Class Name(s):

• 8:18.24 Monoclonal Antibodies

Brand Name(s):

• Keytruda Qlex^®

WHY is this medicine prescribed?

Pembrolizumab and berahyaluronidase alfa-pmph injection is used treat a variety of solid tumors and soft tissue cancers. Pembrolizumab injection is in a class of medications called monoclonal antibodies. It works by helping your immune system to slow or stop the growth of cancer cells. Berahyaluronidase alfa-pmph is an endoglycosidase. It helps to keep pembrolizumab in the body longer so that the medication will have a greater effect.

HOW should this medicine be used?

Pembrolizumab and berahyaluronidase alfa-pmph comes as a liquid to be injected subcutaneously (just under the skin) by a doctor or nurse. It is injected into the thigh or stomach over 1 to 2 minutes once every 3 or 6 weeks. The time between your injections and the length of your treatment will depend on your condition and how well your body responds to treatment.

Pembrolizumab and berahyaluronidase alfa-pmph injection may cause serious reactions during, or shortly after your receive the injection. If you experience any of the following symptoms, tell your doctor immediately: flushing; fever; chills; shaking; dizziness; feeling faint; shortness of breath; swelling of the eyes, face, lips, tongue, or throat; difficulty breathing or swallowing; back pain itching; rash; or hives.

Your doctor may temporarily or permanently stop your treatment. This depends on how well the medication works for you and the side effects you experience. Be sure to tell your doctor how you are feeling during your treatment with pembrolizumab and berahyaluronidase alfa-pmph injection.

You will be given the Medication Guide. Read the information carefully and ask your doctor or pharmacist if you have any questions. You can also visit http://www.fda.gov/Drugs/DrugSafety/ucm085729.htm to obtain the Medication Guide.

Are there OTHER USES for this medication?

This medication may be prescribed for other uses; ask your doctor or pharmacist for more information.

What SPECIAL PRECAUTIONS should I follow?

Before receiving pembrolizumab and berahyaluronidase alfa-pmph injection,

• tell your doctor or pharmacist if you are allergic to this medication, any part of this medication, or any other medications, foods or substances. Tell your doctor or pharmacist about the allergy and what symptoms you had.
• tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take.
• tell your doctor if you have received or plan to receive a stem cell transplant that uses donor stem cells (allogeneic) or if you have ever had an organ transplant, including corneal transplant, or had radiation therapy to your chest area. Also tell your doctor if you have or have ever had an autoimmune disease (condition in which the immune system attacks a healthy part of the body) such as Crohn's disease (condition in which the immune system attacks the lining of the digestive tract causing pain, diarrhea, weight loss, and fever), ulcerative colitis (condition which causes swelling and sores in the lining of the colon [large intestine] and rectum), or lupus (condition in which the immune system attacks many tissues and organs including the skin, joints, blood, and kidneys); diabetes; thyroid problems; any type of lung disease or breathing problems; any condition that affects your nervous system such as myasthenia gravis (a disorder of the nervous system that causes muscle weakness) or Guillain-Barre syndrome (weakness, tingling, and possible paralysis due to sudden nerve damage); or kidney or liver disease.
• tell your doctor if you are pregnant or plan to become pregnant. You may need to take a pregnancy test before starting treatment. You should not become pregnant while you are receiving pembrolizumab and berahyaluronidase alfa-pmph injection and for 4 months after your final dose. Talk to your doctor about birth control methods that will work for you. If you become pregnant while receiving pembrolizumab and berahyaluronidase alfa-pmph injection, call your doctor immediately. Pembrolizumab and berahyaluronidase alfa-pmph injection may harm the fetus.
• tell your doctor if you are breastfeeding or plan to breastfeed. You should not breastfeed while receiving pembrolizumab and berahyaluronidase alfa-pmph injection and for 4 months after your final dose.

What SPECIAL DIETARY instructions should I follow?

Unless your doctor tells you otherwise, continue your normal diet.

What should I do IF I FORGET to take a dose?

If you miss an appointment to receive pembrolizumab and berahyaluronidase alfa-pmph injection, call your doctor as soon as possible.

