Rabbit as an Animal Model for Pharmacokinetics Studies of Enteric Capsule Contains Recombinant Human Keratinocyte Growth Factor Loaded Chitosan Nanoparticles.

BACKGROUND: Recombinant human keratinocyte growth factor (rHuKGF) has gained considerable attention by researchers as epithelial cells proliferating agent. Moreover, intravenous truncated rHuKGF (palifermin) has been approved by Food and Drug Administration (FDA) to treat and prevent chemotherapy-induced oral mucositis and small intestine ulceration. The labile structure and short circulation time of rHuKGF in-vivo are the main obstacles that reduce the oral bioactivity and dosage of such proteins at the target site. OBJECTIVE: Formulation of methacrylic acid-methyl methacrylate copolymer-coated capsules filled with chitosan nanoparticles loaded with rHuKGF for oral delivery. METHODS: We report on chitosan nanoparticles (CNPs) with diameter < 200 nm, prepared by ionic gelation, loaded with rHuKGF and filled in methacrylic acid-methyl methacrylate copolymercoated capsules for oral delivery. The pharmacokinetic parameters were determined based on the serum levels of rHuKGF, following a single intravenous (IV) or oral dosages using a rabbit model. Furthermore, fluorescent microscope imaging was conducted to investigate the cellular uptake of the rhodamine-labelled rHuKGF-loaded nanoparticles. The proliferation effect of the formulation on FHs 74 Int cells was studied as well by MTT assay. RESULTS: The mucoadhesive and absorption enhancement properties of chitosan and the protective effect of methacrylic acid-methyl methacrylate copolymer against rHuKGF release at the stomach, low pH, were combined to promote and ensure rHuKGF intestinal delivery and increase serum levels of rHuKGF. In addition, in-vitro studies revealed the protein bioactivity since rHuKGFloaded CNPs significantly increased the proliferation of FHs 74 Int cells. CONCLUSION: The study revealed that oral administration of rHuKGF-loaded CNPs in methacrylic acid-methyl methacrylate copolymer-coated capsules is practically alternative to the IV administration since the absolute bioavailability of the orally administered rHuKGF-loaded CNPs, using the rabbit as animal model, was 69%. Fluorescent microscope imaging revealed that rhodaminelabelled rHuKGF-loaded CNPs were taken up by FHs 74 Int cells, after 6 hours' incubation time, followed by increase in the proliferation rate.

Safety, Pharmacokinetics, and Efficacy of Palifermin in Children and Adolescents with Acute Leukemias Undergoing Myeloablative Therapy and Allogeneic Hematopoietic Stem Cell Transplantation: A Pediatric Blood and Marrow Transplant Consortium Trial.

Currently, effective pharmacologic treatment to reduce severe oral mucositis (OM) resulting from high-dose myeloablative cytotoxic therapy in the pediatric population is not available. Palifermin has been proven to decrease the incidence and duration of severe OM in adults with hematologic malignancies undergoing hematopoietic stem cell transplantation (HSCT). In the pediatric population, however, data on palifermin treatment are limited. A phase I dose-escalation study of palifermin in pediatric patients with acute leukemias undergoing myeloablative HSCT with total body irradiation, etoposide, and cyclophosphamide was performed to determine a safe and tolerable dose and to characterize the pharmacokinetic (PK) profile and efficacy of palifermin. Twenty-seven patients in 3 age groups (1 to 2, 3 to 11, and 12 to 16 years) and 3 dose levels (40, 60, and 80 µg/kg/day) were studied. There were no deaths, dose-limiting toxicities, or treatment-related serious adverse events. Long-term safety outcomes did not differ from what would be expected in this population. PK data showed no differences between the 3 age groups. Exposure did not increase with increase in dose. The maximum severity of OM (WHO grade 4) occurred in 6 patients (22%), none of whom was in the 80-µg/kg/day dosing group. This study showed that all doses were well tolerated and a good safety profile in all 3 pediatric age groups was seen.

Pharmacokinetic and pharmacodynamic interactions between palifermin and heparin.

