Eltrombopag

12.1 Mechanism of Action Eltrombopag is a TPO-receptor agonist that interacts with the transmembrane domain of the human TPO-receptor (also known as cMpl) and initiates signaling cascades that induce proliferation and differentiation of megakaryocytes leading to increased platelet production.

1 INDICATIONS AND USAGE Eltrombopag is a thrombopoietin receptor agonist indicated: for the treatment of thrombocytopenia in adult and pediatric patients 1 year and older with persistent or chronic immune thrombocytopenia (ITP) who have had an insufficient response to corticosteroids, immunoglobulins, or splenectomy. Eltrombopag tablets should be used only in patients with ITP whose degree of thrombocytopenia and clinical condition increase the risk for bleeding. ( 1.1 ) for the treatment of thrombocytopenia in patients with chronic hepatitis C to allow the initiation and maintenance of interferon-based therapy. Eltrombopag tablets should be used only in patients with chronic hepatitis C whose degree of thrombocytopenia prevents the initiation of interferon-based therapy or limits the ability to maintain interferon-based therapy. ( 1.2 ) in combination with standard immunosuppressive therapy for the first-line treatment of adult and pediatric patients 2 years and older with severe aplastic anemia. ( 1.3 ) for the treatment of patients with severe aplastic anemia who have had an insufficient response to immunosuppressive therapy. ( 1.3 ) Limitations of Use: Eltrombopag tablets are not indicated for the treatment of patients with myelodysplastic syndrome (MDS). ( 1.4 ) Safety and efficacy have not been established in combination with direct-acting antiviral agents used without interferon for treatment of chronic hepatitis C infection. ( 1.4 ) 1.1 Treatment of Thrombocytopenia in Patients With Persistent or Chronic Immune Thrombocytopenia Eltrombopag tablets are indicated for the treatment of thrombocytopenia in adult and pediatric patients 1 year and older with persistent or chronic immune thrombocytopenia (ITP) who have had an insufficient response to corticosteroids, immunoglobulins, or splenectomy. Eltrombopag tablets should be used only in patients with ITP whose degree of thrombocytopenia and clinical condition increase the risk for bleeding. 1.2 Treatment of Thr

2 DOSAGE AND ADMINISTRATION Take eltrombopag tablets without a meal or with a meal low in calcium (≤ 50 mg). Take eltrombopag tablets at least 2 hours before or 4 hours after any medications or products containing polyvalent cations, such as antacids, calcium-rich foods, and mineral supplements. ( 2.4 , 7.1 , 12.3 ) Persistent or Chronic ITP: Initiate eltrombopag tablets at 50 mg orally once daily for most adult and pediatric patients 6 years and older, and at 25 mg orally once daily for pediatric patients aged 1 to 5 years. Dose reductions are needed for patients with hepatic impairment and some patients of East-/Southeast-Asian ancestry. Adjust to maintain platelet count greater than or equal to 50 x 10 9 /L. Do not exceed 75 mg per day. ( 2.1 , 8.6 , 8.7 ) Chronic Hepatitis C-associated Thrombocytopenia: Initiate eltrombopag tablets at 25 mg orally once daily for all patients. Adjust to achieve target platelet count required to initiate antiviral therapy. Do not exceed a daily dose of 100 mg. ( 2.2 ) First-line Severe Aplastic Anemia: Initiate eltrombopag tablets orally once daily at 2.5 mg/kg (in pediatric patients aged 2 to 5 years old), 75 mg (pediatric patients aged 6 to 11 years old) or 150 mg for patients aged 12 years and older concurrently with standard immunosuppressive therapy. Reduce initial dose in patients of East-/Southeast-Asian ancestry. Modify dosage for toxicity or elevated platelet counts. ( 2.3 , 8.7 ) Refractory Severe Aplastic Anemia: Initiate eltrombopag tablets orally at 50 mg once daily. Reduce initial dose in patients with hepatic impairment or patients of East-/Southeast-Asian ancestry. Adjust to maintain platelet count greater than 50 x 10 9 /L. Do not exceed 150 mg per day. ( 2.3 , 8.6 , 8.7 ) 2.1 Persistent or Chronic Immune Thrombocytopenia Use the lowest dose of eltrombopag tablets to achieve and maintain a platelet count greater than or equal to 50 x 10 9 /L as necessary to reduce the risk for bleeding. Dose adjustments are based upon the platelet count response. Do not use eltrombopag tablets to normalize platelet counts [see Warnings and Precautions (5.4) ]. In clinical trials, platelet counts generally increased within 1 to 2 weeks after starting eltrombopag tablets and decreased within 1 to 2 weeks after discontinuing eltrombopag tablets [see Clinical Studies (14.1) ] . Initial Dose Regimen Adult and Pediatric Patients 6 Years and Older with ITP Initiate eltrombopag tablets at a dose of 50 mg orally once daily, except in patients who are of East-/Southeast-Asian ancestry or who have mild to severe hepatic impairment (Child-Pugh class A, B, C). For patients of East-/Southeast-Asian ancestry with ITP, initiate eltrombopag tablets at a reduced dose of 25 mg orally once daily [see Use in Specific Populations (8.7) , Clinical Pharmacology (12.3) ]. For patients with ITP and mild, moderate, or severe hepatic impairment (Child-Pugh class A, B, C), initiate eltrombopag tablets at a reduced dose of 25 mg orally once daily [see Use in Specific Populations (8.6) , Clinical Pharmacology (12.3) ] . For patients of East-/Southeast-Asian ancestry with ITP and hepatic impairment (Child-Pugh class A, B, C), consider initiating eltrombopag tablets at a reduced dose of 12.5 mg orally once daily [see Clinical Pharmacology (12.3) ] . Pediatric Patients with ITP Aged 1 to 5 Years Initiate eltrombopag tablets at a dose of 25 mg orally once daily [see Use in Specific Populations (8.7) , Clinical Pharmacology (12.3) ]. Monitoring and Dose Adjustment After initiating eltrombopag tablets, adjust the dose to achieve and maintain a platelet count greater than or equal to 50 x 10 9 /L as necessary to reduce the risk for bleeding. Do not exceed a dose of 75 mg daily. Monitor clinical hematology and liver tests regularly throughout therapy with eltrombopag tablets and modify the dosage regimen of eltrombopag tablets based on platelet counts as outlined in Table 1. During therapy with eltrombopag tablets, assess complete blood counts (CBCs) with differentials, including platelet counts, weekly until a stable platelet count has been achieved. Obtain CBCs with differentials, including platelet counts, monthly thereafter. When switching between the oral suspension and tablet, assess platelet counts weekly for 2 weeks, and then follow standard monthly monitoring. Table 1: Dose Adjustments of Eltrombopag Tablets in Patients With Persistent or Chronic Immune Thrombocytopenia Platelet count result Dose adjustment or response < 50 x 10 9 /L following at least 2 weeks of eltrombopag tablets Increase daily dose by 25 mg to a maximum of 75 mg/day. For patients taking 12.5 mg once daily, increase the dose to 25 mg daily before increasing the dose amount by 25 mg. ≥ 200 x 10 9 /L to ≤ 400 x 10 9 /L at any time Decrease the daily dose by 25 mg. Wait 2 weeks to assess the effects of this and any subsequent dose adjustments. For patients taking 25 mg once daily, decrease the dose to 12.5 mg once daily. > 400 x 10 9

