On June29, 2020, the U.S. FDA approved Keytruda (pembrolizumab) for intravenous injection for the first-line immunotherapy of patients with metastatic microsatellite instability-high (MSI-H) or mismatch repair deficient (dMMR) colorectal cancer. This marks the first immunotherapy approved for this patient population as a first-line treatment and which is administered to patients without also giving chemotherapy.
MSI-H is short for High levels of MicroSatellite Instability. dMMR stands for deficient MisMatch Repair. MSI-H/dMMR can occur when a cell is unable to repair mistakes made during the division process.
MSI-H and dMMR tumors contain abnormalities that affect the proper repair of DNA inside the cell. The frequency of MSI-H varies across tumor types and stages, and approximately 5% of patients with metastatic colorectal cancer have MSI-H or dMMR tumors.
“Metastatic colorectal cancer is a serious and life-threatening disease with a poor prognosis. Available current therapy with chemotherapy combinations and other biologics are associated with substantial toxicity,” said Richard Pazdur, M.D., director of the FDA’s Oncology Center of Excellence and acting director of the Office of Oncologic Diseases in the FDA’s Center for Drug Evaluation and Research. “Having a non-chemotherapy option available for selected patients is a noteworthy paradigm shift in treatment.”
Keytruda works by targeting the cellular pathway of proteins found on the body’s immune cells and some cancer cells, known as PD-1/PD-L1. By blocking this pathway, Keytruda may help the body’s immune system fight the cancer cells and provide a benefit in patients with MSI-H or dMMR metastatic colorectal cancer. The FDA previously approved Keytruda to treat other types of cancer.
The FDA’s approval for this indication was based on the results of one multicenter, international, open-label, active-controlled, randomized trial that compared Keytruda with chemotherapy treatment in 307 patients with MSI-H or dMMR metastatic colorectal cancer. The study demonstrated a statistically significant improvement in progression-free survival (PFS) as assessed by blinded independent review. Median PFS was 16.5 months in the Keytruda group and 8.2 months in the standard of care group. Longer-term analysis is needed to assess for an effect on survival.
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.
EGFR = epidermal growth factor receptor; ALK = anaplastic lymphoma kinase; PD‑L1 = programmed death ligand 1; HER2/neu = human epidermal growth factor receptor 2.
KEYTRUDA is a medicine that may treat certain cancers by working with your immune system. KEYTRUDA can cause your immune system to attack normal organs and tissues in any area of your body and can affect the way they work. These problems can sometimes become severe or life-threatening and can lead to death. These problems may happen any time during treatment or even after your treatment has ended.
Call or see your doctor right away if you develop any symptoms of the following problems or these symptoms get worse:
Lung problems (pneumonitis). Symptoms of pneumonitis may include shortness of breath, chest pain, or new or worse cough.
Intestinal problems (colitis) that can lead to tears or holes in your intestine. Signs and symptoms of colitis may include diarrhea or more bowel movements than usual; stools that are black, tarry, sticky, or have blood or mucus; or severe stomach-area (abdomen) pain or tenderness.
Liver problems, including hepatitis. Signs and symptoms of liver problems may include yellowing of your skin or the whites of your eyes, nausea or vomiting, pain on the right side of your stomach area (abdomen), dark urine, or bleeding or bruising more easily than normal.
Hormone gland problems (especially the thyroid, pituitary, adrenal glands, and pancreas). Signs and symptoms that your hormone glands are not working properly may include rapid heartbeat, weight loss or weight gain, increased sweating, feeling more hungry or thirsty, urinating more often than usual, hair loss, feeling cold, constipation, your voice gets deeper, muscle aches, feeling very weak, dizziness or fainting, or headaches that will not go away or unusual headache.
Kidney problems, including nephritis and kidney failure. Signs of kidney problems may include change in the amount or color of your urine.
Skin problems. Signs of skin problems may include rash, itching, blisters, peeling or skin sores, or painful sores or ulcers in your mouth or in your nose, throat, or genital area.
