Merck’s KEYTRUDA® (pembrolizumab) Plus Chemotherapy Demonstrated Statistically Significant Improvement in Progression-Free Survival Versus Chemotherapy in Certain Patients with Metastatic Triple-Negative Breast Cancer
May 13, 2020Data from Pivotal Phase 3 Trial Showed KEYTRUDA Plus Chemotherapy Reduced the Risk of Disease Progression or Death by 35% Compared to Chemotherapy Alone as First-Line Treatment in Patients with Metastatic TNBC Whose Tumors Expressed PD-L1 (CPS ≥10)
KENILWORTH, N.J.–(BUSINESS WIRE)–$MRK #MRK–Merck (NYSE: MRK), known as MSD outside the United States and Canada, today announced positive results from the Phase 3 KEYNOTE-355 trial investigating KEYTRUDA, Merck’s anti-PD-1 therapy, in combination with chemotherapy as first-line treatment in patients with metastatic triple-negative breast cancer (mTNBC). In patients whose tumors expressed PD-L1 with Combined Positive Score (CPS) ≥10, KEYTRUDA plus chemotherapy demonstrated a statistically significant and clinically meaningful improvement in progression-free survival (PFS), reducing the risk of disease progression or death by 35% (HR = 0.65 [95% CI, 0.49-0.86], p=0.0012) and improving PFS to a median of 9.7 months compared to 5.6 months for those receiving chemotherapy alone. In patients whose tumors expressed PD-L1 with CPS ≥1, KEYTRUDA plus chemotherapy improved PFS versus chemotherapy alone (median PFS = 7.6 months versus 5.6 months; HR = 0.74 [95% CI, 0.61-0.90], p=0.0014), however these results did not meet statistical significance. As previously announced, the trial will continue without changes to evaluate the other dual primary endpoint of overall survival (OS).
“The progression-free survival results observed in KEYNOTE-355 have the potential to impart real change for certain patients with metastatic triple-negative breast cancer in the first-line setting,” said Dr. Roy Baynes, senior vice president and head of global clinical development, chief medical officer, Merck Research Laboratories. “Merck is committed to evaluating innovative treatment approaches, anchored by KEYTRUDA, across multiple settings and stages of breast cancer. We are encouraged by the positive results from the Phase 3 KEYNOTE-355 and neoadjuvant/adjuvant KEYNOTE-522 studies, which demonstrate the potential of KEYTRUDA in combination with chemotherapy for the treatment of triple-negative breast cancer.”
“There is a significant need for treatment regimens that can help women with metastatic triple-negative breast cancer, an aggressive disease,” said Dr. Javier Cortes, Head Breast Cancer program, IOB Institute of Oncology, Quironsalud Group. “The results of this study, demonstrate that if approved, KEYTRUDA in combination with chemotherapy may offer certain women a new option for first-line treatment.”
These results are being presented as an oral abstract session of the virtual scientific program of the 2020 American Society of Clinical Oncology (ASCO) Annual Meeting (Abstract #1000). As announced, more than 80 abstracts in nearly 20 types of solid tumors and blood cancers will be presented from Merck’s broad oncology portfolio and investigational pipeline. Follow Merck on Twitter via @Merck and keep up to date with ASCO news and updates by using the hashtag #ASCO20.
The KEYTRUDA breast cancer clinical development program encompasses several internal and external collaborative studies. In addition to KEYNOTE-355, in TNBC these include the ongoing registration-enabling studies KEYNOTE-242 and KEYNOTE-522.
KEYNOTE-355 Study Design and Additional Data (Abstract #1000)
KEYNOTE-355 is a randomized, double-blinded, Phase 3 trial (ClinicalTrials.gov, NCT02819518) evaluating KEYTRUDA in combination with one of three different chemotherapies compared with placebo plus one of the three chemotherapy regimens for the treatment of locally recurrent inoperable or mTNBC that has not been previously treated with chemotherapy in the metastatic setting. The dual primary endpoints are PFS and OS in patients whose tumors expressed PD-L1 (CPS ≥1 and CPS ≥10) and in all participants (intention-to-treat [ITT] population). The secondary endpoints include objective response rate (ORR), duration of response (DOR), disease control rate (DCR) and safety.
