Approval summary: Cetuximab in combination with cisplatin or carboplatin and 5-fluorouracil for the first-line treatment of patients with recurrent locoregional or metastatic squamous cell head and neck cancer.

On November 7, 2011, the U.S. Food and Drug Administration approved cetuximab in combination with cisplatin or carboplatin and 5-fluorouracil for the first-line treatment of patients with recurrent locoregional or metastatic squamous cell head and neck cancer. Approval was based on a randomized study of 442 patients conducted outside the U.S. Cisplatin (100 mg/m2 intravenously) or carboplatin (area under the curve 5 intravenously) on day 1 with 5-fluorouracil (1,000 mg/m2/day continuous intravenous infusion days 1-4) were administered every 3 weeks. Cetuximab, 400 mg/m2 intravenously, was administered initially followed by cetuximab, 250 mg/m2 intravenously weekly. After completion of six planned treatment courses, cetuximab patients without progression continued cetuximab 250 mg/m2 weekly. The study used European Union (EU)-approved cetuximab rather than U.S.-approved cetuximab. U.S.-approved cetuximab provides approximately 28% higher exposure relative to EU-approved cetuximab in a pharmacokinetic comparability study in monkeys. Overall survival, the primary efficacy endpoint, was significantly improved in cetuximab-treated patients (hazard ratio [HR]: 0.80; 95% confidence interval [CI]: 0.64-0.98; p = .034, stratified log-rank test). Median survival times were 10.1 and 7.4 months, respectively. Progression-free survival (PFS) was also significantly improved in patients receiving cetuximab (HR: 0.57; 95% CI: 0.46-0.72; p < .0001). Median PFS times were 5.5 and 3.3 months, respectively. Response rates were 35.6% and 19.5% (odds ratio: 2.33; 95% CI: 1.50-3.60; p = .0001). Adverse reactions (≥25%) from cetuximab plus chemotherapy treatment included nausea, anemia, vomiting, neutropenia, rash, asthenia, diarrhea, and anorexia. Conjunctivitis occurred in 10% of cetuximab patients. Other adverse reactions, sometimes severe, included infusion reactions, hypomagnesemia, hypocalcemia, and hypokalemia.

Approval summary: imatinib mesylate for one or three years in the adjuvant treatment of gastrointestinal stromal tumors.

On January 31, 2012, the U.S. Food and Drug Administration granted regular approval of imatinib mesylate tablets (Gleevec®; Novartis Pharmaceuticals Corporation, East Hanover, NJ) for the adjuvant treatment of adult patients following complete gross resection of Kit(+) (CD117(+)) gastrointestinal stromal tumors (GISTs). The recommended dose of imatinib is 400 mg/day administered daily for 3 years. Three hundred ninety-seven patients were enrolled in a randomized adjuvant, multicenter, open label, phase III trial comparing 12 months with 36 months of imatinib treatment. Eligible patients had one of the following: tumor diameter >5 cm and mitotic count >5 per 50 high power fields (HPFs); tumor diameter >10 cm and any mitotic count; tumor of any size with mitotic count >10/50 HPFs; or tumor ruptured into the peritoneal cavity. The primary endpoint was the recurrence-free survival (RFS) interval. The median follow-up for patients without an RFS event was 42 months. There were 84 (42%) RFS events in the 12-month treatment arm and 50 (25%) RFS events in the 36-month treatment arm. Thirty-six months of imatinib treatment led to a significantly longer RFS interval than with 12 months of treatment. The median follow-up for overall survival (OS) evaluation in patients still living was 48 months. Thirty-six months of imatinib treatment led to a significantly longer OS time than with 12 months of imatinib treatment. The most common adverse reactions, as noted in previous imatinib studies, were diarrhea, fatigue, nausea, edema, decreased hemoglobin, rash, vomiting, and abdominal pain.

U.S. Food and Drug Administration Approval: peginterferon-alfa-2b for the adjuvant treatment of patients with melanoma.

On March 29, 2011, the U.S. Food and Drug Administration approved peginterferon alfa-2b (PEG-IFN) (Sylatron™; Schering Corporation, Kenilworth, NJ) for the adjuvant treatment of melanoma patients with microscopic or gross nodal involvement following definitive surgical resection including complete lymphadenectomy. The approval was based on a single, open-label, multicenter trial enrolling 1,256 patients. After surgical resection, patients were randomized (1:1) to either PEG-IFN or observation for 5 years. PEG-IFN, 6 µg/kg per week, was administered s.c. for eight doses, followed by 3 µg/kg per week for up to 252 weeks. Stratification factors included microscopic or gross nodal involvement, number of positive nodes, Breslow thickness, ulceration, sex, and study center. Patients were assessed for recurrence by the investigators based on physical examination every 3 months for 2 years and every 6 months thereafter. The relapse-free survival (RFS) interval, the primary efficacy endpoint, was significantly longer in PEG-IFN-treated patients. The median RFS times were 34.8 months and 25.5 months, respectively. There was no statistically significant difference in the overall survival time. The most common (>60%) grade 1-4 adverse reactions were fatigue, increased alanine aminotransferase (ALT) and aspartate aminotransferase (AST), pyrexia, headache, anorexia, myalgia, nausea, chills, and injection site reactions. The most common serious adverse reactions were fatigue, increased ALT and AST, and pyrexia. Thirty-three percent of patients receiving PEG-IFN discontinued treatment as a result of adverse reactions. Five deaths were reported within 30 days of the last treatment dose, two resulting from cardiovascular disease considered as possibly related to treatment.

