First Anti-PD-1 Therapy in Combination With Chemotherapy to Demonstrate Statistically Significant Overall Survival for These Patients
Data From Phase 3 KEYNOTE-355 Trial Presented at ESMO Congress 2021
KENILWORTH, N.J.–(BUSINESS WIRE)–$MRK #MRK–Merck (NYSE: MRK), known as MSD outside the United States and Canada, today announced the final overall survival (OS) results from the pivotal Phase 3 KEYNOTE-355 trial investigating KEYTRUDA, Merck’s anti-PD-1 therapy, in combination with chemotherapy (paclitaxel, nab-paclitaxel or gemcitabine/carboplatin) for the first-line treatment of patients with metastatic triple-negative breast cancer (mTNBC). KEYTRUDA is the first anti-PD-1 therapy in combination with chemotherapy to demonstrate a statistically significant and clinically meaningful improvement in OS for these patients.
In this study, KEYTRUDA plus chemotherapy reduced the risk of death by 27% (HR=0.73 [95% CI, 0.55-0.95]; p=0.0093) in patients with mTNBC whose tumors expressed PD-L1 (Combined Positive Score [CPS] ≥10), as compared to chemotherapy alone. There was an increase of 6.9 months in median OS with KEYTRUDA plus chemotherapy compared to chemotherapy alone (23.0 months [95% CI, 19.0-26.3] vs. 16.1 months [95% CI, 12.6-18.8], respectively). Although the trial was not powered to compare efficacy between treatment groups by different chemotherapy regimens, the increase in OS was observed for KEYTRUDA plus chemotherapy across the three chemotherapy choices. These data were presented today in an oral presentation at the European Society for Medical Oncology (ESMO) Congress 2021 (Abstract #LBA16).
“Metastatic TNBC has the worst survival prognosis among breast cancer subtypes, and there is an urgent need for treatment options that improve survival,” said Dr. Hope Rugo, director, Breast Oncology and Clinical Trials Education, University of California San Francisco (UCSF) Helen Diller Family Comprehensive Cancer Center. “I am very encouraged to see these new overall survival data for the KEYTRUDA combination, demonstrating a 27% relative reduction in the risk of death compared to chemotherapy alone in patients with mTNBC whose tumors expressed PD-L1 (CPS ≥10).”
There was no statistically significant difference in OS between the treatment groups in the CPS ≥1 population; due to statistical testing hierarchy, formal testing was not performed in the intention-to-treat (ITT) population. The incidence of treatment-related adverse events (TRAEs) was similar among patients in the two treatment groups, with Grade 3-5 TRAEs occurring in 68.1% of patients in the KEYTRUDA plus chemotherapy arm and 66.9% of patients in the chemotherapy arm. Treatment-related adverse events led to discontinuation in 18.3% of patients in the KEYTRUDA plus chemotherapy arm and 11.0% of patients in the chemotherapy arm.
“With these new data, KEYNOTE-355 has now met both primary endpoints, improving progression-free and overall survival for the approximately 40% of patients from this trial with metastatic TNBC whose tumors expressed PD-L1 (CPS ≥10),” said Dr. Vicki Goodman, vice president, clinical research, Merck Research Laboratories. “These OS data add to a strong body of evidence evaluating the use of KEYTRUDA plus chemotherapy for appropriate patients with TNBC. We remain committed to continuing to advance scientific understanding in TNBC.”
These OS data follow prior analyses from KEYNOTE-355 that showed KEYTRUDA plus chemotherapy resulted in a statistically significant and clinically meaningful improvement in progression-free survival (PFS) compared with chemotherapy alone for the first-line treatment of patients with mTNBC whose tumors expressed PD-L1 (CPS ≥10) and supported approval of this regimen in the U.S. and Japan. In the U.S., KEYTRUDA was granted accelerated approval by the U.S. Food and Drug Administration in November 2020 and was subsequently granted regular approval in July 2021. In Europe, the Committee for Medicinal Products for Human Use of the European Medicines Agency recently adopted a positive opinion recommending approval of KEYTRUDA in combination with chemotherapy for this patient population.
Merck is rapidly advancing a broad portfolio in gynecologic and breast cancers through an extensive clinical development program for KEYTRUDA and several other investigational and approved medicines across these areas.
