Selinexor

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.

Tablets: 10 mg, blue, round, bi-convex, film-coated tablets with “X10” debossed on one side and nothing on the other side. 20 mg, blue, round, bi-convex, film-coated tablets with “K20” debossed on one side and nothing on the other side. 40 mg tablets, blue, oval, film-coated, debossed on both sides with “X40”. 50 mg tablets, blue, oval, film-coated, debossed on both sides with “X50”. 60 mg tablets, blue, oval, film-coated, debossed on both sides with “X60”. 80 mg tablets, blue, oval, film-coated, debossed on both sides with “X80”. Tablets:10 mg, 20 mg, 40 mg, 50 mg, 60 mg, 80 mg ( 3 ).

None. None ( 4 ).

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 median time to onset of the first event was 25 days. Febrile neutropenia was reported in 3% of patients. Obtain white blood cell counts with differential at baseline and throughout treatment. Monitor more frequently during the first three months of treatment. Monitor patients for signs and symptoms of concomitant infection and evaluate promptly. Consider supportive measures, including antimicrobials and growth factors (e.g., G-CSF). Interrupt, reduce dose or permanently discontinue based on severity of adverse reaction [see Dosage and Administration ( 2.4 )].

5.3 Gastrointestinal Toxicity XPOVIO can cause severe gastrointestinal toxicities [see Adverse Reactions ( 6.1 )] . Nausea/Vomiting In patients with multiple myeloma who received XPOVIO once weekly (BOSTON, n=195) with use of antiemetic prophylaxis (88% of patients), nausea was reported in 50% of patients and Grade 3 nausea was reported in 8% of patients. The median time to onset of the first event was 6 days. Vomiting was reported in 21% of patients and Grade 3 vomiting was reported in 4.1% of patients. The median time to onset of the first event was 8 days. Permanent discontinuation due to nausea occurred in 3.1% of patients and due to vomiting occurred in 2.1% of patients. In patients with multiple myeloma receiving XPOVIO 80 mg twice weekly (STORM, n=202) with use of antiemetic prophylaxis, nausea was reported as an adverse reaction in 72% of patients and Grade 3 nausea occurred in 9%. The median time to first onset of nausea was 3 days. Vomiting was reported in 41% of patients and Grade 3 vomiting occurred in 4% of patients. The median time to first onset of vomiting was 5 days. Provide prophylactic antiemetics. Administer 5-HT3 receptor antagonists and other anti-nausea agents prior to and during treatment with XPOVIO. Interrupt, reduce dose or permanently discontinue based on severity of adverse reaction [see Dosage and Administration ( 2.4 )] . Administer intravenous fluids to prevent dehydration and replace electrolytes as clinically indicated. Diarrhea In patients with multiple myeloma who received XPOVIO once weekly (BOSTON, n=195), diarrhea was reported in 32% of patients and Grade 3 diarrhea was reported in 6% of patients. The median time to onset of the first event was 50 days. Permanent discontinuation due to diarrhea occurred in 1% of patients. In patients with multiple myeloma who received XPOVIO 80 mg twice weekly (STORM, n=202), diarrhea was reported as an adverse reaction in 44% of patients and Grade 3 diarrhea occurred in 6% of patients. The median time to onset of diarrhea was 15 days. Interrupt, reduce dose or permanently discontinue based on severity of adverse reaction [see Dosage and Administration ( 2.4 )] . Provide standard anti-diarrheal agents, administer intravenous fluids to prevent dehydration and replace electrolytes as clinically indicated. Anorexia/Weight Loss In patients with multiple myeloma who received XPOVIO 100 mg once weekly (BOSTON, n=195), anorexia was reported in 35% of patients and Grade 3 anorexia was reported in 3.6% of patients. The median time to onset of the first event was 35 days. Permanent discontinuations due to anorexia occurred in 2.1% of patients. Weight loss was reported in 26% of patients and Grade 3 weight loss was reported in 2.1% of patients. The median time to onset of the first event was 58 days. Permanent discontinuation due to weight loss occurred in 1% of patients. In patients with multiple myeloma who received XPOVIO 80 mg twice weekly (STORM n=202), anorexia was reported as an adverse reaction in 53% of patients and Grade 3 anorexia occurred in 5% of patients. The median time to onset of anorexia was 8 days. Weight loss was reported as an adverse reaction in 47% of patients and Grade 3 weight loss occurred in 1% of patients treated with XPOVIO. The median time to onset of weight loss was 15 days. Monitor weight, nutritional status, and volume status at baseline and throughout treatment. […]

