Selinexor

1 INDICATIONS AND USAGE XPOVIO is a nuclear export inhibitor indicated: In combination with bortezomib and dexamethasone for the treatment of adult patients with multiple myeloma who have received at least one prior therapy ( 1.1 ). In combination with dexamethasone for the treatment of adult patients with relapsed or refractory multiple myeloma who have received at least four prior therapies and whose disease is refractory to at least two proteasome inhibitors, at least two immunomodulatory agents, and an anti-CD38 monoclonal antibody ( 1.1 ). 1.1 Multiple Myeloma XPOVIO in combination with bortezomib and dexamethasone is indicated for the treatment of adult patients with multiple myeloma who have received at least one prior therapy. XPOVIO in combination with dexamethasone is indicated for the treatment of adult patients with relapsed or refractory multiple myeloma who have received at least four prior therapies and whose disease is refractory to at least two proteasome inhibitors, at least two immunomodulatory agents, and an anti-CD38 monoclonal antibody.

12.1 Mechanism of Action In nonclinical studies, selinexor reversibly inhibits nuclear export of tumor suppressor proteins (TSPs), growth regulators, and mRNAs of oncogenic proteins by blocking exportin 1 (XPO1). XPO1 inhibition by selinexor leads to accumulation of TSPs in the nucleus and reductions in several oncoproteins, such as c-myc and cyclin D1, cell cycle arrest, and apoptosis of cancer cells. Selinexor demonstrated pro-apoptotic activity in vitro in multiple myeloma cells and showed anti-tumor activity in murine xenograft models of multiple myeloma. The combination of selinexor and dexamethasone or bortezomib demonstrated synergistic cytotoxic effects in multiple myeloma in vitro and increased anti-tumor activity in murine xenograft multiple myeloma models in vivo, including those resistant to proteasome inhibitors.

2 DOSAGE AND ADMINISTRATION Multiple Myeloma in Combination with Bortezomib and Dexamethasone (XVd) : Recommended dosage of XPOVIO is 100 mg taken orally once weekly in combination with bortezomib and dexamethasone ( 2.1 ). Multiple Myeloma in Combination with Dexamethasone (Xd) : Recommended dosage of XPOVIO is 80 mg taken orally on Days 1 and 3 of each week in combination with dexamethasone ( 2.1 ). See Full Prescribing Information for dosage in patients with severe hepatic impairment ( 2.5 , 8.6 ). 2.1 Recommended Dosage for Multiple Myeloma In Combination with Bortezomib and Dexamethasone (XVd) The recommended dosage of XPOVIO is 100 mg taken orally once weekly on Day 1 of each week until disease progression or unacceptable toxicity in combination with: Bortezomib 1.3 mg/m 2 administered subcutaneously once weekly on Day 1 of each week for 4 weeks followed by 1 week off. Dexamethasone 20 mg taken orally twice weekly on Days 1 and 2 of each week. Refer to Clinical Studies ( 14.1 ) and the prescribing information of bortezomib and dexamethasone for additional dosing information. In Combination with Dexamethasone (Xd) The recommended dosage of XPOVIO is 80 mg taken orally on Days 1 and 3 of each week until disease progression or unacceptable toxicity in combination with dexamethasone 20 mg taken orally with each dose of XPOVIO on Days 1 and 3 of each week. For additional information regarding the administration of dexamethasone, refer to its prescribing information. 2.2 Recommended Monitoring for Safety Monitor complete blood count (CBC) with differential, standard blood chemistries, body weight, nutritional status, and volume status at baseline and during treatment as clinically indicated. Monitor more frequently during the first three months of treatment [see Warning and Precautions (5.1, 5.2, 5.3, and 5.4)] . Assess the need for dosage modifications of XPOVIO for adverse reactions [see Dosage and Administration ( 2.4 )] . 2.3 Recommended Concomitant Treatments Advise patients to maintain adequate fluid and caloric intake throughout treatment. Consider intravenous hydration for patients at risk of dehydration [see Warnings and Precautions ( 5.3 , 5.4 )] . Provide prophylactic antiemetics. Administer a 5-HT3 receptor antagonist and other anti-nausea agents prior to and during treatment with XPOVIO [see Warnings and Precautions ( 5.3 )] . 2.4 Dosage Modifications for Adverse Reactions Recommended XPOVIO dosage reduction steps are presented in Table 1 . Table 1: XPOVIO Dosage Reduction Steps for Adverse Reactions Recommended Starting Dosage Multiple Myeloma In Combination with Bortezomib and Dexamethasone (XVd) Multiple Myeloma In Combination with Dexamethasone (Xd) 100 mg once weekly 80 mg Days 1 and 3 of each week (160 mg total per week) First Reduction 80 mg once weekly 100 mg once weekly Second Reduction 60 mg once weekly 80 mg once weekly Third Reduction 40 mg once weekly 60 mg once weekly Fourth Reduction Permanently discontinue Permanently discontinue Recommended dosage modifications for hematologic adverse reactions in patients with multiple myeloma are presented in Table 2 . Recommended dosage modifications for non-hematologic adverse reactions are presented in Table 3 . Table 2: XPOVIO Dosage Modification Guidelines for Hematologic Adverse Reactions in Patients with Multiple Myeloma Adverse Reaction Occurrence Action Thrombocytopenia [see Warning and Precautions ( 5.1 )] Platelet count 25,000 to less than 75,000/mcL Any Reduce XPOVIO by 1 dose level (see Table 1 ). Platelet count 25,000 to less than 75,000/mcL with concurrent bleeding Any Interrupt XPOVIO. Restart XPOVIO at 1 dose level lower (see Table 1 ) after bleeding has resolved. Administer platelet transfusions per clinical guidelines. Platelet count less than 25,000/mcL Any Interrupt XPOVIO. Monitor until platelet count returns to at least 50,000/mcL. Restart XPOVIO at 1 dose level lower (see Table 1 ). Neutropenia [see Warning and Precautions ( 5.2 )] Absolu

