Can gadolinium compete with La-Fe-Co-Si in a thermomagnetic generator?

A thermomagnetic generator is a promising technology to harvest low-grade waste heat and convert it into electricity. To make this technology competitive with other technologies for energy harvesting near room temperature, the optimum thermomagnetic material is required. Here we compare the performance of a state of the art thermomagnetic generator using gadolinium and La-Fe-Co-Si as thermomagnetic material, which exhibit strong differences in thermal conductivity and type of magnetic transition. gadolinium is the established benchmark material for magnetocaloric cooling, which follows the reverse energy conversion process as compared to thermomagnetic energy harvesting. Surprisingly, La-Fe-Co-Si outperforms gadolinium in terms of voltage and power output. Our analysis reveals the differences in thermal conductivity are less important than the particular shape of the magnetization curve. In gadolinium an unsymmetrical magnetization curve is responsible for an uncompensated magnetic flux, which results in magnetic stray fields. These stray fields represent an energy barrier in the thermodynamic cycle and reduce the output of the generator. Our detailed experiments and simulations of both, thermomagnetic materials and generator, clearly reveal the importance to minimize magnetic stray fields. This is only possible when using materials with a symmetrical magnetization curve, such as La-Fe-Co-Si.

Clinical applications of palifermin: amelioration of oral mucositis and other potential indications.

Mucositis is one of the most significant toxicities in cancer patients undergoing cytotoxic treatment. It can have a negative impact on both quality of life and health economics. Severe oral mucositis can contribute to hospitalization, need for narcotic analgesics, total parentral nutrition, suboptimal delivery of anti-neoplastic treatment, and morbidity and mortality. Palifermin, a recombinant derivative of human keratinocyte growth factor, is the first active agent approved by the FDA for the prevention of severe oral mucositis in patients undergoing haematopoietic stem cell transplantation (HSCT). Several studies have also shown significant reduction in the incidence, severity and/or duration of oral mucositis in other high-risk settings such as concurrent chemoradiotherapy (CT/RT) for patients with head and neck cancer, and use of mucotoxic chemotherapeutic agents such as doxorubicin in sarcoma and fluorouracil for the treatment of colorectal cancer. The reduction in mucositis has translated into amelioration of symptoms and improvement in daily functioning as measured by patient-reported outcome in multiple studies. The clinical response to palifermin appears to be related in part to epithelial proliferation and mucosal thickening. Palifermin also has other potential clinical applications including the acceleration of immune reconstitution and inhibition of graft-versus-host disease in patients undergoing HSCT, and mitigation of dysphagia in lung cancer patients treated with concurrent CT/RT. Palifermin is generally well tolerated with mild-to-moderate skin and oral adverse events. Future studies may expand the use of palifermin into other areas that would benefit from its cytoprotective and regenerative effects.

Randomized phase II study of palifermin for reducing dysphagia in patients receiving concurrent chemoradiotherapy for locally advanced unresectable non-small cell lung cancer.

INTRODUCTION: Dysphagia is a common, dose-limiting toxicity of combined chemoradiotherapy (CT/RT) in patients with locally advanced non-small cell lung cancer (NSCLC). This study assessed the efficacy and safety of palifermin in reducing dysphagia from CT/RT followed by consolidation chemotherapy (CT). METHODS: This randomized, double-blind, phase II trial enrolled adults with unresectable stage III NSCLC. Subjects received weekly paclitaxel (50 mg/m2) and carboplatin (AUC 2.0) with concurrent daily radiation (RT) of 6000 to 6600 cGy, followed by consolidation CT. Palifermin (n = 49) or placebo (n = 46) was administered before starting concurrent CT/RT and once weekly for 6 weeks. The primary end points were the incidence of grade ≥ 2 dysphagia and safety. RESULTS: The incidence of grade ≥ 2 and ≥ 3 dysphagia was numerically lower in palifermin subjects versus placebo subjects (61% versus 70%; p = 0.36; 22% versus 28%, p = 0.50, respectively). Mean duration of dysphagia (grade ≥ 2) was 25 days for palifermin subjects and 32 days for placebo subjects (p = 0.32). The incidence of adverse events was similar in the two treatment groups, and median overall survival and progression-free survival were not adversely affected by palifermin treatment (overall survival: 513 versus 319 days; progression-free survival: 262 versus 235 days for palifermin versus placebo arms, respectively). The palifermin arm received more doses of CT per study design and significantly more patients received RT doses ≥ 6000 cGy (84% versus 61%, p = 0.01). CONCLUSIONS: The results of this exploratory trial suggest that additional larger studies may be warranted to further evaluate the effect of palifermin on dysphagia, exposure to CT/RT, and long-term survival.

