Extrapolation of Adult Efficacy to Pediatric Patients With Chemotherapy-Induced Nausea and Vomiting.

Chemotherapy-induced nausea and vomiting (CINV) is a common treatment-related adverse event that negatively impacts the quality of life of cancer patients. During pediatric drug development, extrapolation of efficacy from adult to pediatric populations is a pathway that can minimize the exposure of children to unnecessary clinical trials, improve efficiency, and increase the likelihood of success in obtaining a pediatric indication. The acceptability of the use of extrapolation depends on a series of evidence-based assumptions regarding the similarity of disease, response to intervention, and exposure-response relationships between adult and pediatric patients. This study evaluated publicly available summaries of data submitted to the US Food and Drug Administration for drugs approved for CINV to assess the feasibility of extrapolation for future development programs. Extracted data included trial design, emetogenic potential of chemotherapy, primary end points, participant enrollment criteria, and antiemetic pharmacokinetics. Adult and pediatric clinical trial designs for assessment of efficacy and safety shared key design elements. Antiemetic drugs found to be efficacious in adults were also efficacious in pediatric patients. Systemic drug concentrations at approved doses were similar for ondansetron, granisetron, and aprepitant, but an exposure-response analysis of palonosetron in children suggested that higher palonosetron systemic exposure is necessary for the prevention of CINV in the pediatric population. For 5-hydroxytryptamine-3 and neurokinin-1 receptor antagonist antiemetic drugs, efficacy in adults predicts efficacy in children, supporting the extrapolation of effectiveness of an antiemetic product in children from adequate and well-controlled studies in adult patients with CINV.

Exposure-Response of Palonosetron for Prevention of Chemotherapy-Induced Nausea and Vomiting in Pediatric Patients.

OBJECTIVES: Extrapolation of efficacy from adult populations to pediatrics may be appropriate if it is reasonable to assume that the 2 populations have similar disease progression and response to intervention. When full extrapolation of efficacy is deemed appropriate, the pediatric dose can be determined by "matching" exposure to a drug with that observed in adult patients. This approach has been used in certain therapeutic areas to alleviate the burden of pediatric clinical trials. We present here a case in which exposure matching is not appropriate. METHODS: Data analyses including pharmacokinetics and exposure-response were performed using data obtained from 2 pediatric chemotherapy-induced nausea and vomiting trials for intravenously administered palonosetron (Aloxi; a 5-HT3 receptor antagonist) injection and the results were compared with adult findings. RESULTS: At the approved doses for adults (0.25 mg) and pediatric patients (20 µg/kg), mean systemic exposure (area under the curve) of palonosetron in pediatric patients was approximately 3-fold higher than that in adults, whereas the response rate was similar between the 2 populations. Across pediatric patients, those younger than 6 years of age appeared to have a higher response than those ages 6 years or older, even though estimated systemic exposure was comparable between these age groups. CONCLUSIONS: Overall, these analyses provide an example in which pediatric and adult exposure data alone are insufficient to adequately identify effective pediatric doses and raise questions about the appropriateness of exposure matching for other drugs in the same therapeutic class. In such cases, pediatric dose-ranging and efficacy studies are needed.

Well-defined and reliable clinical outcome assessments for pediatric Crohn disease: a critical need for drug development.

OBJECTIVES: The aim of the present study was to identify areas for further development of clinical outcome assessment (COA) in pediatric Crohn disease (CD). METHODS: The study analyzed the measurement properties of all existing COA tools for pediatric CD in literature and published registration trials of approved drugs for pediatric CD based on criteria described in Food and Drug Administration guidance for patient-reported outcome (PRO) development. RESULTS: The Pediatric Crohn's Disease Activity Index (PCDAI) and its derivatives (abbreviated, short, modified, and weighted PCDAIs) were reviewed. The Crohn's Disease Activity Index (CDAI) and Harvey-Bradshaw index (HBI), designed for adult patients, have been adapted for use in a few pediatric CD studies. The use of PCDAI as an endpoint in Remicade and Humira trials led to the Food and Drug Administration-approved indication in pediatric CD. Common issues in measurement properties of COA tools included the absence of direct patient or caregivers' input to generate the items measuring signs and symptoms; absence of evidence demonstrating correlation with clinically relevant inflammation observed with endoscopic measures; lack of standardization in measurement, age-appropriate interviewer script, and response rating criteria for the physician interviewer. CONCLUSIONS: Available evidence indicates that CDAI, HBI, and 5 versions of the PCDAI lack adequate measurement properties for use as a primary endpoint for phase 3 trials intended to support approval of products intended to treat pediatric CD. In order to facilitate pediatric drug development, a well-defined, reliable, sensitive, and globally recognized PRO that measures signs and symptoms in children with CD and that can be used in conjunction with endoscopy-based endpoints and/or biomarkers is sorely needed.