6 ADVERSE REACTIONS The following clinically significant adverse reactions are described in detail in other labeling sections: Thrombocytopenia [see Warnings and Precautions ( 5.1 )] . Neutropenia [see Warnings and Precautions ( 5.2 )] . Gastrointestinal Toxicity [see Warnings and Precautions ( 5.3 )] . Hyponatremia [see Warnings and Precautions ( 5.4 )] . Serious Infection [see Warnings and Precautions ( 5.5 )] . Neurological Toxicity [see Warnings and Precautions ( 5.6 )] . Cataract [see Warnings and Precautions ( 5.8 )] . The most common adverse reactions (≥20%) in patients with multiple myeloma who receive XVd are fatigue, nausea, decreased appetite, diarrhea, peripheral neuropathy, upper respiratory tract infection, weight decreased, cataract, and vomiting. Grade 3-4 laboratory abnormalities (≥10%) are thrombocytopenia, lymphopenia, hypophosphatemia, anemia, hyponatremia, and neutropenia ( 6.1 ). The most common adverse reactions (≥20%) in patients with multiple myeloma who receive Xd are thrombocytopenia, fatigue, nausea, anemia, decreased appetite, weight decreased, diarrhea, vomiting, hyponatremia, neutropenia, leukopenia, constipation, dyspnea, and upper respiratory tract infection ( 6.1 ). To report SUSPECTED ADVERSE REACTIONS, contact Karyopharm Therapeutics Inc. at 1-888-209-9326 or FDA at 1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. Multiple Myeloma XPOVIO in Combination with Bortezomib and Dexamethasone (XVd) The safety of XPOVIO in combination with bortezomib and dexamethasone was evaluated in BOSTON [see Clinical Studies ( 14.1 )]. Patients were randomized to receive XPOVIO 100 mg orally once weekly in combination with bortezomib and dexamethasone (XVd) (n=195) or bortezomib and dexamethasone (Vd) (n=204). Among patients who received XPOVIO, the median duration of XPOVIO treatment was 29 weeks (range: 1 to 120 weeks) and the median dose was 80 mg (range: 30 to 137 mg) per week. Serious adverse reactions occurred in 52% of patients who received XPOVIO in combination with bortezomib and dexamethasone. Serious adverse reactions in >3% of patients included pneumonia (14%), sepsis, diarrhea and vomiting (4% each). Fatal adverse reactions occurred in 6% of patients within 30 days of last treatment, including pneumonia (n=3) and sepsis (n=3). Grade ≥2 peripheral neuropathy, a pre-specified key secondary endpoint, was lower in the XVd arm (21%) compared to the Vd arm (34%); odds ratio 0.50 [95% CI: 0.32, 0.79]. The median treatment duration was 30 weeks (range: 1-120 weeks) in patients who received once weekly XVd as compared to 32 weeks (range: 1-122 weeks) in patients who received twice weekly Vd. Permanent discontinuation of XPOVIO due to an adverse reaction occurred in 19% of patients. Adverse reactions which resulted in permanent discontinuation of XPOVIO in >2% of patients included fatigue (3.6%), nausea (3.1%), thrombocytopenia, decreased appetite, peripheral neuropathy, and vomiting (2.1% each). Dosage interruptions of XPOVIO due to an adverse reaction occurred in 83% of patients. Adverse reactions which required dosage interruption in >5% of patients included thrombocytopenia (33%), fatigue (13%), asthenia (12%), pneumonia (11%), upper respiratory tract infection (10%), decreased appetite (9%), neutropenia (8%), pyrexia (8%), nausea (7%), bronchitis (7%), diarrhea (6%), weight decreased (6%), and anemia (5%). Dose reductions of XPOVIO due to an adverse reaction occurred in 64% of patients. Adverse reactions which required dose reductions in >5% of patients included thrombocytopenia (31%), decreased appetite (8%), nausea, fatigue, weight decreased (7% each), and asthenia (6%). The most common adverse reactions (≥20% with a dif

