KENILWORTH, N.J. & WOODCLIFF LAKE, N.J.--(BUSINESS WIRE)--Merck (NYSE: MRK), known as MSD outside the United States and Canada, and Eisai today announced the first presentation of investigational data from the pivotal Phase 3 KEYNOTE-775/Study 309 trial in an oral plenary session (Plenary Session #10191) at the virtual Society of Gynecologic Oncology (SGO) 2021 Annual Meeting on Women?s Cancer. The trial evaluated the combination of KEYTRUDA, Merck?s anti-PD-1 therapy, plus LENVIMA, the orally available multiple receptor tyrosine kinase inhibitor discovered by Eisai, for the treatment of certain patients with advanced, metastatic or recurrent endometrial cancer following one prior platinum-based regimen in any setting. The study met the dual primary endpoints of progression-free survival (PFS), as assessed by blinded independent central review (BICR) per Response Evaluation Criteria in Solid Tumors (RECIST) v1.1, and overall survival (OS) as well as the secondary efficacy endpoint of objective response rate (ORR), as assessed by BICR per RECIST v1.1, in the all-comer population (mismatch repair proficient [pMMR] and mismatch repair deficient [dMMR]) and in the pMMR subgroup. Median follow-up was 11.4 months for both the all-comer population and the pMMR subgroup. A statistically significant and clinically meaningful improvement in PFS was seen in the all-comer population, in which KEYTRUDA plus LENVIMA (n=411) reduced the risk of disease progression or death by 44% (HR=0.56 [95% CI: 0.47-0.66]; p<0.0001), with a median PFS of 7.2 months (95% CI: 5.7-7.6; number of events=281) versus 3.8 months (95% CI: 3.6-4.2; number of events=286) for patients who received chemotherapy (treatment of physician?s choice [TPC] of doxorubicin or paclitaxel; n=416). Additionally, a statistically significant and clinically meaningful improvement in OS was seen in the all-comer population, in which KEYTRUDA plus LENVIMA reduced the risk of death by 38% (HR=0.62 [95% CI: 0.51-0.75]; p<0.0001), with a median OS of 18.3 months (95% CI: 15.2-20.5; number of events=188) versus 11.4 months (95% CI: 10.5-12.9; number of events=245) for patients who received TPC. The safety profile of KEYTRUDA plus LENVIMA was generally consistent with the established safety profiles of the individual monotherapies. ?Patients diagnosed with endometrial cancer, the most common type of gynecologic cancer in the U.S., face low survival rates when diagnosed at an advanced stage or at recurrence, especially once the disease progresses after prior platinum-based therapy and is not amenable to curative surgery or radiation,? said Dr. Vicky Makker, Principal Investigator and Medical Oncologist, Memorial Sloan Kettering Cancer Center. ?With a 38% reduction in risk of death regardless of mismatch repair status, KEYTRUDA plus LENVIMA significantly improved overall survival compared with chemotherapy in the all-comer group of patients with advanced, metastatic or recurrent endometrial carcinoma, which is very encouraging, as this arm included an investigational patient population for which more data have been sought after by the gynecologic oncology community.? In the all-comer population, the secondary efficacy endpoint of ORR was 31.9% (95% CI: 27.4-36.6), with a complete response (CR) rate of 6.6% and a partial response (PR) rate of 25.3%, for patients who received KEYTRUDA plus LENVIMA versus 14.7% (95% CI: 11.4-18.4), with a CR rate of 2.6% and a PR rate of 12.0% for patients who received TPC (ORR difference versus TPC: 17.2 percentage points; p<0.0001). For patients who responded, the median duration of response (DOR) was 14.4 months (range: 1.6-23.7) for patients who received KEYTRUDA plus LENVIMA versus 5.7 months (range: 0.0-24.2) for patients who received TPC. ?In this confirmatory Phase 3 study, KEYTRUDA plus LENVIMA demonstrated statistically significant improvements in progression-free survival, overall survival and objective response rate versus chemotherapy,? said Dr. Gregory Lubiniecki, Vice President, Oncology Clinical Research, Merck Research Laboratories. ?We are encouraged by these results that reaffirm Merck?s and Eisai?s commitment to explore the potential of the combination to help more patients with difficult-to-treat types of cancer.? ?The positive results seen in KEYNOTE-775/Study 309 help confirm the currently approved use of the KEYTRUDA plus LENVIMA combination in certain patients with advanced