6 ADVERSE REACTIONS The following clinically significant adverse reactions associated with eltrombopag are described in other sections. Hepatic Decompensation in Patients with Chronic Hepatitis C [see Warnings and Precautions (5.1) ] Hepatotoxicity [see Warnings and Precautions (5.2) ] Increased Risk of Death and Progression of Myelodysplastic Syndromes to Acute Myeloid Leukemia [see Warnings and Precautions (5.3) ] Thrombotic/Thromboembolic Complications [see Warnings and Precautions (5.4) ] Cataracts [see Warnings and Precautions (5.5) ] Across all indications, the most common adverse reactions (≥ 20% in any indication) were: anemia, nausea, pyrexia, alanine aminotransferase increased, cough, fatigue, headache, and diarrhea. ( 6.1 ) To report SUSPECTED ADVERSE REACTIONS, contact Amneal Pharmaceuticals LLC at 1-877-835-5472 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 with rates in the clinical trials of another drug and may not reflect the rates observed in practice. Persistent or Chronic Immune Thrombocytopenia Adults In clinical trials, hemorrhage was the most common serious adverse reaction and most hemorrhagic reactions followed discontinuation of eltrombopag. Other serious adverse reactions included thrombotic/thromboembolic complications [see Warnings and Precautions (5.4) ] . The data described below reflect exposure of eltrombopag to patients with persistent or chronic ITP aged 18 to 85 years, of whom 66% were female, in three placebo-controlled trials and one open-label extension trial [see Clinical Studies (14.1) ] . Eltrombopag was administered to 330 patients for at least 6 months and 218 patients for at least 1 year. Table 8 presents the most common adverse drug reactions (experienced by greater than or equal to 3% of patients receiving eltrombopag) from the three placebo-controlled trials, with a higher incidence in eltrombopag versus placebo. Table 8: Adverse Reactions (≥ 3%) From Three Placebo-controlled Trials in Adults With Persistent or Chronic Immune Thrombocytopenia Adverse reaction Eltrombopag 50 mg n = 241 (%) Placebo n = 128 (%) Nausea 9 3 Diarrhea 9 7 Upper respiratory tract infection 7 6 Vomiting 6 < 1 Urinary tract infection a 5 4 Increased ALT 5 3 Myalgia 5 2 Oropharyngeal pain 4 3 Increased AST 4 2 Pharyngitis 4 2 Back pain 3 2 Influenza 3 2 Paresthesia 3 2 Rash 3 2 Abbreviations: ALT, alanine aminotransferase; AST, aspartate aminotransferase. a Includes PTs of urinary tract infection, cystitis, urinary tract infection bacterial, and bacteriuria. In the three controlled clinical persistent or chronic ITP trials, alopecia, musculoskeletal pain, blood alkaline phosphatase increased, and dry mouth were the adverse reactions reported in 2% of patients treated with eltrombopag and in no patients who received placebo. Among 302 patients with persistent or chronic ITP who received eltrombopag in the single-arm extension trial, the adverse reactions occurred in a pattern similar to that seen in the placebo-controlled trials. Table 9 presents the most common treatment-related adverse reactions (experienced by greater than or equal to 3% of patients receiving eltrombopag) from the extension trial. Table 9: Treatment-related Adverse Reactions ( > 3%) From Extension Trial in Adults With Persistent or Chronic Immune Thrombocytopenia Adverse reaction Eltrombopag 50 mg n = 302 (%) Headache 10 ALT increased 5 AST increased 5 Cataract 5 Fatigue 5 Blood bilirubin increased 4 Nausea 4 Hyperbilirubinemia 3 Diarrhea 3 Abbreviations: ALT, alanine aminotransferase; AST, aspartate aminotransferase. In the three controlled persistent or chronic ITP trials, serum liver test abnormalities (predominantly Grade 2 or less in severity) were reported in 11% and 7% of patients for eltrombopag and placebo, respectively. Four patients (1%) treated with eltrombopag and three patients in the placebo group (2%) discontinued treatment due to hepatobiliary laboratory abnormalities. Seventeen of the patients treated with eltrombopag in the controlled trials with hepatobiliary laboratory abnormalities were re-exposed to eltrombopag in the extension trial. Eight of these patients again experienced liver test abnormalities (less than or equal to Grade 3) resulting in discontinuation of eltrombopag in one patient. In the extension persistent or chronic ITP trial, six additional patients had eltrombopag discontinued due to liver test abnormalities (less than or equal to Grade 3). In the three controlled persistent or chronic ITP trials, cataracts developed or worsened in 7% of patients treated with eltrombopag and 7% of patients in the placebo group. All patients had documented, preexisting risk factors for cataractogenesis, including corticosteroid use. In the extension trial, cataracts developed or worsened in 11% of patien

