Oesophageal Doppler guided goal-directed haemodynamic therapy in thoracic surgery - a single centre randomized parallel-arm trial.

BACKGROUND: Postoperative pulmonary and renal complications are frequent in patients undergoing lung surgery. Hyper- and hypovolaemia may contribute to these complications. We hypothesized that goal-directed haemodynamic management based on oesophageal Doppler monitoring would reduce postoperative pulmonary complications in a randomized clinical parallel-arm trial. METHODS: One hundred patients scheduled for thoracic surgery were randomly assigned to either standard haemodynamic management (control group) or goal-directed therapy (GDT group) guided by an oesophageal Doppler monitoring-based algorithm. The primary endpoint was postoperative pulmonary complications, including spirometry. Secondary endpoints included haemodynamic variables, renal, cardiac, and neurological complications, and length of hospital stay. The investigator assessing outcomes was blinded to group assignment. RESULTS: Forty-eight subjects of each group were analysed. Compared to the control group, fewer subjects in the GDT group developed postoperative pulmonary complications (6 vs. 15 patients; P = 0.047), while spirometry did not differ between groups. Compared to the control group, patients of the GDT group showed higher cardiac index (2.9 vs. 2.1 [l min - 1 m - 2 ]; P < 0.001) and stroke volume index (43 vs. 34 [ml m 2 ]; P < 0.001) during surgery. Renal, cardiac and neurological complications did not differ between groups. Length of hospital stay was shorter in the GDT compared to the control group (9 vs. 11 days; P = 0.005). CONCLUSIONS: Compared to standard haemodynamic management, oesophageal Doppler monitor-guided GDT was associated with fewer postoperative pulmonary complications and a shorter hospital stay. CLINICAL TRIAL REGISTRATION.: The study was registered in the German Clinical Trials Register (DRKS 00006961). https://drks-neu.uniklinik-freiburg.de/drks_web/.

Telemedically Supported Case Management of Living-Donor Renal Transplant Recipients to Optimize Routine Evidence-Based Aftercare: A Single-Center Randomized Controlled Trial.

Improving mid-term and long-term outcomes after solid organ transplantation is imperative, and requires both state-of-the-art transplant surgery and optimization of routine, evidence-based aftercare. This randomized, controlled trial assessed the effectiveness of standard aftercare versus telemedically supported case management, an innovative aftercare model, in 46 living-donor renal transplant recipients during the first posttransplant year. The model includes three components: (i) chronic care case management initiated after discharge, (ii) case management initiated in emerging acute care situations, and (iii) a telemedically equipped team comprising a transplant nurse case manager and two senior transplant physicians (nephrologist, surgeon). Analyses revealed a reduction of unplanned inpatient acute care, with considerable cost reductions, in the intervention group. The prevalence of nonadherence over the 1-year study period was 17.4% in the intervention group versus 56.5% in the standard aftercare group (p = 0.013). Only the intervention group achieved their pre-agreed levels of adherence, disease-specific quality of life, and return to employment. This comparative effectiveness study provides the basis for multicenter study testing of telemedically supported case management with the aim of optimizing posttransplant aftercare. The trial was registered with the German Clinical Trials Register (www.DRKS.de), DKRS00007634.

STAT3 expression, activity and functional consequences of STAT3 inhibition in esophageal squamous cell carcinomas and Barrett's adenocarcinomas.

