• Monitor for signs and symptoms of bleeding. Interrupt and/or reduce dose, or permanently discontinue based on severity of adverse reaction. Use platelet transfusion and/or other treatments as clinically indicated.
• Assess for fatigue periodically during therapy. If Grade 2 lasting > 7 days OR Grade 3, hold dose. Monitor until fatigue resolves to Grade 1 or baseline. Restart selinexor at 1 dose level lower.
• Monitor for nausea, vomiting, and diarrhea during therapy. If Grade 1 or 2 nausea (oral intake decreased without significant weight loss, dehydration or malnutrition) OR Grade 1 or 2 vomiting (5 or fewer episodes per day) occurs, maintain therapy and initiate additional anti-nausea medications. If Grade 3 nausea (inadequate oral caloric or fluid intake) OR Grade 3 or higher vomiting (6 or more episodes per day) occurs, hold selinexor. Monitor until nausea or vomiting has resolved to ≤Grade 2 or baseline. Start additional anti-nausea medications. Restart therapy at 1 dose level lower. If Grade 2 diarrhea (increase of 4 to 6 stools per day over baseline) occurs, first occurrence, continue therapy and institute supportive care. 2nd and subsequent occurrence, Reduce dose by 1 dose level. Institute supportive care. If ≥Grade 3 (increase of 7 stools or more per day over baseline; hospitalization indicated) occurs, hold selinexor and institute supportive care. Monitor until diarrhea resolves to ≤ Grade 2. Restart therapy at 1 dose level lower.
• May cause anorexia and weight loss. If weight loss of 10% to < 20% OR anorexia associated with significant weight loss or malnutrition occurs, hold selinexor and institute supportive care. Monitor until weight returns to > 90% of baseline weight. Restart therapy at 1 dose level lower.

Lab Test Considerations:

• Verify negative pregnancy test before starting therapy.Monitor CBC, platelet counts standard blood chemistry, and body weight at baseline and during treatment as clinically indicated. Monitor more frequently during the first 2 mo of therapy. Thrombocytopenia:If platelet count 25,000 to < 75,000/mcL, reduce dose by 1 level. If platelet count 25,000 to < 75,000/mcL with concurrent bleeding, hold dose. Restart at 1 dose level lower after bleeding has resolved. If platelet count < 25,000/mcL, hold dose. Monitor until platelet count returns to at least 50,000/mcL. Restart at 1 dose level lower. Neutropenia:If absolute neutrophil count (ANC) of 0.5 – 1.0 x 10⁹ /L without fever, reduce by 1 dose level. If ANC <0.5 x 10⁹ /L OR febrile neutropenia, hold dose. Monitor until ANC returns to 1.0 x 109 /L or higher. • Restart at 1 dose level lower. Anemia:If hemoglobin < 8.0 g/dL, reduce dose by 1 dose level. Administer blood transfusions and/or other treatments per clinical guidelines. If life-threatening consequences occur, hold dose. Monitor hemoglobin until levels return to ≥8 g/dL. Restart therapy at 1 dose level lower. Administer blood transfusions and/or other treatments per clinical guidelines. Hyponatremia:If sodium level ≤130 mmol/L, hold dose and provide supportive care. Monitor until sodium levels return to ≥130 mmol/L. Restart therapy at 1 dose level lower.