At five years, KEYTRUDA plus LENVIMA showed a 16.7% overall survival (OS) rate for these patients with mismatch repair proficient (pMMR) advanced endometrial carcinoma versus 7.3% for chemotherapy alone in the pivotal Phase 3 KEYNOTE-775/Study 309 trial
Five-year OS results in the pMMR subgroup were consistent with the all-comers study population, which demonstrated an OS rate of 19.9% for KEYTRUDA plus LENVIMA versus 7.7% for chemotherapy
RAHWAY, N.J. & NUTLEY, N.J.–(BUSINESS WIRE)–$MRK #MRK–Merck (NYSE: MRK), known as MSD outside of the United States and Canada, and Eisai today announced long-term follow-up data continued to show durable benefit of KEYTRUDA® (pembrolizumab), Merck’s anti-PD-1 therapy, plus LENVIMA® (lenvatinib), the orally available multiple receptor tyrosine kinase inhibitor (TKI) discovered by Eisai, compared to chemotherapy for patients with advanced endometrial carcinoma following at least one prior platinum-based regimen in any setting. The findings, based on five years of follow-up from the Phase 3 KEYNOTE-775/Study 309 trial evaluating KEYTRUDA plus LENVIMA versus chemotherapy (treatment of physician’s choice of doxorubicin or paclitaxel), for these patients with advanced endometrial carcinoma are being presented during a poster session at the European Society for Medical Oncology (ESMO) Congress 2025 in Berlin, Germany (Presentation #1119P).
In the trial, a total of 827 patients (697 whose cancer was mismatch repair proficient [pMMR] and 130 whose cancer was mismatch repair deficient [dMMR]) were randomized to receive KEYTRUDA plus LENVIMA (n=411) or chemotherapy (n=416). The trial’s primary endpoints, overall survival (OS) and progression-free survival (PFS), were evaluated in patients with pMMR disease and in the intent-to-treat population (also known as the all-comers population), which included all randomized patients (both pMMR and dMMR).
In the pMMR subgroup, after a median follow-up of 68.8 months (range, 60.8–79.0 months for KEYTRUDA plus LENVIMA; range, 60.9–80.0 for chemotherapy), the five-year OS rate was 16.7% for KEYTRUDA plus LENVIMA versus 7.3% for chemotherapy alone. Median OS was 18.0 months (95% CI, 14.9-20.5) for KEYTRUDA plus LENVIMA versus 12.2 months (95% CI, 11.0-14.1) for chemotherapy alone (HR 0.70; 95% CI, 0.60-0.83). Five-year OS results in the pMMR subgroup were consistent with the all-comers population, which demonstrated an OS rate of 19.9% for KEYTRUDA plus LENVIMA versus 7.7% for chemotherapy; median OS was 18.7 months (95% CI, 15.6-21.3) for KEYTRUDA plus LENVIMA versus 11.9 months (95% CI, 10.6-13.3) for chemotherapy (HR 0.66; 95% CI, 0.57-0.77).
The long-term OS data were consistent with the primary analysis presented at the Society of Gynecologic Oncology (SGO) 2021 Annual Meeting and published in the New England Journal of Medicine. In the primary analysis, the median OS was 17.4 months (95% CI, 14.2-19.9) for KEYTRUDA plus LENVIMA versus 12.0 months (95% CI, 10.8-13.3) for chemotherapy in the pMMR subgroup, and 18.3 months (95% CI, 15.2-20.5) versus 11.4 months (95% CI, 10.5-12.9) in the all-comers population. In the five-year analysis, there were no new safety signals and the safety profile of KEYTRUDA plus LENVIMA was consistent with previously reported data on the combination.
“Endometrial carcinoma is difficult-to-treat in the recurrent or advanced stage, especially when tumors are mismatch repair proficient and therefore harder to target with immunotherapy alone,” said Dr. Vicky Makker, Principal Investigator and Gynecologic Medical Oncologist, Memorial Sloan Kettering Cancer Center. “Five-year follow-up data from the KEYNOTE-775/Study 309 trial show sustained survival benefit in patients treated with pembrolizumab plus lenvatinib and underscore the role of this combination as an effective treatment option for patients with advanced endometrial carcinoma who need further treatment after receiving prior platinum-based therapy.”
“Recent advances have led to steady improvement in outcomes for patients with advanced endometrial carcinoma,” said Dr. Gregory Lubiniecki, Vice President, Global Clinical Development, Merck Research Laboratories. “These five-year data highlight the durable survival benefit of KEYTRUDA plus LENVIMA in patients with advanced endometrial carcinoma who have received prior platinum-based therapy and are the result of our ongoing commitment to delivering impactful treatment options for people affected by women’s cancers.”
