Merck Halts Keytruda Cancer Trials Due to Reported Adverse Events, Including One Patient Death

While Keytruda is widely used to treat various forms of cancer, studies in recent years have frequently linked the Merck drug to severe side effects.

Merck Halts Keytruda Cancer Trials After Increased Adverse Events, One Patient Death
Martha Garcia

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Two Keytruda clinical trials were ended early, after the study data showed that the drug provides no benefit for the treatment of lung and skin cancer, and increased the risks of potentially serious side effects for the patients.

Merck announced the discontinuation of two phase 3 clinical trials, the KEYNOTE-867 and KEYNOTE-630 on August 29.  In a press release regarding the decision, the pharmaceutical company said the cancer drug failed to prevent a patient’s risk of the cancer worsening and it led to higher rates of adverse health events, including at least one death.

Keytruda is a monoclonal antibody cancer therapy, known as a PD-1 drug, which helps the body’s immune system fight tumor cells. There are currently more than 1,600 trials studying Keytruda for different types of cancers and treatment settings.

The U.S. Food and Drug Administration (FDA) has approved Keytruda for various types of cancer over the years, including lung, head and neck, bladder, colorectal, gastric, esophageal, cervical, kidney, and liver cancer, as well as Hodgkin lymphoma, melanoma and B-cell lymphoma cancers.

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KEYNOTE-867 was designed to test Keytruda combined with radiation for lung cancer, including cases that can’t be operated on. KEYNOTE-630 tested Keytruda for patients with cutaneous squamous cell carcinoma combined with radiation, compared to those undergoing radiation alone.

According to Merck, the interim analysis indicated the benefit-risk profile did not support continuing either trial. The decision was based on the independent review and recommendation from the Data Monitoring Committee.

The early findings indicated Keytruda did not improve a patient’s survival without recurring cancer or overall survival compared to a placebo. In fact, patients had a higher likelihood of experiencing a number of potential Keytruda side effects, including immune-mediated pneumonia, colitis, hepatitis, liver toxicity, endocrine conditions like adrenal insufficiency, inflamed pituitary, thyroid disorders, type 1 diabetes, inflamed kidneys and death.

This isn’t the first data showing Keytruda may lead to serious side effects. In 2018, the FDA added restrictions to the Keytruda warning label, indicating the drug shouldn’t be used for some bladder cancers. The warning indicates it may lower a patient’s chance of survival when used alone.

More recently, a case study published in the New England Journal of Medicine indicated infants may experience severe immune-related enteritis when exposed to Keytruda during pregnancy.

Federal regulators scheduled a panel of outside advisors to meet in September to review data on the side effects and potential restrictions of Keytruda for the treatment of stomach cancer. Patients using Keytruda to treat stomach cancer face a 20% increased risk of death compared to chemotherapy.

Martha Garcia
Written by: Martha Garcia

Health & Medical Research Writer

Martha Garcia is a health and medical research writer at AboutLawsuits.com with over 15 years of experience covering peer-reviewed studies and emerging public health risks. She previously led content strategy at The Blogsmith and contributes original reporting on drug safety, medical research, and health trends impacting consumers.

Tags: Clinical Trials, Hepatitis, Keytruda, Liver Toxicity, Lung Cancer, Merck, Pneumonia, Skin Cancer
Image Credit: Muhammad Alimaki

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10 Comments

Jeffrey
Keytruda was prescribed to me when Merck’s own trials showed it to be not effective against Melanoma. Now I am a type 1 diabetic due to it
Jeff
I was diagnosed with stage 2 melanoma and part of my program after surgery was to do infusions of Keytruda every 3 weeks for a year. After about 12 infusions I developed Type 1 diabetes and am now on insulin 3 times a day. I want to sue
Lissie
My mom was diagnosed in May 2021 she had her first round of chemo along with Keytruda. A treatment went on, she had two more treatment’s. She kept losing blood. They’d have to do blood transfusions . In June they stated completed another treatmenta follow up scan, and it showed that her cancer was shrinking and .and that day the doctor doctor treatments because her breathing was really bad he sent her home with 24 seven oxygen. At that time, the Dr never mentioned to her that the key treat her was a side effect and causing her breathing issues. She was in the hospital from September 30 of 2021 and she passed on October 13 in the hospital under the hospice program but I kept looking and checking and nobody ever got anything..
Debra
I had 2 treatments with Keytruda. In those 6 weeks my body went totally downhill. Vomited constantly, lost half of my hair, lost all my strength. Now my thyroid is gone and my pituitary gland is swollen. See a neurosurgeon next week. Don’t take Keytruda. I had four rounds of chemo with no issues. Two rounds of Keytruda and I thought I was going to die.
Brian
Diagnosed Stage 4 Lung Cancer 5/2024 Started Alternative Cancer treatment 5/2024 at a cost of $16000.00/ month out of pocket. Insurance pays little. Tumors reduced to 1/4 the original size. Ran out of money. Started Conventional treatment 4/2025. Two rounds with Keytruda has left me a Type 1 Diabetic for life. On the cancer sites little is mentioned of the serious side effects. On the Diabetes sites…. It’s everywhere. My Endo figures as high as 8% or more suffer Pancreas burnout like I did. For 7 weeks now my life is nothing but chasing these numbers all day and trying unsuccessfully to stay in range. This is killing my cancer fight and therefore killing me.
Hope
My husband had lung cancer he had some radiation then the Doc decided it was time for chemo, he had 1 treatment of chemo with immunotherapy Keytruda 3 days later his breathing changed, 8 days later I took him to the hospital as his breathing worsened he passed away exactually 2 weeks later from 1 dose!!!
Becky
My husband had 3 21-day treatments of Keytruda beginnning 2/27/2025. March 12 he was hospitalized with severe hypotension that the physicians nor I connected with Keytruda. Second treatment, 3/20 with no other side effects except ongoing hypotension. Third treatment, 4/10. April 14 hospitalized for hemorrhagic stroke. Discharged 4/18 with cognitive and physical deficits. April 24 hospitalized for severe DKA (he had not been diagnosed with diabetes previously) and exacerbation of afib (diagnosed 2010 but successfully treated) with RVR. Discharged 5/2/25 on sliding scale insulin and long acting insulin. I am a pharmacist and have done extensive research on the severe side effects of Keytruda. I am of the opinion, that the serious/life threatening side effects have been seriously downplayed and hidden from the public. I have given up my job as a pharmacist to care for my husband. Keytruda is responsible for life changing impacts on my husband’s life as well as mine. BTW, our oncologist was not even aware of the possibility of hemorrhagic or ischemic strokes with Keytruda. There are articles out there if you know how to search!
Linda
My best bud died after on treatment of Keytruda one year ago.
Jasmine
My husband died after one treatment of Immunotherapy with Keytruda.
Lesli
We have experienced the bad part of Keytruda. Make sure they tell you EVERYTHING before you agree to treatment

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