Fluorouracil

First and only systemic therapy to improve survival when used before and after surgery for patients with MIBC who are ineligible for cisplatin-based chemotherapy First ever positive Phase 3 study in this cisplatin-ineligible patient population, representing significant advancement in MIBC RAHWAY, NJ, USA I August 12, 2025 I Merck (NYSE: MRK), known as MSD outside the United States and Canada, today announced positive topline results from the Phase 3 KEYNOTE-905 trial (also known as EV-303) in patients with muscle-invasive bladder cancer (MIBC) who are ineligible for cisplatin-based chemotherapy. In this study, KEYTRUDA ® (pembrolizumab) plus Padcev (enfortumab vedotin-ejfv), given before and after surgery (radical cystectomy), demonstrated a statistically significant and clinically meaningful improvement in event-free survival (EFS), the study’s primary endpoint, as well as overall survival (OS) and pathologic complete response (pCR) rate, key secondary endpoints, compared to surgery (radical cystectomy) alone. “Patients with muscle-invasive bladder cancer who are ineligible for cisplatin-based chemotherapy have not seen any treatment advance beyond surgery and face high rates of disease recurrence and a poor prognosis, even after having their bladder removed,” said Dr. Christof Vulsteke, MD, PhD, head of Integrated Cancer Center Ghent (IKG) and Clinical Trial Unit Oncology Ghent and KEYNOTE-905 principal investigator. “The KEYNOTE-905 study results mark the first time a systemic treatment approach, used before and after surgery, significantly extended survival over standard-of-care surgery in this population, demonstrating the potential of this combination to address a critical unmet need.” The trial, evaluating Merck’s KEYTRUDA, an anti-PD-1 therapy, plus Padcev, an antibody-drug conjugate (ADC), was conducted in collaboration with Pfizer (previously Seagen) and Astellas and builds on the clinical success of this combination in locally advanced or metastatic urothelial cancer. The trial is continuing to evaluate the secondary EFS, OS, and pCR rate endpoints for neoadjuvant and adjuvant KEYTRUDA versus surgery alone as they continue to mature. “There is a real and pressing need for more effective options for patients with bladder cancer who are ineligible for cisplatin-based treatment,” said Dr. Marjorie Green, senior vice president and head of oncology, global clinical development, Merck Research Laboratories. “The compelling survival results observed in this study reinforce the potential of combining KEYTRUDA with an antibody-drug conjugate to help address a significant unmet need in this vulnerable population.” The safety profile of KEYTRUDA plus Padcev in this study was consistent with the known safety profiles of each agent. No new safety signals were identified with the combination. The companies plan to share these results with regulatory authorities worldwide and will present the data at an upcoming medical meeting. KEYTRUDA plus Padcev is approved for the treatment of adult patients with locally advanced or metastatic urothelial cancer (la/mUC) in the U.S., the European Union (EU), Japan and several other countries around the world. KEYTRUDA as monotherapy is also approved in the U.S., EU, Japan and other countries for the treatment of certain patients with la/mUC or a type of non-muscle-invasive bladder cancer (NMIBC). Five additional Phase 3 studies are currently evaluating KEYTRUDA across all stages of bladder cancer, including non-muscle-invasive, muscle-invasive and metastatic. Three of these studies are in MIBC including KEYNOTE-866 ( NCT03924856 ), KEYNOTE-992 ( NCT04241185 ) and KEYNOTE-B15 ( NCT04700124 ), which is also known as EV-304 and is being conducted in collaboration with Pfizer and Astellas. KEYTRUDA is also being evaluated in combination with Bacillus Calmette-Guerin (BCG) in patients with NMIBC in the Phase 3 KEYNOTE-676 ( NCT03711032 ) trial, and as adjuvant treatment in patients with localized muscle-invasive urothelial carcinoma and locally advanced urothelial carcinoma KEYNOTE-123 ( NCT03244384 ). About KEYNOTE-905/EV-303 KEYNOTE-905, also