The 2025 ASCO Annual Meeting included the presentation of data from more than 7,000 abstracts and clinical trials set to advance research, uncover findings, and in some cases change the standard of practice across multiple tumor types, moving science forward and improving care for the more than 2 million individuals diagnosed with cancer in the United States annually. In-depth news reports from more than 50 key abstracts are available at ASCOPost.com, along with more than 60 videos from experts who spoke to The ASCO Post on site in Chicago and on camera to share important take-home messages from their respective presentations. Here, we provide brief take-away messages from data presented during the plenary session at the 2025 ASCO Annual Meeting.
Colorectal Cancer: Phase III ATOMIC Trial
For the adjuvant treatment of stage III colon cancer with DNA mismatch repair–deficient (dMMR) tumors, the addition of the checkpoint PD-L1 inhibitor atezolizumab to standard chemotherapy with fluorouracil, leucovorin, and oxaliplatin for 12 cycles over 6 months (modified FOLFOX6) significantly improved disease-free survival in the phase III ATOMIC trial. The results position this approach as a potential new standard of care for this patient subset, according to Frank A. Sinicrope, MD, of the Mayo Clinic, Rochester, Minnesota, who presented the findings during the Plenary Session of the 2025 ASCO Annual Meeting (Abstract LBA1).1
Frank A. Sinicrope, MD
Immunotherapy is now standard therapy for metastatic dMMR colon cancer, and ATOMIC is the first large trial to evaluate immunotherapy in the adjuvant setting, where about 10% to 15% of colon cancers have dMMR status. In the study, the 3-year disease-free survival rate was 86.4% with atezolizumab plus chemotherapy vs 76.6% with chemotherapy alone, corresponding to a 50% reduction in recurrence and death (hazard ratio [HR] = 0.5;
P < .0001).
On June 29, 2025, Dr. Sinicrope shared this comment on X (formerly Twitter): “For dMMR colon cancer, FOLFOX + atezolizumab per ATOMIC is now incorporated into the NCCN Guidelines [for Colon Cancer, version 4.2025].”
Head and Neck Cancer: Phase III NIVOPOSTOP Trial
Adding the PD-1 inhibitor nivolumab to standard chemoradiotherapy after surgery significantly reduced recurrence rates for patients with locally advanced head and neck squamous cell carcinoma who are at high risk for recurrence, according to data from the phase III NIVOPOSTOP trial presented during the Plenary Session at the 2025 ASCO Annual Meeting (Abstract LBA2).2
At a median follow-up of just over 2.5 years, findings from the NIVOPOSTOP study showed a significant improvement in the primary endpoint of disease-free survival among patients treated with nivolumab plus chemoradiotherapy vs the control group of patients receiving chemoradiotherapy alone (63.1% vs 52.5%). The odds of disease-free survival were 24% higher in the patients with head and neck squamous cell carcinoma who received nivolumab with chemoradiotherapy compared with those who received standard chemoradiotherapy alone.
“The outcome for patients with locoregionally advanced head and neck cancers remains generally poor,” said lead study author Jean Bourhis, MD, PhD, Chief Medical Doctor, Radiation Oncology, Lausanne University Hospital. “With the developments over the past decade, including this research, we can now consider updating this long-standing standard of care.”
Invited discussant of the NIVOPOSTOP trial, Stuart J. Wong, MD, Professor of Medicine in Hematology Oncology and Director of the Head and Neck Cancer Program at the Medical College of Wisconsin, Milwaukee, underscored the transformative potential of the study’s findings. “Postoperative chemoradiation with nivolumab clearly improves disease-free survival for patients with resected, locally advanced head and neck cancer featuring high-risk pathologic indicators,” he said. “This represents a significant potential advancement in our treatment standards.”
Polycythemia Vera: Phase III VERIFY Trial
The global phase III VERIFY study in patients with the rare blood cancer polycythemia vera requiring frequent phlebotomies found that the investigational hepcidin mimetic rusfertide, given as a weekly subcutaneous injection, more than doubled the clinical response rate and significantly improved quality of life. Andrew Kuykendall, MD, Associate Member in the Department of Malignant Hematology at Moffitt Cancer Center in Tampa, Florida, presented the study during the Plenary Session at the 2025 ASCO Annual Meeting (Abstract LBA3).3
Rusfertide significantly improved multiple endpoints: reducing the need for phlebotomy, improving hematocrit control, and reducing symptoms across two patient-reported outcome instruments. And it did so while maintaining a manageable safety profile that was consistent with prior studies, according to the investigators, thus meeting the primary endpoint and key secondary endpoints.