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 difference between arms of >5% compared to Vd) were fatigue, nausea, decreased appetite, diarrhea, peripheral neuropathy, upper respiratory tract infection, weight decreased, cataract, and vomiting. Grade 3-4 laboratory abnormalities (≥10%) were thrombocytopenia, lymphopenia, hypophosphatemia, anemia, hyponatremia, and neutropenia. Table 6 summarizes the adverse reactions in BOSTON. Table 6: Adverse Reactions (≥10%) in Patients with Multiple Myeloma Who Received XPOVIO in Combination with Bortezomib and Dexamethasone (XVd) with a Difference Between Arms of >5% Compared to Vd in BOSTON Key: X=XPOVIO, Vd=bortezomib-dexamethasone a. Fatigue includes fatigue and asthenia. b. Peripheral neuropathy includes neuropathy peripheral, peripheral sensory neuropathy, polyneuropathy, peripheral sensorimotor neuropathy, toxic neuropathy, and peripheral motor neuropathy. c. Upper respiratory tract infection includes upper respiratory infection, nasopharyngitis, pharyngitis, respiratory syncytial virus infection, respiratory tract infection, rhinitis, and viral upper respiratory tract infection. d. Vision blurred includes blurred vision, visual acuity reduced, and visual impairment. Adverse Reaction Weekly XVd (n=195) Twice Weekly Vd (n=204) All Grades (%) Grade 3 or 4 (%) All Grades (%) Grade 3 or 4 (%) Gastrointestinal Nausea 50 8 10 0 Diarrhea 32 6 25 <1 Vomiting 21 4.1 4.4 0 General Conditions Fatigue a 59 21 28 5 Pyrexia 15 1.5 11 1 Metabolism and Nutrition Decreased appetite 35 3.6 5 0 Weight decreased 26 2.1 12 1 Nervous System Peripheral neuropathy b 32 4.6 47 9 Dizziness 12 <1 3.9 0 Infections Upper respiratory tract infection c 29 3.6 22

1.5 Eye Disorders Cataract 22 9 6

1.5 Vision blurred d 13 <1 6 0 Clinically relevant adverse reactions in <10% of patients who received XPOVIO in combination with bortezomib and dexamethasone included: Neurologic disorders: mental status changes (9%) and syncope (3.6%) Table 7 summarizes selected laboratory abnormalities in BOSTON. Table 7: Select Laboratory Abnormalities (≥15%) That Worsened from Baseline in Patients with Multiple Myeloma Who Received XPOVIO in Combination with Bortezomib and Dexamethasone (XVd) in BOSTON Laboratory Abnormality Weekly XVd Twice Weekly Vd All Grades (%) Grade 3 or 4 (%) All Grades (%) Grade 3 or 4 (%) The denominator used to calculate the rate varied from 91 to 201 based on the number of patients with at least one post-treatment value. a. Includes one fatal anemia. Hematologic Platelet count decrease 92 43 51 19 Lymphocyte count decrease 77 38 70 27 Hemoglobin decrease 71 17 51 a 12 Neutrophil count decrease 48 12 19 7 Chemistry Glucose increase 62 3.8 47

4.1 Phosphate decrease 61 23 42 11 Sodium decrease 58 14 25 3 Calcium decrease 55 2.1 47 1 Blood urea nitrogen increase 41 5 40 5 Creatinine increase 28 3.6 24

1.5 Potassium decrease 27 6 22

3.5 Magnesium decrease 27 <1 23

1.5 Potassium increase 18 4.1 21

2.5 Hepatic ALT increase 33 3.1 30 <1 Albumin decrease 27 <1 35 <1 AST increase 24 1.5 19 <1 Bilirubin increase 16 1 13 2 ALP increase 12 0 16 <1 XPOVIO in Combination with Dexamethasone (Xd) The safety of XPOVIO in combination with dexamethasone was evaluated in STORM [see Clinical Studies ( 14.1 )]. Patients received XPOVIO 80 mg orally with dexamethasone 20 mg on Days 1 and 3 of every week (n=202). The median duration of XPOVIO treatment was 8 weeks (range: 1 to 60 weeks). The median dose was 115 mg (range: 36 to 200 mg) per week. Fatal adverse reactions occurred in 9% of XPOVIO treated patients. Serious adverse reactions occurred in 58% of patients. The treatment discontinuation rate due to adverse reactions was 27%; 53% of patients had a reduction in the XPOVIO dose, and 65% had the dose of XPOVIO interrupted. Thrombocytopenia was the leading cause of dose modification, resulting in dose reduction and/or interruption in >25% of patients. […]

Lactation : Advise not to breastfeed ( 8.2 ).