known as EV-303, is an open-label, randomized, multi-arm, controlled, Phase 3 trial (ClinicalTrials.gov, NCT03924895 ) evaluating perioperative KEYTRUDA, with or without Padcev, versus surgery alone in patients with MIBC who are either not eligible for or declined cisplatin-based chemotherapy. The trial enrolled 595 patients who were randomized to receive either: The primary objective of this trial was to compare EFS between arm C and arm B, defined as the time from randomization to the first occurrence of any of the following events: progression of disease that precludes radical cystectomy (RC) surgery or failure to undergo RC surgery in participants with residual disease, gross residual disease left behind at the time of surgery, local or distant recurrence as assessed by imaging and/or biopsy or death due to any cause. The key secondary objectives were to compare OS and difference in pCR rate between arm C and arm B, as well as EFS, OS and the difference in pCR rate between arm A and arm B. The study remains ongoing to test hypotheses between arm A and arm B. About bladder cancer Bladder cancer is the ninth most common cancer worldwide, diagnosed in more than 614,000 patients each year globally. Muscle-invasive bladder cancer represents approximately 30% of all bladder cancer cases. The standard treatment for patients with MIBC is neoadjuvant cisplatin-based chemotherapy followed by surgery, which has been shown to prolong survival. However, up to half of patients with MIBC are not eligible to receive cisplatin and face limited treatment options, typically undergoing surgery alone. About Merck’s early-stage cancer clinical program Finding cancer at an earlier stage may give patients a greater chance of long-term survival. Many cancers are considered most treatable and potentially curable in their earliest stage of disease. Building on the strong understanding of the role of KEYTRUDA in later-stage cancers, Merck is studying KEYTRUDA in earlier disease states, with more than 25 ongoing registrational studies across multiple types of cancer. About KEYTRUDA ® (pembrolizumab) injection, 100 mg KEYTRUDA is an anti-programmed death receptor-1 (PD-1) therapy that works by increasing the ability of the body’s immune system to help detect and fight tumor cells. KEYTRUDA is a humanized monoclonal antibody that blocks the interaction between PD-1 and its ligands, PD- L1 and PD-L2, thereby activating T lymphocytes which may affect both tumor cells and healthy cells. Merck has the industry’s largest immuno-oncology clinical research program. There are currently more than 1,600 trials studying KEYTRUDA across a wide variety of cancers and treatment settings. The KEYTRUDA clinical program seeks to understand the role of KEYTRUDA across cancers and the factors that may predict a patient’s likelihood of benefitting from treatment with KEYTRUDA, including exploring several different biomarkers. Selected KEYTRUDA ® (pembrolizumab) Indications in the U.S. Urothelial Cancer KEYTRUDA, in combination with enfortumab vedotin, is indicated for the treatment of adult patients with locally advanced or metastatic urothelial cancer. KEYTRUDA, as a single agent, is indicated for the treatment of patients with locally advanced or metastatic urothelial carcinoma: KEYTRUDA, as a single agent, is indicated for the treatment of patients with Bacillus Calmette-Guerin (BCG)-unresponsive, high-risk, non-muscle invasive bladder cancer (NMIBC) with carcinoma in situ (CIS) with or without papillary tumors who are ineligible for or have elected not to undergo cystectomy. Melanoma KEYTRUDA is indicated for the treatment of patients with unresectable or metastatic melanoma. KEYTRUDA is indicated for the adjuvant treatment of adult and pediatric (12 years and older) patients with Stage IIB, IIC, or III melanoma following complete resection. Non-Small Cell Lung Cancer KEYTRUDA, in combination with pemetrexed and platinum chemotherapy, is indicated for the first-line treatment of patients with metastatic nonsquamous non-small cell lung cancer (NSCLC), with no EGFR or ALK genomic tumor aberrations. KEYTRUDA, in combination with