KEYNOTE-355 enrolled 847 patients who were randomized 2:1 to receive KEYTRUDA (200 mg every 3 weeks) plus chemotherapy (investigator’s choice of nab-paclitaxel, paclitaxel or gemcitabine/carboplatin); or placebo plus nab-paclitaxel, paclitaxel or gemcitabine/carboplatin. 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 had tumors expressing PD-L1 with CPS ≥10 (n = 220/566 for KEYTRUDA plus chemotherapy; n = 103/281 for chemotherapy alone).
As of data cut-off for this interim analysis (December 11, 2019), median time from randomization to data cut-off was 25.9 months for KEYTRUDA plus chemotherapy and 26.3 months for chemotherapy alone. KEYTRUDA plus chemotherapy significantly improved PFS versus chemotherapy alone in patients whose tumors expressed PD-L1 with CPS ≥10 (HR = 0.65 [95% CI, 0.49-0.86], p=0.0012). In patients whose tumors expressed PD-L1 with CPS ≥1, statistical significance for KEYTRUDA plus chemotherapy was not met, but KEYTRUDA plus chemotherapy improved PFS in this patient population versus chemotherapy alone (median PFS = 7.6 months versus 5.6 months; HR = 0.74 [95% CI, 0.61-0.90], p=0.0014). PFS was tested using a hierarchical strategy, such that testing was first performed in patients whose tumors expressed PD-L1 with CPS ≥10, then in patients whose tumors expressed PD-L1 with CPS ≥1, with partial alpha from PFS in patients with CPS ≥10 transferred over, and finally in the ITT population. Thus, statistical significance was not tested in the ITT population (median PFS = 7.5 months for KEYTRUDA plus chemotherapy versus 5.6 months for chemotherapy alone; HR = 0.82 [0.69-0.97]).
Safety was consistent with the known profiles of each regimen, and no new safety signals were observed. Treatment-related adverse events (TRAEs) of any grade occurred in 96.3% of patients receiving KEYTRUDA plus chemotherapy (n=562) and 95.0% of patients receiving chemotherapy (n=281). Grade 3-5 TRAEs occurred in 68.1% of patients receiving KEYTRUDA plus chemotherapy and 66.9% of patients receiving chemotherapy. The most common Grade 3-5 TRAEs (occurring in ≥10% of patients) were neutropenia (29.7%), decreased neutrophil count (17.4%) and anemia (16.4%) for KEYTRUDA plus chemotherapy and neutropenia (29.9%), decreased neutrophil count (20.3%), and anemia (14.6%) for chemotherapy. TRAEs resulting in discontinuation of any treatment occurred in 18.1% of patients receiving KEYTRUDA plus chemotherapy and 11.0% of patients receiving chemotherapy. There were two treatment-related deaths in patients receiving KEYTRUDA plus chemotherapy.
Immune-mediated adverse events (AEs) of any grade occurred in 25.6% of patients receiving the KEYTRUDA plus chemotherapy and 6.0% of patients receiving chemotherapy. For patients receiving KEYTRUDA plus chemotherapy, the most common immune-mediated AE (occurring in ≥10% of patients) was hypothyroidism (15.5%). There were no immune-mediated AEs occurring in ≥10% of patients receiving chemotherapy.
Merck Investor Event
Merck will hold a virtual investor event in conjunction with the 2020 ASCO Annual Meeting on Tuesday, June 2 at 2 p.m. ET. Details will be provided at a date closer to the event at http://investors.merck.com/home/default.aspx.