Palifermin decreases severe oral mucositis of patients undergoing postoperative radiochemotherapy for head and neck cancer: a randomized, placebo-controlled trial.

PURPOSE: Radiochemotherapy of head and neck cancer causes severe mucositis in most patients. We investigated whether palifermin reduces this debilitating sequela. METHODS: We conducted a multicenter, double-blind, randomized, placebo-controlled trial in 186 patients with stages II to IVB carcinoma of the oral cavity, oropharynx, hypopharynx, or larynx. Patients received 60 or 66 Gy after complete (R0) or incomplete resection (R1), respectively, at 2 Gy/fraction and five fractions per week. Cisplatin 100 mg/m(2) was administered on days 1 and 22 (and on day 43 with R1). Patients were randomly assigned to receive weekly palifermin 120 µg/kg or placebo from 3 days before and continuing throughout radiochemotherapy. Trained evaluators performed oral assessments twice weekly. The primary end point was the incidence of severe oral mucositis (WHO grades 3 to 4). Overall survival and time to locoregional progression were also assessed. Analysis was by intention to treat. RESULTS: Severe oral mucositis was seen in 47 (51%) of 92 patients administered palifermin and 63 (67%) of 94 administered placebo (P = .027). Palifermin decreased the duration (median, 4.5 v 22.0 days) and prolonged the time to develop (median, 45 v 32 days) severe mucositis. Neither patient-reported mouth and throat soreness scores nor treatment breaks differed between treatment arms. After median follow-up of 32.8 months, 23 deaths (25%) had occurred in both treatment arms, and disease had recurred in 25 (27%) and 22 (24%) of palifermin- and placebo-treated patients, respectively. CONCLUSION: Palifermin reduced the occurrence of severe oral mucositis in patients with head and neck cancer undergoing postoperative radiochemotherapy. Additional clinical exploration of palifermin with postoperative radiochemotherapy would be useful.

Palifermin reduces severe mucositis in definitive chemoradiotherapy of locally advanced head and neck cancer: a randomized, placebo-controlled study.

PURPOSE: Oral mucositis (OM) is a debilitating toxicity of chemoradiotherapy for head and neck cancer (HNC). This randomized, placebo-controlled, double-blind study evaluated the efficacy and safety of palifermin to reduce OM associated with definitive chemoradiotherapy for locally advanced HNC. PATIENTS AND METHODS: Patients receiving conventionally fractionated radiotherapy (2.0 Gy/d, 5 days/wk to 70 Gy) with cisplatin (100 mg/m(2) on days 1, 22, and 43) received palifermin (180 µg/kg) or placebo before starting chemoradiotherapy and then once weekly for 7 weeks. The primary end point was the incidence of severe, observable, and functional OM (WHO grade 3 to 4). RESULTS: The palifermin (n = 94) and placebo (n = 94) arms were well balanced. The incidence of severe OM was significantly lower for palifermin than for placebo (54% v 69%; P = .041). In the palifermin arm, median time to severe OM was delayed (47 v 35 days), median duration of severe OM was shortened (5 v 26 days), and the incidence of xerostomia grade ≥ 2 was lower (67% v 80%), favoring palifermin; however, the differences were not significant after multiplicity adjustment. Opioid analgesic use, average mouth and throat soreness scores, and chemoradiotherapy compliance were not significantly different between treatment arms. Adverse events were similar between arms (98%, palifermin; 93%, placebo). The most common study drug-related adverse events were rash, flushing, and dysgeusia. After median follow-up of 25.8 months, overall survival and progression-free survival were similar between treatment arms. CONCLUSION: Although palifermin reduced severe functional OM, its role in the management of locally advanced HNC during chemoradiotherapy remains to be elucidated.