Signal transducer and activator of transcription 3 (STAT3) is altered in several epithelial cancers and represents a potential therapeutic target. Here, STAT3 expression, activity and cellular functions were examined in two main histotypes of esophageal carcinomas. In situ, immunohistochemistry for STAT3 and STAT3-Tyr705 phosphorylation (P-STAT3) in esophageal squamous cell carcinomas (ESCC, n=49) and Barrett's adenocarcinomas (BAC, n=61) revealed similar STAT3 expression in ESCCs and BACs (P=0.109), but preferentially activated P-STAT3 in ESCCs (P=0.013). In vitro, strong STAT3 activation was seen by epidermal growth factor (EGF) stimulation in OE21 (ESCC) cells, whereas OE33 (BAC) cells showed constitutive weak STAT3 activation. STAT3 knockdown significantly reduced cell proliferation of OE21 (P=0.0148) and OE33 (P=0.0243) cells. Importantly, STAT3 knockdown reduced cell migration of OE33 cells by 2.5-fold in two types of migration assays (P=0.073, P=0.015), but not in OE21 cells (P=0.1079, P=0.386). Investigation of transcriptome analysis of STAT3 knockdown revealed a reduced STAT3 level associated with significant downregulation of cell cycle genes in both OE21 (P<0.0001) and OE33 (P=0.01) cells. In contrast, genes promoting cell migration (CTHRC1) were markedly upregulated in OE21 cells, whereas a gene linked to tight-junction stabilization and restricted cell motility (SHROOM2) was downregulated in OE21 but upregulated in OE33 cells. This study shows frequent, but distinct, patterns of STAT3 expression and activation in ESCCs and BACs. STAT3 knockdown reduces cell proliferation in ESCC and BAC cells, inhibits migration of BAC cells and may support cell migration of ESCC cells. Thereby, novel STAT3-regulated genes involved in ESCC and BAC cell proliferation and cell migration were identified. Thus, STAT3 may be further exploited as a potential novel therapeutic target, however, by careful distinction between the two histotypes of esophageal cancers.

Somatropin treatment of spinal muscular atrophy: a placebo-controlled, double-blind crossover pilot study.

In preclinical studies growth hormone and its primary mediator IGF-1 have shown potential to increase muscle mass and strength. A single patient with spinal muscular atrophy reported benefit after compassionate use of growth hormone. Therefore we evaluated the efficacy and safety of growth hormone treatment for spinal muscular atrophy in a multicenter, randomised, double-blind, placebo-controlled, crossover pilot trial. Patients (n = 19) with type II/III spinal muscular atrophy were randomised to receive either somatropin (0.03 mg/kg/day) or placebo subcutaneously for 3 months, followed by a 2-month wash-out phase before 3 months of treatment with the contrary remedy. Changes in upper limb muscle strength (megascore for elbow flexion and hand-grip in Newton) were assessed by hand-held myometry as the primary measure of outcome. Secondary outcome measures included lower limb muscle strength, motor function using the Hammersmith Functional Motor Scale and other functional tests for motor function and pulmonary function. Somatropin treatment did not significantly affect upper limb muscle strength (point estimate mean: 0.08 N, 95% confidence interval (CI:-3.79;3.95, p = 0.965), lower limb muscle strength (point estimate mean: 2.23 N, CI:-2.19;6.63, p = 0.302) or muscle and pulmonary function. Side effects occurring during somatropin treatment corresponded with well-known side effects of growth hormone substitution in patients with growth hormone deficiency. In this pilot study, growth hormone treatment did not improve muscle strength or function in patients with spinal muscular atrophy type II/III.

[Differential diagnosis of myeloproliferative neoplasms. Quantitative NF-E2 immunohistochemistry for differentiating between essential thrombocythemia and primary myelofibrosis]. / Differenzialdiagnose myelproliferativer Neoplasien. Quantitative NF-E2-Immunhistochemie zur Unterscheidung zwischen essenzieller Thrombozythämie und primärer Myelofibrose.

BACKGROUND: Besides essential thrombocythemia (ET), polycythemia vera (PV) and primary myelofibrosis (PMF) the myeloproliferative neoplasms (MPN) defined by the World Health Organization (WHO) comprise the entity of unclassifiable MPNs (MPN, U). The exact differential diagnosis of the specific MPN entities can be challenging particularly at early stages of the diseases. So far, pathologists have had to rely only on histomorphological evaluation of bone marrow biopsies in combination with laboratory data because helpful ancillary tests are not yet available. Even molecular tests, such as JAK2 mutation analysis are not helpful particularly in the differential diagnosis of ET and PMF because both entities are associated with the V617F mutation in 50 % of the cases. Recently overexpression of the transcription factor NF-E2 in MPN was described. MATERIALS AND METHODS: A collective of samples consisting of 163 bone marrow biopsies including 139 MPN cases was stained immunohistochemically for NF-E2 and analyzed regarding the subcellular localization of NF-E2 in erythroid progenitor cells. The results were compared between the MPN entities as well as the controls and statistical analyses were conducted. RESULTS AND DISCUSSION: This study showed that NF-E2 immunohistochemistry and analysis of the proportion of nuclear positive erythroblasts of all erythroid precursor cells can help to distinguish between ET and PMF even in early stages of the diseases. An MPN, U case showing a proportion of more than 20 % nuclear positive erythroblasts can be classified as a PMF with 92 % accuracy.

