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Selinexor

Formula Drugs

What is Selinexor?

Selinexor is the first in a new family of drugs known as a selective inhibitor of nuclear export compounds. This is used for the treatment of multiple myeloma. 

Multiple myeloma is cancer that forms in a type of white blood cell called a plasma cell. Plasma cells help you fight infections by making antibodies that recognize and attack germs. This condition causes cancer to accumulate in the bone marrow. It is where they crowd out healthy blood cells. Rather than produce helpful antibodies, the cancer cells produce abnormal proteins that can cause complications. The treatment for this condition is not always needed for people who are not experiencing any signs or symptoms. The signs and symptoms of multiple myeloma can vary and early in the disease, there may be none, when signs and symptoms do occur, they can be:

  • Nausea
  • Bone pain especially in your spine or chest
  • Loss of appetite
  • Constipation
  • Fatigue
  • Mental fogginess or confusion
  • Frequent infections
  • Weakness or numbness in your legs
  • Weight loss 
  • Excessive thirst 

Doctors know that myeloma begins with one abnormal plasma cell in your bone marrow. Bone marrow is the soft, blood-producing tissue that fills in the center of most of your bones. The abnormal cell multiplies rapidly. Because cancer cells don’t mature and then die as normal cells do, they accumulate, eventually overwhelming the production of healthy cells. In the bone marrow, myeloma cells crowd out healthy white blood cells and red blood cells. In which it leads to fatigue and an inability to fight infections.

The myeloma cells continue trying to produce antibodies, as healthy plasma cells do. But, the myeloma cells produce abnormal antibodies that the body can’t use. Instead, the abnormal antibodies build up in the body and cause problems such as damage to the kidneys. Cancer cells can also cause damage to the bones that increases the risk of broken bones. 

Complications of multiple myeloma include:

  1. Frequent infections

Myeloma cells inhibit your body’s ability to fight infections.

  • Bone problems

Multiple myeloma can also affect your bones which may lead to bone pain, broken bones, and thinning bones.

  • Reduced kidney function

Multiple myeloma may cause problems with kidney function including kidney failure. Higher calcium levels in the blood related to eroding bones can interfere with the ability of your kidney to filter your blood’s waste. The proteins produced by the myeloma cells can cause similar problems.

  • Low red blood cell count (anemia)

As myeloma cells crowd out normal blood cells, multiple myeloma can also cause anemia and other blood problems.

How does it work?

Selinexor blocks the action of a protein called XPO1 within the nucleus of myeloma cells. XPO1 is a protein responsible for moving other proteins between different parts of the cell. 

Cells are made up of two compartments called the cytoplasm and the nucleus. These are separated by a plasma membrane. Some proteins involved in the life cycle of the cell, for example, so-called tumor suppressor proteins, are active only when located within the nucleus. Other proteins must be moved from the nucleus into the cytoplasm to become active. The compartment in which different proteins are located can, therefore, affect the growth and survival of the cell. XPO1 is a transport protein responsible for moving proteins out of the nucleus of a cell into the cytoplasm. One of the characteristics of myeloma cells that make them different from healthy cells is their high level of XPO1, which is essential for myeloma cell survival. Myeloma cells use XPO1 to move tumor suppressor proteins from the nucleus into the cytoplasm. This deactivates them and allows the myeloma cells to multiply uninhibited. 

How to use Selinexor?

Selinexor is in a tablet form to be taken by mouth. It can be given on its own as a monotherapy. But, it has shown to be most effective when used in combination with other myeloma treatments such as dexamethasone. The usual maximum dose of Selinexor is 80mg twice a week or sometimes 100mg once a week. The dosage is based on your medical condition, age, and response to the treatment. 

Swallow the tablets whole with water. Do not break, chew, crush, or split the tablets. Drink plenty of fluids during treatment with this medication unless otherwise directed by your doctor. Your doctor may direct you to take this medication once a week if you have certain side effects. Follow your doctor’s instructions carefully. If you vomit after taking your dose of the medication, do not take an extra dose. Take the next dose of your medication at a regular time. Do not increase your dose or use this drug more often or for longer than prescribed. Your condition will not improve any faster, and your risk of serious side effects will increase. Let your doctor know right away if your condition does not improve or if it gets worse. 

Side Effects

Common side effects:

  • Fatigue
  • Low blood platelets 
  • Anemia
  • Nausea
  • Weight loss
  • Decreased appetite
  • Vomiting
  • Diarrhea
  • Constipation
  • Low white blood cell counts
  • Low blood sodium
  • Shortness of breath
  • Upper respiratory tract infection 

If you have the following signs of an allergic reaction, call your doctor or call for medical assistance right away:

  • Hives
  • Difficulty or trouble breathing
  • Swelling of your tongue, lips, throat, or face 

Warnings 

  • Before taking this medication, tell your doctor if you are allergic to it or if you have any other allergies. This may contain inactive ingredients that may cause allergic reactions or other complications. 
  • Inform as well your doctor about the medical history that you had. 
  • This drug can make you more likely to get infections or may worsen any current infections. Avoid contact with people who have infections that may spread to others. Consult your doctor if you have been exposed to an infection or for more details.
  • Do not have any vaccinations or immunizations without the consent of your doctor. Avoid contact with people who recently received live vaccines. 
  • To lower the chance of getting cut, bruised, or injured, use caution with sharp objects like razors and nail cutters, and avoid activities such as contact sports.
  • This can make you dizzy. Avoid doing things that may require your full alertness.