Bortezomib

INDICATIONS AND USAGE Bortezomib for injection is a proteasome inhibitor indicated for: treatment of adult patients with multiple myeloma ( 1.1 ) treatment of adult patients with mantle cell lymphoma ( 1.2 ) 1.1 Multiple Myeloma Bortezomib for injection , 3.5 mg/vial is indicated for the treatment of adult patients with multiple myeloma. 1.2 Mantle Cell Lymphoma Bortezomib for injection is indicated for the treatment of adult patients with mantle cell lymphoma.

DOSAGE AND ADMINISTRATION • For subcutaneous or intravenous use only. Each route of administration has a different reconstituted concentration. Exercise caution when calculating the volume to be administered. ( 2.1 , 2.10 ) • The recommended starting dose of bortezomib for injection is 1.3 mg/m 2 administered either as a 3 to 5 second bolus intravenous injection or subcutaneous injection. ( 2.2 , 2.4 , 2.6 ) • Retreatment for Multiple Myeloma: May retreat starting at the last tolerated dose. ( 2.6 ) • Hepatic Impairment: Use a lower starting dose for patients with moderate or severe hepatic impairment. ( 2.8 ) • Dose must be individualized to prevent overdose. ( 2.10 ) 2.1 Important Dosing Guidelines Bortezomib for injection is for intravenous or subcutaneous use only. Do not administer bortezomib for injection by any other route. Because each route of administration has a different reconstituted concentration, use caution when calculating the volume to be administered. The recommended starting dose of bortezomib for injection is 1.3 mg/m 2 . Bortezomib for injection is administered intravenously at a concentration of 1 mg/mL, or subcutaneously at a concentration of 2.5 mg/mL [see Dosage and Administration ( 2.10 )]. Bortezomib for injection retreatment may be considered for patients with multiple myeloma who had previously responded to treatment with bortezomib for injection and who have relapsed at least six months after completing prior bortezomib for injection treatment. Treatment may be started at the last tolerated dose [see Dosage and Administration ( 2.6 )]. When administered intravenously, administer bortezomib for injection as a 3 to 5 second bolus intravenous injection. 2.2 Dosage in Previously Untreated Multiple Myeloma Bortezomib for injection is administered in combination with oral melphalan and oral prednisone for 9, six week treatment cycles as shown in Table 1 . In Cycles 1 to 4, bortezomib for injection is administered twice weekly (Days 1, 4, 8, 11, 22, 25, 29 and 32). In Cycles 5 to 9, bortezomib for injection is administered once weekly (Days 1, 8, 22 and 29). At least 72 hours should elapse between consecutive doses of bortezomib for injection. Table 1: Dosage Regimen for Patients with Previously Untreated Multiple Myeloma Twice Weekly Bortezomib for Injection (Cycles 1 to 4) Week 1 2 3 4 5 6 Bortezomib for injection (1.3 mg/m 2 ) Day 1 -- -- Day 4 Day 8 Day 11 rest period Day 22 Day 25 Day 29 Day 32 rest period Melphalan (9 mg/m 2 ) Prednisone (60 mg/m 2 ) Day 1 Day 2 Day 3 Day 4 -- -- rest period -- -- -- -- rest period Once Weekly Bortezomib for Injection (Cycles 5 to 9 when used in combination with Melphalan and Prednisone) Week 1 2 3 4 5 6 Bortezomib for injection (1.3 mg/m 2 ) Day 1 -- -- Day 8 rest period Day 22 Day 29 rest period Melphalan (9 mg/m 2 ) Prednisone (60 mg/m 2 ) Day 1 Day 2 Day 3 Day 4 -- -- rest period -- -- -- -- rest period 2.3 Dose Modification Guidelines for Bortezomib for Injection When Given in Combination with Melphalan and Prednisone Prior to initiating any cycle of therapy with bortezomib for injection in combination with melphalan and prednisone: • Platelet count should be at least 70 x 10 9 /L and the absolute neutrophil count (ANC) should be at least 1 x 10 9 /L • Nonhematological toxicities should have resolved to Grade 1 or baseline Table 2: Dose Modifications During