Oral mucositis, a severe complication during chemo- and/or radiotherapy, is prevented with palifermin treatment, a recombinant human keratinocyte growth factor (KGF/FGF-7). The FGF family belongs to the larger family of heparin-binding growth factors. Because it has been shown that heparin modulates binding of KGF to the KGF receptor and subsequently affects cellular proliferation induced by the KGF mitogenic signal, it is critical to understand the drug-drug interactions between palifermin and heparin, particularly because of heparin's narrow therapeutic margin. Two studies were performed in healthy subjects to characterize the effect of palifermin on the pharmacodynamics of heparin (activated partial thromboplastin time) and evaluate the impact of heparin on the pharmacokinetics and pharmacodynamics (Ki67 staining of buccal mucosal tissue) of palifermin. Results demonstrated a pronounced pharmacokinetic interaction; heparin coadministration increased the palifermin AUC 4- to 5-fold and decreased its half-life by 40%-45%, suggesting an approximate 70%-80% decrease in palifermin clearance and volume of distribution. These changes in the pharmacokinetics of palifermin during coadministration of heparin, however, did not affect the pharmacodynamic effect of palifermin, or the anticoagulant activity of heparin, and did not lead to increased safety findings. Therefore, these results suggest that dose adjustments for heparin and palifermin are not warranted when administered concurrently.

Phase I study of the tolerability and pharmacokinetics of palifermin in children undergoing allogeneic hematopoietic stem cell transplantation.

The maximum tolerated dose of palifermin, a keratinocyte growth factor, in children is not known, and its pharmacokinetics in this population has not been well studied. This is a phase I study of palifermin was designed to evaluate its tolerability at doses of 40, 60, and 90 µg/kg/day in children age 2-18 years of age, receiving a myeloablative preparative regimen for allogeneic hematopoietic stem cell transplantation (HSCT). In each cohort, palifermin was given for 3 consecutive days before the preparative regimen and for 3 days after the stem cell infusion. Twelve patients were enrolled. Palifermin 90 µg/kg/day was tolerated in 6 patients without dose-limiting toxicity. All patients had at least 1 adverse event, mostly National Cancer Institute grade 1 or 2 severity. Skin rash, grade 2 or lower, was the most common adverse event, seen in 67% of patients. Only 3 patients (25%) had mucositis. The area under the concentration-time curve increased proportionally to the dose, and approximately 97% of palifermin exposure occurred in the first 24 hours after administration. Palifermin clearance increased linearly with body weight, supporting dosing by body weight. The mean clearance was 1893 mL/hour/kg, and it did not change significantly between administration of the first and last doses (P = .80). The mean elimination half-life was 4.6 hours. Our data show that palifermin was tolerated at a dose of 90 µg/kg/day, and exhibits linear pharmacokinetics in children undergoing allogeneic HSCT.

Pharmacokinetic evaluation of palifermin for mucosal protection from chemotherapy and radiation.

INTRODUCTION: Oral mucositis, one of the major side effects of chemotherapy and irradiation, is still a burden of modern oncology. The keratinocyte growth factor (KGF) palifermin has been approved as a new, targeted therapy for the prevention of severe oral mucositis. AREAS COVERED: The authors review the literature on pharmacokintetics and clinical use of palifermin in patients with hematological malignancies and solid tumors for the prevention of chemo- and radiation-induced mucositis by using the PubMed database and additional literature where applicable. The article includes in vitro data, clinical trials as well as case reports regarding dosage, administration schedule, efficacy and adverse events. EXPERT OPINION: There is sufficient data for a beneficial effect of palifermin prophylaxis for patients with hematological cancers receiving high-dose chemotherapy and total body irradiation as well as patients with head and neck cancer receiving combined irradiation and chemotherapy. In less mucotoxic regimens, dose and schedule of palifermin to achieve protection from mucositis are less well defined. The balance of benefit and unwanted effects has to be evaluated and weighed for individual chemotherapy regimens and patient groups. Further research on the prevention of mucositis should aim to determine the patient's individual risk to develop severe mucositis.

Drug release kinetics and transport mechanisms from semi-interpenetrating networks of gelatin and poly(ethylene glycol) diacrylate.

PURPOSE: To elucidate the key parameters affecting solute transport from semi-interpenetrating networks (sIPNs) comprised of poly(ethylene glycol) diacrylate (PEGdA) and gelatin that are partially crosslinked, water-swellable and biodegradable. Effects of material compositions, solute size, solubility, and loading density have been investigated. MATERIALS AND METHODS: sIPNs of following gelatin/PEGdA weight-to-weight ratios were prepared: 10:15, 10:20, 10:30, 15:15, 20:15. Five model solutes of different physicochemical properties were selected, i.e. silver sulfadiazine (AgSD), bupivacaine hydrochloride (Bup), sulfadiazine sodium (NaSD), keratinocyte growth factor (KGF), and bovine serum albumin conjugated with fluorescein isothiocyanate (BSA-FITC). Release studies were performed and the results were analyzed using three hydrogel based common theories (free volume, hydrodynamic and obstruction). RESULTS: The release kinetics of model solutes was influenced by each factor under investigation. Specifically, the initial release rates and intra-gel diffusivity decreased with increasing PEGdA content or increasing solute molecular weight. However, the initial release rate and intra-gel diffusivity increased with increasing gelatin content or increasing solute water solubility, which contradicted with the classical hydrogel based solute transport theories, i.e. increasing polymer volume leads to decreased solute diffusivity within the gel. CONCLUSION: This analysis provides structure-functional information of the sIPN as a potential therapeutic delivery matrix.

