On April 28, 2025 Accent Therapeutics, a clinical-stage biopharmaceutical company pioneering novel, targeted, small molecule cancer therapeutics, reported new preclinical data on its first-in-class oral DHX9 inhibitor, ATX-559, and its potentially best-in-class KIF18A inhibitor, ATX-295, in poster and oral presentations, respectively, at the AACR (Free AACR Whitepaper) Annual Meeting 2025 taking place April 25-30 in Chicago, Illinois (Press release, Accent Therapeutics, APR 28, 2025, View Source [SID1234652263]). ATX-559 and ATX-295 are currently under investigation in Phase 1/2 clinical trials.

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"Our presentations at the AACR (Free AACR Whitepaper) annual meeting showcase the outputs of Accent’s precision oncology approach to drug development, with strong foundational data that inform our current and future clinical development plans for our lead programs, ATX-559 and ATX-295," said Serena Silver, Ph.D., Chief Scientific Officer of Accent Therapeutics. "These preclinical data reinforce our assets’ therapeutic potential across several cancer indications with high unmet need."

The company’s poster presentation includes preclinical data supporting continued clinical evaluation of ATX-559, a first-in-class potent, selective, and orally bioavailable small-molecule inhibitor of DHX9. Results within characterize the compound’s activity in cancer cell lines with genomic instability and elevated replication stress spanning several indications, including dMMR/MSI-H colorectal cancer and BRCA-altered triple negative breast cancer, and in subtypes of lung, gastric, ovarian, and prostate cancers. ATX-559 was shown to be well tolerated in vivo, leading to robust and dose dependent tumor growth inhibition and regression in BRCA deficient breast cancer and dMMR/MSI-H cell- and patient-derived xenograft models.

ATX-559 is currently under investigation in a first-in-human, Phase 1/2, open-label, dose-escalation and expansion study, with a focus on advanced or metastatic patients with BRCA-1 and/or BRCA-2-deficient breast cancer or MSI-H and/or dMMR solid tumors (NCT06625515). Additional undisclosed solid tumor indications undergoing replicative stress and representing significant patient populations may be explored either in parallel or in subsequent studies.

For Accent’s second lead program, preclinical data included in the company’s oral presentation demonstrates sensitivity to KIF18A inhibition across several solid tumor indications with high chromosomal instability, signaling significant opportunity for patient impact by leveraging KIF18A as a selective oncology target. Results further characterize ATX-295 as a potent and selective KIF18A inhibitor capable of inducing mitotic arrest, cell death, and anti-tumor activity in cancer models with high chromosomal instability. Studies in relevant cellular and xenograft models exhibiting whole genome doubling confirm selective anti-cancer activity, providing rationale for whole genome doubling as a predictive biomarker of ATX-295 sensitivity in ovarian and triple negative breast cancer.

Accent recently initiated clinical evaluation of ATX-295 in a first-in-human Phase 1/2 open-label, dose-escalation and expansion study designed to evaluate the molecule’s safety, tolerability, and preliminary efficacy in patients with locally advanced or metastatic solid tumors, including high-grade serious ovarian cancer (NCT06799065).

Details for the presentations are as follows:

Presentation Title: Activity of the Novel KIF18A Inhibitor, ATX-295, is Enriched in Whole Genome Doubled Ovarian Cancer Pre-Clinical Models

Abstract Number: 3784
Session Type: Minisymposium
Session Title: Novel Antitumor Agents
Session Date and Time: Monday, April 28, 2:30 pm – 4:30 pm CT
Location: Room S103 – McCormick Place South (Level 1)
Presenter: Maureen Lynes, Ph.D.
Poster Title: ATX-559, a First in Class DHX9 Inhibitor, and Targeted Therapeutic for Molecularly Defined Tumors with Genomic Instability and Replicative Stress

Abstract Number: 1758
Session Title: Novel Antitumor Agents 1
Session Date and Time: Monday, April 28, 9:00 am – 12:00 pm CT
Location: Poster Section 22
Poster Board Number: 10
Presenter: Jennifer Castro
About ATX-559
ATX-559 is a first-in-class potent and selective inhibitor of DHX9, a novel and previously undrugged RNA and DNA/RNA helicase, shown to play a critical role in tumors with high levels of replication stress (including breast, ovarian, colorectal, endometrial, gastric, and others), representing large patient populations with significant unmet medical need. DHX9 has been reported to play important roles in replication, transcription, translation, RNA splicing, RNA processing, and maintenance of genomic stability, making it a compelling novel oncology target. In addition to exploiting key tumor vulnerabilities in DNA repair deficient backgrounds (e.g., BRCA) and hyper-mutated states (e.g., MSI-H/dMMR), Accent is exploring the sensitivity of other tumor types to DHX9 inhibition, and the potential to combine DHX9 inhibitors with other cancer treatments to maximize its full potential for helping patients. Accent retains full worldwide rights to ATX-559, currently being evaluated in a Phase 1/2 clinical trial (NCT06625515), and the DHX9 program.