endometrial carcinoma,? said Dr. Takashi Owa, Chief Medicine Creation Officer and Chief Discovery Officer, Oncology Business Group at Eisai. ?As this stage of disease has been notoriously difficult to treat, Eisai and Merck remain committed to addressing the unmet need of advanced endometrial carcinoma. We are grateful to the patients and healthcare providers whose participation and persistence amid a global pandemic have made this milestone possible.? Results were similar across the all-comer population and the pMMR subgroup. In the pMMR subgroup, KEYTRUDA plus LENVIMA reduced the risk of disease progression or death by 40% (HR=0.60 [95% CI: 0.50-0.72]; p<0.0001), with a median PFS of 6.6 months (95% CI: 5.6-7.4; number of events=247) versus 3.8 months (95% CI: 3.6-5.0; number of events=238) for patients who received TPC. KEYTRUDA plus LENVIMA reduced the risk of death by 32% (HR=0.68 [95% CI: 0.56-0.84]; p=0.0001), with a median OS of 17.4 months (95% CI: 14.2-19.9; number of events=165) versus 12.0 months (95% CI: 10.8-13.3; number of events=203) for patients who received TPC. The secondary endpoint of ORR was 30.3% (95% CI: 25.5-35.5), with a CR rate of 5.2% and a PR rate of 25.1%, for patients who received KEYTRUDA plus LENVIMA versus 15.1% (95% CI: 11.5-19.3), with a CR rate of 2.6% and a PR rate of 12.5%, for patients who received TPC (ORR difference versus TPC: 15.2 percentage points; p<0.0001). For patients who responded, the median DOR was 9.2 months (range: 1.6-23.7) for patients who received KEYTRUDA plus LENVIMA versus 5.7 months (range: 0.0-24.2) for patients who received TPC. In the all-comer population, in the KEYTRUDA plus LENVIMA arm (n=406), treatment-emergent adverse events (TEAEs) of any grade led to discontinuation of KEYTRUDA in 18.7% of patients, of LENVIMA in 30.8% of patients, and of both in 14.0% of patients. In the TPC arm (n=388), TEAEs of any grade led to discontinuation of chemotherapy in 8.0% of patients. Grade 5 TEAEs of any cause occurred in 5.7% of patients in the KEYTRUDA plus LENVIMA arm and in 4.9% of patients in the TPC arm. Grade =3 TEAEs occurred in 88.9% of patients in the KEYTRUDA plus LENVIMA arm and in 72.7% of patients in the TPC arm. In the KEYTRUDA plus LENVIMA arm, the most common TEAEs of any grade occurring in at least 25% of patients were hypertension (64.0%), hypothyroidism (57.4%), diarrhea (54.2%), nausea (49.5%), decreased appetite (44.8%), vomiting (36.7%), weight decrease (34.0%), fatigue (33.0%), arthralgia (30.5%), proteinuria (28.8%), anemia (26.1%), constipation (25.9%) and urinary tract infection (25.6%). In the TPC arm, the most common TEAEs of any grade occurring in at least 25% of patients were anemia (48.7%), nausea (46.1%), neutropenia (33.8%), alopecia (30.9%), and fatigue (27.6%). Median treatment duration was 231 days (range: 1-817) with KEYTRUDA plus LENVIMA and 104.5 days (range: 1-785) with TPC. KEYNOTE-775/Study 309 is the confirmatory trial for KEYNOTE-146/Study 111, which supported the U.S. Food and Drug Administration?s (FDA) 2019 accelerated approval of the KEYTRUDA plus LENVIMA combination for the treatment of patients with advanced endometrial carcinoma that is not MSI-H or dMMR, who have disease progression following prior systemic therapy and are not candidates for curative surgery or radiation. KEYNOTE-775/Study 309 Trial Design (Plenary Session #10191) KEYNOTE-775/Study 309 is a multicenter, randomized, open-label, Phase 3 trial (ClinicalTrials.gov,?NCT03517449) evaluating KEYTRUDA in combination with LENVIMA in patients with advanced endometrial cancer following one prior platinum-based regimen in any setting. The dual primary endpoints are PFS, as assessed by BICR per RECIST v1.1, and OS. Select secondary endpoints include ORR, as assessed by BICR per RECIST v1.1, and safety/tolerability. Of the 827 patients enrolled, 697 patients had tumors that were pMMR, and 130 patients had tumors that were dMMR. Patients were randomized 1:1 to receive:

• KEYTRUDA (200 mg intravenously [IV] every three weeks for up to 35 cycles [approximately two years]) in combination with LENVIMA (20 mg orally once daily); or
• Chemotherapy treatment of physician?s choice (TPC) of either doxorubicin (60 mg/m²?IV every three weeks for up to a maximum cumulative dose of 500 mg/m²) or paclitaxel (80 mg/m²?IV on a 28-day cycle [three weeks of receiving weekly paclitaxel and one week of not receiving paclitaxel]).

