Merck’s KEYTRUDA® (pembrolizumab) Plus Chemotherapy Significantly Improved Overall Survival Compared to Chemotherapy Alone in Patients With Advanced or Unresectable Biliary Tract Cancer

Merck’s KEYTRUDA® (pembrolizumab) Plus Chemotherapy Significantly Improved Overall Survival Compared to Chemotherapy Alone in Patients With Advanced or Unresectable Biliary Tract Cancer

Results from Phase 3 KEYNOTE-966 to be presented at AACR 2023 Annual Meeting during Clinical Trials Plenary Session, included in official meeting press program and published simultaneously in The Lancet

RAHWAY, N.J.–(BUSINESS WIRE)–$MRK #MRK–Merck (NYSE: MRK), known as MSD outside of the United States and Canada, today announced results from the Phase 3 KEYNOTE-966 trial investigating KEYTRUDA, Merck’s anti-PD-1 therapy, in combination with standard of care chemotherapy (gemcitabine and cisplatin) for the first-line treatment of patients with advanced or unresectable biliary tract cancer (BTC). Results from the trial showed the KEYTRUDA regimen demonstrated a statistically significant and clinically meaningful improvement in overall survival (OS) compared to chemotherapy alone for these patients. These data are being presented during a Clinical Trials Plenary Session at the American Association for Cancer Research (AACR) 2023 Annual Meeting (abstract #CT008), were selected for the AACR press program and are being simultaneously published in The Lancet. The results are also being shared with regulatory authorities worldwide.

Biliary tract cancer is rising in incidence worldwide, and unfortunately most patients are diagnosed with this devastating type of cancer at an advanced stage, when the five-year survival rate is less than 5%,” said Dr. Robin Kate Kelley, professor of clinical medicine in the division of hematology/oncology, University of California, San Francisco. “This trial shows that adding KEYTRUDA to chemotherapy holds the potential to extend life for these patients.”

After a median follow-up of 25.6 months (range, 18.3-38.4), KEYTRUDA plus chemotherapy reduced the risk of death by 17% (HR=0.83 [95% CI, 0.72-0.95]; p=0.0034) compared to chemotherapy alone for these patients. Median OS was 12.7 months (95% CI, 11.5-13.6) for the KEYTRUDA regimen versus 10.9 months (95% CI, 9.9-11.6) for chemotherapy alone. The one-year OS rate was 52% for the KEYTRUDA regimen versus 44% for chemotherapy alone; the two-year OS rates were 24.9% versus 18.1%, respectively. The OS results were generally consistent across subgroups.

The safety profile of KEYTRUDA in this trial was consistent with that observed in previously reported studies. Grade 3-4 treatment-related adverse events (TRAEs) occurred in 70% of patients receiving the KEYTRUDA regimen and 69% of patients receiving chemotherapy alone; TRAEs led to death in eight (2%) versus three (1%) patients, respectively. No new safety signals were identified. Grade 3-4 immune-mediated adverse events (AEs) occurred in 7% of patients receiving the KEYTRUDA regimen and 4% of patients receiving chemotherapy alone; immune-mediated AEs led to death in one patient (<1%) receiving the KEYTRUDA regimen.

Based on these results, we hope to expand the use of KEYTRUDA in combination with chemotherapy as a first-line immunotherapy option for appropriate biliary tract cancer patients who may benefit and who are in need of new treatment options that may help them live longer,” said Dr. Scot Ebbinghaus, vice president, global clinical development, Merck Research Laboratories. “These results also demonstrate our commitment to improving outcomes for patients with different types of gastrointestinal cancers, including hepatobiliary tumors. We look forward to discussing these data with regulatory authorities.”

Merck has an extensive clinical development program evaluating KEYTRUDA as monotherapy and in combination across multiple gastrointestinal cancers including hepatobiliary, gastric, esophageal, pancreatic and colorectal cancers. In liver cancer, KEYTRUDA is being evaluated in earlier-stage hepatocellular carcinoma (HCC) in the KEYNOTE-937 study as well as in combination with LENVIMA® (lenvatinib, in collaboration with Eisai) and transarterial chemoembolization (TACE) in the LEAP-012 study.

This clinical development program for KEYTRUDA also includes KEYNOTE-811 in first-line advanced human epidermal growth factor receptor 2 (HER2)-positive gastric cancer, KEYNOTE-859 in HER2-negative gastric or gastroesophageal junction adenocarcinoma, and KEYNOTE-585 in early-stage gastric cancer. Additional exploration of KEYTRUDA is being conducted in combination with LENVIMA in advanced/metastatic esophageal cancer in the LEAP-014 study and gastric cancer in the LEAP-015 study. A coformulation of pembrolizumab and favezelimab (MK-4280A, Merck’s investigational anti-LAG-3 antibody) is being evaluated across multiple solid tumors, including colorectal cancer (MK-4280A-007, NCT05064059).

KEYNOTE-966 study design and additional data

KEYNOTE-966 is a randomized, double-blind Phase 3 trial (ClinicalTrials.gov, NCT04003636) evaluating KEYTRUDA in combination with gemcitabine and cisplatin compared to placebo plus gemcitabine and cisplatin for the first-line treatment of advanced and/or unresectable BTC. The primary endpoint was OS, and the secondary endpoints included progression-free survival (PFS), objective response rate (ORR), duration of response (DOR) and safety. The trial enrolled 1,069 patients who were randomized to receive KEYTRUDA (200 mg every three weeks for up to approximately two years) plus gemcitabine and cisplatin, or placebo plus gemcitabine and cisplatin.