Approval summary: letrozole (Femara® tablets) for adjuvant and extended adjuvant postmenopausal breast cancer treatment: conversion of accelerated to full approval.

On April 30, 2010, the U.S. Food and Drug Administration converted letrozole (Femara®; Novartis Pharmaceuticals Corporation, East Hanover, NJ) from accelerated to full approval for adjuvant and extended adjuvant (following 5 years of tamoxifen) treatment of postmenopausal women with hormone receptor-positive early breast cancer. The initial accelerated approvals of letrozole for adjuvant and extended adjuvant treatment on December 28, 2005 and October 29, 2004, respectively, were based on an analysis of the disease-free survival (DFS) outcome of patients followed for medians of 26 months and 28 months, respectively. Both trials were double-blind, multicenter studies. Both trials were unblinded early when an interim analysis showed a favorable letrozole effect on DFS. In updated intention-to-treat analyses of both trials, the risk for a DFS event was lower with letrozole than with tamoxifen (hazard ratio [HR], 0.87; 95% confidence interval [CI], 0.77-0.99; p = .03) in the adjuvant trial and was lower than with placebo (HR, 0.89; 95% CI, 0.76-1.03; p = .12) in the extended adjuvant trial. The latter analysis ignores the interim switch of 60% of placebo-treated patients to letrozole. Bone fractures and osteoporosis were reported more frequently following treatment with letrozole whereas tamoxifen was associated with a higher risk for endometrial proliferation and endometrial cancer. Myocardial infarction was more frequently reported with letrozole than with tamoxifen, but the incidence of thromboembolic events was higher with tamoxifen than with letrozole. Lipid-lowering medications were required for 25% of patients on letrozole and 16% of patients on tamoxifen.

Approval summary: pemetrexed maintenance therapy of advanced/metastatic nonsquamous, non-small cell lung cancer (NSCLC).

On July 2, 2009, the U.S. Food and Drug Administration approved pemetrexed injection (Alimta® Injection; Eli Lilly and Company, Indianapolis, IN) for maintenance treatment of patients with locally advanced or metastatic nonsquamous non-small cell lung cancer whose disease has not progressed after four cycles of platinum-based doublet induction chemotherapy. A double-blind study of pemetrexed plus best supportive care versus placebo plus best supportive care was conducted. Pemetrexed, 500 mg/m(2) i.v., was administered every 21 days until disease progression. Folic acid, vitamin B(12), and a corticosteroid were given to all study patients. There were 663 randomized patients (pemetrexed, 441; placebo, 222). Treatments were well balanced with respect to baseline disease characteristics and stratification factors. The median overall survival (OS) time for intent-to-treat (ITT) patients was 13.4 months for patients receiving pemetrexed and 10.6 months for those receiving placebo (hazard ratio [HR] 0.79; 95% confidence interval [CI], 0.65-0.95; p = .012). Median OS times were 15.5 months versus 10.3 months for patients with nonsquamous histologies receiving pemetrexed and placebo, respectively (HR, 0.70; 95% CI, 0.56-0.88). The median OS time in patients with squamous histology receiving pemetrexed was 9.9 months, versus 10.8 months for those receiving placebo (HR, 1.07; 95% CI, 0.77-1.50). A significantly longer progression-free survival interval for both the ITT and nonsquamous patient populations receiving pemetrexed maintenance therapy was also observed. The most common (>5%) adverse reactions in patients receiving pemetrexed were hematologic toxicity, an increase in hepatic enzymes, fatigue, gastrointestinal toxicity, sensory neuropathy, and skin rash.

Approval summary: imatinib mesylate in the adjuvant treatment of malignant gastrointestinal stromal tumors.

On December 19, 2008, the U.S. Food and Drug Administration approved imatinib mesylate tablets for oral use (Gleevec(R); Novartis Pharmaceuticals Corporation, East Hanover, NJ) for the adjuvant treatment of adult patients following complete gross resection of Kit(+) (CD117(+)) gastrointestinal stromal tumor (GIST). A randomized, double-blind, placebo-controlled study enrolling 713 patients was submitted. The primary objective of the clinical trial was to compare the recurrence-free survival (RFS) intervals of the two groups. Overall survival (OS) was a secondary endpoint. Eligible patients were > or =18 years of age with a histological diagnosis of GIST (Kit(+)), resected tumor size > or =3 cm, and a complete gross resection within 14-70 days prior to registration. Imatinib, 400 mg orally, was administered once daily for 1 year. The study was terminated after completion of the third protocol-specified interim analysis. At that time, 100 RFS events were confirmed by a blinded central independent review. With a median follow-up of 14 months, 30 RFS events were observed in the imatinib group and 70 were observed in the placebo group (hazard ratio, 0.398; 95% confidence interval, 0.259-0.610; two-sided p-value < .0001). OS results are immature. Most patients in both groups experienced at least one adverse reaction, and 31% of the imatinib group and 18% of the placebo group experienced grade > or =3 adverse reactions. The most frequently reported adverse reactions (> or =20%) were diarrhea, fatigue, nausea, edema, decreased hemoglobin, rash, vomiting, and abdominal pain. Drug was discontinued for adverse reactions in 17% and 3% of the imatinib and placebo-treated patients, respectively.