carboplatin and either paclitaxel or paclitaxel protein-bound, is indicated for the first-line treatment of patients with metastatic squamous NSCLC. KEYTRUDA, as a single agent, is indicated for the first-line treatment of patients with NSCLC expressing PD-L1 [Tumor Proportion Score (TPS) ≥1%] as determined by an FDA-approved test, with no EGFR or ALK genomic tumor aberrations, and is: KEYTRUDA, as a single agent, is indicated for the treatment of patients with metastatic NSCLC whose tumors express PD-L1 (TPS ≥1%) as determined by an FDA-approved test, with disease progression on or after platinum-containing chemotherapy. Patients with EGFR or ALK genomic tumor aberrations should have disease progression on FDA-approved therapy for these aberrations prior to receiving KEYTRUDA. KEYTRUDA is indicated for the treatment of patients with resectable (tumors ≥4 cm or node positive) NSCLC in combination with platinum-containing chemotherapy as neoadjuvant treatment, and then continued as a single agent as adjuvant treatment after surgery. KEYTRUDA, as a single agent, is indicated as adjuvant treatment following resection and platinum-based chemotherapy for adult patients with Stage IB (T2a ≥4 cm), II, or IIIA NSCLC. Malignant Pleural Mesothelioma KEYTRUDA, in combination with pemetrexed and platinum chemotherapy, is indicated for the first-line treatment of adult patients with unresectable advanced or metastatic malignant pleural mesothelioma (MPM). Head and Neck Squamous Cell Cancer KEYTRUDA is indicated for the treatment of adult patients with resectable locally advanced head and neck squamous cell carcinoma (HNSCC) whose tumors express PD-L1 [Combined Positive Score (CPS) ≥1] as determined by an FDA-approved test, as a single agent as neoadjuvant treatment, continued as adjuvant treatment in combination with radiotherapy (RT) with or without cisplatin and then as a single agent. KEYTRUDA, in combination with platinum and fluorouracil (FU), is indicated for the first-line treatment of patients with metastatic or with unresectable, recurrent HNSCC. KEYTRUDA, as a single agent, is indicated for the first-line treatment of patients with metastatic or with unresectable, recurrent HNSCC whose tumors express PD-L1 (CPS ≥1) as determined by an FDA-approved test. KEYTRUDA, as a single agent, is indicated for the treatment of patients with recurrent or metastatic HNSCC with disease progression on or after platinum-containing chemotherapy. Classical Hodgkin Lymphoma KEYTRUDA is indicated for the treatment of adult patients with relapsed or refractory classical Hodgkin lymphoma (cHL). KEYTRUDA is indicated for the treatment of pediatric patients with refractory cHL, or cHL that has relapsed after 2 or more lines of therapy. Primary Mediastinal Large B-Cell Lymphoma KEYTRUDA is indicated for the treatment of adult and pediatric patients with refractory primary mediastinal large B-cell lymphoma (PMBCL), or who have relapsed after 2 or more prior lines of therapy. KEYTRUDA is not recommended for treatment of patients with PMBCL who require urgent cytoreductive therapy. Microsatellite Instability-High or Mismatch Repair Deficient Cancer KEYTRUDA is indicated for the treatment of adult and pediatric patients with unresectable or metastatic microsatellite instability-high (MSI-H) or mismatch repair deficient (dMMR) solid tumors, as determined by an FDA-approved test, that have progressed following prior treatment and who have no satisfactory alternative treatment options. Microsatellite Instability-High or Mismatch Repair Deficient Colorectal Cancer KEYTRUDA is indicated for the treatment of patients with unresectable or metastatic MSI-H or dMMR colorectal cancer (CRC) as determined by an FDA-approved test. Gastric Cancer KEYTRUDA, in combination with trastuzumab, fluoropyrimidine- and platinum-containing chemotherapy, is indicated for the first-line treatment of adults with locally advanced unresectable or metastatic HER2-positive gastric or gastroesophageal junction (GEJ) adenocarcinoma whose tumors express PD-L1 (CPS ≥1) as determined by an FDA-approved test. KEYTRUDA, in combination with fluoropyrimidine- and