonstrated that ATNM-400 is more efficacious than Pluvicto and produced a statistically significant (p < 0.0001) reduction in tumor volume in 22Rv1 prostate cancer models demonstrating its transformative therapeutic potential.

ATNM-400 is a highly innovative, first-in-class prostate cancer candidate in comparison to Pluvicto and the majority of radiotherapies in development for prostate cancer which target PSMA and are either non-differentiated or barely differentiated, as it targets a distinct non-PSMA receptor. The receptor specifically targeted by ATNM-400 is highly expressed in metastatic castration-resistant prostate cancer (mCRPC) and continues to be expressed at a high level even after Pluvicto treatment which does not appear to impact target expression levels. ATNM-400 leverages the alpha-particle emitter Ac-225, which is more potent than Lu-177, can cause lethal double-stranded irreversible DNA breaks, and has a shorter path length that could result in fewer off-target effects.

Key Data and Highlights From the ATNM-400 AACR (Free AACR Whitepaper) Presentation

In vivo studies demonstrated that ATNM-400 is more efficacious than Pluvicto and produced a statistically significant (p < 0.0001) reduction in tumor volume in 22Rv1 prostate cancer models demonstrating its transformative therapeutic potential.

In mice bearing Pluvicto-failed tumors, ATNM-400 was administered on day 14 following Pluvicto treatment, demonstrating robust antitumor activity and tumor growth inhibition in Pluvicto- resistant tumor models.

Expression of the target receptor for ATNM-400 persists following Pluvicto therapy and ATNM-400 demonstrates sustained tumor control after Pluvicto stops working

ATNM-400 demonstrated greater efficacy than Pluvicto in prostate cancer models with 99.8% tumor growth inhibition achieved with a single 40 µCi/kg dose of ATNM-400 supporting its potential to be offered as an alternative option

ATNM-400 internalizes rapidly, exhibiting potent cytotoxicity and prostate cancer cell killing via double strand DNA breaks that are produced by the Ac-225 alpha-particle emitting radionuclide payload of ATNM-400

Biodistribution analyses showed sustained uptake in the tumor up to the 216-hour time point, with rapid clearance from the blood by the 48-hour time point and clearance from essential organs including the kidneys, intestines and liver

ATNM-400 was well tolerated with body weight recovery and no apparent toxicity at both doses evaluated in vivo
Sandesh Seth, Actinium’s Chairman and CEO, said, "We are thrilled to unveil these exciting results demonstrating the transformative therapeutic potential of ATNM-400. There is a significant unmet need for a therapy that can address patients who are treated with Pluvicto and progress, which we only expect to increase following the recent approval of Pluvicto in the earlier line, pre-taxane setting. Consistent with our focus on leading-edge innovation, ATNM-400 is highly novel given it is a non-PSMA target receptor, which is highly expressed in mCRPC, and as we have presented at AACR (Free AACR Whitepaper), continues to be expressed following Pluvicto therapy. ATNM-400 capitalizes on the potency and precision of the Ac-225 isotope payload that can overcome resistance via lethal double strand DNA breaks. Our enthusiasm for ATNM-400 was validated by the significant interest this data received at AACR (Free AACR Whitepaper) and we look forward to validating the potential of this exciting radiotherapy candidate as we advance its development with additional data expected later this year".

The ATNM-400 AACR (Free AACR Whitepaper) presentation is available for viewing on the Presentations & Webinars page of Actinium’s website HERE.

Title: ATNM-400 is a novel Actinium-225 antibody radioconjugate with strong efficacy in preclinical models of prostate cancer
Abstract Number: 578

On April 28, 2025 TuHURA Biosciences, Inc. (NASDAQ:HURA) ("TuHURA"), a Phase 3 immune-oncology company developing novel technologies to overcome resistance to cancer immunotherapy, reported on poster presentations of Kineta Inc.’s ("Kineta") KVA12123 novel anti-VISTA antibody and TuHURA’s IFx-Hu2.0 in advanced melanoma and at the American Association for Cancer Research (AACR) (Free AACR Whitepaper) Annual Meeting in Chicago, IL (Press release, TuHURA Biosciences, APR 28, 2025, View Source [SID1234652249]).