Katherine Walsh, MD, MAEd, Associate Professor of Medicine in the Division of Hematology and Oncology, and Director of the Hematology/Oncology Fellowship Program at Vanderbilt University Medical Center in Nashville, discussed the study and noted the significance by asking: “Why are we talking about this abstract at the ASCO Plenary, when we have so many malignancies and so many wonderful presentations here?” She answered: “It’s about how important this issue is to our patients—their high symptom burden, the amount of time these patients spend coming in for phlebotomies, the high risk of thrombosis they must live with throughout their lives, and the impact of these findings.”
Dr. Walsh added: “Not only was hematocrit better controlled and phlebotomy needs were lower, but patients just felt better.” Additionally, she said, the ability to self-inject the drug is another win for this medication, “giving patients time back in their lives.”
HER2-Negative Breast Cancer: Phase III SERENA-6 Trial
Early detection of an ESR1 mutation by monitoringcirculating tumor DNA (ctDNA), leading to a switch of endocrine therapy, led to an almost doubling in progression-free survival in the SERENA-6 trial, the global registrational study for the investigational oral selective estrogen receptor degrader (SERD) camizestrant, researchers reported during the Plenary Session at the 2025 ASCO Annual Meeting (Abstract LBA4).4 Based on these outcomes, camizestrant was granted Breakthrough Therapy designation by the U.S. Food and Drug Administration.
Nicholas C. Turner, MD, PhD, FRCP, FMedSci, Director of Clinical Research and a consultant medical oncologist at the Royal Marsden Hospital and Institute of Cancer Research, London, presented the study findings. Results of the trial were concurrently published in TheNew England Journal of Medicine.5
Earlier monitoring of patients with advanced hormone receptor–positive, HER2-negative breast cancer with ctDNA testing may reveal ESR1 mutations that could guide an endocrine therapy switch before disease progression is evident on imaging. Using this approach proved successful in the phase III SERENA-6 study, in which switching from an aromatase inhibitor to the oral selective estrogen receptor degrader camizestrant, with continuation of the CDK4/6 inhibitor, significantly improved progression-free survival in patients, from 9.2 months to 16.0 months (HR = 0.44; P < .0001).
“SERENA-6 represents a milestone in precision oncology, providing concrete evidence for the benefit of early, ctDNA-guided intervention,” said Dr. Turner. “This treatment strategy has the potential to significantly enhance first-line therapy outcomes for patients with advanced breast cancer and optimize treatment decisions before clinical disease progression manifests.”
Gastric or GEJ Cancer: Phase III MATTERHORN Trial
In patients with resectable gastric or gastroesophageal junction (GEJ) adenocarcinoma, perioperative treatment with the checkpoint inhibitor durvalumab in combination with standard chemotherapy significantly reduced the risk of recurrence or death by 29% in the phase III MATTERHORN trial. The findings, which experts agree may represent a new standard of care in this cancer, were reported during the Plenary Session of the 2025 ASCO Annual Meeting by Yelena Y. Janjigian, MD, Chief of the Gastrointestinal Oncology Service at Memorial Sloan Kettering Cancer Center in New York (Abstract LBA5).6 The findings were published concurrently in TheNew England Journal of Medicine.7
See a comprehensive report on the MATTERHORN trial in this issue (pages 3 and 4), and visit ASCOPost.com for more reports from the 2025 ASCO Annual Meeting.