About ATX-295
Accent’s second lead program is a potential best-in-class inhibitor for KIF18A which may address a large patient population across several cancer indications, including ovarian and triple negative breast cancer (TNBC). KIF18A is a mitotic kinesin motor protein critical for cell division in select tumors with chromosomal instability, but not in healthy cells. KIF18A inhibitor treatment results in rapid cell death for cancers with an abnormal number of chromosomes (aneuploid) in vitro and in vivo, while cells with normal numbers of chromosomes (euploid) are unaffected. Accent retains full worldwide rights to ATX-295, which is currently being evaluated in a Phase 1/2 clinical trial (NCT06799065), and the KIF18A program.

On April 28, 2025 Personalis, Inc. (Nasdaq: PSNL), a leader in advanced genomics for precision oncology, reported new interim analysis results of the VICTORI study showing strong performance of its ultra-sensitive NeXT Personal assay in detecting early signs of residual or recurrent colorectal cancer (CRC) (Press release, Personalis, APR 28, 2025, View Source [SID1234652279]).

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The study, led by Dr. Jonathan Loree’s team at BC Cancer in Vancouver, Canada, utilized NeXT Personal to look for small traces of circulating tumor DNA (ctDNA) in blood samples from a cohort of 71 patients with resectable Stage I-IV CRC. The data was presented at the American Association for Cancer Research (AACR) (Free AACR Whitepaper) Annual Meeting in Chicago, Illinois by Emma Titmuss at BC Cancer, in an oral presentation titled Detection of post-surgical minimal residual disease (MRD) in colorectal cancer; preliminary results from the VICTORI study.

"After surgery, ctDNA-based liquid biopsies may help identify patients who would benefit most from additional treatment," said Jonathan Loree, MD, MS, a medical oncologist at BC Cancer and the senior investigator of the study. "Alternatively, this may help patients with good prognosis avoid toxicities from unnecessary chemotherapy. By monitoring patients for recurrences, liquid biopsies can continue to support clinical care and allow more patients to undergo second curative intent surgeries to remove early recurrences."

Key findings presented from the interim analysis for VICTORI:

100% of patients who have recurred were detected as ctDNA positive by NeXT Personal prior to detection on imaging.
100% of patients who have been ctDNA negative throughout the study remain disease-free.
87% of clinical recurrences were detectable within the early "landmark window" 2 to 8 weeks after surgery, with 85% detectable by 4 weeks.
64% of detections within the landmark window were in the ultrasensitive range (under 100 ppm).
100% of distant metastatic recurrences were detected prior to imaging, including lung metastasis, an area which has traditionally been more challenging to detect by ctDNA testing.
70% of the first ctDNA detections were in the ultrasensitive range, with a median of 24.4PPM and as low as 2.45 PPM.
Median patient follow-up at the time of the interim analysis was 15.75 months, with the patients continuing to be followed clinically.

"The initial results from our study show the importance of using a highly sensitive MRD assay like NeXT Personal in colorectal cancer," said Dr. Loree.

"We are encouraged by the preliminary results from the VICTORI study, which show the ability of our ultrasensitive ctDNA assay NeXT Personal to detect residual and recurrent colorectal cancer at high rates in the early landmark window after surgery," said Dr. Richard Chen, Chief Medical Officer and Executive Vice President, R&D at Personalis. "We continue to expand this prospective study as we strive towards helping patients with colorectal cancer detect and treat recurrence earlier."

On April 28, 2025 Genprex, Inc. ("Genprex" or the "Company") (NASDAQ: GNPX), a clinical-stage gene therapy company focused on developing life-changing therapies for patients with cancer and diabetes, reported it has signed an exclusive patent license agreement with NYU Langone Health related to the drug candidate, Reqorsa Gene Therapy (quaratusugene ozeplasmid) (Press release, Genprex, APR 28, 2025, View Source [SID1234652232]). The therapy is under investigation as a potential treatment for mesothelioma. The subject patent is co-owned by Genprex and NYU Langone Health, and the license provides Genprex with patent exclusivity.