Aurora-B protein expression is linked to initial response to taxane-based first-line chemotherapy in stage III ovarian carcinoma.

AIMS: Aurora kinases are central to cell proliferation and considered to be prognostic/predictive markers and therapeutic targets for epithelial cancers. Here, the prognostic/predictive value of Aurora-B protein expression was evaluated in patients with serous, FIGO stage III ovarian carcinomas treated with taxane- or platinum-based first-line chemotherapy (1st-CTx). METHODS: Immunohistochemistry was performed on tissue microarrays, including 80 ovarian carcinomas and 18 non-neoplastic ovaries, previously characterised for Aurora-A protein expression. None or marginal (score 0+1), moderate (score 2) and strong (score 3) Aurora-B protein expression was correlated with clinico-pathological parameters as well as recurrence-free survival (RFS) and overall survival (OS). RESULTS: While non-neoplastic ovaries were negative for Aurora-B, almost all (79/80; 99%) ovarian carcinomas exhibited Aurora-B positive tumour cells, with score 1 in 41/80 (51%), score 2 in 23/80 (29%) and score 3 in 15/80 (19%) cases. Aurora-B and Aurora-A protein expression correlated significantly (p=0.002). In optimal debulked patients, Aurora-B protein expression was associated with RFS (p=0.011, n=53) and marginally with OS (p=0.460; n=53). Moreover, Aurora-B protein expression was predictive for RFS of optimal debulked patients with taxane-based (p=0.006; n=32), but not with platinum-based (p=0.720; n=20) 1st-CTx. Aurora-B protein expression was not linked to OS in optimal debulked patients with either of the two 1st-CTx. CONCLUSIONS: Aurora-B protein expression frequently occurs in serous, FIGO stage III ovarian carcinomas, making it a 'drugable' molecular target in the majority of ovarian carcinoma patients. Moreover, Aurora-B protein expression is predictive for initial response to taxane-based 1st-CTx in optimal debulked, late stage ovarian carcinoma patients.

Roflumilast, a once-daily oral phosphodiesterase 4 inhibitor, lacks relevant pharmacokinetic interactions with inhaled salbutamol when co-administered in healthy subjects.

OBJECTIVE: Roflumilast is an oral, once-daily phosphodiesterase 4 inhibitor under investigation for the treatment of chronic obstructive pulmonary disease and asthma. In clinical practice, the drug is likely to be co-administered with inhaled bronchodilating beta2-adrenoceptor agonists. Therefore, this study investigated the pharmacokinetic characteristics of roflumilast and its pharmacodynamically active metabolite roflumilast N-oxide when co-administered with orally inhaled salbutamol in healthy subjects. METHODS: In this open, randomized clinical study, 12 healthy male subjects received repeated doses of oral roflumilast 500 microg once daily, orally inhaled salbutamol 200 microg 3 times daily, and a combination of both drugs over 7 days according to a 3-period, changeover design with 14 days washout between treatments. RESULTS: Co-administration of roflumilast and salbutamol did not markedly change roflumilast or roflumilast N-oxide disposition. Point estimates (90% confidence intervals) of area under the curve from 0-24 h (AUC 0-24) and maximum plasma concentration in steady state (Cmax,ss) for roflumilast with salbutamol versus roflumilast alone were 1.05 (0.94, 1.17) and 0.97 (0.84, 1.10); the respective point estimates (90% confidence intervals) for AUC 0-24 and Cmax,ss of roflumilast N-oxide were 0.98 (0.91, 1.06) and 0.98 (0.92, 1.03). Roflumilast co-administration did not alter the pharmacokinetics of steady state salbutamol. The respective point estimates (90% confidence intervals) for AUC 0-6 and Cmax,ss of salbutamol with roflumilast versus salbutamol alone were 1.10 (0.99, 1.21), 1.08 (0.91, 1.28). The combination of both drugs was well tolerated. CONCLUSION: There were no relevant pharmacokinetic interactions between roflumilast and salbutamol at therapeutically effective doses.