FDA drug approval summary: bevacizumab plus interferon for advanced renal cell carcinoma.

On July 31, 2009, the U.S. Food and Drug Administration granted approval for the use of bevacizumab (Avastin(R); Genentech, Inc., South San Francisco, CA) in combination with interferon (IFN)-alpha2a for the treatment of patients with metastatic renal cell carcinoma. The approval was primarily based on results from a randomized, double-blind, placebo-controlled clinical trial. The primary efficacy endpoint, progression-free survival (PFS), was assessed by investigators and by an independent review committee (IRC) blinded to treatment assignment. In total, 649 patients (bevacizumab plus IFN, 327; placebo plus IFN, 322) were enrolled. The median PFS times, by investigator determination, were 10.2 months for the bevacizumab plus IFN arm and 5.4 months for the placebo plus IFN arm (hazard ratio [HR], 0.60; 95% confidence interval [CI], 0.49-0.72; p < .0001). The IRC analysis of 569 patients with available radiographs yielded similar results (median PFS time, 10.4 months versus 5.5 months; HR, 0.57; 95% CI, 0.45-0.72; p < .0001). There was no survival advantage (HR, 0.86; 95% CI, 0.72-1.04; p = .13). Support for the above results was provided by summarized results of a North American cooperative group study of bevacizumab plus IFN-alpha2b versus IFN-alpha2b alone. The median PFS times were 8.4 months versus 4.9 months in favor of the bevacizumab combination. There was no survival advantage. In the reviewed trial, serious adverse events and National Cancer Institute Common Terminology Criteria for Adverse Events grade >/=3 adverse events were reported more frequently in bevacizumab-treated patients (31% versus 19% and 63% versus 47%, respectively). The most common bevacizumab-related toxicities were bleeding/hemorrhage, hypertension, proteinuria, and venous or arterial thromboembolic events.

Approval summary: erlotinib maintenance therapy of advanced/metastatic non-small cell lung cancer (NSCLC).

On April 16, 2010, the U. S. Food and Drug Administration (FDA) approved erlotinib tablets (Tarceva®; OSI Pharmaceuticals, Inc., Melville, NY) for maintenance treatment of patients with stage IIIB/IV non-small cell lung cancer (NSCLC) whose disease had not progressed after four cycles of platinum-based first-line chemotherapy. In total, 889 patients received either erlotinib (150 mg) or placebo once daily. Progression-free survival (PFS), in all patients and in patients with epidermal growth factor receptor (EGFR)(+) tumors by immunohistochemistry (IHC), was the primary efficacy endpoint. Overall survival (OS) was a secondary sponsor endpoint but was the primary regulatory endpoint. Median PFS times were 2.8 months and 2.6 months in the erlotinib and placebo arms, respectively (hazard ratio [HR], 0.71; 95% confidence interval [CI], 0.62-0.82; p < .001). Median OS times were 12.0 months and 11.0 months, favoring erlotinib (HR, 0.81; 95% CI, 0.70-0.95). The PFS and OS HRs in patients with EGFR(+) tumors by IHC were 0.69 (95% CI, 0.58-0.82) and 0.77 (95% CI, 0.64-0.93), respectively. The PFS and OS HRs in patients with EGFR(-) tumors by IHC were 0.77 (95% CI, 0.51-1.14) and 0.91 (95% CI, 0.59-1.38), respectively. Following disease progression, 57% of placebo-treated patients received additional chemotherapy, compared with 47% of erlotinib-treated patients. Fourteen percent of placebo-treated patients received erlotinib or gefitinib, 31% received docetaxel, and 14% received pemetrexed. In total, 59% of placebo-treated patients who received treatment received FDA approved second-line NSCLC drugs. The most common adverse reactions in patients receiving erlotinib were rash and diarrhea.

FDA report: Ferumoxytol for intravenous iron therapy in adult patients with chronic kidney disease.