Pharmacokinetics of palifermin administered as the standard dose and as a collapsed dose in patients with hematologic malignancies.

STUDY OBJECTIVE: To assess the pharmacokinetic profile of palifermin after intravenous dosing with either a collapsed dose of 180 microg/kg/day for 1 day or a standard dose of 60 microg/kg/day for 3 days, before and after myeloablative chemoradiotherapy and peripheral blood progenitor cell (PBPC) transplantation. DESIGN: Prospective, open-label pharmacokinetic study. SETTING: University-affiliated hematology and oncology center. PATIENTS: Twenty-five adult patients with hematologic malignancies receiving myeloablative therapy; 13 were in the standard-dose group, and 12 were in the collapsed-dose group. INTERVENTION: Patients received total-body irradiation (study days -8 to -5), etoposide (day -4), cyclophosphamide (day -2), and PBPC transplantation (day 0). Standard-dose palifermin was administered on days -11, -10, -9, 0, 1, and 2; collapsed-dose palifermin was administered on days -11 and 0. MEASUREMENTS AND MAIN RESULTS: Baseline demographic and clinical characteristics were recorded. Blood samples were obtained for pharmacokinetic assessment, presence of palifermin antibodies, and routine chemistry and hematology panels. Adverse events were documented daily. For both dosing groups, palifermin concentrations declined rapidly (>or= 98%) in the first 30 minutes and increased slightly between 1 and 4 hours after dosing, with a terminal decay phase. For standard-dose palifermin, mean values for area under the serum concentration-time curve (AUC) were within 15% between doses 1 and 3 and within 1% between doses 1 and 4. For collapsed-dose palifermin, mean AUC values and other pharmacokinetic parameters were within 2% between doses 1 and 2. Mean AUC on days -11 and 0 were approximately 4-fold higher for collapseddose palifermin than for standard-dose palifermin. Both dosing regimens were well tolerated. CONCLUSIONS: Our results were consistent with approximately dose-linear pharmacokinetics for the two dosing regimens, with no observed accumulation. A randomized, controlled study is warranted to assess the safety and efficacy of collapsed-dose palifermin, which may provide a more convenient administration schedule.

Recombinant human keratinocyte growth factor palifermin reduces oral mucositis and improves patient outcomes after stem cell transplant.

Oral mucositis, the breakdown of the mucosal lining of the oropharynx, occurs as a result of a toxic insult to the normal epithelium of the oral mucosa. Typically this is seen after exposure to a toxic agent such as radiation or chemotherapy; therefore, it is a frequent problem for patients undergoing treatment for cancer. In clinical trials, mucositis has been reported in up to 98% of patients receiving high-dose chemotherapy followed by hematological stem cell transplant. When mucositis develops it causes severe patient symptoms such as pain, but it is also associated with inferior clinical outcomes including increased infection, narcotic use and even mortality. In clinical trials, palifermin, a recombinant humanized keratinocyte growth factor (rHuKGF), has demonstrated an ability to decrease the incidence and duration of mucositis. In the registrational phase III trial in patients undergoing stem cell transplant for hematological malignancies, only 63% of patients who received palifermin developed World Health Organization grade 3 or 4 mucositis compared to 98% of patients on the placebo arm (1). The patients on the palifermin arm also had a shorter duration of mucositis with significantly decreased pain, use of narcotics, need for total parenteral nutrition and febrile neutropenia. Based on these results, palifermin became the first drug that has been approved by the U.S. Food and Drug Administration (FDA) to decrease the incidence and duration of severe oral mucositis in patients with hematological malignancies receiving high-dose chemotherapy requiring hematopoietic stem cell support. The development of mucositis is also a problem for patients receiving treatment for nonhematological tumors. In clinical trials, mucositis has been reported in over 75% of patients receiving combined chemo-/radiotherapy for head and neck cancer or fluorouracil for metastatic colon cancer. Initial phase I and II clinical trials of palifermin have demonstrated a benefit in patients receiving chemotherapy with or without radiation therapy for solid tumors; however, large phase III trials need to be completed before palifermin can gain FDA approval for this indication.

Effect of renal function on the pharmacokinetics of palifermin.