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"We are pleased to expand our robust oncology franchise, intellectual property portfolio and research program for REQORSA to continue exploring how it may serve as a therapeutic treatment for some of the most difficult to treat cancers and diseases," said Thomas Gallagher, Senior Vice President of Intellectual Property and Licensing. "We believe REQORSA has the potential to treat mesothelioma, and this license agreement positions Genprex to expand its clinical development pipeline with future clinical studies that are within the scope of the licensed patent."

Expression of TUSC2 is downregulated in 84% of mesotheliomas. TUSC2 is the tumor suppressor gene used in REQORSA. Research collaborators at NYU presented positive preclinical data from a study of REQORSA for the treatment of mesothelioma at the 2024 EORTC-NCI-AACR (Free EORTC-NCI-AACR Whitepaper) Symposium on Molecular Targets and Cancer Therapeutics.

In this study, four Malignant Pleural Mesothelioma (MPM) cell lines and tert-transformed mesothelial LP9 cells were treated with REQORSA and control liposomes for 48h. Treated cells were then evaluated for TUSC2 expression by semi quantitative RT-PCR, Western blot analysis, and functional assays including cell proliferation, invasion, and apoptosis.

The researchers demonstrated that REQORSA treatment resulted in a significant decrease in cell proliferation, cell invasion, and a significant increase in cell apoptosis in all four MPM cell lines. Data also demonstrated potent tumor suppressive activity of the TUSC2 gene delivered by REQORSA, and thus, its re-expression could serve as a potential therapeutic strategy for the treatment of MPM.

In 2024, Genprex announced the formation of its Mesothelioma Clinical Advisory Board to support the Company’s preclinical mesothelioma oncology program. The Board is comprised of four world-renown researchers from major research institutions specializing in the treatment of mesothelioma.

According to the Centers for Disease Control and Prevention, mesothelioma is a cancer that forms in the thin tissue that lines many internal organs, called the mesothelium. The most common kind of mesothelioma forms in the tissue around the lungs, called the pleura. This is called pleural mesothelioma, which accounts for 80-90% of all mesothelioma diagnoses. Approximately 3,000 new cases of mesothelioma are diagnosed each year in the U.S., and there are approximately 2,500 mesothelioma-related deaths each year in the U.S. The life expectancy for pleural mesothelioma is 18 months, and the 3-year survival rate with treatment for pleural mesothelioma is 23%.

About Reqorsa Gene Therapy

REQORSA (quaratusugene ozeplasmid) consists of a plasmid containing the TUSC2 gene encapsulated in non-viral lipid-based nanoparticles in a lipoplex form (the Company’s Oncoprex Delivery System), which has a positive charge. REQORSA is injected intravenously and specifically targets cancer cells. REQORSA is designed to deliver the functioning TUSC2 gene to negatively charged cancer cells while minimizing uptake by normal tissue. Laboratory studies conducted at MD Anderson show that the uptake of TUSC2 in tumor cells in vitro after REQORSA treatment was 10 to 33 times the uptake in normal cells.

On April 28, 2025 SELLAS Life Sciences Group, Inc. (NASDAQ: SLS) ("SELLAS" or the "Company"), a late-stage clinical biopharmaceutical company focused on the development of novel therapies for a broad range of cancer indications, reported that preclinical efficacy of SLS009 in TP53 mutated Acute Myeloid Leukemia (AML) cells are being presented in a poster session at the American Association for Cancer Research (AACR) (Free AACR Whitepaper) taking place from April 25th – 30th at McCormick Place Convention Center, Chicago, IL (Press release, Sellas Life Sciences, APR 28, 2025, View Source [SID1234652247]).

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Patients with TP53–mutated AML continue to face extremely poor outcomes, even with intensive chemotherapy or the addition of stem cell transplantation. Preclinical data suggest that SLS009, a highly selective CDK9 inhibitor, can induce apoptosis downstream of p53 by targeting critical proteins such as MCL-1 and survivin, regardless of p53 status. Immunoblot analysis reveals near-complete removal of these proteins in treated cells within 8 hours of exposure to SLS009. Furthermore, the treatment reduced TP53-mutated leukemia cell populations by up to 97% in combination with azacitidine–venetoclax, and by up to 80% as monotherapy.

"These findings are an exciting step forward in addressing one of the most challenging subsets of AML," said Angelos Stergiou, MD, ScD h.c., President and Chief Executive Officer of SELLAS. "The ability of SLS009 to overcome TP-53 driven resistance in preclinical models, combined with the positive data we have seen in our ongoing Phase 2 AML program, including a response in a patient with a TP53 mutation, gives us hope that we may one day offer an effective therapeutic option to patients with AML who have long been underserved."