On June 30, 2009, the United States Food and Drug Administration (FDA) approved ferumoxytol (Feraheme injection, AMAG Pharmaceuticals), an iron-containing product for intravenous (IV) administration, for the treatment of iron deficiency anemia in adult patients with chronic kidney disease (CKD). The safety and efficacy of ferumoxytol were assessed in three randomized, open-label, controlled clinical trials. Two trials evaluated patients with nondialysis dependent CKD and a third trial assessed patients undergoing hemodialysis. Randomization was either to ferumoxytol or oral iron. Ferumoxytol was administered as two 510 mg IV injections, separated by 3-8 days. Oral iron, Ferro-Sequels, was administered at a dose of 100 mg twice daily for 21 days. In all three clinical trials, ferumoxytol administration increased the mean blood hemoglobin (Hgb) concentrations by approximately 1.0 g/dL over the 35 day period, a mean increase that was greater than what was observed in patients receiving oral iron. Patients receiving ferumoxytol also had increases in blood transferrin saturation (TSAT) and ferritin values. For the proposed ferumoxytol dosing regimen, 4.9% of patients had serum ferritin >or=800 ng/mL and TSAT >or=50% post-treatment. The most important ferumoxytol safety concerns were hypersensitivity reactions and/or hypotension. Anaphylaxis or anaphylactoid reactions were reported in 0.2% of subjects, and other adverse reactions potentially associated with hypersensitivity (e.g., pruritus, rash, urticaria, or wheezing) were reported in 3.7%. Hypotension was observed in 1.9%, including three patients with serious hypotensive reactions. Ferumoxytol administration may transiently affect the diagnostic ability of magnetic resonance imaging and the drug label provides further information regarding this effect.

Approval summary: pemetrexed in the initial treatment of advanced/metastatic non-small cell lung cancer.

On September 26, 2008, the U.S. Food and Drug Administration approved pemetrexed injection (Alimta Injection; Eli Lilly and Company, Indianapolis, IN) for use in combination with cisplatin for the initial treatment of patients with stage IIIB/IV nonsquamous non-small cell lung cancer (NSCLC). A randomized, phase III, open-label study was conducted in 1,725 patients. Patients were randomly assigned to receive 21-day cycles of pemetrexed plus cisplatin (AC) or gemcitabine plus cisplatin (GC). The primary objective was overall survival. The median survival time was 10.3 months in both the AC arm and the GC arm (adjusted hazard ratio [HR], 0.94; 95% confidence interval [CI], 0.84-1.05). The median progression-free survival times were 4.8 and 5.1 months for the AC and GC arms, respectively (adjusted HR, 1.04; 95% CI, 0.94-1.15). The overall response rates were 27.1% and 24.7% for the AC and GC arms, respectively. A prespecified analysis of the impact of NSCLC histology on overall survival was conducted. In the nonsquamous NSCLC subgroup, the median survival times were 11.0 and 10.1 months in the AC and GC groups, respectively (unadjusted HR, 0.84; 95% CI, 0.74-0.96). However, in the squamous cell histology subgroup, the median survival times were 9.4 versus 10.8 months in the AC and GC groups, respectively (unadjusted HR, 1.22; 95% CI, 0.99-1.50). This unfavorable effect of squamous histology on overall survival was also noted in a retrospective analysis of a trial that compared pemetrexed with docetaxel in NSCLC patients who received prior chemotherapy. No new pemetrexed safety signals were observed.

FDA review of a panitumumab (Vectibix) clinical trial for first-line treatment of metastatic colorectal cancer.

On September 27, 2006, the U.S. Food and Drug Administration granted accelerated approval to panitumumab (Vectibix; Amgen, Inc., Thousand Oaks, CA) for the treatment of patients with epidermal growth factor receptor-expressing, metastatic colorectal carcinoma with disease progression on or following fluoropyrimidine-, oxaliplatin-, and irinotecan-containing chemotherapy regimens. Accelerated approval was based on demonstration of a beneficial effect on progression-free survival (PFS). The present submission summarizes a second clinical trial, to be included in the panitumumab package insert in June 2008, of chemotherapy and bevacizumab with and without panitumumab in the first-line treatment of patients with metastatic colorectal cancer. The study was closed when inferior PFS and greater toxicity were demonstrated at the time of the planned interim efficacy analysis. Patients receiving panitumumab in combination with bevacizumab and chemotherapy experienced a higher incidence of death (9% versus 4%) and a higher risk for grade 3 and 4 toxicities than patients receiving bevacizumab and chemotherapy alone. The incidences of any Common Terminology Criteria for Adverse Events grade 3 and 4 adverse events (AEs) were 87% and 72% in the panitumumab and control groups, respectively. Grade 3 and 4 AEs occurring more commonly in panitumumab-treated patients included rash/acneiform dermatitis, diarrhea, dehydration, primarily resulting from diarrhea, hypokalemia, stomatitis/mucositis, and pulmonary embolism. The addition of panitumumab to bevacizumab and chemotherapy for the first-line treatment of metastatic colorectal cancer was harmful when compared with bevacizumab and chemotherapy alone. The use of panitumumab in this setting cannot be recommended.

Approval summary: imatinib mesylate in the treatment of metastatic and/or unresectable malignant gastrointestinal stromal tumors.

