RAHWAY, N.J.--(BUSINESS WIRE)-- Merck (NYSE: MRK), known as MSD outside the United States and Canada, today announced that the Phase 3 KEYNOTE-412 trial evaluating KEYTRUDA® (pembrolizumab), Merck’s anti-PD-1 therapy, with concurrent chemoradiation therapy (CRT) followed by KEYTRUDA as maintenance therapy (the KEYTRUDA regimen), did not meet its primary endpoint of event-free survival (EFS) for the treatment of patients with unresected locally advanced head and neck squamous cell carcinoma (HNSCC). At the final analysis of the study, there was an improvement in EFS for patients who received the KEYTRUDA regimen compared to placebo plus CRT; however, these results did not meet statistical significance per the pre-specified statistical plan. The safety profile of KEYTRUDA in this trial was consistent with previously reported studies in HNSCC. Results will be presented at an upcoming medical meeting.

“There have been limited advances for patients with locally advanced HNSCC, and unfortunately, these results suggest that this disease remains very challenging to treat,” said Dr. Eliav Barr, senior vice president, head of global clinical development and chief medical officer, Merck Research Laboratories. “We are proud of the significant role KEYTRUDA plays in the treatment of certain later stages of HNSCC, and we are committed to investigating KEYTRUDA-based regimens for this debilitating type of cancer in earlier stages of disease. We are grateful to the patients and investigators for their participation in this study.”

KEYTRUDA is currently approved as monotherapy and in combination regimens for appropriate patients with metastatic or with unresectable, recurrent HNSCC in the U.S., Europe, China, Japan and other countries around the world. Merck currently has the largest immuno-oncology clinical development program in HNSCC and is continuing to advance multiple registration-enabling studies investigating KEYTRUDA as monotherapy and in combination with other medicines, including KEYNOTE-689 for the neoadjuvant and adjuvant treatment of resectable locally advanced HNSCC.

About KEYNOTE-412 KEYNOTE-412 is a randomized, double-blind Phase 3 trial (ClinicalTrials.gov, NCT03040999) evaluating KEYTRUDA with concurrent CRT, followed by KEYTRUDA as maintenance therapy for the treatment of patients with unresected locally advanced HNSCC. The primary endpoint was EFS, and the secondary endpoints included overall survival and safety. The trial enrolled an estimated 780 newly diagnosed adults with oropharyngeal or larynx/hypopharynx/oral cavity squamous cell carcinoma who were randomized to receive KEYTRUDA (200 mg every three weeks) in combination with CRT (cisplatin plus radiation), followed by KEYTRUDA as maintenance therapy for approximately one year, or placebo plus cisplatin and CRT, followed by placebo.

About head and neck cancer Head and neck cancer describes a number of different tumors that develop in or around the throat, larynx, nose, sinuses and mouth. Most head and neck cancers are squamous cell carcinomas that begin in the flat, squamous cells that make up the thin surface layer of the structures in the head and neck. There are several factors that greatly increase the risk of developing head and neck cancer, including tobacco and alcohol use and human papillomavirus (HPV). It is estimated there were more than 930,000 new cases of head and neck cancer diagnosed and over 465,000 deaths from the disease in 2020 globally. In the U.S., it is estimated there will be more than 66,000 new cases of head and neck cancer diagnosed and more than 15,000 deaths from the disease in 2022.

About Merck’s early-stage cancer clinical program Finding cancer at an earlier stage may give patients a greater chance of long-term survival. Many cancers are considered most treatable and potentially curable in their earliest stage of disease. Building on the strong understanding of the role of KEYTRUDA in later-stage cancers, Merck is studying KEYTRUDA in earlier disease states, with approximately 20 ongoing registrational studies across multiple types of cancer.

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 1,700 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.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.

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.

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 (