Keytruda Qlex is a new form of pembrolizumab, a cancer-fighting lab-made antibody that helps your immune system find and attack cancer cells. Unlike the original 30-minute intravenous (IV) drip, the Keytruda Qlex shot is a quick injection given under the skin in your thigh or belly by your health care provider in one to two minutes.
This new option includes another ingredient called berahyaluronidase alfa, which improves the medicine's absorption and spread, allowing Keytruda to be given as a swift injection under the skin. The FDA has approved this medicine for use in adults and teens age 12 years or older for most of the same cancers that are treated by its IV option. These include non-small-cell lung cancer, melanoma, kidney cancer, bladder cancer, endometrial cancer, triple-negative breast cancer, certain types of colorectal cancer, and cervical cancer.
This is the first time a medicine in this class – an immune checkpoint inhibitor – has been approved for under-the-skin use across so many types of cancer. This new option may make treatment easier for you if you have trouble with IV infusions, hard-to-access veins, or if you want shorter clinic visits. Apart from the ease of taking the medicine, Keytruda Qlex also offers you two dosing options and greater flexibility in where you receive treatment.
Why was it approved?
Keytruda Qlex was approved because it is just as effective and safe as the IV option of pembrolizumab. In a study involving 377 patients with advanced non-small-cell lung cancer and who were getting standard chemotherapy, those who got the under-the-skin Keytruda Qlex shot showed similar results to those who got the IV option (45% and 42% responders, respectively). Also, no major differences in how long people stayed cancer-free and their overall survival were seen between the two groups.
When used alone, common side effects include tiredness, muscle or joint pain, rash, diarrhea, fever, coughing, low appetite, itchiness, and thyroid issues. When combined with chemotherapy or radiation, other side effects may include nausea, constipation, vomiting, nerve problems, infections, mouth sores, trouble sleeping, urinary tract infections, and hair loss. When used with chemotherapy and bevacizumab (another monoclonal antibody), other side effects include low blood cell counts and high blood pressure.
In some people, Keytruda Qlex, alone or along with chemotherapy, may cause serious immune-related side effects, such as inflammation in the lungs, liver, intestines, kidneys, skin, thyroid, and other hormone-producing glands. These reactions can be dangerous, may affect more than one organ at a time, and can happen anytime – during treatment or even after it ends.
What do I need to know?
This medicine is given as a shot under the skin by a health care provider. It can be given either over one minute every three weeks or over two minutes every six weeks, depending on your treatment plan. The shot goes into your thigh or belly, but not too close to your belly button.
This option is not the same as the IV form of pembrolizumab. Because the dose and how it's given are different, you should not switch between them on your own. If you're already getting the IV form, your health care provider may switch you to Keytruda Qlex at your next visit if it's right for you.
You should not get this medicine if you're allergic to any of its ingredients, including berahyaluronidase alfa. Serious immune-related side effects, whose symptoms may include trouble breathing, severe itching, yellow skin or eyes, severe diarrhea, or extreme tiredness, can happen during or after treatment. If you notice any of these symptoms, contact your health care provider right away.
Your health care provider will check your liver, kidney, and thyroid function before and during treatment and will watch for any side effects while giving you the shot. Be sure to tell your health care provider if you have an autoimmune condition, take immune-suppressing medicines, or have had an organ transplant (including a corneal transplant).
This medicine may harm an unborn baby. Let your health care provider know if you are pregnant or plan to become pregnant. If you can become pregnant, use birth control during treatment and for four months after your last dose. You should also avoid breastfeeding for the same duration.
Merck expects Keytruda Qlex to be available in the U.S. by late September 2025.
This content was created using several editorial tools, including AI, as part of the process. Human editors reviewed this content before publication.