The purpose of the present application was to fulfill a postmarketing commitment to provide long-term efficacy and safety data on treatment with imatinib mesylate (Gleevec; Novartis Pharmaceuticals, East Hanover, NJ) in patients with CD117(+) unresectable and/or metastatic malignant gastrointestinal stromal tumors (GISTs). In addition, this application also provides evidence to support a change in the label to allow for an escalation of imatinib dosing to 800 mg/day for patients with progressive disease on a lower dose. Two open-label, controlled, multicenter, intergroup, international, randomized phase III studies were submitted -- one conducted by the European Organization for Research and Treatment of Cancer (n = 946) and the other by the Southwest Oncology Group (n = 746). These studies compared 400 mg/day of imatinib with 800 mg/day of imatinib. A combined analysis of the two studies was prospectively defined and agreed to by both groups. Both protocols allowed patients randomized to the 400-mg/day imatinib arm to cross over to 800 mg/day imatinib at progression. Objective responses were achieved in >50% of patients receiving either imatinib dose. The median progression-free survival time was approximately 20 months and the median overall survival (OS) time was approximately 49 months. In the combined analysis, 347 patients crossed over to 800 mg/day imatinib at the time of progression. The median OS time after crossover was 14.3 months. The most common adverse events (AEs) were fluid retention, nausea, fatigue, skin rash, gastrointestinal complaints, and myalgia. The most common laboratory abnormality was anemia. Most often the AEs were of mild-to-moderate severity. Fluid retention events and skin rash were numerically reported more often in the 800-mg/day treatment cohort of patients.

FDA drug approval summary: bevacizumab (Avastin) as treatment of recurrent glioblastoma multiforme.

On May 5, 2009, the U.S. Food and Drug Administration granted accelerated approval to bevacizumab injection (Avastin; Genentech, Inc., South San Francisco, CA) as a single agent for patients with glioblastoma multiforme (GBM) with progressive disease following prior therapy. The approval was based on durable objective responses (independent radiologic review with stable or decreasing corticosteroid use). Two trials evaluating bevacizumab, 10 mg/kg by i.v. infusion every 2 weeks, were submitted. One trial also randomized patients to bevacizumab plus irinotecan treatment. All patients had received prior surgery, radiotherapy, and temozolomide. Patients with active brain hemorrhage were excluded. One trial enrolled 78 independently confirmed GBM patients. Partial responses were observed in 25.9% (95% confidence interval [CI], 17.0%-36.1%) of the patients. The median response duration was 4.2 months (95% CI, 3.0-5.7 months). The second trial enrolled 56 GBM patients. Partial responses were observed in 19.6% (95% CI, 10.9%-31.3%) of the patients. The median response duration was 3.9 months (95% CI, 2.4-17.4 months). Safety data were provided for the first study. The most frequently reported bevacizumab adverse events of any grade were infection, fatigue, headache, hypertension, epistaxis, and diarrhea. Grade 3-5 bevacizumab-related adverse events included bleeding/hemorrhage, central nervous system (CNS) hemorrhage, hypertension, venous and arterial thromboembolic events, wound-healing complications, proteinuria, gastrointestinal perforation, and reversible posterior leukoencephalopathy. The attribution of certain adverse events (e.g., CNS hemorrhage, wound-healing complications, and thromboembolic events) to either bevacizumab, underlying disease, or both could not be determined because of the single-arm, noncomparative study design.

FDA drug approval summary: lapatinib in combination with capecitabine for previously treated metastatic breast cancer that overexpresses HER-2.

On March 13, 2007, the U.S. Food and Drug Administration approved lapatinib (Tykerb tablets; GlaxoSmithKline, Philadelphia), an oral, small molecule, dual tyrosine kinase inhibitor of ErbB-2 and ErbB-1, for use in combination with capecitabine for the treatment of patients with human epidermal growth factor receptor (HER)-2-overexpressing metastatic breast cancer who had received prior therapy including an anthracycline, a taxane, and trastuzumab. One multicenter, open-label, randomized trial was submitted. Eligible patients had stage IIIb or IV breast cancer, ErbB-2 overexpression (immunohistochemistry 3+ or 2+ with fluorescence in situ hybridization confirmation), measurable disease, a 0 or 1 Eastern Cooperative Oncology Group performance status score, a cardiac ejection fraction within the institutional normal range, and adequate laboratory function. Patients received either lapatinib (1,250 mg once daily on days 1-21) plus capecitabine (1,000 mg/m(2) every 12 hours on days 1-14) every 21 days or capecitabine alone (1,250 mg/m(2) every 12 hours on days 1-14) every 21 days. The primary endpoint was time to progression (TTP) determined by a blinded independent review panel. After TTP results of a prespecified interim analysis were made available, study enrollment was discontinued (399 patients enrolled). The median TTP was 27.1 versus 18.6 weeks (hazard ratio, 0.57; p = .00013) favoring the lapatinib plus capecitabine arm. Response rates were 23.7% (lapatinib plus capecitabine) versus 13.9% (capecitabine alone). Survival data were not mature. Although the toxicities observed in the lapatinib and capecitabine combination arm were generally similar to those in the capecitabine alone arm, a higher incidence of diarrhea and rash was noted with the combination. Grade 3 or 4 adverse reactions that occurred with a frequency of >5% in patients on the combination arm were diarrhea (13%) and palmar-plantar erythrodysesthesia (12%). There was a 2% incidence of reversible decreased left ventricular function in the combination arm.

FDA report: eculizumab (Soliris) for the treatment of patients with paroxysmal nocturnal hemoglobinuria.