About Triple-Negative Breast Cancer (TNBC)
TNBC is an aggressive type of breast cancer that characteristically has a high recurrence rate within the first five years after diagnosis. While some breast cancers may test positive for estrogen receptor, progesterone receptor or human epidermal growth factor receptor 2 (HER2), TNBC tests negative for all three. As a result, TNBC does not respond to therapies targeting these markers, making it more difficult to treat. Approximately 15-20% of patients with breast cancer are diagnosed with TNBC.
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 1,200 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
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.
Small Cell Lung Cancer
KEYTRUDA is indicated for the treatment of patients with metastatic small cell lung cancer (SCLC) with disease progression on or after platinum-based chemotherapy and at least 1 other prior line of 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 confirmatory trials.
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 head and neck squamous cell carcinoma (HNSCC) with disease progression on or after platinum-containing chemotherapy.
Classical Hodgkin Lymphoma
KEYTRUDA is indicated for the treatment of adult and pediatric patients with refractory classical Hodgkin lymphoma (cHL), or who have relapsed after 3 or more prior lines of 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.
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. 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 confirmatory trials. 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 [combined positive score (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 (MSI-H) 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.
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).
Selected Important Safety Information for KEYTRUDA
Immune-Mediated Pneumonitis
KEYTRUDA can cause immune-mediated pneumonitis, including fatal cases. Pneumonitis occurred in 3.4% (94/2799) of patients with various cancers receiving KEYTRUDA, including Grade 1 (0.8%), 2 (1.3%), 3 (0.9%), 4 (0.3%), and 5 (0.1%). Pneumonitis occurred in 8.2% (65/790) of NSCLC patients receiving KEYTRUDA as a single agent, including Grades 3-4 in 3.2% of patients, and occurred more frequently in patients with a history of prior thoracic radiation (17%) compared to those without (7.7%). Pneumonitis occurred in 6% (18/300) of HNSCC patients receiving KEYTRUDA as a single agent, including Grades 3-5 in 1.6% of patients, and occurred in 5.4% (15/276) of patients receiving KEYTRUDA in combination with platinum and FU as first-line therapy for advanced disease, including Grades 3-5 in 1.5% of patients.
Monitor patients for signs and symptoms of pneumonitis. Evaluate suspected pneumonitis with radiographic imaging. Administer corticosteroids for Grade 2 or greater pneumonitis. Withhold KEYTRUDA for Grade 2; permanently discontinue KEYTRUDA for Grade 3 or 4 or recurrent Grade 2 pneumonitis.
Immune-Mediated Colitis
KEYTRUDA can cause immune-mediated colitis. Colitis occurred in 1.7% (48/2799) of patients receiving KEYTRUDA, including Grade 2 (0.4%), 3 (1.1%), and 4 (<0.1%). Monitor patients for signs and symptoms of colitis. Administer corticosteroids for Grade 2 or greater colitis. Withhold KEYTRUDA for Grade 2 or 3; permanently discontinue KEYTRUDA for Grade 4 colitis.
Immune-Mediated Hepatitis (KEYTRUDA) and Hepatotoxicity (KEYTRUDA in Combination With Axitinib)
Immune-Mediated Hepatitis
KEYTRUDA can cause immune-mediated hepatitis. Hepatitis occurred in 0.7% (19/2799) of patients receiving KEYTRUDA, including Grade 2 (0.1%), 3 (0.4%), and 4 (<0.1%). Monitor patients for changes in liver function. Administer corticosteroids for Grade 2 or greater hepatitis and, based on severity of liver enzyme elevations, withhold or discontinue KEYTRUDA.
Hepatotoxicity in Combination With Axitinib
KEYTRUDA in combination with axitinib can cause hepatic toxicity with higher than expected frequencies of Grades 3 and 4 ALT and AST elevations compared to KEYTRUDA alone. With the combination of KEYTRUDA and axitinib, Grades 3 and 4 increased ALT (20%) and increased AST (13%) were seen. Monitor liver enzymes before initiation of and periodically throughout treatment. Consider more frequent monitoring of liver enzymes 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.