Cycles of Combination Bortezomib for Injection, Melphalan and Prednisone Therapy Toxicity Dose Moidification or Delay Hematological toxicity during a cycle: If prolonged Grade 4 neutropenia or thrombocytopenia, or thrombocytopenia with bleeding is observed in the previous cycle Consider reduction of the melphalan dose by 25% in the next cycle If platelet count is not above 30 x 10 9 /L or ANC is not above 0.75 x 10 9 /L on a bortezomib for injection dosing day (other than Day 1) Withhold bortezomib for injection dose If several bortezomib for injection doses in consecutive cycles are withheld due to toxicity Reduce bortezomib for injection dose by one dose level (from 1.3 mg/m 2 to 1 mg/m 2 , or from 1 mg/m 2 to 0.7 mg/m 2 ) Grade 3 or higher nonhematological toxicities Withhold bortezomib for injection therapy until symptoms of toxicity have resolved to Grade 1 or baseline. Then, bortezomib for injection may be reinitiated with one dose level reduction (from 1.3 mg/m 2 to 1 mg/m 2 , or from 1 mg/m 2 to 0.7 mg/m 2 ). For bortezomib for injection-related neuropathic pain and/or peripheral neuropathy, hold or modify bortezomib for injection as outlined in Table 5 . For information concerning melphalan and prednisone, see manufacturer's prescribing information. Dose modifications guidelines for peripheral neuropathy are provided [see Dosage and Administration ( 2.7 )]. 2.4 Dosage in Previously Untreated Mantle Cell Lymphoma Bortezomib for injection (1.3 mg/m 2 ) is administered intravenously in combination with intravenous rituximab, cyclophosphamide, doxorubicin and oral prednisone (VcR-CAP) for 6, three week treatment cycles as shown in Table 3 . Bortezomib for injection is administered first followed by rituximab. Bortezomib for injection is administered twice weekly for two weeks (Days 1, 4, 8, and 11) followed by a ten day rest period on Days 12 to 21. For patients with a response first documented at Cycle 6, two additional VcR-CAP cycles are recommended. At least 72 hours should elapse between consecutive doses of bortezomib for injection. Table 3: Dosage Regimen for Patients with Previously Untreated Mantle Cell Lymphoma Twice Weekly Bortezomib for Injection (6, Three Week Cycles) * Week 1 2 3 Bortezomib for injection (1.3 mg/m 2 ) Day 1 -- -- Day 4 -- Day 8 Day 11 rest period Rituximab (375 mg/m 2 ) Cyclophosphamide (750 mg/m 2 ) Doxorubicin (50 mg/m 2 ) Day 1 -- -- -- rest period Prednisone (100 mg/m 2 ) Day 1 Day 2 Day 3 Day 4 Day 5 -- -- rest period * Dosing may continue for two more cycles (for a total of eight cycles) if response is first seen at Cycle 6. 2.5 Dose Modification Guidelines for Bortezomib for Injection When Given in Combination with Rituximab, Cyclophosphamide, Doxorubicin and Prednisone Prior to the first day of each cycle (other than Cycle 1): • Platelet count should be at least 100 x 10 9 /L and absolute neutrophil count (ANC) should be at least 1.5 x 10 9 /L • Hemoglobin should be at least 8 g/dL (at least 4.96 mmol/L) • Nonhematologic toxicity should have recovered to Grade 1 or baseline Interrupt bortezomib for injection treatment at the onset of any Grade 3 hematologic or nonhematological toxicities, excluding neuropathy [see Table 5, Warnings and Precautions ( 5 )]. For dose adjustments, see Table 4 below. Table 4: Dose Modifications on Days 4, 8, and 11 During Cycles of Combination Bortezomib for Injection, Rituximab, Cyclophosphamide, Doxorubicin and Prednisone Therapy Toxicity Dose Modification or Delay Hematological Toxicity Grade 3 or higher neutropenia, or a platelet count not at or above 25 × 10 9 /L Withhold bortezomib for injection therapy for up to 2 weeks until the patient has an ANC at or above 0.75 × 10 9 /L and a platelet count at or above 25 × 10 9 /L. • If, after bortezomib for injection has been withheld, the toxicity does not resolve, discontinue