On March 16, 2007, eculizumab (Soliris; Alexion Pharmaceuticals, Inc. Cheshire, CT), a humanized monoclonal antibody that binds to the human C5 complement protein, received accelerated approval by the U.S. Food and Drug Administration for the treatment of patients with paroxysmal nocturnal hemoglobinuria (PNH) to reduce hemolysis. Eculizumab was studied in a randomized, double-blind, placebo-controlled clinical trial in 87 RBC transfusion-dependent adult PNH patients and in a supportive single-arm study in 96 patients. The eculizumab dose was 600 mg as a 35-minute i.v. infusion administered weekly for the first 4 weeks followed by 900 mg (week 5) then 900 mg every 14 days thereafter. Hemoglobin stabilized in 21 of 43 (48.8%) eculizumab-treated patients, compared with none of 44 placebo-treated patients. Eculizumab-treated patients required significantly fewer RBC transfusions than placebo-treated patients (median, 0 versus 10 units). There was also a significant reduction in the serum lactate dehydrogenase area under the curve with eculizumab compared with placebo treatment. Results of the phase II supportive study were similar to those of the phase III study. The safety database included 196 adult patients with PNH. Significant findings included the development of human anti-human antibody responses in three patients and serious meningococcal infections in three patients. Patients should undergo meningococcal vaccination at least 2 weeks prior to receiving the first eculizumab treatment and have revaccination according to current medical guidelines. Patients must be monitored and evaluated immediately for early signs of meningococcal infections and treated with antibiotics as indicated.

Approval summary: nelarabine for the treatment of T-cell lymphoblastic leukemia/lymphoma.

PURPOSE: To describe the clinical studies, chemistry manufacturing and controls, and clinical pharmacology and toxicology that led to Food and Drug Administration approval of nelarabine (Arranon) for the treatment of T-cell acute lymphoblastic leukemia/lymphoblastic lymphoma. EXPERIMENTAL DESIGN: Two phase 2 trials, one conducted in pediatric patients and the other in adult patients, were reviewed. The i.v. dose and schedule of nelarabine in the pediatric and adult studies was 650 mg/m2/d daily for 5 days and 1,500 mg/m2 on days 1, 3, and 5, respectively. Treatments were repeated every 21 days. Study end points were the rates of complete response (CR) and CR with incomplete hematologic or bone marrow recovery (CR*). RESULTS: The pediatric efficacy population consisted of 39 patients who had relapsed or had been refractory to two or more induction regimens. CR to nelarabine treatment was observed in 5 (13%) patients and CR+CR* was observed in 9 (23%) patients. The adult efficacy population consisted of 28 patients. CR to nelarabine treatment was observed in 5 (18%) patients and CR+CR* was observed in 6 (21%) patients. Neurologic toxicity was dose limiting for both pediatric and adult patients. Other severe toxicities included laboratory abnormalities in pediatric patients and gastrointestinal and pulmonary toxicities in adults. CONCLUSIONS: On October 28, 2005, the Food and Drug Administration granted accelerated approval for nelarabine for treatment of patients with relapsed or refractory T-cell acute lymphoblastic leukemia/lymphoblastic lymphoma after at least two prior regimens. This use is based on the induction of CRs. The applicant will conduct postmarketing clinical trials to show clinical benefit (e.g., survival prolongation).

Food and Drug Administration Drug approval summary: temozolomide plus radiation therapy for the treatment of newly diagnosed glioblastoma multiforme.

On March 15, 2005, the U.S. Food and Drug Administration approved temozolomide (Temodar capsules, Schering-Plough Research Institute) for the treatment of adult patients with newly diagnosed glioblastoma multiforme concomitantly with radiotherapy and then as maintenance treatment. Five hundred seventy-three glioblastoma multiforme patients were randomized to receive either temozolomide + radiotherapy (n = 287) or radiotherapy alone (n = 286). Patients in the temozolomide + radiotherapy arm received concomitant temozolomide (75 mg/m2) once daily for the duration of radiation therapy (42-49 days). This was followed, 4 weeks later, by six cycles of temozolomide, 150 or 200 mg/m2 daily for 5 days, every 4 weeks. Patients in the control arm received radiotherapy only. In both arms, radiotherapy was delivered as 60 Gy/30 fractions to the tumor site with a 2 to 3 cm margin. Pneumocystis carinii pneumonia prophylaxis was required during temozolomide + radiotherapy treatment and was continued until recovery of lymphocytopenia (Common Toxicity Criteria grade <1). At disease progression, temozolomide salvage treatment was given to 161 of 282 patients (57%) in the radiotherapy alone arm, and to 62 of 277 patients (22%) in the temozolomide + radiotherapy arm. Patients receiving concomitant and maintenance temozolomide + radiotherapy had significantly improved overall survival. The hazard ratio was 0.63 (95% confidence interval, 0.52-0.75; log-rank, P < 0.0001). Median survival was 14.6 months (temozolomide + radiotherapy) versus 12.1 months (radiotherapy alone). Adverse events during temozolomide treatment included thrombocytopenia, nausea, vomiting, anorexia, constipation, alopecia, headache, fatigue, and convulsions.

U.S. Food and Drug Administration Drug Approval Summary: conversion of imatinib mesylate (STI571; Gleevec) tablets from accelerated approval to full approval.

