Merck Announces Findings from Phase 2 KeyVibe-002 Trial Evaluating an Investigational Coformulation of Vibostolimab and Pembrolizumab in Previously Treated Patients with Metastatic Non-Small Cell Lung Cancer (NSCLC)

First Presentation of KeyVibe-002 Results at ESMO I-O 2023 Annual Meeting

RAHWAY, N.J.--(BUSINESS WIRE)--Merck (NYSE: MRK), known as MSD outside of the United States and Canada, today announced full results from the non-registrational Phase 2 KeyVibe-002 trial evaluating vibostolimab/pembrolizumab, an investigational coformulation of vibostolimab, an anti-TIGIT antibody, and pembrolizumab (KEYTRUDA^®), Merck’s anti-PD-1 therapy, with or without docetaxel for the treatment of patients with metastatic non-small cell lung cancer (NSCLC) with progressive disease after treatment with immunotherapy and platinum-doublet chemotherapy. These results are being presented today during a poster session at the 2023 European Society of Medical Oncology (ESMO) Immuno-Oncology (I-O) Annual Congress (abstract #121P).

Data presented at ESMO I-O showed that vibostolimab/pembrolizumab plus docetaxel extended median progression-free survival (PFS) by 2.4 months compared to those treated with docetaxel alone, though the results did not reach statistical significance (5.6 months vs. 3.2 months; HR=0.77 [95% CI, 0.53-1.13]; p=0.0910). Vibostolimab/pembrolizumab alone did not show an improvement in median PFS compared to docetaxel alone (2.7 months vs. 3.2 months; HR=1.40 [95% CI, 0.96-2.02]; p=0.9622).

“This study was designed to evaluate a coformulation of vibostolimab and pembrolizumab in a population of patients who are heavily pre-treated and have progressed following treatment with standard of care therapies, often leaving them with limited treatment options and a poor prognosis,” said Dr. Scot Ebbinghaus, vice president, global clinical development, Merck Research Laboratories. “We will leverage our evolving understanding of novel combinations and coformulations to help inform our comprehensive research program evaluating this coformulation across a wide range of tumor types.”

Data from key secondary endpoints, including overall survival (OS), overall response rate (ORR) and duration of response (DOR) were also presented. Vibostolimab/pembrolizumab plus docetaxel improved OS compared with docetaxel alone, though these results did not reach statistical significance (HR=0.76 [95% CI, 0.50-1.15]). Vibostolimab/pembrolizumab alone did not show an improvement in OS compared to docetaxel alone (HR=1.05 [95% CI, 0.70-1.58). The median OS for vibostolimab/pembrolizumab plus docetaxel was 10.2 months (95% CI, 8.6-14.9), 7.5 months (95% CI, 5.2-13.4) for vibostolimab/pembrolizumab alone and 8.8 months (95% CI, 6.4-11.1) for docetaxel. The ORR for patients receiving vibostolimab/pembrolizumab plus docetaxel was 29.9% (95% CI, 20.5-40.6), 6.0% (95% CI, 2.0-13.5) for vibostolimab/pembrolizumab alone and 15.3% (95% CI, 8.4-24.7) for docetaxel. Median DOR was 6.5 months (range, 2.1+ to 15.4+ months) for the vibostolimab/pembrolizumab plus docetaxel arm. Median DOR was not reached for the vibostolimab/pembrolizumab arm (range, 2.6+ to 6.2+ months) and for the docetaxel arm (range, 1.6 to 11.1+ months).

The safety profile of vibostolimab/pembrolizumab was consistent with that observed for vibostolimab and pembrolizumab in previously reported studies, with no new safety signals observed. Immune-mediated adverse events and infusion reactions occurred in 29.4% of patients who received vibostolimab/pembrolizumab plus docetaxel, 20.5% of those who received vibostolimab/pembrolizumab alone and 12% of those who received docetaxel alone. There were four treatment-related deaths in the vibostolimab/pembrolizumab plus docetaxel arm of the study, and one in each of the vibostolimab/pembrolizumab and docetaxel only arms. In the vibostolimab/pembrolizumab only arm of the study, there was a lower incidence of treatment-related adverse events (TRAEs) of any grade compared to the docetaxel only arm (60.2% vs. 89.2%), and 96.5% of patients in the vibostolimab/pembrolizumab plus docetaxel arm had TRAEs. The most common severe (grade 3-5) TRAEs in the study were neutropenia (16.5%), anemia (7.1%) and asthenia (4.7%) for treatment with vibostolimab/pembrolizumab plus docetaxel; asthenia (2.4%) and diarrhea (2.4%) for vibostolimab/pembrolizumab alone and neutropenia (14.5%) and anemia (6.0%) for docetaxel alone.