[Biometrical methods for the proof of efficacy in regulatory submissions. Non-inferiority in clinical studies]. / Biometrische Verfahren zum Wirksamkeitsnachweis im Zulassungsverfahren Nicht-Unterlegenheit in klinischen Studien.

The increasing number of approved efficacious therapies for various indications raises the question of whether the inclusion of a placebo group is still justified. In addition, pharmaceutical companies and regulatory agencies acknowledge that it may be sufficient to prove that a new therapy is comparable to an approved reference therapy regarding efficacy and safety in some situations. This becomes especially striking for the approval to market a generic drug. Another, perhaps even more important example is the increasing resistance of bacteria which calls for new antibiotics based on new therapeutic principles without having the claim for better efficacy. In these situations, a comparable efficacy would constitute progress. In the present paper, we discuss the numerous methodological challenges and approaches to overcome these problems that occur when it is not possible or even not wanted to use the classic approach of a randomized placebo-controlled superiority trial. Here, the field of medical biometry, which has proved in the last 25 years to be an integral part of the development of new drugs, demonstrates its suitability as a flexible and scientifically based means to fulfil the requirements resulting from clinical practice. Starting from the fact that statistical methods are not able to prove "equality" of two treatments, "shifted" hypotheses are considered and their importance for the different study designs is discussed. We show how the classic hypotheses known from placebo-controlled clinical trials can be embedded in this concept. The implications of this approach for the analysis and interpretation of study results is further discussed. The relevant guidelines of the European and US regulatory agencies are taken into account.

Dose linearity and steady state pharmacokinetics of the new antiparkinson agent budipine after oral administration.

The dose-dependency of budipine pharmacokinetic characteristics was studied. Eighteen healthy male subjects were given 10, 20 and 30 mg oral single doses according to a randomized, open, 3-period crossover design. Additionally, the steady state conditions were investigated after repeated intake of 10 mg t.i.d for 10 days and compared to the 10 mg single dose. The area under the concentration vs time curve (AUC) and the maximum serum concentration (Cmax) showed a linear increase in line with ascending doses of orally given budipine. Time to maximum serum concentration (tmax) and terminal half-life (t1/2) were independent of the administered dose. As compared to the 10 mg single dose pharmacokinetics, the repeated oral administration of budipine 10 mg t.i.d. resulted in an increase in AUC of 11% and 93% for budipine and its metabolite p-OH-budipine, respectively. In clinical practice, a predictable response in proportion to the dose is to be expected.

The U.S. draft guidance regarding population and individual bioequivalence approaches: comments by a research-based pharmaceutical company.

Generally, the motivation for switching from average bioequivalence to population and/or individual bio-equivalence is well recognized in the light of certain limitations of the concept of average bioequivalence. However, this switch still results in unresolved issues which should be addressed before the regulatory guidance is finalized.

Identifying the maximum safe dose: a multiple testing approach.

Identifying the maximum safe dose (MAXSD) is an objective of both randomized clinical dose-finding studies for the safety endpoint and toxicological studies. MAXSD is defined as the highest experimental dose with no significant increased safety effect relative to the placebo or control group. In safety assessment, the primary control of the false-negative error rate is more important than that of the false-positive rate. Therefore, we propose a multiple testing procedure for equivalence in the many-to-one design with a priori ordered contrasts (shifted control vs. dose), where the acceptable risk delta is defined in advance. Tests for shifted and ratio hypotheses are presented and discussed.

Approximate sample sizes for testing hypotheses about the ratio and difference of two means.