UNLABELLED: Imatinib mesylate (Gleevec, Novartis Pharmaceuticals East Manruer, NJ) received accelerated approval on May 10, 2001 for the treatment of patients with chronic myeloid leukemia (CML) in (a) chronic phase after failure of IFN-alpha therapy, (b) accelerated phase, and (c) blast crisis. The accelerated approval was accompanied by a postmarketing commitment by Novartis Pharmaceuticals to continue patient follow-up to determine duration of treatment response and survival. The present review, based on a safety and efficacy report submitted on December 20, 2002, summarizes data applicable to the conversion of these three CML indications to full approval status. RESULTS: Chronic phase CML: Five hundred thirty-two chronic phase CML patients who had not benefited from prior IFN therapy were treated at a starting imatinib mesylate dose of 400 mg p.o. qd; dose escalation to 800 mg p.o. qd was allowed. Patients had received a median of 14 months of IFN therapy at doses > or =25 million IU/wk and were all in late chronic phase, with a median time from diagnosis of 32 months. Median duration of imatinib mesylate treatment was 29 months, with 81% of patients treated for > or =24 months (maximum 31.5 months). Initial favorable treatment responses were sustained. An estimated 87.8% of patients who had a major cytogenetic response maintained their response 2 years after their initial response. After 2 years of treatment, an estimated 85.4% of patients were free of progression to accelerated phase or blast crisis, and the estimated overall survival was 90.8% (95% confidence interval, 88.3-93.2). Accelerated phase CML: Patients enrolled totaled 293: 235 with CML accelerated phase, 48 with relapsed/refractory acute lymphocytic leukemia, 2 with relapsed/refractory acute myelocytic leukemia, and 8 with relapsed/refractory CML in lymphoid blast crisis. Patients received imatinib mesylate 400 or 600 mg p.o. qd. Dose escalation was permitted, to a maximum of 800 mg/d, taken as 400 mg bid. Efficacy results were improved in patients receiving imatinib mesylate 600 mg qd versus patients receiving 400 mg qd. The median duration of hematologic response was 29 versus 17 months and the estimated 24-month maintained hematologic response rate was 61% versus 42%. The median survival of patients treated with imatinib mesylate 600 mg qd was not reached versus 20.9 months for patients receiving 400 mg qd. Estimated 24-month survival rate was 66% versus 46%. The median survival in the advanced leukemia population (acute lymphocytic leukemia, acute myelocytic leukemia, and lymphoid blast crisis) was only 5 months, and only two patients are still on treatment. Blast crisis CML: A total of 260 patients were recruited. The imatinib mesylate dose was initially 400 mg qd (37 patients) but was subsequently increased to 600 mg qd (223 patients). Patients receiving imatinib mesylate 600 mg qd had a higher hematologic response rate than did patients receiving 400 mg (33% versus 16%). Major cytogenetic responses occurred in 15% of the 260 study patients. The overall median survival was 6.9 months: 7.1 months for patients treated with imatinib mesylate 600 mg and 4.7 months for patients receiving imatinib mesylate 400 mg. Estimated 12-month survival rate for all study patients was 32.1% and estimated 24-month survival rate was 18.3%. SAFETY: Imatinib mesylate was generally well tolerated, but relatively frequent reports of common toxicity criteria grade 3/4 neutropenia and thrombocytopenia were encountered. The most frequently reported adverse events included gastrointestinal disturbances, edema, rash, and musculoskeletal complaints. These rarely led to discontinuation of therapy. CONCLUSIONS: The results confirm those of the interim analysis and suggest that imatinib mesylate represents an effective therapeutic agent for the treatment of patients with CML in chronic phase after failure of IFN-alpha therapy, in blast crisis, and in accelerated phase.

Approval summary: letrozole in the treatment of postmenopausal women with advanced breast cancer.