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In the first poster presentation, (CT041/20) TuHURA and Kineta provided updated results from VISTA-101, a Phase I-II first-in-human study of KVA12123 alone and in combination with pembrolizumab in patients with advanced solid tumors (NCT05708950). The poster, was presented by Thierry Guillaudeux, Ph.D., Chief Scientific Officer of Kineta. KVA12123 was found to be generally safe and well tolerated in all monotherapy and combination arms, with no dose-limiting toxicities observed. Additionally, KVA12123 demonstrated a favorable pharmacokinetic (PK) and pharmacodynamic (PD) profile at all dose levels, including:

At 1,000mg every two weeks, KVA12123 demonstrated greater than dose proportional PK profile exceeding 90% VISTA receptor occupancy, providing important PK data for determining recommended Phase 2 dose.
No dose limiting toxicities were observed in the study, including at the 1,000mg dose level, among the 24 patients treated in the monotherapy or in the 17 patients in the combination with pembrolizumab arms
"We are pleased to have Thierry present the latest data from the KVA12123 program, a valuable drug candidate that TuHURA will acquire following the closure of the proposed merger with Kineta which is currently targeted for the end of Q2 2025. TuHURA’s exclusivity payment last July allowed Kineta the ability to restart and complete the Phase I study providing important data regarding receptor occupancy and other PK, PD and translational biomarker data at the previously unstudied 1,000mg dose level. The study demonstrated in excess of 90% VISTA receptor occupancy over the entire Q2W dosing interval where PK simulations would predict similar receptor occupancy even at 750mg Q2W dosing, which we believe will be the recommended Phase 2 dose and schedule", stated James Bianco, M.D., President and Chief Executive Officer of TuHURA Biosciences.

Dr. Bianco continued, "Our primary interest in VISTA is its potential in immunologic tolerance in a variety of blood related cancers. Recent scientific data demonstrates that NPM1 mutation, present in 30% to 35% of patients with acute myeloid leukemia (AML) results in the high expression of VISTA on leukemic blasts. This is believed to be the mechanism by which leukemia escapes immune recognition and attack and is responsible for high rate of treatment failures in AML. We look forward to evaluating the VISTA inhibiting antibody in a Phase 2 randomized study in relapsed AML, which we expect to initiate in the fourth quarter of 2025 based on the anticipated closing of the proposed merger with Kineta."

TuHURA also announced that the Markowitz Lab at Moffitt Cancer Center also presented a poster of TuHURA’s IFx-Hu2.0 in patients with advanced treatment refractory Melanoma who, like patients in TuHURA’s Phase 1b Merkel cell carcinoma trial, progressed while on CPI therapy. The data demonstrated that, among heavily pre-treated patients with advanced Melanoma who were resistant to anti-PD-1-based therapy, following IFx-Hu2.0, three of four patients achieved clinically meaningful, durable anti-tumor responses following re-administration of a CPI.

"Demonstration of the development of antibody specific response to the Emm55 bacterial protein expressed on the surface of the tumor cell following IFx-Hu2.0 in the phase 1 study and an abscopal effect in murine model of melanoma is consistent with the data generated in patients with advanced cutaneous malignancies like melanoma or Merkel cell carcinoma," noted Dr. Bianco. "We look forward to that anticipated initiation of our Phase 3 accelerated approval trial in first line treatment of patients with advanced or metastatic Merkel cell carcinoma targeted for later this quarter."

In the second poster presentation relating to IFx-Hu2.0 entitled: "Mechanistic Insights into IFx- Hu2.0 Responses in the First Human Trial After Prior Anti-PD-1 Therapy Failure," (3428/23) IFx-Hu2.0’s first-in-human study demonstrated stimulation of an innate immune response, with increased T cell and B cell production in peripheral blood compared to tumor tissue. This innate immune activation underscores the potential of IFx-Hu2.0 to generate tumor specific activate T and B cells for patients who are resistant to anti-PD-1 CPIs. Additionally, IFx-Hu2.0 was generally safe and well tolerated, with only mild Grade 1 and Grade 2 adverse events, largely injection site reactions.

As previously announced, on December 11, 2024, TuHURA entered into a definitive agreement with Kineta, Inc. (OTC Pink: KANT) ("Kineta"), in which TuHURA agreed to acquire Kineta, including the rights to Kineta’s novel KVA12123 antibody, for a combination of cash and shares of TuHURA common stock via a merger transaction upon the terms and conditions and subject to the conditions set forth in TuHURA’s Form 8-K filed on December 12, 2024. The merger is currently targeted to close in Q2 2025 pending the satisfaction of certain closing conditions.