Workshop on imaging science development for cancer prevention and preemption.

The concept of intraepithelial neoplasm (IEN) as a near-obligate precursor of cancers has generated opportunities to examine drug or device intervention strategies that may reverse or retard the sometimes lengthy process of carcinogenesis. Chemopreventive agents with high therapeutic indices, well-monitored for efficacy and safety, are greatly needed, as is development of less invasive or minimally disruptive visualization and assessment methods to safely screen nominally healthy but at-risk patients, often for extended periods of time and at repeated intervals. Imaging devices, alone or in combination with anticancer drugs, may also provide novel interventions to treat or prevent precancer.

Population pharmacokinetic-based dosing of intravenous busulfan in pediatric patients.

The objective of this study was to characterize the pharmacokinetics (PK) of intravenous busulfan in pediatric patients and provide dosing recommendations. Twenty-four pediatric patients were treated with intravenous busulfan, 1.0 or 0.8 mg/kg for ages < or = 4 years or > 4 years, respectively, 4 times a day for 4 days. Dense PK sampling was performed. Body weight, age, gender, and body surface area were explored for effects on PK, and Monte Carlo simulations were performed to assess different dosing regimens. The PK of intravenous busulfan was described by a 1-compartment model with clearance of 4.04 L/h/20 kg and volume of distribution of 12.8 L/20 kg. Simulations indicated that the mg/kg and mg/m2 regimens were similar and achieved the desired target exposure in approximately 60% of patients. This model suggests that patients < or = 12 kg should be dosed at 1.1 mg/kg and those > 12 kg dosed at 0.8 mg/kg. Therapeutic drug monitoring and dose adjustment will further improve therapeutic targeting.

Evaluation of health-related quality-of-life measures in oncology drug product applications: issues and concerns.

Health-related quality-of-life outcomes as reported by patients are valuable data and ideally should be critical to evaluating clinical benefit. The unblinded or open-label designs commonly adapted in oncology trials have the potential to introduce selection bias, reporting bias, and analyses bias. In this paper, issues surrounding use of patient reported outcomes to evaluate oncology drug products, including definition of hypothesis, study design, analysis, and interpretation of patient reported outcome data, are reported.

FDA drug approval summaries: oxaliplatin.

The purpose of this report is to summarize information on oxaliplatin, a drug recently approved by the U.S. Food and Drug Administration. Information provided includes regulatory history, study design, efficacy and safety results, and pertinent literature references. A single, multicenter, randomized trial, enrolling 463 patients with metastatic colorectal carcinoma whose disease had recurred or progressed during or within 6 months of completion of therapy with the combination of bolus 5-fluorouracil (FU)/leucovorin (LV) and irinotecan, was submitted. Study arms included infusional 5-FU/LV alone (arm A), oxaliplatin alone (arm B), and the combination of oxaliplatin and infusional 5-FU/LV(arm C). Oxaliplatin, at a dose of 85 mg/m2, was administered to patients in arms B and C intravenously over 2 hours in 250-500 ml of dextrose 5% in water (D5W) on day 1 only. A 200-mg/m2 dose of LV was administered simultaneously to arm C patients, in a separate bag using a Y-line, or alone to arm A patients, by i.v. infusion, over 2 hours. 5-FU was then administered to arms A and C patients, first as a bolus injection over 2-4 minutes at a dose of 400 mg/m2, then as a continuous infusion in 500 ml of D5W over 22 hours at a dose of 600 mg/m2. LV was repeated on day 2 of the cycle (arms A and C) followed by a 400-mg/m2 5-FU bolus and a 600-mg/m2 22-hour infusion. Treatment was repeated every 2 weeks. Response rate was the prespecified end point for accelerated approval. Time to progression (TTP) was a secondary end point. The prespecified primary comparison was between the 5-FU/LV regimen and the 5-FU/LV/ oxaliplatin combination regimen. The three arms were well balanced for patient prognostic factors. There were no complete responders. The partial response rates were 0%, 1%, and 9% for the 5-FU/LV, oxaliplatin, and oxaliplatin plus 5-FU/LV treatments, respectively (p = 0.0002, arm C versus arm A). The median times to radiographic tumor progression, based on available radiographs, were 2.7 months, 1.6 months, and 4.6 months, respectively (p < 0.0001, arm C versus arm A). Common adverse events associated with the combination treatment included peripheral neuropathy, fatigue, diarrhea, nausea, vomiting, stomatitis, and abdominal pain. Neutropenia was the major hematologic toxicity. Adverse events were similar in men and women and in patients <65 and > or =65 years of age, but older patients may have been more susceptible to dehydration, diarrhea, hypokalemia, and fatigue. Oxaliplatin in combination with infusional 5-FU/LV was approved for the treatment of patients with metastatic carcinoma of the colon or rectum whose disease has recurred or progressed during or within 6 months of completion of first-line therapy with the combination of bolus 5-FU/LV and irinotecan. Approval was based on response rate and on an interim analysis of TTP. No results are available, at this time, that demonstrate a clinical benefit, such as improvement in disease-related symptoms or survival.