“The five-year results from KEYNOTE-775/Study 309 represent the longest reported follow-up for a trial evaluating an immunotherapy plus tyrosine kinase inhibitor combination in advanced endometrial carcinoma,” said Dr. Corina Dutcus, Senior Vice President, Oncology Global Clinical Development Lead at Eisai Inc. “These findings demonstrate the continued overall survival benefit observed with KEYTRUDA plus LENVIMA, further supporting the combination’s therapeutic value for patients facing this disease. We are deeply grateful to the patients, their families, and the dedicated investigators whose participation and commitment made this research possible.”
Treatment-related adverse events (TRAEs) occurred in 97.3% of patients receiving KEYTRUDA plus LENVIMA versus 93.8% of patients receiving chemotherapy and led to the discontinuation of KEYTRUDA and/or LENVIMA in 40.1% of patients (16.0% discontinued both drugs) versus the discontinuation of chemotherapy in 8.0% of patients. The most common adverse events (≥ 20%) in the KEYTRUDA plus LENVIMA group were hypertension (61.8%), hypothyroidism (55.7%), diarrhea (43.3%), nausea (40.1%), decreased appetite (37.9%), fatigue (28.8%), proteinuria (27.6%), vomiting (24.4%), arthralgia (23.9%), decreased weight (22.7%) and palmar-plantar erythrodysesthesia syndrome (20.7%).
Based on the primary analysis results in 2021 from the Phase 3 KEYNOTE-775/Study 309 trial, KEYTRUDA plus LENVIMA is approved in the U.S. for patients with advanced endometrial carcinoma that is pMMR or not microsatellite instability-high (MSI-H), 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. KEYTRUDA plus LENVIMA is also approved in the European Union (EU) and Japan for certain patients with advanced or recurrent endometrial carcinoma regardless of mismatch repair status. Lenvatinib is approved as KISPLYX for advanced renal cell carcinoma in the EU.
Dr. Makker has provided consulting and advisory services for Merck and Eisai.
Study design and additional data from KEYNOTE-775/Study 309
KEYNOTE-775/Study 309 (ClinicalTrials.gov, NCT03517449) is a Phase 3, multicenter, open-label, randomized, active-controlled study evaluating KEYTRUDA plus LENVIMA for the treatment of patients with advanced endometrial carcinoma who had been previously treated with at least one prior platinum-based chemotherapy regimen in any setting, including in the neoadjuvant and adjuvant settings. Participants may have received up to two platinum-containing therapies in total, as long as one was given in the neoadjuvant or adjuvant treatment setting. The study excluded patients with endometrial sarcoma, carcinosarcoma, pre-existing Grade ≥3 fistula, uncontrolled blood pressure (>150/90 mmHg), significant cardiovascular impairment or event within the last 12 months or patients who had active autoimmune disease or a medical condition that required immunosuppression. The primary efficacy outcome measures were OS and PFS as assessed by blinded independent central review (BICR) according to Response Evaluation Criteria in Solid Tumors version 1.1 (RECIST v1.1). Secondary efficacy outcome measures included objective response rate (ORR) as assessed by BICR and safety. The study randomized 827 patients 1:1 to receive:
- KEYTRUDA (200 mg intravenously every three weeks) plus LENVIMA (20 mg orally once daily); or
- Investigator’s choice, consisting of either doxorubicin (60 mg/m2 every three weeks) or paclitaxel (80 mg/m2 given weekly, three weeks on/one week off).
Treatment with KEYTRUDA plus LENVIMA continued until RECIST v1.1-defined progression of disease as verified by BICR, unacceptable toxicity or, for KEYTRUDA, a maximum of 35 cycles. Administration of KEYTRUDA plus LENVIMA was permitted beyond RECIST v1.1-defined disease progression if the treating investigator considered the patient to be deriving clinical benefit and the treatment was tolerated.
In the pMMR subgroup, KEYTRUDA plus LENVIMA demonstrated a five-year PFS rate of 6.3% versus 2.1% for chemotherapy alone. Median PFS was 6.7 months (95% CI, 5.6-7.4) for KEYTRUDA plus LENVIMA versus 3.8 months (95% CI, 3.6-5.0) for chemotherapy alone. At five years, ORR was 32.4% (95% CI, 27.5-37.6) for KEYTRUDA plus LENVIMA compared with 14.8% (95% CI, 11.3-19.0) for chemotherapy.