Vibostolimab is Merck’s investigational anti-TIGIT antibody that restores antitumor activity by blocking the TIGIT receptor from binding to its ligands (CD112 and CD155), thereby activating T lymphocytes that help destroy tumor cells. Merck has an extensive clinical development program evaluating the safety and efficacy of the vibostolimab/pembrolizumab coformulation alone and in combination with other agents in over 4,000 patients. Ongoing Phase 3 studies in lung cancer include KeyVibe-003, KeyVibe-006, KeyVibe-007 and KeyVibe-008, as well as KeyVibe-010 in melanoma.

About KeyVibe-002

KeyVibe-002 is a randomized, partially blind Phase 2 trial (ClinicalTrials.gov, NCT04725188) evaluating vibostolimab/pembrolizumab, a coformulation of vibostolimab and pembrolizumab, with or without docetaxel versus placebo plus docetaxel in patients with metastatic NSCLC with progressive disease after treatment with immunotherapy and platinum-doublet chemotherapy. The trial’s primary endpoint is PFS, as assessed by blinded independent central review (BICR) per Response Evaluation Criteria in Solid Tumors (RECIST) v1.1. Key secondary endpoints include OS and ORR, as assessed by BICR per RECIST v1.1. The study enrolled 255 patients who were randomly assigned in three separate study arms (1:1:1) to receive either:

• Arm 1 (Blinded): Vibostolimab/pembrolizumab (pembrolizumab 200 mg plus vibostolimab 200 mg/20 mL intravenously [IV] every 3 three weeks [Q3W] until a discontinuation criterion is met or completion of 35 cycles) plus docetaxel (75 mg/m² IV Q3W until a discontinuation criterion is met or as per approved local label); or
• Arm 2 (Open-label): Vibostolimab/pembrolizumab (pembrolizumab 200 mg plus vibostolimab 200 mg/20 mL IV Q3W until a discontinuation criterion is met or completion of 35 cycles); or
• Arm 3 (Placebo-blinded): Placebo (saline IV Q3W) plus docetaxel (75 mg/m² IV Q3W until a discontinuation criterion is met or as per approved local label).

KeyVibe-002, a non-registrational study, was designed with two primary objectives: 1) to evaluate the efficacy of vibostolimab/pembrolizumab alone compared with docetaxel, a standard of care; and 2) in a blinded assessment, evaluate the efficacy of adding vibostolimab/pembrolizumab to docetaxel, compared with docetaxel alone.

About lung cancer

Lung cancer is the leading cause of cancer death worldwide. In 2020 alone, there were more than 2.2 million new cases and approximately 1.8 million deaths from lung cancer globally. Non-small cell lung cancer is the most common type of lung cancer, accounting for about 81% of all cases. In the U.S., the overall five-year survival rate for patients diagnosed with lung cancer is 26.2%, which is a 22% improvement over the last five years. Improved survival rates are due, in part, to advances in diagnostic and surgical procedures, as well as the introduction of new therapies. However, screening, early detection and improving treatment rates remain an important unmet need, as 44% of lung cancer cases are not found until they are advanced. Only 4.5% of people in the U.S. who are eligible were screened for lung cancer in 2022.

About Merck’s research in lung cancer

Merck is advancing research aimed at transforming the way lung cancer is treated, with a goal of improving outcomes for patients affected by this deadly disease. Through nearly 200 clinical trials evaluating more than 36,000 patients around the world, Merck is at the forefront of lung cancer research. In NSCLC, KEYTRUDA has six approved U.S. indications (see indications below) and is approved for advanced disease in more than 95 countries. Among Merck’s research efforts are trials focused on evaluating KEYTRUDA in earlier stages of lung cancer as well as identifying new combinations and coformulations with KEYTRUDA.

About vibostolimab

Vibostolimab is an investigational humanized anti-TIGIT antibody discovered and developed by Merck. Vibostolimab restores antitumor activity by blocking the TIGIT receptor from binding to its ligands (CD112 and CD155), thereby activating T lymphocytes that help destroy tumor cells. Vibostolimab/pembrolizumab is a coformulation of both vibostolimab and pembrolizumab and is being evaluated in a wide range of cancers, including lung, other solid tumors and blood cancers.

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.

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.

KEYTRUDA is indicated for the treatment of patients with resectable (tumors ≥4 cm or node positive) NSCLC in combination with platinum-containing chemotherapy as neoadjuvant treatment, and then continued as a single agent as adjuvant treatment after surgery.

KEYTRUDA, as a single agent, is indicated as adjuvant treatment following resection and platinum-based chemotherapy for adult patients with Stage IB (T2a ≥4 cm), II, or IIIA NSCLC.

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.

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Damini Chokshi
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