Palifermin (deltaN23KGF) decreases the incidence, severity, and duration of oral mucositis. The objectives of this open-label study were to evaluate the pharmacokinetics of single-dose palifermin in subjects with varying degrees of renal function. A single 90-mcg/kg intravenous dose of palifermin was administered to 31 subjects with varying levels of renal function (normal to requiring hemodialysis). Pharmacokinetic analyses were conducted using serum palifermin concentrations. There was considerable overlap in mean palifermin serum clearance among the groups, ranging from 318 to 495 mL/h/kg, indicating that the level of renal function did not affect clearance in humans; thus, no dose adjustment of palifermin is indicated for patients with renal dysfunction.

Pharmacokinetics, pharmacodynamics, and safety assessment of palifermin (rHuKGF) in healthy volunteers.

BACKGROUND: Palifermin is a recombinant human keratinocyte growth factor approved to decrease the incidence and duration of severe oral mucositis in patients with hematologic malignancies who received myelotoxic therapy requiring hematopoietic stem cell support. METHODS: This randomized, double-blind, placebo-controlled study investigated the pharmacokinetics, pharmacodynamics, and safety of palifermin in healthy volunteers after single, escalating doses (60 to 250 mug/kg). Pharmacodynamic measurements (Ki67 staining) assessing buccal mucosal epithelial proliferation were performed at baseline and at 48 or 72 hours after dosing. RESULTS: Exposure to palifermin increased approximately dose proportionally, with a 3-fold increase observed for a 4-fold increase in dose. Palifermin concentrations decreased sharply during the first 0.5 to 1.5 hours after dosing, slightly increased or plateaued between 1.5 and 6 hours, and subsequently decreased. The overall mean systemic clearance and volume of distribution at steady state were 590 mL/h/kg and 2000 mL/kg, respectively. The mean half-life ranged from 4.5 to 6 hours across the dose levels. The mean and SD ratio of Ki67 staining at 48 hours after dosing to baseline was 1.19 (0.24) for placebo, 2.02 (0.60) for 60 mug/kg, 3.04 (1.13) for 120 mug/kg, and 4.66 (0.77) for 250 mug/kg-treated groups. CONCLUSION: Palifermin exhibited linear pharmacokinetics and caused dose-dependent epithelial proliferation.

Palifermin: in myelotoxic therapy-induced oral mucositis.

Palifermin, a recombinant human keratinocyte growth factor (KGF), mimics the actions of endogenous KGF and has shown efficacy in the management of myelotoxic therapy-induced oral mucositis in cancer patients. In a randomised, double-blind trial in patients with haemtaological malignancies receiving conditioning radiochemotherapy before undergoing autologous stem cell transplant, intravenous palifermin 60 microg/kg/day (two 3-day cycles, administered before myelotoxic therapy and after transplant) significantly reduced the median duration (primary endpoint) [3 vs 9 days] and incidence (63% vs 98%) of WHO grade 3 or 4 oral mucositis, compared with placebo. Patient-reported outcomes also showed significant improvement with palifermin treatment, which was associated with significant reductions in healthcare resource utilisation, compared with placebo. The drug was generally well tolerated, with skin/oral toxicities, pain/arthralgias and dysaesthesia being the most common palifermin-related adverse reactions.

Palifermin (Kepivance) for the treatment of oral mucositis in patients with hematologic malignancies requiring hematopoietic stem cell support.

OBJECTIVE: To provide a comprehensive review of the clinical use of the recombinant biological agent, palifermin, with particular reference to its use in its approved indication, oral mucositis resulting from high dose chemotherapy and radiation in patients with hematologic malignancies requiring hematopoietic stem cell support. DATA SOURCES: A MEDLINE search was conducted using the terms 'palifermin' and 'Kepivance.' All data available from MEDLINE were reviewed. The reference lists from retrieved articles were reviewed and other relevant papers were identified. DATA SUMMARY: Keratinocyte growth factor (KGF) is a growth factor that acts specifically on epithelial cells playing a role in proliferation, migration, and morphogenesis. Palifermin is a recombinant human form of KGF. Because of its ability to cause proliferation of the oral mucosa and to protect against mucosal injury, palifermin is a treatment option for patients who are at high risk for oral mucositis, specifically patients with hematological malignancies receiving stem cell transplantation (SCT). In a phase III study of these patients, the overall incidence of World Health Organization (WHO) grade 3 or 4 oral mucositis was significantly reduced in the palifermin group (palifermin = 63% versus placebo = 98%, P < 0.001). Among the patients who experienced WHO grade 3 or 4 oral mucositis the average duration of this grade of mucositis in the palifermin group was six days compared with nine days in the placebo group (P < 0.001). Common adverse effects of palifermin include pruritus, erythema, mouth and tongue disorders, and taste alterations.