This article deals with a unifying approach to approximate sample size determination for different types of hypotheses formulated in terms of two means of normally distributed data. A simple approximation is given to the sample size required for testing hypotheses about the ratio of the means. The formula includes the situations of testing noninferiority, superiority, or equivalence. We present a more general formula that also covers hypotheses formulated in terms of the difference of means. We show that over a wide range of parameter values the approximation provides reliable sample sizes.

Effects of early treatment with rSP-C surfactant on oxygenation and histology in rats with acute lung injury.

Surfactant treatment in patients with acute respiratory distress syndrome (ARDS) may be a promising treatment strategy. The aim of this study was to investigate whether addition of a recombinant surfactant protein C (rSP-C) to a plain phospholipid (PL) surfactant (PL surfactant) can result in activity comparable to commercially available surfactant preparations (Alveofact and bLES) which contain surfactant protein B and C. In this investigation dose-response comparisons of four surfactants were performed in an animal model of ARDS induced by total lung lavage. The surfactants were given shortly (;10 min) after the last lavage. The effects of surfactant treatment were compared with respect to improve oxygenation and to prevent histopathological changes, such as hyaline membrane formation. The surfactants were compared to lavaged, untreated controls. The surfactants were administered at doses of 25, 50 and 100 mg total amount of phospholipids/kg body weight. At 120 min after early treatment, all three doses of rSP-C surfactant showed statistically significant higher improvements in oxygenation than PL surfactant. This improvement was comparable to bLES and superior to Alveofact. The rSP-C surfactant showed the most prominent effect on preventing hyaline membrane formation. It was again superior to PL surfactant and comparable to bLES. It is concluded that addition of rSP-C enhances the activity of a pure PL surfactant. The rSP-C surfactant showed comparable or even superior activity to bovine-derived surfactant preparations containing both, SP-B and SP-C.

Sample size determination for proving equivalence based on the ratio of two means for normally distributed data.

Equivalence trials aim to demonstrate that two treatments do not differ by more than a prespecified clinically irrelevant amount. We consider the problem when equivalence is defined in terms of the ratio of population means and the original (untransformed) data are normally distributed. Application of the intersection-union principle to the test proposed by Sasabuchi results in a two one-sided tests procedure of size alpha. We give the associated 100 (1-2 alpha) per cent confidence interval and derive the exact methods for calculation of power and sample sizes for the parallel group design and the two-period cross-over. We present tables and figures of required sample sizes and achieved power.

Intratracheally applied rSP-C surfactant exhibits no anaphylactic shock reactions in a guinea pig model of acute lung hypersensitivity.

The effect of the intratracheal administration of the recombinant SP-C surfactant apoprotein (rSP-C) with phospholipids (PL) in comparison to an ovalbumin induced anaphylactic shock reaction was studied in guinea pigs lungs. Narcotized guinea pigs were challenged by intratracheal administration on test day 24/25 once with a suspension of rSP-C/PL (reconstituted suspension). These animals were priorily sensitized on test day 1, 3 and 5 intraperitoneally with rSP-C/PL suspension or with Ovalbumin (OV) respectively. The following groups were used to assess the anaphylactic lung shock symptoms: group 1: positive control, 1 mg/kg OV protein, 2 ml/kg application volume, (Appl. vol.), N: 5 animals; group 2: 1 mg rSP-C/50 mg PL/0.5 ml/kg Appl. vol., N: 10; group 3: 2 mg rSP-C/100 mg PL/1.0 ml/kg Appl. vol., N: 10; group 4: 4 mg rSP-C/200 mg PL/2.0 ml/kg Appl. vol., N: 10. Clinical signs, mortality, lung weights and histopathological changes were evaluated. Additionally the lungs were investigated immunohistologically with polyclonal antibodies against rSP-C to determine the pulmonary distribution of the intratracheal applied rSP-C. In the OV-treated positive control group, all animals died within 4 minutes after intratracheal challenge, while only 1 animal of group 4 died probably due to an narcosis related respiratory arrest. In the rSP-C/PL treated groups, the lung weights showed a dose-related increase, but nevertheless all these rSP-C-treated groups showed a significant lower lung weight in comparison to the OV treated positive control group. The histopathology assessment of the lungs in the OV-treated animals revealed a severe generalised bronchoconstriction and a hyperemia in connection with a slight interstitial edema in all five animals. The rSP-C/PL-treated animals, which were sacrificed after 3 days, showed no bronchoconstriction but a slight increase in the severity of bronchus-associated infiltration with eosinophilic granulocytes and in the formation of peripheral emphysema, but with no dose-dependency. A slight dose-dependent increase in the deposition of peribronchiolar eosinophilic foreign material was evident. In contrast to this, the number of lipid-laden alveolar macrophages seemed to decrease with increasing doses of rSP-C/PL. The immunohistological investigation with a polyclonal antibody against rSP-C showed an intraalveolar distribution of the intratracheally applied rSP-C which is mainly located in the peribronchiolar alveolar parenchyma. A rSP-C-positive staining was visible within the cytoplasm of alveolar histiocytes, type II pneumocytes and also as an extracellularly rim along the alveolar walls. The polyclonal antibody showed no cross reaction with natural occuring SP-C-protein of the guinea pigs. We conclude that the intratracheal application of the rSP-C surfactant containing phospholipids (PL) exhibits no significant risk of an anaphylactic shock reaction in this guinea pig lung hypersensitivity model. The immunohistological investigation with polyclonal antibodies against rSP-C demonstrated clearly the distribution of intratracheal applied material in this toxicological animal model.