7 DRUG INTERACTIONS 7.1 Polyvalent Cations (Chelation) Eltrombopag chelates polyvalent cations (such as iron, calcium, aluminum, magnesium, selenium, and zinc) in foods, mineral supplements, and antacids. Take eltrombopag tablets at least 2 hours before or 4 hours after any medications or products containing polyvalent cations, such as antacids, dairy products, and mineral supplements to avoid significant reduction in absorption of eltrombopag due to chelation [see Dosage and Administration (2.4) , Clinical Pharmacology (12.3) ] . 7.2 Transporters Use caution when concomitantly administering eltrombopag and drugs that are substrates of OATP1B1 (e.g., atorvastatin, bosentan, ezetimibe, fluvastatin, glyburide, olmesartan, pitavastatin, pravastatin, rosuvastatin, repaglinide, rifampin, simvastatin acid, SN-38 [active metabolite of irinotecan], valsartan) or breast cancer resistance protein (BCRP) (e.g., imatinib, irinotecan, lapatinib, methotrexate, mitoxantrone, rosuvastatin, sulfasalazine, topotecan). Monitor patients closely for signs and symptoms of excessive exposure to the drugs that are substrates of OATP1B1 or BCRP and consider reduction of the dose of these drugs, if appropriate. In clinical trials with eltrombopag, a dose reduction of rosuvastatin by 50% was recommended. 7.3 Protease Inhibitors HIV Protease Inhibitors: No dose adjustment is recommended when eltrombopag is co-administered with lopinavir/ritonavir (LPV/RTV). Drug interactions with other HIV protease inhibitors have not been evaluated. Hepatitis C Virus Protease Inhibitors: No dose adjustments are recommended when eltrombopag is co-administered with boceprevir or telaprevir. Drug interactions with other hepatitis C virus (HCV) protease inhibitors have not been evaluated. 7.4 Peginterferon Alfa-2a/b Therapy No dose adjustments are recommended when eltrombopag is co-administered with peginterferon alfa-2a (PEGASYS ® ) or -2b (PEGINTRON ® ). 7.5 Interference with Clinical Laboratory Tests Eltrombopag is highly colored and can cause patient sample discoloration, which is reported to interfere with some clinical laboratory tests, including, but not limited to bilirubin and creatinine. Bilirubin Testing : Eltrombopag can cause both positive and negative interference with bilirubin assays. If the laboratory results for bilirubin are inconsistent with clinical observations, further evaluation of liver function should be performed to clarify the clinical status of the patient. Evaluating contemporaneous aminotransferase values (AST, ALT) may help determine the validity of normal total bilirubin levels in the presence of clinical jaundice. Creatinine Testing : Eltrombopag can cause positive interference with creatinine measurements, leading to falsely elevated creatinine levels. In the event of an unexpected serum creatinine test result, further evaluation of renal function should be performed. Blood urea should be evaluated if serum creatinine is unexpectedly high. Communicate to the lab conducting testing if the patient is taking eltrombopag. Re-testing using other methods may also help in determining the validity of the test results.