Subcutaneous or intravenous administration of romiplostim in thrombocytopenic patients with lower risk myelodysplastic syndromes.

BACKGROUND: Romiplostim is a peptibody protein that augments thrombopoiesis by activating the thrombopoietin receptor. METHODS: In this phase 2, multicenter, open-label study, 28 thrombocytopenic patients with lower risk myelodysplastic syndromes (MDS) were assigned to receive romiplostim 750 µg administered subcutaneously either weekly or biweekly or administered as biweekly intravenous injections for 8 weeks. Patients also could enter a 1-year study extension phase. RESULTS: At least 1 adverse event was observed in 93% of patients. The most common adverse events were fatigue and headache (18% for both, and 5 events were grade 3 or 4. There was 1 serious treatment-related adverse event in the biweekly intravenous cohort (hypersensitivity). This hypersensitivity resolved without discontinuation of study treatment. No patients developed neutralizing antibodies or bone marrow fibrosis. Of the patients who completed 8 weeks of treatment, 57% had a complete platelet response, an additional 8% had a major platelet response, and 61% did not require a platelet transfusion during this period. Weekly subcutaneous injections achieved the highest mean trough concentrations. CONCLUSIONS: The safety and efficacy profiles of romiplostim in this study suggested that weekly subcutaneous administration of 750 µg romiplostim is an appropriate starting dose for future clinical studies in patients with MDS and thrombocytopenia.

Romiplostim or standard of care in patients with immune thrombocytopenia.

BACKGROUND: Romiplostim, a thrombopoietin mimetic, increases platelet counts in patients with immune thrombocytopenia, with few adverse effects. METHODS: In this open-label, 52-week study, we randomly assigned 234 adult patients with immune thrombocytopenia, who had not undergone splenectomy, to receive the standard of care (77 patients) or weekly subcutaneous injections of romiplostim (157 patients). Primary end points were incidences of treatment failure and splenectomy. Secondary end points included the rate of a platelet response (a platelet count >50×10(9) per liter at any scheduled visit), safety outcomes, and the quality of life. RESULTS: The rate of a platelet response in the romiplostim group was 2.3 times that in the standard-of-care group (95% confidence interval [CI], 2.0 to 2.6; P<0.001). Patients receiving romiplostim had a significantly lower incidence of treatment failure (18 of 157 patients [11%]) than those receiving the standard of care (23 of 77 patients [30%], P<0.001) (odds ratio with romiplostim, 0.31; 95% CI, 0.15 to 0.61). Splenectomy also was performed less frequently in patients receiving romiplostim (14 of 157 patients [9%]) than in those receiving the standard of care (28 of 77 patients [36%], P<0.001) (odds ratio, 0.17; 95% CI, 0.08 to 0.35). The romiplostim group had a lower rate of bleeding events, fewer blood transfusions, and greater improvements in the quality of life than the standard-of-care group. Serious adverse events occurred in 23% of patients (35 of 154) receiving romiplostim and 37% of patients (28 of 75) receiving the standard of care. CONCLUSIONS: Patients treated with romiplostim had a higher rate of a platelet response, lower incidence of treatment failure and splenectomy, less bleeding and fewer blood transfusions, and a higher quality of life than patients treated with the standard of care. ( ClinicalTrials.gov number, NCT00415532.).

Phase 2 study of romiplostim in patients with low- or intermediate-risk myelodysplastic syndrome receiving azacitidine therapy.

We evaluated the efficacy and safety of romiplostim, a thrombopoietin mimetic, in patients with low- or intermediate-risk myelodysplastic syndromes (MDS) receiving azacitidine therapy. Forty patients with low- or intermediate-risk MDS were stratified by baseline platelet counts (< 50 vs ≥ 50 × 10(9)/L) and randomized to romiplostim 500 µg or 750 µg or placebo subcutaneously once weekly during 4 cycles of azacitidine. The primary endpoint was the incidence of clinically significant thrombocytopenic events, defined by grade 3 or 4 thrombocytopenia starting on day 15 of the first cycle or platelet transfusion at any time during the 4-cycle treatment period. No formal hypothesis testing was planned. The incidence of clinically significant thrombocytopenic events in patients receiving romiplostim 500 µg, romiplostim 750 µg, or placebo was 62%, 71%, and 85%, respectively. The incidence of platelet transfusions was 46%, 36%, and 69%, respectively. These differences were not statistically significant with the small numbers in each group. Romiplostim 750 µg significantly raised median platelet counts during cycle 3 on day 1 (P = .0373) and at the nadir (P = .0035) compared with placebo. Grade 3 rash and arthralgia each were reported in 1 romiplostim-treated patient (4%). This study suggests romiplostim may provide clinical benefits in MDS patients during azacitidine therapy.