U.S. Food and Drug Administration drug approval summaries: imatinib mesylate, mesna tablets, and zoledronic acid.

The purpose of this report is to summarize information on drugs recently approved by the U.S. Food and Drug Administration. Three drugs have recently been approved: Gleevec (imatinib mesylate) at a starting dose of 400 or 600 mg daily for the treatment of malignant unresectable and/or metastatic gastrointestinal stromal tumors; Mesnex (mesna) tablets as a prophylactic agent to reduce the incidence of ifosfamide-induced hemorrhagic cystitis, and Zometa (zoledronic acid) for the treatment of patients with multiple myeloma and for patients with documented bone metastases from solid tumors, in conjunction with standard antineoplastic therapy. Prostate cancer should have progressed after treatment with at least one hormonal therapy. The recommended dose and schedule is 4 mg infused over 15 minutes every 3-4 weeks. These three drugs represent three different types of drug approval: Gleevec is an accelerated approval and supplemental new drug application (NDA); Mesnex tablets represent an oral formulation of a drug approved 14 years ago as an intravenous formulation, and Zometa represents a standard NDA for a noncytotoxic, supportive-care drug. Information provided includes rationale for drug development, study design, efficacy and safety results, and pertinent literature references.

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

PURPOSE: Imatinib mesylate (Gleevec; Novartis, East Hanover, NJ)is a receptor tyrosine kinase inhibitor approved previously in 2001 by the United States Food and Drug Administration for the treatment of chronic myelogenous leukemia in blast crisis, accelerated phase, or in chronic phase after failure of IFN-alpha therapy. We review herein the clinical profile of this drug and the regulatory review leading to the approval of a supplemental New Drug Application for the treatment of metastatic and/or unresectable malignant gastrointestinal stromal tumors (GISTs). EXPERIMENTAL DESIGN: We discuss the efficacy and side effects of imatinib mesylate in a Phase II trial of 147 patients with metastatic and/or unresectable malignant GISTs, the basis for marketing approval, and postmarketing commitments by the drug's manufacturer. RESULTS: Imatinib was assessed in a single, open-label trial involving one European center and three centers in the United States. Seventy-three patients were randomly allocated to receive 400 mg of imatinib daily, and 74 patients received 600 mg daily. At the study report cutoff date, an objective response was confirmed in 56 patients; the overall response rate for the combined study arms was 38% (95% confidence interval, 30-46%). These responses were all partial responses. There was no statistically significant difference in response rates between the two dose groups. Adverse events included edema, fluid retention, nausea, vomiting, diarrhea, myalgias, skin rash, bone marrow suppression, bleeding, and elevations in aspartate aminotransferase, alanine aminotransferase, or bilirubin. Bleeding into the gastrointestinal tract or intratumoral sites occurred in 7 patients (5%) and was not correlated with thrombocytopenia or tumor bulk. The pharmacokinetics of imatinib in GIST patients were similar to those of chronic myelogenous leukemia patients. CONCLUSIONS: On February 1, 2001, imatinib mesylate was approved by the United States Food and Drug Administration for the treatment of malignant metastatic and/or unresectable GISTs. The recommended dose is 400 or 600 mg daily.