About Endometrial Cancer Endometrial cancer 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. In 2020, it was estimated there were more than 417,000 new cases and more than 97,000 deaths from uterine body cancers worldwide (these estimates include both endometrial cancers and uterine sarcomas; more than 90% of uterine body cancers occur in the endometrium, so the actual numbers for endometrial cancer cases and deaths are slightly lower than these estimates). In the U.S., it is estimated there will be more than 66,000 new cases of uterine body cancer and nearly 13,000 deaths from the disease in 2021. The five-year survival rate for metastatic endometrial cancer (stage IV) is estimated to be approximately 17%. About KEYTRUDA^??(pembrolizumab) Injection, 100 mg KEYTRUDA is an anti-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 1,400 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. Melanoma KEYTRUDA is indicated for the treatment of patients with unresectable or metastatic melanoma. KEYTRUDA is indicated for the adjuvant treatment of patients with melanoma with involvement of lymph node(s) 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 stage III where patients are not candidates for surgical resection or definitive chemoradiation, or metastatic. 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. Head and Neck Squamous Cell Cancer KEYTRUDA, in combination with platinum and fluorouracil (FU), is indicated for the first-line treatment of patients with metastatic or with unresectable, recurrent head and neck squamous cell carcinoma (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 [combined positive score (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. Urothelial Carcinoma KEYTRUDA is indicated for the treatment of patients with locally advanced or metastatic urothelial carcinoma (mUC) who are not eligible for cisplatin-containing chemotherapy and whose tumors express PD-L1 (CPS =10), as determined by an FDA-approved test, or in patients who are not eligible for any platinum-containing chemotherapy regardless of PD-L1 status. This indication is approved under accelerated approval based on tumor response rate and duration of response. Continued approval for this indication may be contingent upon verification and description of clinical benefit in confirmatory trials. KEYTRUDA is indicated for the treatment of patients with locally advanced or metastatic urothelial carcinoma (mUC) who have disease progression during or following platinum-containing chemotherapy or within 12 months of neoadjuvant or adjuvant treatment with platinum-containing chemotherapy. KEYTRUDA 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. 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 that have progressed following prior treatment and who have no satisfactory alternative treatment options, or
• colorectal cancer that has progressed following treatment with fluoropyrimidine, oxaliplatin, and irinotecan.