In the all-comers population, KEYTRUDA plus LENVIMA demonstrated a five-year PFS rate of 9.8% versus 3.2% for chemotherapy alone. Median PFS was 7.3 months (95% CI, 5.7-7.6) for KEYTRUDA plus LENVIMA versus 3.8 months (95% CI, 3.6-4.2) for chemotherapy alone. At five years, ORR was 33.8% (95% CI, 29.3-38.6) for KEYTRUDA plus LENVIMA compared with 14.4% (95% CI, 11.2-18.2) for chemotherapy.
The long-term PFS data were also consistent with the primary analysis, in which the median PFS was 6.6 months (95% CI, 5.6-7.4) for KEYTRUDA plus LENVIMA versus 3.8 months (95% CI, 3.6-5.0) for chemotherapy in the pMMR subgroup, and 7.2 months (95% CI, 5.7-7.6) versus 3.8 months (95% CI, 3.6-4.2) in the all-comers population.
In the all-comers population, 44.8% of patients treated with KEYTRUDA plus LENVIMA and 51.2% of patients treated with chemotherapy used subsequent systemic anticancer therapy (compared with 28.0% and 48.1%, respectively, at the primary analysis). In the chemotherapy group, 10.1% of patients crossed over to receive KEYTRUDA plus LENVIMA. At the data cut-off (Feb. 26, 2025), 86 patients were alive after treatment with KEYTRUDA plus LENVIMA, compared to 53 patients treated with chemotherapy.
While the trial was not powered to compare KEYTRUDA plus LENVIMA with chemotherapy in the dMMR subgroup, a clinically meaningful improvement was observed across efficacy endpoints. The five-year OS rate was 36.5% for KEYTRUDA plus LENVIMA versus 9.8% for chemotherapy alone. Median OS was 31.9 months (95% CI, 15.6-47.7) for KEYTRUDA plus LENVIMA versus 8.6 months (95% CI, 5.5-13.4) for chemotherapy alone. KEYTRUDA plus LENVIMA demonstrated a five-year PFS rate of 26.4% versus 10.8% for chemotherapy. Median PFS was 14.8 months (95% CI, 5.6-31.9) for KEYTRUDA plus LENVIMA versus 3.7 months (95% CI, 3.1-4.4) for chemotherapy alone. The ORR at five years was 41.5% (95% CI, 29.4-54.4) for KEYTRUDA plus LENVIMA compared with 12.3% (95% CI, 5.5-22.8) for chemotherapy.
About endometrial carcinoma
Endometrial carcinoma begins in the inner lining of the uterus, which is known as the endometrium, and is the most common type of cancer in the uterus. More than 90% of uterine body cancers occur in the endometrium. In the U.S., it is estimated there will be approximately 69,120 patients diagnosed with uterine body cancer and approximately 13,860 patient deaths from the disease in 2025. Globally, endometrial cancer is the sixth most common cancer in women and the 15th most common cancer overall. Following primary treatment, patients face a risk of their cancer returning, often as distant metastasis, which is associated with poorer outcomes.
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.
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, in combination with lenvatinib, is indicated for the treatment of adult patients with advanced endometrial carcinoma that is mismatch repair proficient (pMMR) or not MSI-H as determined by an FDA-approved test, who have disease progression following prior systemic therapy in any setting are not candidates for curative surgery or radiation.
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.
See additional selected KEYTRUDA indications in the U.S. after the Selected Important Safety Information.
Selected Important Safety Information for KEYTRUDA
Severe and Fatal Immune-Mediated Adverse Reactions
KEYTRUDA is a monoclonal antibody that belongs to a class of drugs that bind to either the programmed death receptor-1 (PD-1) or the programmed death ligand 1 (PD-L1), blocking the PD-1/PD-L1 pathway, thereby removing inhibition of the immune response, potentially breaking peripheral tolerance and inducing immune-mediated adverse reactions. Immune-mediated adverse reactions, which may be severe or fatal, can occur in any organ system or tissue, can affect more than one body system simultaneously, and can occur at any time after starting treatment or after discontinuation of treatment. Important immune-mediated adverse reactions listed here may not include all possible severe and fatal immune-mediated adverse reactions.
Monitor patients closely for symptoms and signs that may be clinical manifestations of underlying immune-mediated adverse reactions. Early identification and management are essential to ensure safe use of anti–PD-1/PD-L1 treatments. Evaluate liver enzymes, creatinine, and thyroid function at baseline and periodically during treatment. For patients with TNBC treated with KEYTRUDA in the neoadjuvant setting, monitor blood cortisol at baseline, prior to surgery, and as clinically indicated. In cases of suspected immune-mediated adverse reactions, initiate appropriate workup to exclude alternative etiologies, including infection. Institute medical management promptly, including specialty consultation as appropriate.