bortezomib for injection. • If toxicity resolves such that the patient has an ANC at or above 0.75 × 10 9 /L and a platelet count at or above 25 × 10 9 /L, bortezomib for injection dose should be reduced by 1 dose level (from 1.3 mg/m 2 to 1 mg/m 2 , or from 1 mg/m 2 to 0.7 mg/m 2 ). Grade 3 or higher nonhematological toxicities Withhold bortezomib for injection therapy until symptoms of the toxicity have resolved to Grade 2 or better. Then, bortezomib for injection may be reinitiated with one dose level reduction (from 1.3 mg/m 2 to 1 mg/m 2 , or from 1 mg/m 2 to 0.7 mg/m 2 ). For bortezomib for injection-related neuropathic pain and/or peripheral neuropathy, hold or modify bortezomib for injection as outlined in Table 5 . For informat

WARNINGS AND PRECAUTIONS • Peripheral Neuropathy: Manage with dose modification or discontinuation. ( 2.7 ) Patients with pre-existing severe neuropathy should be treated with bortezomib only after careful risk-benefit assessment. ( 2.7 , 5.1 ) • Hypotension: Use caution when treating patients taking anti hypertensives, with a history of syncope, or with dehydration. ( 5.2 ) • Cardiac Toxicity: Worsening of and development of cardiac failure has occurred. Closely monitor patients with existing heart disease or risk factors for heart disease. ( 5.3 ) • Pulmonary Toxicity: Acute respiratory syndromes have occurred. Monitor closely for new or worsening symptoms and consider interrupting bortezomib therapy. ( 5.4 ) • Posterior Reversible Encephalopathy Syndrome: Consider MRI imaging for onset of visual or neurological symptoms; discontinue bortezomib if suspected. ( 5.5 ) • Gastrointestinal Toxicity: Nausea, diarrhea, constipation, and vomiting may require use of antiemetic and antidiarrheal medications or fluid replacement. ( 5.6 ) • Thrombocytopenia and Neutropenia: Monitor complete blood counts regularly throughout treatment. ( 5.7 ) • Tumor Lysis Syndrome: Closely monitor patients with high tumor burden. ( 5.8 ) • Hepatic Toxicity: Monitor hepatic enzymes during treatment. Interrupt bortezomib therapy to assess reversibility. ( 5.9 ) • Thrombotic Microangiopathy: Monitor for signs and symptoms. Discontinue bortezomib if suspected. ( 5.10 ) • Embryo-Fetal Toxicity: Bortezomib can cause fetal harm. Advise females of reproductive potential and males with female partners of reproductive potential of the potential risk to a fetus and to use effective contraception. ( 5.11 ) 5.1 Peripheral Neuropathy Bortezomib treatment causes a peripheral neuropathy that is predominantly sensory; however, cases of severe sensory and motor peripheral neuropathy have been reported. Patients with pre-existing symptoms (numbness, pain or a burning feeling in the feet or hands) and/or signs of peripheral neuropathy may experience worsening peripheral neuropathy (including ≥ Grade 3) during treatment with bortezomib. Patients should be monitored for symptoms of neuropathy, such as a burning sensation, hyperesthesia, hypoesthesia, paresthesia, discomfort, neuropathic pain or weakness. In the Phase 3 relapsed multiple myeloma trial comparing bortezomib subcutaneous vs intravenous, the incidence of Grade ≥ 2 peripheral neuropathy was 24% for subcutaneous and 39% for intravenous. Grade ≥ 3 peripheral neuropathy occurred in 6% of patients in the subcutaneous treatment group, compared with 15% in the intravenous treatment group [see Adverse Reactions ( 6.1 )] . Starting bortezomib subcutaneously may be considered for patients with pre-existing or at high risk of peripheral neuropathy. Patients experiencing new or worsening peripheral neuropathy during bortezomib therapy may require a decrease in the dose and/or a less dose-intense schedule [see Dosage and Administration ( 2.7 )]. In the bortezomib vs dexamethasone Phase 3 relapsed multiple myeloma study, improvement in or resolution of peripheral neuropathy was reported in 48% of patients with ≥ Grade 2 peripheral neuropathy following dose adjustment or interruption. Improvement in or resolution of peripheral neuropathy was reported in 73% of patients who discontinued due to Grade 2 neuropathy or who had ≥ Grade 3 peripheral neuropathy in the Phase 2 multiple myeloma studies. The long-term outcome of peripheral neuropathy has not been studied in mantle cell lymphoma. 