5 WARNINGS AND PRECAUTIONS Thrombocytopenia : Monitor platelet counts throughout treatment. Manage with dose interruption and/or reduction and supportive care ( 2.4 , 5.1 ). Neutropenia : Monitor neutrophil counts throughout treatment. Manage with dose interruption and/or reduction and granulocyte colony-stimulating factors ( 2.4 , 5.2 ). Gastrointestinal Toxicity : Nausea, vomiting, diarrhea, anorexia, and weight loss may occur. Provide antiemetic prophylaxis. Manage with dose interruption and/or reduction, antiemetics, and supportive care ( 2.4 , 5.3 ). Hyponatremia : Monitor serum sodium levels throughout treatment. Correct for concurrent hyperglycemia and high serum paraprotein levels. Manage with dose interruption, reduction, or discontinuation, and supportive care ( 2.4 , 5.4 ). Serious Infection : Monitor for infection and treat promptly ( 5.2 , 5.5 ). Neurological Toxicity : Advise patients to refrain from driving and engaging in hazardous occupations or activities until neurological toxicity resolves. Optimize hydration status and concomitant medications to avoid dizziness or mental status changes ( 5.6 ). Embryo-Fetal Toxicity : Can cause fetal harm. Advise females of reproductive potential and males with a female partner of reproductive potential, of the potential risk to a fetus and use of effective contraception ( 5.7 , 8.1 , 8.3 ). Cataract : Cataracts may develop or progress. Treatment of cataracts usually requires surgical removal of the cataract ( 5.8 ). 5.1 Thrombocytopenia XPOVIO can cause life-threatening thrombocytopenia, potentially leading to hemorrhage. Thrombocytopenia is the leading cause of dosage modifications [see Adverse Reactions ( 6.1 )] . In patients with multiple myeloma who received XPOVIO 100 mg once weekly (BOSTON, n=195), thrombocytopenia was reported in 92% of patients and severe (Grade 3-4) thrombocytopenia was reported in 43% of patients. The median time to first onset was 22 days for any grade thrombocytopenia and 43 days for Grade 3 or 4 thrombocytopenia. Bleeding occurred in 16% of patients with thrombocytopenia, clinically significant bleeding (Grade ≥3 bleeding) occurred in 4% of patients with thrombocytopenia, and fatal hemorrhage occurred in 2% of patients with thrombocytopenia. Permanent discontinuations of XPOVIO due to thrombocytopenia occurred in 2% of patients. In patients with multiple myeloma who received XPOVIO 80 mg twice weekly (STORM, n=202), thrombocytopenia was reported as an adverse reaction in 74% of patients and severe (Grade 3-4) thrombocytopenia was reported in 61% of patients. The median time to onset of the first event was 22 days. Bleeding occurred in 23% of patients with thrombocytopenia, clinically significant bleeding occurred in 5% of patients with thrombocytopenia, and fatal hemorrhage occurred in <1% of patients. Monitor platelet counts at baseline and throughout treatment. Monitor more frequently during the first three months of treatment. Institute platelet transfusion and/or other treatments as clinically indicated. Monitor patients for signs and symptoms of bleeding and evaluate promptly. Interrupt, reduce dose, or permanently discontinue based on severity of adverse reaction [see Dosage and Administration ( 2.4 )]. 5.2 Neutropenia XPOVIO can cause life-threatening neutropenia, potentially increasing the risk of infection [see Adverse Reactions ( 6.1 )] . In patients with multiple myeloma who received XPOVIO 100 mg once weekly (BOSTON, n=195), neutropenia was reported in 48% of patients and severe neutropenia (Grade 3-4) was reported in 12% of patients. The median time to onset of the first event was 23 days for any grade neutropenia and 40 days for Grade 3-4 neutropenia. Febrile neutropenia was reported in <1% of patients. In patients with multiple myeloma who received XPOVIO 80 mg twice weekly (STORM, n=202), neutropenia was reported as an adverse reaction in 34% of patients and severe (Grade 3-4) neutropenia was reported in 21% of patients. The m

4 CONTRAINDICATIONS None. None ( 4 ).