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FDA Approves Merck’s Keytruda (pembrolizumab) Combined With Trastuzumab and Chemotherapy as First-line Treatment in Locally Advanced Unresectable or Metastatic HER2-Positive Gastric or Gastroesophageal Junction Adenocarcinoma

KENILWORTH, N.J.--(BUSINESS WIRE) May 5, 2021-- Merck (NYSE: MRK), known as MSD outside the United States and Canada, today announced that the U.S. Food and Drug Administration (FDA) has approved Keytruda, Merck’s anti-PD-1 therapy, in combination with trastuzumab, fluoropyrimidine- and platinum-containing chemotherapy, 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. This approval is based on data from the ongoing Phase 3 KEYNOTE-811 trial, in which Keytruda in combination with trastuzumab and either 5-fluorouracil plus cisplatin or capecitabine plus oxaliplatin demonstrated a statistically significant objective response rate (ORR) of 74% (95% CI, 66-82) for patients who received the regimen with Keytruda versus 52% (95% CI, 43-61) for those who received trastuzumab and chemotherapy alone (p<0.0001). For patients who received the regimen with Keytruda, the complete response rate was 11% and the partial response rate was 63%. For patients who received trastuzumab and chemotherapy alone, the complete response rate was 3.1% and the partial response rate was 49%.

Immune-mediated adverse reactions, which may be severe or fatal, can occur in any organ system or tissue and can affect more than one body system simultaneously. Immune-mediated adverse reactions can occur at any time during or after treatment with Keytruda, including pneumonitis, colitis, hepatitis, endocrinopathies, nephritis, dermatologic reactions, solid organ transplant rejection, and complications of allogeneic hematopoietic stem cell transplantation. Important immune-mediated adverse reactions listed here may not include all possible severe and fatal immune-mediated adverse reactions. Early identification and management of immune-mediated adverse reactions are essential to ensure safe use of Keytruda. Based on the severity of the adverse reaction, Keytruda should be withheld or permanently discontinued and corticosteroids administered if appropriate. Keytruda can also cause severe or life-threatening infusion-related reactions. Based on its mechanism of action, Keytruda can cause fetal harm when administered to a pregnant woman. For more information, see “Selected Important Safety Information” below.

“Today’s approval marks an important milestone, as this is the first time an anti-PD-1 therapy has been approved in combination with anti-HER2 therapy and chemotherapy as a first-line treatment for these patients,” said Dr. Roy Baynes, senior vice president and head of global clinical development, chief medical officer, Merck Research Laboratories. “From the start of Keytruda’s development, we have thoughtfully pursued novel combinations to help more patients with cancer. We are pleased to bring a new first-line combination regimen with Keytruda that has shown meaningful improvement in ORR over standard treatment to patients with HER2-positive gastric and GEJ cancer.”

This submission was reviewed under the FDA’s Real-Time Oncology Review (RTOR) pilot program.

Data Supporting the Approval

The approval was based on data from KEYNOTE-811 (ClinicalTrials.gov, NCT03615326), a multicenter, randomized, double-blind, placebo-controlled trial that was designed to enroll 692 patients with HER2-positive advanced gastric or GEJ adenocarcinoma who had not previously received systemic therapy for metastatic disease. Randomization was stratified by PD‑L1 expression (Combined Positive Score [CPS] ≥1 or CPS <1), chemotherapy regimen (5-fluorouracil [5-FU] plus cisplatin [FP regimen] or capecitabine plus oxaliplatin [CAPOX regimen]), and geographic region (Europe/Israel/North America/Australia, Asia or Rest of the World). Patients were randomized (1:1) to receive one of the following treatment arms:

  • Keytruda 200 mg, trastuzumab 8 mg/kg on first infusion and 6 mg/kg in subsequent cycles, followed by investigator’s choice of combination chemotherapy of cisplatin 80 mg/m2 for up to six cycles and 5-FU 800 mg/m2/day for five days (FP) or oxaliplatin 130 mg/m2 up to six to eight cycles and capecitabine 1,000 mg/m2 bid for 14 days (CAPOX). Keytruda was administered prior to trastuzumab and chemotherapy on Day 1 of each cycle; or
  • Placebo, trastuzumab, followed by investigator’s choice of chemotherapy regimen: FP regimen or CAPOX regimen, dosed as above

All study medications, except oral capecitabine, were administered as an intravenous infusion for every three-week cycle. Treatment with Keytruda continued until RECIST v1.1‑defined progression of disease as determined by blinded independent central review (BICR), unacceptable toxicity or a maximum of 24 months. In an interim efficacy analysis, major outcome measures assessed were ORR and duration of response (DOR) by BICR using RECIST v1.1, modified to follow a maximum of 10 target lesions and a maximum of five target lesions per organ.