5.2 Hypotension The incidence of hypotension (postural, orthostatic, and hypotension NOS) was 8% [see Adverse Reactions ( 6.1 )] . These events are observed throughout therapy. Patients with a history of syncope, patients receiving medications known to be associated with hypotension, and patients who are dehydrated may be at increased risk of hypotension. Management of orthostatic/postural hypotension may include adjustment of antihypertensive medications, hydration, and administration of mineralocorticoids and/or sympathomimetics. 5.3 Cardiac Toxicity Acute development or exacerbation of congestive heart failure and new onset of decreased left ventricular ejection fraction have occurred during bortezomib therapy, including reports in patients with no risk factors for decreased left ventricular ejection fraction [see Adverse Reactions ( 6.1 )] . Patients with risk factors for, or existing heart disease should be frequently monitored. In the relapsed multiple myeloma study of bortezomib vs dexamethasone, the incidence of any treatment-related cardiac disorder was 8% and 5% in the bortezomib and dexamethasone groups, respectively. The incidence of adverse reactions suggestive of heart failure (acute pulmonary edema, pulmonary edema, cardiac failure, congestive cardiac failure, cardiogenic shock) was ≤ 1% for each individual reaction in the bortezomib group. In the dexamethasone group the incidence was ≤ 1% for cardiac failure and congestive cardiac failure; there were no reported reactions of acute pulmonary edema, pulmonary edema, or cardiogenic shock. There have been isolated cases of QT-interval prolongation in clinical studies; causality has not been established. 5.4 Pulmonary Toxicity Acute Respiratory Distress Syndrome (ARDS) and acute diffuse infiltrative pulmonary disease of unknown etiology such as pneumonitis, interstitial pneumonia, lung infiltration have occurred in patients receiving bortezomib. Some of these events have been fatal. In a clinical trial, the first two patients given high-dose cytarabine (2 g/m 2 per day) by continuous infusion with daunorubicin and bortezomib for relapsed acute myelogenous leukemia died of ARDS early in the course of therapy. There have been reports of pulmonary hypertension associated with bortezomib administration in the absence of left heart failure or significant pulmonary disease. In the event of new or worsening cardiopulmonary symptoms, consider interrupting bortezomib until a prompt and comprehensive diagnostic evaluation is conducted. 5.5 Posterior Reversible Encephalopathy Syndrome (PRES) Posterior Reversible Encephalopathy Syndrome (PRES; formerly termed Reversible Posterior Leukoencephalopathy Syndrome (RPLS)) has occurred in patients receiving bortezomib. PRES is a rare, reversible, neurological disorder which can present with seizure, hypertension, headache, lethargy, confusion, blindness, and other visual and neurological disturbances. Brain imaging, preferably MRI (Magnetic Resonance Imaging), is used to confirm the diagnosis. In patients developing PRES, discontinue bortezomib. The safety of reinitiating bortezomib therapy in patients previously experiencing PRES is not known. 5.6 Gastrointestinal Toxicity Bortezomib treatment can cause nausea, diarrhea, constipation, and vomiting [see Adverse Reactions ( 6.1 )] sometimes requiring use of antiemetic and antidiarrheal medications. Ileus can occur. Fluid and electrolyte replacement should be administered to prevent dehydration. Interrupt bortezomib for severe symptoms. 