Withhold or permanently discontinue KEYTRUDA depending on severity of the immune-mediated adverse reaction. In general, if KEYTRUDA requires interruption or discontinuation, administer systemic corticosteroid therapy (1 to 2 mg/kg/day prednisone or equivalent) until improvement to Grade 1 or less. Upon improvement to Grade 1 or less, initiate corticosteroid taper and continue to taper over at least 1 month. Consider administration of other systemic immunosuppressants in patients whose adverse reactions are not controlled with corticosteroid therapy.
Immune-Mediated Pneumonitis
KEYTRUDA can cause immune-mediated pneumonitis. The incidence is higher in patients who have received prior thoracic radiation. Immune-mediated pneumonitis occurred in 3.4% (94/2799) of patients receiving KEYTRUDA, including fatal (0.1%), Grade 4 (0.3%), Grade 3 (0.9%), and Grade 2 (1.3%) reactions. Systemic corticosteroids were required in 67% (63/94) of patients. Pneumonitis led to permanent discontinuation of KEYTRUDA in 1.3% (36) and withholding in 0.9% (26) of patients. All patients who were withheld reinitiated KEYTRUDA after symptom improvement; of these, 23% had recurrence. Pneumonitis resolved in 59% of the 94 patients.
Pneumonitis occurred in 8% (31/389) of adult patients with cHL receiving KEYTRUDA as a single agent, including Grades 3-4 in 2.3% of patients. Patients received high-dose corticosteroids for a median duration of 10 days (range: 2 days to 53 months). Pneumonitis rates were similar in patients with and without prior thoracic radiation. Pneumonitis led to discontinuation of KEYTRUDA in 5.4% (21) of patients. Of the patients who developed pneumonitis, 42% interrupted KEYTRUDA, 68% discontinued KEYTRUDA, and 77% had resolution.
Pneumonitis occurred in 7% (41/580) of adult patients with resected NSCLC who received KEYTRUDA as a single agent for adjuvant treatment of NSCLC, including fatal (0.2%), Grade 4 (0.3%), and Grade 3 (1%) adverse reactions. Patients received high-dose corticosteroids for a median duration of 10 days (range: 1 day to 2.3 months). Pneumonitis led to discontinuation of KEYTRUDA in 26 (4.5%) of patients. Of the patients who developed pneumonitis, 54% interrupted KEYTRUDA, 63% discontinued KEYTRUDA, and 71% had resolution.
Immune-Mediated Colitis
KEYTRUDA can cause immune-mediated colitis, which may present with diarrhea. Cytomegalovirus infection/reactivation has been reported in patients with corticosteroid-refractory immune-mediated colitis. In cases of corticosteroid-refractory colitis, consider repeating infectious workup to exclude alternative etiologies. Immune-mediated colitis occurred in 1.7% (48/2799) of patients receiving KEYTRUDA, including Grade 4 (<0.1%), Grade 3 (1.1%), and Grade 2 (0.4%) reactions. Systemic corticosteroids were required in 69% (33/48); additional immunosuppressant therapy was required in 4.2% of patients. Colitis led to permanent discontinuation of KEYTRUDA in 0.5% (15) and withholding in 0.5% (13) of patients. All patients who were withheld reinitiated KEYTRUDA after symptom improvement; of these, 23% had recurrence. Colitis resolved in 85% of the 48 patients.
Hepatotoxicity and Immune-Mediated Hepatitis
KEYTRUDA as a Single Agent
KEYTRUDA can cause immune-mediated hepatitis. Immune-mediated hepatitis occurred in 0.7% (19/2799) of patients receiving KEYTRUDA, including Grade 4 (<0.1%), Grade 3 (0.4%), and Grade 2 (0.1%) reactions. Systemic corticosteroids were required in 68% (13/19) of patients; additional immunosuppressant therapy was required in 11% of patients. Hepatitis led to permanent discontinuation of KEYTRUDA in 0.2% (6) and withholding in 0.3% (9) of patients. All patients who were withheld reinitiated KEYTRUDA after symptom improvement; of these, none had recurrence. Hepatitis resolved in 79% of the 19 patients.
