• Monitor for signs and symptoms of bleeding. Interrupt and/or ↓ 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 one dose level lower.
• Monitor for nausea, vomiting, and diarrhea during therapy. If Grade 1 or 2 nausea (oral intake ↓ without significant weight loss, dehydration, or malnutrition) OR Grade 1 or 2 vomiting (≤5 episodes per day) occurs, maintain therapy and initiate additional antinausea medications. If Grade 3 nausea (inadequate oral caloric or fluid intake) OR ≥Grade 3 vomiting (≥6 episodes per day) occurs, hold selinexor. Monitor until nausea or vomiting has resolved to ≤Grade 2 or baseline. Start additional antinausea medications. Restart therapy at one dose level lower. If Grade 2 diarrhea (↑ of 4–6 stools per day over baseline) occurs, at first occurrence, continue therapy and institute supportive care. At second and subsequent occurrence, ↓ by one dose level. Institute supportive care. If ≥Grade 3 (↑ of ≥7 stools per day over baseline; hospitalization indicated) occurs, hold selinexor and institute supportive care. Monitor until diarrhea resolves to ≤Grade 2. Restart therapy at one 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 one dose level lower.

Lab Test Considerations:

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