5.7 Thrombocytopenia/Neutropenia Bortezomib is associated with thrombocytopenia and neutropenia that follow a cyclical pattern with nadirs occurring following the last dose of each cycle and typically recovering prior to initiation of the subsequent cycle. The cyclical pattern of platelet and neutrophil decreases and recovery remain consistent in the studies of multiple myeloma and mantle cell lymphoma, with no evidence of cumulative thrombocytopenia or neutropenia in the treatment regimens studied. Monitor complete blood counts (CBC) frequently during treatment with bortezomib. Measure platelet counts prior to each dose of bortezomib. Adjust dose/schedule for thrombocytopenia [see Dosage and Administration ( 2.6 )] . Gastrointestinal and intracerebral hemorrhage has occurred during thrombocytopenia in association with bortezomib. Support with transfusions and supportive care, according to publi

CONTRAINDICATIONS Bortezomib for Injection is contraindicated in patients with hypersensitivity (not including local reactions) to bortezomib, boron, or mannitol. Reactions have included anaphylactic reactions [see Adverse Reactions ( 6.1 )] . Bortezomib for Injection is contraindicated for intrathecal administration. Fatal events have occurred with intrathecal administration of Bortezomib for Injection. • Patients with hypersensitivity (not including local reactions) to bortezomib, boron, or mannitol, including anaphylactic reactions. ( 4 ) • Contraindicated for intrathecal administration. ( 4 )

DRUG INTERACTIONS Bortezomib is a substrate of cytochrome P450 enzyme 3A4, 2C19 and 1A2. Co-administration with strong CYP3A4 inhibitors can increase Bortezomib for Injection exposure. Closely monitor patients receiving Bortezomib for Injection in combination with strong CYP3A4 inhibitors. ( 7.1 ) Co-administration with strong CYP3A4 inducers can decrease Bortezomib for Injection exposure. Avoid concomitant use of strong CYP3A4 inducers. ( 7.3 ) 7.1 Effects of Other Drugs on Bortezomib for Injection Strong CYP3A4 Inducers Coadministration with a strong CYP3A4 inducer decreases the exposure of bortezomib [see Clinical Pharmacology (12.3) ] which may decrease Bortezomib for Injection efficacy. Avoid coadministration with strong CYP3A4 inducers. Strong CYP3A4 Inhibitors Coadministration with a strong CYP3A4 inhibitor increases the exposure of bortezomib [see Clinical Pharmacology (12.3) ] which may increase the risk of Bortezomib for Injection toxicities. Monitor patients for signs of bortezomib toxicity and consider a bortezomib dose reduction if bortezomib must be given in combination with strong CYP3A4 inhibitors. 7.2 Drugs Without Clinically Significant Interactions with Bortezomib for Injection No clinically significant drug interactions have been observed when Bortezomib for Injection was coadministered with dexamethasone, omeprazole, or melphalan in combination with prednisone [see Clinical Pharmacology (12.3) ].

ADVERSE REACTIONS The following clinically significant adverse reactions are also discussed in other sections of the labeling: • Peripheral Neuropathy [see Warnings and Precautions ( 5.1 )] • Hypotension [see Warnings and Precautions ( 5.2 )] • Cardiac Toxicity [see Warnings and Precautions ( 5.3 )] • Pulmonary Toxicity [see Warnings and Precautions ( 5.4 )] • Posterior Reversible Encephalopathy Syndrome (PRES) [see Warnings and Precautions ( 5.5 )] • Gastrointestinal Toxicity [see Warnings and Precautions ( 5.6 )] • Thrombocytopenia/Neutropenia [see Warnings and Precautions ( 5.7 )] • Tumor Lysis Syndrome [see Warnings and Precautions ( 5.8 )] • Hepatic Toxicity [see Warnings and Precautions ( 5.9 )] • Thrombotic Microangiopathy [see Warnings and Precautions ( 5.10 )] Most commonly reported adverse reactions (incidence ≥ 20%) in clinical studies include nausea, diarrhea, thrombocytopenia, neutropenia, peripheral neuropathy, fatigue, neuralgia, anemia, leukopenia, constipation, vomiting, lymphopenia, rash, pyrexia, and anorexia. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Hetero Labs Limited at 1-866-495-1995 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 clinical practice. Summary of Clinical Trial in Patients with Previously Untreated Multiple Myeloma Table 9 describes safety data from 340 patients with previously untreated multiple myeloma who received bortezomib (1.3 mg/m 2 ) administered intravenously in combination with melphalan (9 mg/m 2 ) and prednisone (60 mg/m 2 ) in a prospective randomized study. The safety profile of bortezomib in combination with melphalan/prednisone is consistent with the known safety profiles of both bortezomib and melphalan/prednisone. Table 9: Most Commonly Reported Adverse Reactions (≥ 10% in the Bortezomib, Melphalan and Prednisone Arm) with Grades 3 and ≥ 4 Intensity in the Previously Untreated Multiple Myeloma Study Bortezomib, Melphalan and Prednisone Melphalan and Prednisone (n=340) ( n =337) Body System Total Toxicity Grade, n (%) Total Toxicity Grade, n (%) Adverse Reaction n (%) 3 ≥ 4 n (%) 3 ≥ 4 Blood and Lymphatic System Disorders Thrombocytopenia 164 (48) 60 (18) 57 (17) 140 (42) 48 (14) 39 (12) Neutropenia 160 (47) 101 (30) 33 (10) 143 (42) 77 (23) 42 (12) Anemia 109 (32) 41 (12) 4 (1) 156 (46) 61 (18) 18 (5) Leukopenia 108 (32) 64 (19) 8 (2) 93 (28) 53 (16) 11 (3) Lymphopenia 78 (23) 46 (14) 17 (5) 51 (15) 26 (8) 7 (2) Gastrointestinal Disorders Nausea 134 (39) 10 (3) 0 70 (21) 1 (< 1) 0 Diarrhea 119 (35) 19 (6) 2 (1) 20 (6) 1 (< 1) 0 Vomiting 87 (26) 13 (4) 0 41 (12) 2 (1) 0 Constipation 77 (23) 2 (1) 0 14 (4) 0 0 Abdominal pain upper 34 (10) 1 (< 1) 0 20 (6) 0 0 Nervous System Disorders Peripheral neuropathy * 156 (46) 42 (12) 2 (1) 4 (1) 0 0 Neuralgia 117 (34) 27 (8) 2 (1) 1 (< 1) 0 0 Paresthesia 42 (12) 6 (2) 0 4 (1) 0 0 General Disorders and Administration Site Conditions Fatigue 85 (25) 19 (6) 2 (1) 48 (14) 4 (1) 0 Asthenia 54 (16) 18 (5) 0 23 (7) 3 (1) 0 Pyrexia 53 (16) 4 (1) 0 19 (6) 1 (< 1) 1 (< 1) Infections and Infestations Herpes Zoster 39 (11) 11 (3) 0 9 (3) 4 (1) 0 Metabolism and Nutrition Disorders Anorexia 64 (19) 6 (2) 0 19 (6) 0 0 Skin and Subcutaneous Tissue Disorders Rash 38 (11) 2 (1) 0 7 (2) 0 0 Psychiatric Disorders Insomnia 35 (10) 1 (< 1) 0 21 (6) 0 0 * Represents High Level Term Peripheral Neuropathies NEC Relapsed Multiple Myeloma Randomized Study of Bortezomib vs Dexamethasone The safety data described below and in Table 10 reflect exposure to either bortezomib (n=331) or dexamethasone (n=332) in a study of patients with relapsed multiple myeloma. Bortezomib was administered intravenously at doses of 1.3 mg/m 2 twice weekly for two out of three weeks (21 day cycle). After eight, 21 day cycles patients continued therapy for three, 35 day cycles on a weekly schedule. Duration of treatment was up to 11 cycles (nine months) with a median duration of six cycles (4.1 months). For inclusion in the trial, patients must have had measurable disease and one to three prior therapies. There was no upper age limit for entry. Creatinine clearance could be as low as 20 mL/min and bilirubin levels as high as 1.5 times the upper limit of normal. The overall frequency of adverse reactions was similar in men and women, and in patients < 65 and ≥ 65 years of age. Most patients were Caucasian [see Clinical Studies ( 14.1 )]. Among the 331 bortezomib-treated patients, the most commonly reported (> 20%) adverse reactions overall were nausea (52%), diarrhea (52%), fatigue (39%), peripheral neuropathies (35%), thrombocytopenia (33%), constipation (30%), vomiting (29%), and anorexia (21%). The most commonly