platinum-containing chemotherapy, is indicated for the first-line treatment of adults with locally advanced unresectable or metastatic HER2-negative gastric or gastroesophageal junction (GEJ) adenocarcinoma whose tumors express PD-L1 (CPS ≥ 1) as determined by an FDA approved test. Esophageal Cancer KEYTRUDA is indicated for the treatment of patients with locally advanced or metastatic esophageal or gastroesophageal junction (GEJ) (tumors with epicenter 1 to 5 centimeters above the GEJ) carcinoma that is not amenable to surgical resection or definitive chemoradiation either: Cervical Cancer KEYTRUDA, in combination with chemoradiotherapy (CRT), is indicated for the treatment of patients with locally advanced cervical cancer involving the lower third of the vagina, with or without extension to pelvic sidewall, or hydronephrosis/non-functioning kidney, or spread to adjacent pelvic organs (FIGO 2014 Stage III-IVA). KEYTRUDA, in combination with chemotherapy, with or without bevacizumab, is indicated for the treatment of patients with persistent, recurrent, or metastatic cervical cancer whose tumors express PD-L1 (CPS ≥1) as determined by an FDA-approved test. KEYTRUDA, as a single agent, is indicated for the treatment of patients with recurrent or metastatic cervical cancer with disease progression on or after chemotherapy whose tumors express PD-L1 (CPS ≥1) as determined by an FDA-approved test. Hepatocellular Carcinoma KEYTRUDA is indicated for the treatment of patients with hepatocellular carcinoma (HCC) secondary to hepatitis B who have received prior systemic therapy other than a PD-1/PD-L1-containing regimen. Biliary Tract Cancer KEYTRUDA, in combination with gemcitabine and cisplatin, is indicated for the treatment of patients with locally advanced unresectable or metastatic biliary tract cancer (BTC). Merkel Cell Carcinoma KEYTRUDA is indicated for the treatment of adult and pediatric patients with recurrent locally advanced or metastatic Merkel cell carcinoma (MCC). Renal Cell Carcinoma KEYTRUDA, in combination with axitinib, is indicated for the first-line treatment of adult patients with advanced renal cell carcinoma (RCC). KEYTRUDA is indicated for the adjuvant treatment of patients with RCC at intermediate-high or high risk of recurrence following nephrectomy, or following nephrectomy and resection of metastatic lesions. Endometrial Carcinoma KEYTRUDA, in combination with carboplatin and paclitaxel, followed by KEYTRUDA as a single agent, is indicated for the treatment of adult patients with primary advanced or recurrent endometrial carcinoma. KEYTRUDA, as a single agent, is indicated for the treatment of adult patients with advanced endometrial carcinoma that is MSI-H or dMMR, as determined by an FDA-approved test, who have disease progression following prior systemic therapy in any setting and are not candidates for curative surgery or radiation. Tumor Mutational Burden-High Cancer KEYTRUDA is indicated for the treatment of adult and pediatric patients with unresectable or metastatic tumor mutational burden-high (TMB-H) [≥10 mutations/megabase (mut/Mb)] solid tumors, as determined by an FDA-approved test, that have progressed following prior treatment and who have no satisfactory alternative treatment options. This indication is approved under accelerated approval based on tumor response rate and durability of response. Continued approval for this indication may be contingent upon verification and description of clinical benefit in the confirmatory trials. The safety and effectiveness of KEYTRUDA in pediatric patients with TMB-H central nervous system cancers have not been established. Cutaneous Squamous Cell Carcinoma KEYTRUDA is indicated for the treatment of patients with recurrent or metastatic cutaneous squamous cell carcinoma (cSCC) or locally advanced cSCC that is not curable by surgery or radiation. Triple-Negative Breast Cancer KEYTRUDA is indicated for the treatment of patients with high-risk early-stage triple-negative breast cancer (TNBC) in combination with chemotherapy as neoadjuvant treatment, and then continued as a single agent as adjuvant treatment