8.1 Pregnancy Risk Summary Based on findings in animal studies and its mechanism of action [see Clinical Pharmacology ( 12.1 )] , XPOVIO can cause fetal harm when administered to a pregnant woman. There are no available data in pregnant women to inform the drug-associated risk. In animal reproduction studies, administration of selinexor to pregnant rats during organogenesis resulted in structural abnormalities and alterations to growth at exposures that were below those occurring clinically at the recommended dose (see Data ) . Advise pregnant women of the risks to a fetus. The estimated background risk of major birth defects and miscarriage for the indicated population is unknown. All pregnancies have a background risk of birth defect, loss, or other adverse outcomes. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2% to 4% and 15% to 20%, respectively. Data Animal data In an embryo-fetal development study in pregnant rats, daily oral administration of selinexor at 0, 0.25, 0.75, or 2 mg/kg throughout organogenesis caused incomplete or delayed ossification, skeletal variations, and reduced fetal weight compared with controls at a dose of 0.75 mg/kg (approximately 0.08-fold of human area under the curve [AUC] at the recommended dose). Malformations were observed at 2 mg/kg, including microphthalmia, fetal edema, malpositioned kidney, and persistent truncus arteriosus.

8.2 Lactation Risk Summary There is no information regarding the presence of selinexor or its metabolites in human milk, or their effects on the breastfed child or milk production. Because of the potential for serious adverse reactions in a breastfed child, advise women not to breastfeed during treatment with XPOVIO and for 1 week after the last dose.

8.3 Females and Males of Reproductive Potential XPOVIO can cause fetal harm when administered to a pregnant woman [see Use in Specific Populations ( 8.1 )] . Pregnancy Testing Verify the pregnancy status of females of reproductive potential prior to initiating XPOVIO [see Use in Specific Populations ( 8.1 )] . Contraception Females Advise females of reproductive potential to use effective contraception during treatment with XPOVIO and for 1 week after the last dose. Males Advise males with a female partner of reproductive potential to use effective contraception during treatment with XPOVIO and for 1 week after the last dose. Infertility Females and Males Based on findings in animals, XPOVIO may impair fertility in females and males of reproductive potential [see Nonclinical Toxicology ( 13.1 )] .

8.4 Pediatric Use The safety and effectiveness of XPOVIO have not been established in pediatric patients.

8.5 Geriatric Use In BOSTON, of the 195 patients with multiple myeloma who received XPOVIO in combination with bortezomib and dexamethasone, 56% were 65 years of age and older, while 17% were 75 years of age and older. No overall differences in effectiveness were observed between these patients and younger patients. When comparing patients 65 years of age and older to younger patients, older patients had a higher incidence of discontinuation due to an adverse reaction (28% vs 13%) and a higher incidence of serious adverse reactions (56% vs 47%). In STORM, of the 202 patients with multiple myeloma who received XPOVIO, 49% were 65 years of age and older, while 11% were 75 years of age and older. No overall difference in effectiveness was observed in patients over 65 years of age, including patients over 75 years of age, when compared with younger patients. When comparing patients 75 years of age and older to younger patients, older patients had a higher incidence of discontinuation due to an adverse reaction (44% vs 27%), higher incidence of serious adverse reactions (70% vs 58%), and higher incidence of fatal adverse reactions (17% vs 9%).

8.6 Hepatic Impairment No dose adjustment for selinexor is required for mild (total bilirubin ≤1x ULN and AST >1x ULN, or total bilirubin >1.0 to 1.5x ULN and any AST) or moderate (total bilirubin >1.5x to 3.0x ULN, and any AST) hepatic impairment. Reduce the starting dose in patients with severe (total bilirubin >3.0x ULN, and any AST) hepatic impairment [see Dosage and Administration ( 2.5 ) and Clinical Pharmacology ( 12.3 )] .

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.