reported (> 20%) adverse reaction reported among the 332 patients in the dexamethasone group was fatigue (25%). Eight percent (8%) of patients in the bortezomibtreated arm experienced a Grade 4 adverse reaction; the most common reactions were thrombocytopenia (4%) and neutropenia (2%). Nine percent (9%) of dexamethasone-treated patients experienced a Grade 4 adverse reaction. All individual dexamethasone- related Grade 4 adverse reactions were less than 1%. Serious Adverse Reactions and Adverse Reactions Leading to Treatment Discontinuation in the Relapsed Multiple Myeloma Study of Bortezomib vs Dexamethasone Serious adverse reactions are defined as any reaction that results in death, is life-threatening, requires hospitalization or prolongs a current hospitalization, results in a significant disability, or is deemed to be an important medical event. A total of 80 (24%) patients from the bortezomib treatment arm experienced a serious adverse reaction during the study, as did 83 (25%) dexamethasone-treated patients. The most commonly reported serious adverse reactions in the bortezomib treatment arm were diarrhea (3%), dehydration, herpes zoster, pyrexia, nausea, vomiting, dyspnea, and thrombocytopenia (2% each). In the dexamethasone treatment group, the most commonly reported serious adverse reactions were pneumonia (4%), hyperglycemia (3%), pyrexia, and psychotic disorder (2% each). A total of 145 patients, including 84 (25%) of 331 patients in the bortezomib treatment group and 61 (18%) of 332 patients in the dexamethasone treatment group were discontinued from treatment due to adverse reactions. Among the 331 bortezomib-treated patients, the most commonly reported adverse reaction leading to discontinuation was peripheral neuropathy (8%). Among the 332 patients in the dexamethasone group, the most commonly reported adverse reactions leading to treatment discontinuation were psychotic disorder and hyperglycemia (2% each). Four deaths were considered to be bortezomib -related in this relapsed multiple myeloma study: one case each of cardiogenic shock, respiratory insufficiency, congestive heart failure and cardiac arrest. Four deaths were considered dexamethasone-related: two cases of sepsis, one case of bacterial meningitis, and one case of sudden death at home. Most Commonly Reported Adverse Reactions in the Relapsed Multiple Myeloma Study of Bortezomib vs Dexamethasone The most common adverse reactions from the relapsed multiple myeloma study are shown in Table 10 . All adverse reactions with incidence ≥ 10% in the bortezomib arm are included. Table 10: Most Commonly Reported Adverse Reactions ( ≥ 10% in Bortezomib Arm), with Grades 3 and 4 Intensity in the Relapsed Multiple Myeloma Study of Bortezomib vs Dexamethasone (N=663) Bortezomib (N=331) Dexamethasone (N=332) Adverse Reactions All Grade 3 Grade 4 All Grade 3 Grade 4 Any Adverse Reactions 324 (98) 193 (58) 28 (8) 297 (89) 110 (33) 29 (9) Nausea 172 (52) 8 (2) 0 31 (9) 0 0 Diarrhea NOS 171 (52) 22 (7) 0 36 (11) 2 (< 1) 0 Fatigue 130 (39) 15 (

Mechanism of Action Bortezomib is a reversible inhibitor of the chymotrypsin-like activity of the 26S proteasome in mammalian cells. The 26S proteasome is a large protein complex that degrades ubiquitinated proteins. The ubiquitin­-proteasome pathway plays an essential role in regulating the intracellular concentration of specific proteins, thereby maintaining homeostasis within cells. Inhibition of the 26S proteasome prevents this targeted proteolysis, which can affect multiple signaling cascades within the cell. This disruption of normal homeostatic mechanisms can lead to cell death. Experiments have demonstrated that bortezomib is cytotoxic to a variety of cancer cell types in vitro . Bortezomib causes a delay in tumor growth in vivo in nonclinical tumor models, including multiple myeloma.