Assessment of immunogenicity of romiplostim in clinical studies with ITP subjects.

Romiplostim is an Fc-peptide fusion protein that activates intracellular transcriptional pathways via the thrombopoietin (TPO) receptor leading to increased platelet production. Romiplostim has been engineered to have no amino acid sequence homology to endogenous TPO. Recombinant protein therapeutics can be at a risk of development of an antibody response that can impact efficacy and safety. Hence, a strategy to detect potential antibody formation to the drug and to related endogenous molecules can be useful. The immunogenicity assessment strategy involved both the detection and characterization of binding and neutralizing antibodies. The method for detection was based on a surface plasmon resonance biosensor platform using the Biacore 3000. Samples that tested positive for binding antibodies in the Biacore immunoassay were then tested in a neutralization assay. Serum samples from 225 subjects with immune thrombocytopenic purpura (ITP) dosed with romiplostim and 45 ITP subjects dosed with placebo were tested for romiplostim and TPO antibodies. Prior to romiplostim treatment, 17 subjects (7%) tested romiplostim antibody positive and 12 subjects (5%) tested TPO antibody positive for pre-existing binding antibodies. After romiplostim exposure, 11% of the subjects exhibited binding antibodies against romiplostim and 5% of the subjects with ITP showed binding antibodies against TPO. The antibodies against romiplostim did not cross-react with TPO and vice versa. No cases of anti-TPO neutralizing antibodies were detected in romiplostim-treated subjects. The incidence of anti-romiplostim neutralizing antibodies to romiplostim was 0.4% (one subject); this subject tested negative at the time of follow-up 4 months later. No impact on platelet profiles were apparent in subjects that had antibodies to romiplostim to date. In summary, administration of romiplostim in ITP subjects resulted in the development of a binding antibody response against romiplostim and TPO ligand. One subject developed a neutralizing antibody response to romiplostim that impacted the platelet counts of this subject. No neutralizing antibodies to endogenous TPO were observed.

Safety and efficacy of romiplostim in patients with lower-risk myelodysplastic syndrome and thrombocytopenia.

PURPOSE: To assess the safety and efficacy of romiplostim, a peptibody that increases platelet production, for treatment of thrombocytopenic patients with myelodysplastic syndromes (MDS). PATIENTS AND METHODS: Eligible patients had lower-risk MDS (International Prognostic Scoring System low or intermediate 1), a mean baseline platelet count

A phase II, open-label, sequential-cohort, dose-escalation study of romiplostim in Japanese patients with chronic immune thrombocytopenic purpura.

This phase II, multicenter, open-label, sequential-cohort, dose-escalation study was designed to evaluate the safety and efficacy of romiplostim, a novel peptibody that increases platelet production, in Japanese patients with chronic immune thrombocytopenic purpura (ITP). Sequential cohorts of four patients each received romiplostim (1, 3, or 6 microg/kg) subcutaneously on days 1 and 8 of the dose-escalation phase. Patients who achieved platelet responses (doubling of baseline platelet counts to > or =50 x 10(9)/L) continued romiplostim weekly during the treatment-continuation phase. Romiplostim produced dose-dependent increases in mean and peak platelet counts. Five patients received romiplostim during the treatment-continuation phase, with platelet counts > or =50 x 10(9)/L maintained in approximately half of the weekly assessments. Romiplostim was well tolerated. No severe, serious, or life-threatening adverse events were reported. No binding antibodies to romiplostim or thrombopoietin were detected. Romiplostim is safe and well tolerated in Japanese patients with chronic ITP and is effective in producing platelet count increases, consistent with the results from studies in non-Japanese patients. On the basis of these findings, a starting dose of 3 microg/kg was recommended for phase III evaluation of romiplostim in Japanese patients with chronic ITP.