Immune-Mediated Endocrinopathies
KEYTRUDA can cause adrenal insufficiency (primary and secondary), hypophysitis, thyroid disorders, and type 1 diabetes mellitus. Adrenal insufficiency occurred in 0.8% (22/2799) of patients, including Grade 2 (0.3%), 3 (0.3%), and 4 (<0.1%). Hypophysitis occurred in 0.6% (17/2799) of patients, including Grade 2 (0.2%), 3 (0.3%), and 4 (<0.1%). Hypothyroidism occurred in 8.5% (237/2799) of patients, including Grade 2 (6.2%) and 3 (0.1%). The incidence of new or worsening hypothyroidism was higher in 1185 patients with HNSCC (16%) receiving KEYTRUDA, as a single agent or in combination with platinum and FU, including Grade 3 (0.3%) hypothyroidism. Hyperthyroidism occurred in 3.4% (96/2799) of patients, including Grade 2 (0.8%) and 3 (0.1%), and thyroiditis occurred in 0.6% (16/2799) of patients, including Grade 2 (0.3%). Type 1 diabetes mellitus, including diabetic ketoacidosis, occurred in 0.2% (6/2799) of patients.
Monitor patients for signs and symptoms of adrenal insufficiency, hypophysitis (including hypopituitarism), thyroid function (prior to and periodically during treatment), and hyperglycemia. For adrenal insufficiency or hypophysitis, administer corticosteroids and hormone replacement as clinically indicated. Withhold KEYTRUDA for Grade 2 adrenal insufficiency or hypophysitis and withhold or discontinue KEYTRUDA for Grade 3 or Grade 4 adrenal insufficiency or hypophysitis. Administer hormone replacement for hypothyroidism and manage hyperthyroidism with thionamides and beta-blockers as appropriate. Withhold or discontinue KEYTRUDA for Grade 3 or 4 hyperthyroidism. Administer insulin for type 1 diabetes, and withhold KEYTRUDA and administer antihyperglycemics in patients with severe hyperglycemia.
Immune-Mediated Nephritis and Renal Dysfunction
KEYTRUDA can cause immune-mediated nephritis. Nephritis occurred in 0.3% (9/2799) of patients receiving KEYTRUDA, including Grade 2 (0.1%), 3 (0.1%), and 4 (<0.1%) nephritis. Nephritis occurred in 1.7% (7/405) of patients receiving KEYTRUDA in combination with pemetrexed and platinum chemotherapy. Monitor patients for changes in renal function. Administer corticosteroids for Grade 2 or greater nephritis. Withhold KEYTRUDA for Grade 2; permanently discontinue for Grade 3 or 4 nephritis.
Immune-Mediated Skin Reactions
Immune-mediated rashes, including Stevens-Johnson syndrome (SJS), toxic epidermal necrolysis (TEN) (some cases with fatal outcome), exfoliative dermatitis, and bullous pemphigoid, can occur. Monitor patients for suspected severe skin reactions and based on the severity of the adverse reaction, withhold or permanently discontinue KEYTRUDA and administer corticosteroids. For signs or symptoms of SJS or TEN, withhold KEYTRUDA and refer the patient for specialized care for assessment and treatment. If SJS or TEN is confirmed, permanently discontinue KEYTRUDA.
Other Immune-Mediated Adverse Reactions
Immune-mediated adverse reactions, which may be severe or fatal, can occur in any organ system or tissue in patients receiving KEYTRUDA and may also occur after discontinuation of treatment. For suspected immune-mediated adverse reactions, ensure adequate evaluation to confirm etiology or exclude other causes. Based on the severity of the adverse reaction, withhold KEYTRUDA and administer corticosteroids. Upon improvement to Grade 1 or less, initiate corticosteroid taper and continue to taper over at least 1 month. Based on limited data from clinical studies in patients whose immune-related adverse reactions could not be controlled with corticosteroid use, administration of other systemic immunosuppressants can be considered.
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