At the time of the interim analysis, ORR and DOR were assessed in the first 264 patients randomized. Among the 264 patients, the population characteristics were: median age of 62 years (range, 19 to 84), 41% age 65 or older; 82% male; 63% white, 31% Asian and 0.8% Black; 47% Eastern Cooperative Oncology Group (ECOG) performance status (PS) of 0, and 53% ECOG PS of 1. Ninety-seven percent of patients had metastatic disease (stage IV), and 3% had locally advanced unresectable disease. Eighty-seven percent had tumors that expressed PD‑L1 with a CPS ≥1. Ninety-one percent (n=240) had tumors that were not microsatellite instability-high (MSI‑H), 1% (n=2) had tumors that were MSI‑H, and in 8% (n=22), the status was not known. Eighty-seven percent of patients received CAPOX.

A statistically significant improvement in ORR was demonstrated in patients randomized to KEYTRUDA in combination with trastuzumab and chemotherapy compared with placebo in combination with trastuzumab and chemotherapy. Efficacy results showed:

Endpoint

KEYTRUDA + Trastuzumab
+ Fluoropyrimidine and
Platinum Chemotherapy
(n=133)

Placebo + Trastuzumab +
Fluoropyrimidine and
Platinum Chemotherapy
(n=131)

ORR

ORR* (95% CI)

74% (66, 82)

52% (43, 61)

Complete response rate

11%

3.1%

Partial response rate

63%

49%

p-value

<0.0001

DOR

n=99

n=68

Median in months (range)

10.6 (1.1+, 16.5+)

9.5 (1.4+, 15.4+)

% with duration ≥ 6 months

65%

53%

* Response: Best objective response as confirmed complete response or partial response

p-value based on stratified Miettinen and Nurminen method (compared to an alpha boundary of 0.002)


The safety analysis of the study included 217 patients with HER2-positive gastric cancer who received Keytruda 200 mg, trastuzumab, and CAPOX (n=189) or FP (n=28) every three weeks, compared to 216 patients who received placebo, trastuzumab, and CAPOX (n=187) or FP (n=29) every three weeks. The median duration of exposure to Keytruda was 5.8 months (range, 1 day to 17.7 months). Keytruda and placebo were discontinued due to adverse reactions in 6% of patients in each arm. The most common adverse reaction resulting in permanent discontinuation of Keytruda was pneumonitis (1.4%). Adverse reactions leading to interruption of Keytruda occurred in 58% of patients; the most common adverse reactions or laboratory abnormalities leading to interruption of Keytruda (≥2%) were neutropenia (18%), thrombocytopenia (12%), diarrhea (6%), anemia (3.7%), hypokalemia (3.7%), fatigue/asthenia (3.2%), decreased appetite (3.2%), increased aspartate aminotransferase (AST) (2.8%), increased blood bilirubin (2.8%), pneumonia (2.8%), increased alanine aminotransferase (ALT) (2.3%) and vomiting (2.3%).

In the Keytruda arm versus placebo, there was a difference of ≥5% in the incidence between patients treated with Keytruda versus standard of care for diarrhea (53% vs. 44%) and nausea (49% vs. 44%). There were no clinically meaningful differences in the incidence of Grade 3-4 toxicity between the two arms.

There was a difference of ≥5% in the incidence between patients treated with Keytruda versus standard of care for increased ALT (34% vs. 29%) and increased creatinine (20% vs. 10%). There were no clinically meaningful differences in the incidence of Grade 3-4 toxicity between the two arms.

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 1,400 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 cisplatin-containing chemotherapy and whose tumors express PD-L1 (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 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, 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.

Microsatellite Instability-High or Mismatch Repair Deficient Colorectal Cancer

Keytruda is indicated for the first-line treatment of patients with unresectable or metastatic MSI-H or dMMR colorectal cancer (CRC).

Gastric Carcinoma

Keytruda, in combination with trastuzumab, and 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.

Keytruda, as a single agent, 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 Carcinoma

Keytruda is indicated for the treatment of patients with locally advanced or metastatic esophageal or gastroesophageal junction (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 Carcinoma

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).

Tumor Mutational Burden-High

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) that is not curable by surgery or radiation.