KEYTRUDA With Axitinib
KEYTRUDA in combination with axitinib can cause hepatic toxicity. Monitor liver enzymes before initiation of and periodically throughout treatment. Consider monitoring more frequently as compared to when the drugs are administered as single agents. For elevated liver enzymes, interrupt KEYTRUDA and axitinib, and consider administering corticosteroids as needed. With the combination of KEYTRUDA and axitinib, Grades 3 and 4 increased alanine aminotransferase (ALT) (20%) and increased aspartate aminotransferase (AST) (13%) were seen at a higher frequency compared to KEYTRUDA alone. Fifty-nine percent of the patients with increased ALT received systemic corticosteroids. In patients with ALT ≥3 times upper limit of normal (ULN) (Grades 2-4, n=116), ALT resolved to Grades 0-1 in 94%. Among the 92 patients who were rechallenged with either KEYTRUDA (n=3) or axitinib (n=34) administered as a single agent or with both (n=55), recurrence of ALT ≥3 times ULN was observed in 1 patient receiving KEYTRUDA, 16 patients receiving axitinib, and 24 patients receiving both. All patients with a recurrence of ALT ≥3 ULN subsequently recovered from the event.
Immune-Mediated Endocrinopathies
Adrenal Insufficiency
KEYTRUDA can cause primary or secondary adrenal insufficiency. For Grade 2 or higher, initiate symptomatic treatment, including hormone replacement as clinically indicated. Withhold KEYTRUDA depending on severity. Adrenal insufficiency occurred in 0.8% (22/2799) of patients receiving KEYTRUDA, including Grade 4 (<0.1%), Grade 3 (0.3%), and Grade 2 (0.3%) reactions. Systemic corticosteroids were required in 77% (17/22) of patients; of these, the majority remained on systemic corticosteroids. Adrenal insufficiency led to permanent discontinuation of KEYTRUDA in <0.1% (1) and withholding in 0.3% (8) of patients. All patients who were withheld reinitiated KEYTRUDA after symptom improvement.
Hypophysitis
KEYTRUDA can cause immune-mediated hypophysitis. Hypophysitis can present with acute symptoms associated with mass effect such as headache, photophobia, or visual field defects. Hypophysitis can cause hypopituitarism. Initiate hormone replacement as indicated. Withhold or permanently discontinue KEYTRUDA depending on severity. Hypophysitis occurred in 0.6% (17/2799) of patients receiving KEYTRUDA, including Grade 4 (<0.1%), Grade 3 (0.3%), and Grade 2 (0.2%) reactions. Systemic corticosteroids were required in 94% (16/17) of patients; of these, the majority remained on systemic corticosteroids. Hypophysitis led to permanent discontinuation of KEYTRUDA in 0.1% (4) and withholding in 0.3% (7) of patients. All patients who were withheld reinitiated KEYTRUDA after symptom improvement.
Thyroid Disorders
KEYTRUDA can cause immune-mediated thyroid disorders. Thyroiditis can present with or without endocrinopathy. Hypothyroidism can follow hyperthyroidism. Initiate hormone replacement for hypothyroidism or institute medical management of hyperthyroidism as clinically indicated. Withhold or permanently discontinue KEYTRUDA depending on severity. Thyroiditis occurred in 0.6% (16/2799) of patients receiving KEYTRUDA, including Grade 2 (0.3%). None discontinued, but KEYTRUDA was withheld in <0.1% (1) of patients.
Hyperthyroidism occurred in 3.4% (96/2799) of patients receiving KEYTRUDA, including Grade 3 (0.1%) and Grade 2 (0.8%). It led to permanent discontinuation of KEYTRUDA in <0.1% (2) and withholding in 0.3% (7) of patients. All patients who were withheld reinitiated KEYTRUDA after symptom improvement. Hypothyroidism occurred in 8% (237/2799) of patients receiving KEYTRUDA, including Grade 3 (0.1%) and Grade 2 (6.2%). It led to permanent discontinuation of KEYTRUDA in <0.1% (1) and withholding in 0.5% (14) of patients. All patients who were withheld reinitiated KEYTRUDA after symptom improvement. The majority of patients with hypothyroidism required long-term thyroid hormone replacement. The incidence of new or worsening hypothyroidism was higher in 1185 patients with HNSCC, occurring in 16% of patients receiving KEYTRUDA as a single agent or in combination with platinum and FU, including Grade 3 (0.3%) hypothyroidism. The incidence of new or worsening hypothyroidism was higher in 389 adult patients with cHL (17%) receiving KEYTRUDA as a single agent, including Grade 1 (6.
Contacts
Media Contacts:
Merck:
Julie Cunningham
(617) 519-6264
John Infanti
(609) 500-4714
Eisai:
Michele Randazzo
(201) 248-2228
Investor Contacts:
Merck:
Peter Dannenbaum
(732) 594-1579
Steven Graziano
(732) 594-1583