Letrozole (Femara; Novartis Pharmaceuticals Corp., East Hanover, NJ) is a nonsteroidal inhibitor of aromatase enzyme complex. It inhibits the peripheral conversion of circulating androgens to estrogens. In postmenopausal women, letrozole decreases plasma concentrations of estradiol, estrone, and estrone sulfate by 75-95% from baseline with maximal suppression achieved within 2-3 days of treatment initiation. Suppression is dose related, with doses of >or=0.5 mg giving estrone and estrone sulfate values that were often below assay detection limits. At clinically used dosage, letrozole does not impair adrenal synthesis of glucocorticoids or aldosterone. In 1998, letrozole was approved by the United States Food and Drug Administration (FDA) for the treatment of advanced breast cancer in postmenopausal women, with hormone receptor positive or unknown breast cancer, who had failed one prior antiestrogen treatment (i.e., for "second-line" treatment). Approval was based on two randomized trials comparing tumor RRs of patients receiving 0.5 mg of letrozole, 2.5 mg of letrozole, and either megestrol acetate (MA) or aminoglutethimide. In the megestrol trial, 2.5 mg/day letrozole was superior to 0.5 mg of letrozole and MA (RRs 24, 13, and 16%, respectively), whereas in the aminoglutethimide trial, there was no significant difference in 2.5 mg of letrozole and 0.5 mg of letrozole RRs (20 and 17%). There was a trend toward RR superiority of 2.5 mg of letrozole over aminoglutethimide (P = 0.06). Letrozole (2.5 mg) was the dose chosen for comparison with tamoxifen in the first-line setting. In July 2000, a marketing application for first-line letrozole treatment of postmenopausal women with hormone receptor positive or hormone receptor unknown locally advanced or metastatic breast cancer was submitted to the FDA. A single double-blind, double dummy, randomized, and multicenter trial compared 2.5 mg of letrozole to 20 mg of tamoxifen (456 patients/arm). Letrozole was superior to tamoxifen with regard to time to progression (TTP) and objective response rate (RR). The median TTP for letrozole treatment was 9.9 months [95% confidence interval (CI) 9.1-12.2] versus 6.2 months (95% CI 5.8-8.5) for tamoxifen, P = 0.0001, hazard ratio 0.713, (95% CI 0.61-0.84). RR was 32% for letrozole versus 21% for tamoxifen (odds ratio 1.74, 95% CI 1.29-2.34, P = 0.0003). Preliminary survival data (survival data are still blinded) indicate that letrozole is unlikely to be worse than tamoxifen. Both treatments were similarly tolerated. On the basis of these results, the United States FDA approved letrozole tablets, 2.5 mg/day, for first-line treatment of postmenopausal women with hormone receptor-positive or hormone receptor-unknown locally advanced or metastatic breast cancer. The manufacturer made a commitment to provide updated information on survival.

United States Food and Drug Administration Drug Approval summary: Gefitinib (ZD1839; Iressa) tablets.

On May 5, 2003, gefitinib (Iressa; ZD1839) 250-mg tablets (AstraZeneca Inc.) received accelerated approval by the United States Food and Drug Administration as monotherapy for patients with locally advanced or metastatic non-small cell lung cancer after failure of both platinum-based and docetaxel chemotherapies. Information provided in this summary includes chemistry manufacturing and controls, clinical pharmacology, and clinical trial efficacy and safety results. Gefitinib is an anilinoquinazoline compound with the chemical name 4-quinazolinamine,N-(3-chloro-4-flurophenyl)-7-methoxy-6-[3-(4-morpholinyl)propoxy]. It has the molecular formula C(22)H(24)ClFN(4)O(3). Gefitinib is often referred to as a "specific" or "selective" inhibitor of epidermal growth factor receptor. Studies demonstrate, however, that gefitinib inhibits the activity of other intracellular transmembrane tyrosine-specific protein kinases at concentrations similar to those at which it inhibits the epidermal growth factor signal. Maximum plasma concentrations resulting from clinically relevant doses are 0.5-1 microM or more, well within the IC(50) values of several tyrosine kinases. No clinical studies have been performed that demonstrate a correlation between epidermal growth factor receptor expression and response to gefitinib. Gefitinib is 60% available after oral administration and is widely distributed throughout the body. Gefitinib is extensively metabolized in the liver by cytochrome P450 3A4 enzyme. Over a 10-day period, approximately 86% of an orally administered radioactive dose is recovered in the feces, with <4% of the dose in the urine. After daily oral administration, steady-state plasma levels are reached in 10 days and are 2-fold higher than those achieved after single doses. Gefitinib effectiveness was demonstrated in a randomized, double-blind, Phase II, multicenter trial comparing two oral doses of gefitinib (250 versus 500 mg/day). A total of 216 patients were enrolled. The 142 patients who were refractory to or intolerant of a platinum and docetaxel comprised the evaluable population for the efficacy analysis. A partial tumor response occurred in 14% (9 of 66) of patients receiving 250 mg/day gefitinib and in 8% (6 of 76) of patients receiving 500 mg/day gefitinib. The overall objective response rate (RR) for both doses combined was 10.6% (15 of 142 patients; 95% confidence interval, 6.0-16.8%). Responses were more frequent in females and in nonsmokers. The median duration of response was 7.0 months (range, 4.6-18.6+ months). Other submitted data included the results of two large trials conducted in chemotherapy-naive, stage III and IV non-small cell lung cancer patients. Patients were randomized to receive gefitinib (250 or 500 mg daily) or placebo, in combination with either gemcitabine plus cisplatin (n = 1093) or carboplatin plus paclitaxel (n = 1037). Results from this study showed no benefit (RR, time to progression, or survival) from adding gefitinib to chemotherapy. Consequently, gefinitib is only recommended for use as monotherapy. Common adverse events associated with gefitinib treatment included diarrhea, rash, acne, dry skin, nausea, and vomiting. Interstitial lung disease has been observed in patients receiving gefitinib. Worldwide, the incidence of interstitial lung disease was about 1% (2% in the Japanese post-marketing experience and about 0.3% in a United States expanded access program). Approximately one-third of the cases have been fatal. Gefitinib was approved under accelerated approval regulations on the basis of a surrogate end point, RR. No controlled gefitinib trials, to date, demonstrate a clinical benefit, such as improvement in disease-related symptoms or increased survival. Accelerated approval regulations require the sponsor to conduct additional studies to verify that gefitinib therapy produces such benefit.