Triple-Negative Breast Cancer

Keytruda, in combination with chemotherapy, is indicated for the treatment of patients with locally recurrent unresectable or metastatic triple-negative breast cancer (TNBC) whose tumors express PD-L1 (CPS ≥10) as determined by an FDA-approved test. This indication is approved under accelerated approval based on progression-free survival. Continued approval for this indication may be contingent upon verification and description of clinical benefit in the confirmatory trials.

Merck’s Focus on Cancer

Our goal is to translate breakthrough science into innovative oncology medicines to help people with cancer worldwide. At Merck, the potential to bring new hope to people with cancer drives our purpose and supporting accessibility to our cancer medicines is our commitment. As part of our focus on cancer, Merck is committed to exploring the potential of immuno-oncology with one of the largest development programs in the industry across more than 30 tumor types. We also continue to strengthen our portfolio through strategic acquisitions and are prioritizing the development of several promising oncology candidates with the potential to improve the treatment of advanced cancers. For more information about our oncology clinical trials, visit www.merck.com/clinicaltrials.

About the Merck Access Program for Keytruda

At Merck, we are committed to supporting accessibility to our cancer medicines. Merck provides multiple programs to help appropriate patients who are prescribed Keytruda have access to our anti-PD-1 therapy. The Merck Access Program provides reimbursement support for patients receiving KEYTRUDA, including information to help with out-of-pocket costs and co-pay assistance for eligible patients. More information is available by calling 855-257-3932 or visiting www.merckaccessprogram-keytruda.com.

About Merck’s Patient Support Program for Keytruda

Merck is committed to helping provide patients and their caregivers support throughout their treatment with KEYTRUDA. The KEY+YOU Patient Support Program provides a range of resources and support. For further information and to sign up, eligible patients may call 85-KEYTRUDA (855-398-7832) or visit www.keytruda.com.

About Merck

For 130 years, Merck, known as MSD outside of the United States and Canada, has been inventing for life, bringing forward medicines and vaccines for many of the world’s most challenging diseases in pursuit of our mission to save and improve lives. We demonstrate our commitment to patients and population health by increasing access to health care through far-reaching policies, programs and partnerships. Today, Merck continues to be at the forefront of research to prevent and treat diseases that threaten people and animals – including cancer, infectious diseases such as HIV and Ebola, and emerging animal diseases – as we aspire to be the premier research-intensive biopharmaceutical company in the world. For more information, visit www.merck.com and connect with us on Twitter, Facebook, Instagram, YouTube and LinkedIn.

Forward-Looking Statement of Merck & Co., Inc., Kenilworth, N.J., USA

This news release of Merck & Co., Inc., Kenilworth, N.J., USA (the “company”) includes “forward-looking statements” within the meaning of the safe harbor provisions of the U.S. Private Securities Litigation Reform Act of 1995. These statements are based upon the current beliefs and expectations of the company’s management and are subject to significant risks and uncertainties. There can be no guarantees with respect to pipeline products that the products will receive the necessary regulatory approvals or that they will prove to be commercially successful. If underlying assumptions prove inaccurate or risks or uncertainties materialize, actual results may differ materially from those set forth in the forward-looking statements.

Risks and uncertainties include but are not limited to, general industry conditions and competition; general economic factors, including interest rate and currency exchange rate fluctuations; the impact of the global outbreak of novel coronavirus disease (COVID-19); the impact of pharmaceutical industry regulation and health care legislation in the United States and internationally; global trends toward health care cost containment; technological advances, new products and patents attained by competitors; challenges inherent in new product development, including obtaining regulatory approval; the company’s ability to accurately predict future market conditions; manufacturing difficulties or delays; financial instability of international economies and sovereign risk; dependence on the effectiveness of the company’s patents and other protections for innovative products; and the exposure to litigation, including patent litigation, and/or regulatory actions.

The company undertakes no obligation to publicly update any forward-looking statement, whether as a result of new information, future events or otherwise. Additional factors that could cause results to differ materially from those described in the forward-looking statements can be found in the company’s 2020 Annual Report on Form 10-K and the company’s other filings with the Securities and Exchange Commission (SEC) available at the SEC’s Internet site (www.sec.gov).

Please see Prescribing Information for KEYTRUDA (pembrolizumab) at http://www.merck.com/product/usa/pi_circulars/k/keytruda/keytruda_pi.pdf and Medication Guide for KEYTRUDA at http://www.merck.com/product/usa/pi_circulars/k/keytruda/keytruda_mg.pdf.

Source: Merck & Co., Inc.
 

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