after surgery. KEYTRUDA, in combination with chemotherapy, is indicated for the treatment of patients with locally recurrent unresectable or metastatic TNBC whose tumors express PD-L1 (CPS ≥10) as determined by an FDA-approved test. About Merck At Merck, known as MSD outside of the United States and Canada, we are unified around our purpose: We use the power of leading-edge science to save and improve lives around the world. For more than 130 years, we have brought hope to humanity through the development of important medicines and vaccines. We aspire to be the premier research-intensive biopharmaceutical company in the world – and today, we are at the forefront of research to deliver innovative health solutions that advance the prevention and treatment of diseases in people and animals. We foster a diverse and inclusive global workforce and operate responsibly every day to enable a safe, sustainable and healthy future for all people and communities. For more information, visit www.merck.com and connect with us on X (formerly Twitter) , Facebook , Instagram , YouTube and LinkedIn . About the Merck, Pfizer and Astellas collaboration Merck previously entered a clinical collaboration agreement with Seagen and Astellas to evaluate the combination of Merck’s KEYTRUDA ® (pembrolizumab) and Seagen’s and Astellas’ Padcev ® (enfortumab vedotin-ejfv) in patients with muscle-invasive bladder cancer (MIBC) who are not eligible for or declined cisplatin-based chemotherapy. Pfizer Inc. successfully completed its acquisition of Seagen on December 14, 2023. Padcev ® and the Padcev device are trademarks jointly owned by Agensys, Inc., and Seagen Inc. Pfizer Inc. completed its acquisition of Seagen on December 14, 2023. SOURCE: Merck

AstraZeneca’s Imfinzi (durvalumab) has been granted priority review by the US Food and Drug Administration (FDA) to treat early-stage gastric cancer. The decision specifically applies to patients with resectable, early-stage and locally advanced (stages 2, 3 and 4a) gastric and gastroesophageal junction (GEJ) cancers. The immunotherapy, which was also recently granted breakthrough therapy designation by the US regulator in this setting, will now benefit from an expedited review process. AZ’s application is based on results from the late-stage MATTERHORN trial, which has been evaluating Imfinzi in combination with standard-of-care fluorouracil, leucovorin, oxaliplatin and docetaxel chemotherapy prior to surgery, followed by Imfinzi plus chemotherapy after surgery, then Imfinzi monotherapy. In the study, the Imfinzi-based regimen was associated with a 29% reduction in the risk of disease progression, recurrence or death versus chemotherapy alone, while estimated median event-free survival (EFS) was not yet reached for the Imfinzi arm versus 32.8 months for the comparator arm. Gastric cancer is the fifth leading cause of cancer-related deaths globally, with almost one million cases of the disease diagnosed globally in 2022. Despite undergoing surgery with curative intent and treatment with neoadjuvant/adjuvant chemotherapy, around one in four patients with resectable gastric cancer develop recurrent disease within one year, and one in four do not survive beyond two years. Imfinzi is designed to target the PD-L1 protein, which cancer cells use to evade the immune system, and is already approved in the US to treat certain cases of lung cancer, biliary tract cancer, bladder cancer, endometrial cancer and hepatocellular carcinoma. Commenting on the latest decision on the drug, Susan Galbraith, executive vice president, oncology haematology research and development, AZ, said: “This priority review reinforces the potential for a perioperative approach with Imfinzi to transform care for patients with early gastric and GEJ cancers, who frequently face disease recurrence or progression even after curative-intent surgery and perioperative chemotherapy. “This novel treatment is the only immunotherapy-based regimen to show a statistically significant reduction in the risk of progression, recurrence or death in this setting, and if approved, is poised to change the clinical paradigm.”