How Do PDGFR-alpha Inhibitors Work?

Platelet-derived growth factor receptor A (PDGFR-A) inhibitors are a class of drugs used to treat gastrointestinal stromal tumors (a type of tumor that grows in the stomach, intestine, bowel, or esophagus [the tube that connects the throat with the stomach]), acute lymphoblastic leukemia (a type of cancer of the blood and bone marrow), chronic myeloid leukemia (a rare type of cancer of the bone marrow), and myelodysplastic/myeloproliferative diseases (a group of diseases in which the bone marrow produces an excess of white blood cells). 

They are also used to treat certain immune system disorders such as aggressive systemic mastocytosis (a rare disorder that results in accumulation of mast cells in the body) and hypereosinophilic syndrome (a group of blood disorders characterized by persistent eosinophilia).

PDGFR-alpha inhibitors are chemotherapy medications and a selective tyrosine kinase inhibitor of KIT and PDGFR-A (a receptor located on the surface of cells) that helps in inhibiting the proliferation of tumor cells and induces apoptosis (death of cells that occurs as a normal and controlled part of an organism's growth or development).

PDGFR-alpha inhibitors are administered via oral route, typically once or twice a day with or without food.

PDGFR-alpha inhibitors work in the following ways:

• They belong to a class of drugs known as "kinase inhibitors" that work by slowing down or stopping the growth of cancer cells and certain immune system cells (mast cells).
• They inhibit various gene mutations, increasing progression-free survival in patients with leukemias.

PDGFR-alpha inhibitors are used to treat conditions such as:

• Gastrointestinal stromal tumors (a type of tumor located in the gastrointestinal tract)
• Systemic mastocytosis (a rare disorder that results in the accumulation of mast cells in the body)
• Acute lymphoblastic leukemia (a type of cancer of the blood and bone marrow)
• Myelodysplastic/myeloproliferative diseases (a group of diseases in which the bone marrow produces an excess of white blood cells)
• Hypereosinophilic syndrome (a group of blood disorders characterized by persistent eosinophilia)
• Chronic eosinophilic leukemia (a rare neoplasm characterized by overproduction of eosinophils in the bone marrow)
• Chronic Philadelphia chromosome-positive myeloid leukemia (abnormal changes in the chromosomes, leading to high levels of abnormal cells in the bone marrow and blood)
• Dermatofibrosarcoma protuberans (a tumor that forms under the top layer of the skin) 

Some of the common side effects include:

• Nausea
• Vomiting
• Diarrhea
• Stomach upset
• Headache
• Muscle/joint pain
• Change in taste sensation
• Loss of appetite
• Watery eyes
• Abdominal pain
• Tiredness/weakness
• Mouth sores
• Dry mouth
• Dyspepsia (a persistent or recurrent pain or discomfort in the upper abdomen)

Other rare side effects include:

• Dizziness 
• Blurred vision
• Fatigue 
• Hair loss
• Unexplained weight gain
• Anemia (low red blood cell count)
• Shortness of breath
• Thrombocytopenia (low blood platelet count)
• Stomatitis (inflammation of the mucous membrane of the mouth)
• Pyrexia (fever)
• Rash
• Swelling of hands, ankles, or feet
• Yellowing of the skin or eyes
• Hypophosphatemia (low blood phosphate level)
• Hypokalemia (low blood potassium level)
• Increased creatinine 
• Hyponatremia (low blood sodium level)
• Hair color changes
• Hypocalcemia (low blood calcium level)
• Periorbital edema (swelling around the eyes)
• Increased liver enzymes
• Insomnia 
• Hypertension (high blood pressure)

Information contained herein is not intended to cover all possible side effects, precautions, warnings, drug interactions, allergic reactions, or adverse effects. Check with your doctor or pharmacist to make sure these drugs do not cause any harm when you take them along with other medicines. Never stop taking your medication and never change your dose or frequency without consulting your doctor.

Generic and brand names of PDGFR-alpha inhibitors include:

• Avapritinib
• Ayvakit
• Gleevec
• Imatinib
• Qinlock
• Ripretinib