Phase II study of palifermin and concurrent chemoradiation in head and neck squamous cell carcinoma.

PURPOSE: Acute mucositis is a dose-limiting toxicity of concurrent chemoradiotherapy regimens for locally advanced head and neck cancer. Palifermin (a recombinant human keratinocyte growth factor; DeltaN23-KGF) stimulates the proliferation and differentiation of mucosal epithelium to reduce mucositis in patients receiving intensive therapy for hematologic cancers. This study assessed the efficacy and safety of palifermin in patients receiving concurrent chemoradiotherapy for advanced head and neck squamous cell carcinoma. PATIENTS AND METHODS: In a phase II trial, standard radiotherapy was delivered in daily 2-Gy fractions to 70 Gy, or hyperfractionated radiotherapy was delivered in 1.25-Gy fractions twice daily to 72 Gy, over 7 weeks. Chemotherapy included cisplatin 20 mg/m(2) for 4 days and continuous-infusion fluorouracil 1,000 mg/m(2)/d for 4 days on weeks 1 and 5 of irradiation. Patients were randomly assigned 2:1 to palifermin 60 microg/kg or placebo once weekly for 10 doses. A follow-up trial evaluated long-term survival. RESULTS: Sixty-seven patients received palifermin and 32 received placebo. The median duration of grade >or= 2 mucositis was 6.5 and 8.1 weeks in the palifermin and placebo groups, respectively (P = .157). Palifermin appeared to reduce mucositis, dysphagia, and xerostomia during hyperfractionated radiotherapy (n = 40) but not standard radiation therapy (n = 59). Adverse events were similar between treatment groups. Palifermin did not alter tumor response or survival. CONCLUSION: Ten once-weekly doses of palifermin at 60 microg/kg were well tolerated. Most patients completed treatment, but palifermin did not reduce the morbidity of concurrent chemotherapy and radiotherapy. Future studies should evaluate higher palifermin doses with longer and more standardized assessment of acute mucositis.

Pegfilgrastim support for full delivery of BEACOPP-14 chemotherapy for patients with high-risk Hodgkin's lymphoma: results of a phase II study.

The primary endpoint of this feasibility study was to determine whether pegfilgrastim support could enable the delivery of the full dose of BEACOPP chemotherapy every 14 days on schedule. Forty-one patients with high-risk Hodgkin's lymphoma were randomized to receive pegfilgrastim (6 mg) on day 4 or 8 of each cycle. Eighty-one percent of cycles administered were delivered at full dose and on schedule (FDOS). Response was retrospectively assessed in 27 patients at 6 months; 23 of these 27 patients (85%) achieved a complete response and one (4%) achieved a partial response. Toxicities were mostly moderate in intensity. These results support the feasibility of delivering full dose, on schedule BEACOPP-14, chemotherapy with pegfilgrastim support.

Comparative neurotoxicity of weekly non-break paclitaxel infusions over 1 versus 3 h.

We evaluated the effects of weekly short infusions of paclitaxel (PAC) on the development of a peripheral neuropathy (PNP) as primary endpoint. Patients with advanced cancer were randomized to a weekly regimen of PAC (100 mg/m2) infused over 1 versus 3 h. PNP was evaluated by a clinical score including sensory symptoms, strength, tendon reflexes and vibratory sense (range 0-12; PNP >3 points). Kaplan-Meier-type curves were calculated. In total, 22 study centers enrolled 121 patients, 92 assessable for analysis. The probability to exceed a PNP score of 3 increased from 0.20 versus 0.30 after six to 0.68 versus 0.47 after 12 administrations (1 versus 3 h: p = 0.66). After 12 weeks of therapy only a quarter of assessable patients were free of PNP. Cox analysis yielded a relative risk of 1.10 for 1-h infusions (p = 0.80). We observed a rapid increasing risk of PNP manifestation in the course of weekly PAC administrations without significant differences between 1- and 3-h infusions. This is in contrast to pharmacokinetic observations indicating that a shortening of infusion time might enhance neurotoxicity by increasing the AUC of Cremophor. A majority of patients experiencing neurotoxic effects require the investigation of potential nerve protectors in future clinical trials accompanying PAC therapy.