Additional results from the trial showed the KEYTRUDA regimen prolonged DOR compared to chemotherapy alone. At the final analysis, median DOR was 8.3 months (range, 6.9-10.2) for the KEYTRUDA regimen and 6.8 months (range, 5.7-7.1) for chemotherapy alone. As of data cutoff for the first interim analysis (Dec. 15, 2021), which was specified as the final analysis for the secondary endpoints of PFS and ORR, the median study follow-up was 13.6 months. Median PFS was 6.5 months (95% CI, 5.7-6.9) for the KEYTRUDA regimen versus 5.6 months (95% CI, 5.1-6.6) for chemotherapy alone, with estimated 12-month PFS rates of 25% (95% CI, 21-30) versus 20% (95% CI, 16-24), respectively. The difference in PFS did not reach statistical significance. The ORR was 29% (95% CI, 25-33), with a complete response (CR) rate of 2% and a partial response rate of 27%, for patients receiving the KEYTRUDA regimen and 29% (95% CI, 25-33), with a CR rate of 1% and a PR rate of 27% for those receiving chemotherapy alone. The difference in ORR did not reach statistical significance. An exploratory analysis showed similar outcomes for PFS and ORR at the final analysis.

About biliary tract cancer (BTC)

Biliary tract cancer is a group of rare and highly aggressive cancers in the gallbladder and bile ducts. Biliary tract cancer is the second most common type of primary liver cancer after HCC, accounting for 15% of all liver cancers. It is estimated there are approximately 211,000 patients diagnosed with BTC and 174,000 patient deaths from the disease each year globally. Biliary tract cancer is most frequently diagnosed in patients between 50 to 70 years old, and 70% of BTC patients are diagnosed at an advanced stage. Patients diagnosed with BTC face a very poor prognosis, with a five-year survival rate of 2% for those with advanced disease, and across all stages of between 5% and 15%.

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.

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.

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 PD-1 or the 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 (6.2%) and Grade 2 (10.8%) hypothyroidism. The incidence of new or worsening hyperthyroidism was higher in 580 patients with resected NSCLC, occurring in 11% of patients receiving KEYTRUDA as a single agent as adjuvant treatment, including Grade 3 (0.2%) hyperthyroidism. The incidence of new or worsening hypothyroidism was higher in 580 patients with resected NSCLC, occurring in 22% of patients receiving KEYTRUDA as a single agent as adjuvant treatment (KEYNOTE-091), including Grade 3 (0.3%) 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) of patients. 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 for some of these adverse reactions. Cardiac/Vascular: Myocarditis, pericarditis, vasculitis; Nervous System: Meningitis, encephalitis, myelitis and demyelination, myasthenic syndrome/myasthenia gravis (including exacerbation), Guillain-Barré syndrome, nerve paresis, autoimmune neuropathy; Ocular: Uveitis, iritis and other ocular inflammatory toxicities can occur. Some cases can be associated with retinal detachment. Various grades of visual impairment, including blindness, can occur. If uveitis occurs in combination with other immune-mediated adverse reactions, consider a Vogt-Koyanagi-Harada-like syndrome, as this may require treatment with systemic steroids to reduce the risk of permanent vision loss; Gastrointestinal: Pancreatitis, to include increases in serum amylase and lipase levels, gastritis, duodenitis; Musculoskeletal and Connective Tissue: Myositis/polymyositis, rhabdomyolysis (and associated sequelae, including renal failure), arthritis (1.5%), polymyalgia rheumatica; Endocrine: Hypoparathyroidism; Hematologic/Immune: Hemolytic anemia, aplastic anemia, hemophagocytic lymphohistiocytosis, systemic inflammatory response syndrome, histiocytic necrotizing lymphadenitis (Kikuchi lymphadenitis), sarcoidosis, immune thrombocytopenic purpura, solid organ transplant rejection.

Infusion-Related Reactions

KEYTRUDA can cause severe or life-threatening infusion-related reactions, including hypersensitivity and anaphylaxis, which have been reported in 0.2% of 2799 patients receiving KEYTRUDA. Monitor for signs and symptoms of infusion-related reactions. Interrupt or slow the rate of infusion for Grade 1 or Grade 2 reactions. For Grade 3 or Grade 4 reactions, stop infusion and permanently discontinue KEYTRUDA.

Complications of Allogeneic Hematopoietic Stem Cell Transplantation (HSCT)

Fatal and other serious complications can occur in patients who receive allogeneic HSCT before or after anti–PD-1/PD-L1 treatments. Transplant-related complications include hyperacute graft-versus-host disease (GVHD), acute and chronic GVHD, hepatic veno-occlusive disease after reduced intensity conditioning, and steroid-requiring febrile syndrome (without an identified infectious cause).

Contacts

Media:

Julie Cunningham

(617) 519-6264

John Infanti

(609) 500-4714

Investor:

Peter Dannenbaum

(908) 740-1037

Damini Chokshi

(908) 740-1807

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