A compendium of presentations and posters of Merck-led studies is available here. Follow Merck on Twitter via @Merck, and keep up to date with ESMO news and updates by using the hashtag #ESMO21.
About KEYNOTE-355
KEYNOTE-355 is a randomized, two-part, placebo-controlled Phase 3 trial (ClinicalTrials.gov, NCT02819518) evaluating KEYTRUDA in combination with one of the three different chemotherapies compared with placebo plus one of the three chemotherapy regimens for the first-line treatment of mTNBC that has not been previously treated with chemotherapy in the advanced setting. The study endpoints include OS and PFS in patients whose tumors expressed PD-L1 (CPS ≥1 and CPS ≥10) and in all participants (ITT population). The other endpoints include objective response rate, duration of response, disease control rate, patient-reported outcomes and safety. Part 2 enrolled 847 patients who were randomized 2:1 to receive KEYTRUDA (200 mg every three weeks) plus chemotherapy (investigator’s choice of paclitaxel, nab-paclitaxel or gemcitabine/carboplatin) or placebo plus paclitaxel, nab-paclitaxel or gemcitabine/carboplatin.
The study population characteristics were: median age of 53 years (range, 22 to 85), 21% age 65 or older; 100% female; 68% white, 21% Asian and 4% Black; 59% Eastern Cooperative Oncology Group (ECOG) performance status (PS) of 0, and 41% ECOG PS of 1; and 68% were post-menopausal. Among enrolled patients in each treatment group, approximately 75% had tumors expressing PD-L1 with CPS ≥1 (n=425/566 for KEYTRUDA plus chemotherapy; n=211/281 for chemotherapy alone), and approximately 38% had tumors expressing PD-L1 with CPS ≥10 (n=220/566 for KEYTRUDA plus chemotherapy; n=103/281 for chemotherapy alone).
Immune-mediated adverse reactions (AEs) of any grade occurred in 26.5% of patients receiving KEYTRUDA plus chemotherapy and 6.4% of patients receiving chemotherapy alone. For patients receiving KEYTRUDA plus chemotherapy, the most common immune-mediated AE (occurring in ≥10% of patients) was hypothyroidism (15.8%). There were two treatment-related deaths due to acute kidney injury and pneumonia in patients receiving KEYTRUDA plus chemotherapy; neither was considered immune-mediated.
About Triple-Negative Breast Cancer
Triple-negative breast cancer is a type of breast cancer that tests negative for estrogen hormone receptors, progesterone hormone receptors and overexpression of human epidermal growth factor receptor 2 (HER2). It is an aggressive type of breast cancer that characteristically has a high recurrence rate within the first five years after diagnosis. Approximately 10-15% of patients with breast cancer are diagnosed with TNBC, which tends to be more common in people who are younger than 40 years of age, who are African American or who have a BRCA1 mutation.
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.
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 any platinum-containing chemotherapy, or
- 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-unresponsive, high-risk, non-muscle invasive bladder cancer (NMIBC) with carcinoma in situ 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.
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 treatment of patients with unresectable or metastatic MSI-H or dMMR colorectal cancer (CRC).
Gastric Cancer
KEYTRUDA, in combination with trastuzumab, fluoropyrimidine- and platinum-containing chemotherapy, is indicated for the first-line treatment of patients with locally advanced unresectable or metastatic HER2-positive gastric or gastroesophageal junction (GEJ) adenocarcinoma.
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 locally advanced or metastatic esophageal or GEJ (tumors with epicenter 1 to 5 centimeters above the GEJ) carcinoma that is not amenable to surgical resection or definitive chemoradiation either:
- in combination with platinum- and fluoropyrimidine-based chemotherapy, or
- as a single agent after one or more prior lines of systemic therapy for patients with tumors of squamous cell histology that express PD-L1 (CPS ≥10) as determined by an FDA-approved test.
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 adult patients with advanced renal cell carcinoma.
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] 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.
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.
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.
Contacts
Media Contacts:
Melissa Moody
(215) 407-3536
Andrea Park
(929) 481-2599
Investor Contacts:
Peter Dannenbaum
(908) 740-1037
Raychel Kruper
(908) 740-2107