DISCLOSURE: LBA1: Dr. Sinicrope reported having stock and other ownership interests in Eli Lilly; has served as a consultant or advisor to Guardant Health and Roche Holdings AG; has received institutional research funding from Ventana Medical Systems; and has an immediate family member who is employed by Woven Health Collective. LBA2: This study was funded by Bristol Myers Squibb and GORTEC. Dr. Bourhis has served as a consultant or advisor to AstraZeneca, Bristol Myers Squibb, Merck Serono, and MSD. Dr. Wong has received research funding from Novartis, Merck, and Hookipa Pharma. LBA3: Dr. Kuykendall has received honoraria from AbbVie/Genentech, Blueprint Medicines, BMS, GlaxoSmithKline, Incyte, MorphoSys, Opna Bio, PharmaEssentia, and Swedish Orphan Biovitrum (SOBI); has served as a consultant or advisor to GlaxoSmithKline, Karyopharm Therapeutics, Keros Therapeutics, MorphoSys, and Protagonist Therapeutics; institutional research funding from Blueprint Medicines, Bristol Myers Squibb/Celgene, Geron, GlaxoSmithKline, Janssen Oncology, Kartos Therapeutics, MorphoSys, Novartis, and Protagonist Therapeutics; and reimbursement for travel expenses from AbbVie, GlaxoSmithKline, PharmaEssentia, and Protagonist Therapeutics. Dr. Walsh has received honoraria from Blueprint Medicines. LBA4: The SERENA-6 trial was supported by research funding from AstraZeneca. Dr. Turner has served as a consultant or advisor to AstraZeneca, Lilly, Pfizer, Roche/Genentech, Novartis, GlaxoSmithKline, Repare Therapeutics, Inivata, Guardant Health, and Exact Sciences; and has received research funding from AstraZeneca, Pfizer, Roche/Genentech, Merck Sharp and Dohme, Guardant Health, Invitae, Inivata, Personalis, and Natera. LBA5: Dr. Janjigian reported financial relationships with AbbVie, AmerisourceBergen, Arcus Biosciences, AskGene Pharma, Astellas Pharma, AstraZeneca, Axis Medical Education, Basilea Pharmaceutical, Bayer, Boehringer Ingelheim, Bristol Myers Squibb, Clinical Care Options, Daiichi Sankyo, eChinaHealth, Ed Med Resources (OncInfo), Eisai, Geneos, Genzyme, Giants of Cancer Care, GlaxoSmithKline, Guardant Health, HC Wainwright & Co, HMP Education, Imedex, Imugene, Inspirna, Jazz Pharmaceuticals, Lilly, Lynx Health, Master Clinician Alliance, Merck, Merck Serono, Mersana, Michael J. Hennessy Associates, Paradigm, PeerView, Pfizer, Physicians’ Education Resource, Research to Practice, Seagen, Silverback Therapeutics, Suzhou Liangyihui Network Technology, Talem Health, TotalCME, WebMD, and Zymeworks. For full disclosures of all study authors from all plenary abstracts, visit coi.asco.org.
REFERENCES
1. Sinicrope FA, Ou FS, Arnold D, et al: Randomized trial of standard chemotherapy alone or combined with atezolizumab as adjuvant therapy for patients with stage III deficient DNA mismatch repair colon cancer (Alliance A021502; ATOMIC). 2025 ASCO Annual Meeting. Abstract LBA1. Presented June 1, 2025.
2. Bourhis J, Auperin A, Borel C, et al. NIVOPOSTOP (GORTEC 2018-01): A phase III randomized trial of adjuvant nivolumab added to radio-chemotherapy in patients with resected head and neck squamous cell carcinoma at high risk of relapse. 2025 ASCO Annual Meeting. LBA2. Presented June 1, 2025.
3. Kuykendall AT, Pemmaraju N, Pettit K, et al: Results from VERIFY, a phase 3, double-blind, placebo-controlled study of rusfertide for treatment of polycythemia vera. 2025 ASCO Annual Meeting. Abstract LBA3. Presented June 1, 2025.
4. Turner NC, Mayer E, Park YH, et al: Camizestrant + CDK4/6 inhibitor for the treatment of emergent ESR1 mutations during first-line endocrine-based therapy and ahead of disease progression in patients with HR+/HER2– advanced breast cancer: Phase 3, double-blind ctDNA-guided SERENA-6 trial. 2025 ASCO Annual Meeting. Abstract LBA4. Presented June 1, 2025.
5. Bidard FC, Mayer EL, Park YH, et al: First-line camizestrant for emerging ESR1-mutated advanced breast cancer. N Engl J Med. June 1, 2025 (early release online).
6. Janjigian YY, Al-Batran SE, Wainberg Z, et al: Event-free survival in MATTERHORN: A randomized, phase 3 study of durvalumab plus 5-fluorouracil, leucovorin, oxaliplatin and docetaxel chemotherapy (FLOT) in resectable gastric/gastroesophageal junction cancer. 2025 ASCO Annual Meeting. Abstract LBA5. Presented June 1, 2025.
7. Janjigian YY, Al-Batran SE, Wainberg ZA, et al: Perioperative durvalumab in gastric and gastroesophageal junction cancer. N Engl J Med. June 1, 2025 (early release online).