SLS009 is currently in Phase 2 clinical trials in patients with relapsed or refractory (r/r) AML following venetoclax-based regimens, including patients with TP53-mutated leukemia. Recently announced data revealed that r/r AML patients receiving 30 mg of SLS009 BIW achieved a mOS of 8.8 months for all patients, while the mOS in AML myelodysplasia-related-changes (MRC) patients reached 8.9 months – far surpassing the historical benchmark of 2.5 months. Among patients with mutation ASXL1, 4/6 (67%) responded; among those with RUNX1 3/5 (60%) responded, and among those with TP53 1/3 (33%) responded. In addition, there were 3 patients with adverse karyotypes, and 1 responded.

"Over the past decade we’ve seen significant progress in the treatment of AML, particularly with the introduction of the venetoclax/azacitidine regimen, the use of targeted agents, and safer application of haploidentical stem cell transplants," said Dr Phillip Amrein, MD, Clinical Investigator, Massachusetts General Hospital, Assistant Professor of Medicine Harvard Medical School, the senior author of the study. "Yet, leukemias characterized by TP53 remain a major area of unmet need, with poor outcomes even with bone marrow transplantation. The preclinical findings suggest that CDK9 inhibition might have the potential to overcome this resistance and restore sensitivity to existing therapies, offering a promising new path forward for high-risk patient populations."

Poster presentation details:

Title: CDK9 inhibition enhances apoptosis of TP53 mutated AML when combined with standard chemotherapy

Session Date and Time: Monday, April 28, 20025, 9:00 AM to 12:00 noon

Session Title: CDK9 inhibition enhances apoptosis of TP53 mutated AML when combined with standard chemotherapy

Location: Poster Section 17

Poster Board #: 1626

The poster will be available on SELLAS websites following the session.

SLS009 is currently being investigated in a Phase 2 open-label, single-arm, multi-center study designed to evaluate the safety, tolerability, and efficacy of SLS009 in combination with venetoclax and azacitidine, including AML patients with ASXL1 mutations. Initial clinical safety and efficacy data are available. In addition, the study aims to identify biomarkers for the target patient population and enrichment for further trials. For more information on the study, visit clinicaltrial.gov identifier NCT04588922.

On April 28, 2025 Adela, Inc., an innovator in blood testing for molecular residual disease (MRD) monitoring and early cancer detection through a proprietary genome-wide methylome enrichment technology, reported initial results demonstrating the ability of its MRD test to predict recurrence in early-stage non-small cell lung cancer, at the American Association for Cancer Research (AACR) (Free AACR Whitepaper) Annual Meeting from April 25-30, 2025 (Press release, Adela, APR 28, 2025, View Source [SID1234652264]).

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Adela’s MRD test is a blood-only, tissue-free approach for detecting recurrence prior to clinical exam and imaging, eliminating the need for tumor tissue samples and enabling broader access to MRD testing. A blood-only approach is especially important in lung cancer, where nearly 40% of patients do not have sufficient tumor tissue for tissue-informed MRD tests.1

The ability of Adela’s test to quantify cfDNA cancer signal and predict recurrence was evaluated in 136 samples from 24 patients diagnosed with stage I-II non-small cell lung cancer treated at New York University Langone Medical Center. Blood draws occurred prior to surgery, after surgery and at intervals before recurrence or last clinical follow-up. Adela’s test demonstrated the ability to identify recurrences up to 35.9 months before standard of care clinical exam and imaging, with a mean lead time of 16.6 months. Significant differences in recurrence-free survival (RFS) were observed when patients were stratified by MRD positivity (hazard ratio of 3.58, P=0.038).

"We are greatly encouraged by these results which highlight the ability of Adela’s tissue-free MRD test to detect recurrence in lung cancer well in advance of standard of care," said Dr. Anne-Renee Hartman, Chief Medical Officer of Adela. "Adela’s MRD test has been clinically validated for head & neck cancer. These results further validate the strong performance of Adela’s genome-wide methylome enrichment platform and demonstrate its applicability across multiple cancer types."

Adela’s MRD test based on its genome-wide methylome enrichment platform is currently available to biopharmaceutical companies and other investigators for Research Use Only (RUO), including for biomarker discovery and drug development. Adela plans to commercialize the test in 2025 for use in patients who have received curative intent treatment for head & neck cancer, regardless of HPV status, to detect recurrence earlier and help guide treatment decision-making.

Presentation Details

Abstract #: 3249: The Development of a Tissue-Agnostic Genome-Wide Methylome Enrichment Assay for Lung Cancer

Harvey I. Pass2

Monday Apr 28, 2025 2:00 PM – 5:00 PM

Poster Section 29, Poster Board Number: 14