Problems in other organs. Signs and symptoms of these problems may include changes in eyesight; severe or persistent muscle or joint pains; severe muscle weakness; low red blood cells (anemia); swollen lymph nodes, rash or tender lumps on skin, cough, shortness of breath, vision changes, or eye pain (sarcoidosis); confusion, fever, muscle weakness, balance problems, nausea, vomiting, stiff neck, memory problems, or seizures (encephalitis); and shortness of breath, irregular heartbeat, feeling tired, or chest pain (myocarditis).
Infusion (IV) reactions that can sometimes be severe and life-threatening. Signs and symptoms of infusion reactions may include chills or shaking, shortness of breath or wheezing, itching or rash, flushing, dizziness, fever, or feeling like passing out.
Rejection of a transplanted organ. People who have had an organ transplant may have an increased risk of organ transplant rejection if they are treated with KEYTRUDA.
Complications, including graft-versus-host disease (GVHD), in people who have received a bone marrow (stem cell) transplant that uses donor stem cells (allogeneic). These complications can be severe and can lead to death. These complications may happen if you underwent transplantation either before or after being treated with KEYTRUDA. Your doctor will monitor you for the following signs and symptoms: skin rash, liver inflammation, abdominal pain, and diarrhea.
Getting medical treatment right away may help keep these problems from becoming more serious. Your doctor will check you for these problems during treatment with KEYTRUDA. Your doctor may treat you with corticosteroid or hormone replacement medicines. Your doctor may also need to delay or completely stop treatment with KEYTRUDA if you have severe side effects.
Before you receive KEYTRUDA, tell your doctor if you have immune system problems such as Crohn’s disease, ulcerative colitis, or lupus; have had an organ transplant or plan to have or have had a bone marrow (stem cell) transplant that used donor stem cells (allogeneic); have lung or breathing problems; have liver problems; or have any other medical problems.
If you are pregnant or plan to become pregnant, tell your doctor. KEYTRUDA can harm your unborn baby. If you are able to become pregnant, your doctor will give you a pregnancy test before you start treatment. Use effective birth control during treatment and for at least 4 months after the final dose of KEYTRUDA. Tell your doctor right away if you think you may be pregnant or you become pregnant during treatment with KEYTRUDA.
If you are breastfeeding or plan to breastfeed, tell your doctor. It is not known if KEYTRUDA passes into your breast milk. Do not breastfeed during treatment with KEYTRUDA and for 4 months after your final dose of KEYTRUDA.
Tell your doctor about all the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements.
Common side effects of KEYTRUDA when used alone include feeling tired; pain, including pain in muscles, bones, or joints and stomach area (abdominal) pain; decreased appetite; itching; diarrhea; nausea; rash; fever; cough; shortness of breath; and constipation.
Common side effects of KEYTRUDA when given with certain chemotherapy medicines include feeling tired or weak; nausea; constipation; diarrhea; decreased appetite; rash; vomiting; cough; trouble breathing; fever; hair loss; inflammation of the nerves that may cause pain, weakness, and paralysis in the arms and legs; swelling of the lining of the mouth, nose, eyes, throat, intestines, or vagina; and mouth sores.
Common side effects of KEYTRUDA when given with axitinib include diarrhea; feeling tired or weak; high blood pressure; liver problems; low levels of thyroid hormone; decreased appetite; blisters or rash on the palms of your hands and soles of your feet; nausea; mouth sores or swelling of the lining of the mouth, nose, eyes, throat, intestines, or vagina; hoarseness; rash; cough; and constipation.
In children, feeling tired, vomiting and stomach-area (abdominal) pain, and increased levels of liver enzymes and decreased levels of salt (sodium) in the blood are more common than in adults.
These are not all the possible side effects of KEYTRUDA. Tell your doctor if you have any side effect that bothers you or that does not go away. For more information, ask your doctor or pharmacist.