What SIDE EFFECTS can this medicine cause?

Pembrolizumab and berahyaluronidase alfa-pmph injection may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:

• muscle, joint, or bone pain
• extreme tiredness or lack of energy
• nausea
• vomiting
• constipation
• decreased appetite
• stomach pain
• hair loss
• dry eyes

Some side effects can be serious. If you experience any of these symptoms, call your doctor immediately or get emergency medical treatment:

• new or worsening cough, shortness of breath, or chest pain
• diarrhea; stools that are black, tarry, sticky, or contain blood or mucus; or severe abdominal pain
• yellowing of the skin or eyes, pain in upper right part of the stomach, easy bleeding or bruising, severe nausea and vomiting, or dark-colored urine
• tiredness or weakness; feeling cold; fast heartbeat; changes in weight (gain or loss); hair loss; increased sweating; feeling cold; deepening of voice or hoarseness; changes in mood or behavior (decreased sex drive, irritability, or forgetfulness); headaches, including those that are unusual or will not go away; constipation; increased urination; or increased thirst
• rash; itching; blistering or peeling skin; painful sores or ulcers in mouth, nose, throat, or genital area; fever or flu-like symptoms; or swollen glands
• confusion, sleepiness, memory problems, stiff neck, balance problems, or tingling and weakness in the arms or legs
• chest pain, shortness of breath, irregular heartbeat, or swelling of ankles
• persistent muscle weakness, pain, or cramping
• dizziness, lightheadedness, or fainting
• decreased urination; blood in urine; swelling of feet, ankles, or lower legs; or decreased urination
• changes in vision, including sensitivity to light, double vision, blurry vision, or eye pain

Pembrolizumab and berahyaluronidase alfa-pmph injection may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.

If you experience a serious side effect, you or your doctor may send a report to the Food and Drug Administration's (FDA) MedWatch Adverse Event Reporting program online (http://www.fda.gov/Safety/MedWatch) or by phone (1-800-332-1088).

What should I do in case of OVERDOSE?

In case of overdose, call the poison control helpline at 1-800-222-1222. Information is also available online at http://www.poisonhelp.org/help. If the victim has collapsed, had a seizure, has trouble breathing, or can't be awakened, immediately call emergency services at 911.

What OTHER INFORMATION should I know?

Keep all appointments with your doctor and the laboratory. Your doctor will order certain lab tests to check your body's response to pembrolizumab and berahyaluronidase alfa-pmph injection. For some conditions, your doctor will order a lab test before you begin your treatment to see whether your cancer can be treated with pembrolizumab and berahyaluronidase alfa-pmph.

Keep a written list of all of the prescription and nonprescription (over-the-counter) medicines, vitamins, minerals, and dietary supplements you are taking. Bring this list with you each time you visit a doctor or if you are admitted to the hospital. You should carry the list with you in case of emergencies.

This report on medications is for your information only, and is not considered individual patient advice. Because of the changing nature of drug information, please consult your physician or pharmacist about specific clinical use.

The American Society of Health-System Pharmacists, Inc. represents that the information provided hereunder was formulated with a reasonable standard of care, and in conformity with professional standards in the field. The American Society of Health-System Pharmacists, Inc. makes no representations or warranties, express or implied, including, but not limited to, any implied warranty of merchantability and/or fitness for a particular purpose, with respect to such information and specifically disclaims all such warranties. Users are advised that decisions regarding drug therapy are complex medical decisions requiring the independent, informed decision of an appropriate health care professional, and the information is provided for informational purposes only. The entire monograph for a drug should be reviewed for a thorough understanding of the drug's actions, uses and side effects. The American Society of Health-System Pharmacists, Inc. does not endorse or recommend the use of any drug. The information is not a substitute for medical care.

AHFS^® Patient Medication Information™ Copyright, 2026. The American Society of Health-System Pharmacists^®, 4500 East-West Highway, Suite 900, Bethesda, Maryland. All Rights Reserved. Duplication for commercial use must be authorized by ASHP.

Selected Revisions: December 15, 2025.