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 MSI-H central nervous system cancers have not been established. Microsatellite Instability-High or Mismatch Repair Deficient Colorectal Cancer KEYTRUDA is indicated for the first-line treatment of patients with unresectable or metastatic MSI-H or dMMR colorectal cancer (CRC). Gastric Cancer KEYTRUDA is indicated for the treatment of patients with recurrent locally advanced or metastatic gastric or gastroesophageal junction (GEJ) adenocarcinoma whose tumors express PD-L1 (CPS =1) as determined by an FDA-approved test, with disease progression on or after two or more prior lines of therapy including fluoropyrimidine- and platinum-containing chemotherapy and if appropriate, HER2/neu-targeted therapy. 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. Esophageal Cancer KEYTRUDA is indicated for the treatment of patients with recurrent locally advanced or metastatic squamous cell carcinoma of the esophagus whose tumors express PD-L1 (CPS =10) as determined by an FDA-approved test, with disease progression after one or more prior lines of systemic therapy. Cervical Cancer KEYTRUDA 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. 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. Hepatocellular Carcinoma KEYTRUDA is indicated for the treatment of patients with hepatocellular carcinoma (HCC) who have been previously treated with sorafenib. 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. Merkel Cell Carcinoma KEYTRUDA is indicated for the treatment of adult and pediatric patients with recurrent locally advanced or metastatic Merkel cell carcinoma (MCC). 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. Renal Cell Carcinoma KEYTRUDA, in combination with axitinib, is indicated for the first-line treatment of patients with advanced renal cell carcinoma (RCC). Endometrial Carcinoma KEYTRUDA, in combination with LENVIMA, is indicated for the treatment of patients with advanced endometrial carcinoma that is not MSI-H or dMMR, who have disease progression following prior systemic therapy and are not candidates for curative surgery or radiation. 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 trial. Tumor Mutational Burden-High KEYTRUDA is indicated for the treatment of adult and pediatric patients with unresectable or metastatic tumor mutational burden-high (TMB-H) [=10 mutations/megabase] 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) that is not curable by surgery or radiation. Triple-Negative Breast Cancer KEYTRUDA, in combination with chemotherapy, is indicated for the treatment of patients with locally recurrent unresectable or metastatic triple-negative breast cancer (TNBC) whose tumors express PD-L1 (CPS =10) as determined by an FDA-approved test. This indication is approved under accelerated approval based on progression-free survival. Continued approval for this indication may be contingent upon verification and description of clinical benefit in the confirmatory trials. 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. 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% of these patients interrupted KEYTRUDA, 68% discontinued KEYTRUDA, and 77% 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, which was 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 (6.2%) and Grade 2 (10.8%) hypothyroidism. Type 1 Diabetes Mellitus (DM), Which Can Present With Diabetic Ketoacidosis Monitor patients for hyperglycemia or other signs and symptoms of diabetes. Initiate treatment with insulin as clinically indicated. Withhold KEYTRUDA depending on severity. Type 1 DM occurred in 0.2% (6/2799) of patients receiving KEYTRUDA. It led to permanent discontinuation in <0.1% (1) and withholding of KEYTRUDA in <0.1% (1). All patients who were withheld reinitiated KEYTRUDA after symptom improvement. Immune-Mediated Nephritis With Renal Dysfunction KEYTRUDA can cause immune-mediated nephritis. Immune-mediated nephritis occurred in 0.3% (9/2799) of patients receiving KEYTRUDA, including Grade 4 (<0.1%), Grade 3 (0.1%), and Grade 2 (0.1%) reactions. Systemic corticosteroids were required in 89% (8/9) of patients. Nephritis led to permanent discontinuation of KEYTRUDA in 0.1% (3) and withholding in 0.1% (3) of patients. All patients who were withheld reinitiated KEYTRUDA after symptom improvement; of these, none had recurrence. Nephritis resolved in 56% of the 9 patients. Immune-Mediated Dermatologic Adverse Reactions KEYTRUDA can cause immune-mediated rash or dermatitis. Exfoliative dermatitis, including Stevens-Johnson syndrome, drug rash with eosinophilia and systemic symptoms, and toxic epidermal necrolysis, has occurred with anti?PD-1/PD-L1 treatments. Topical emollients and/or topical corticosteroids may be adequate to treat mild to moderate nonexfoliative rashes. Withhold or permanently discontinue KEYTRUDA depending on severity. Immune-mediated dermatologic adverse reactions occurred in 1.4% (38/2799) of patients receiving KEYTRUDA, including Grade 3 (1%) and Grade 2 (0.1%) reactions. Systemic corticosteroids were required in 40% (15/38) of patients. These reactions led to permanent discontinuation in 0.1% (2) and withholding of KEYTRUDA in 0.6% (16) of patients. All patients who were withheld reinitiated KEYTRUDA after symptom improvement; of these, 6% had recurrence. The reactions resolved in 79% of the 38 patients. Other Immune-Mediated Adverse Reactions The following clinically significant immune-mediated adverse reactions occurred at an incidence of <1% (unless otherwise noted) in patients who received KEYTRUDA or were reported with the use of other anti?PD-1/PD-L1 treatments. Severe or fatal cases have been reported