Characterisation of the rat lung lavage model as biological assay for testing the activity of surfactant preparations.

The present report describes how pharmacological assays may be validated and sets a basis for a discussion on the validation of biological test systems. The note for guidance on the validation of analytical procedures published by the European agency for the evaluation of medicinal products was adapted to the validation of a pharmacological test system. The presently described rat lung lavage test (RLL-test) is an animal model that has great similarities to the pathophysiology of the acute respiratory distress syndrome of humans. In this RLL-test, the activity of surfactants can be tested in a standardised fashion. The usefulness of the point estimator and the corresponding confidence intervals (CI) as a statistical test procedure for equivalence was demonstrated. A validation can be based on the above mentioned guidance but should be adjusted to pharmacological needs. Based on the presented experiences, it can be concluded that a specific guideline for validation of pharmacological or biological tests is desirable.

Comparison of rSP-C surfactant with natural and synthetic surfactants after late treatment in a rat model of the acute respiratory distress syndrome.

1. In a previous paper we showed that an SP-C containing surfactant preparation has similar activity as bovine-derived surfactants in a rat lung lavage model of the adult respiratory distress syndrome. In this study surfactant was given ten minutes after the last lavage (early treatment). In the present investigation we were interested how different surfactant preparations behave when they are administered 1 h after the last lavage (late treatment). 2. Four protein containing surfactants (rSP-C surfactant, bLES, Infasurf and Survanta) were compared with three protein-free surfactants (ALEC, Exosurf and the phospholipid (PL) mixture of the rSP-C surfactant termed PL surfactant) with respect to their ability to improve gas exchange in this more stringent model when surfactant is given one hour after the last lavage. For better comparison of the surfactants the doses were related to phospholipids. The surfactants were given at doses of 25, 50 and 100 mg kg(-1) body weight. The surfactants were compared to an untreated control group that was only ventilated for the whole experimental period. 3. Tracheotomized rats (8-12 per dose and surfactant) were pressure-controlled ventilated (Siemens Servo Ventilator 900C) with 100% oxygen at a respiratory rate of 30 breaths min(-1), inspiration expiration ratio of 1:2, peak inspiratory pressure of 28 cmH2O at positive endexpiratory pressure (PEEP) of 8 cmH2O. Animals were ventilated for one hour after the last lavage and thereafter the surfactants were intratracheally instilled. During the whole experimental period the ventilation was not changed. 4. Partial arterial oxygen pressures (PaO2, mmHg) at 30 min and 120 min after treatment were used for statistical comparison. All protein containing surfactants caused a dose-dependent increase of the reduced PaO2 values at 30 min after treatment. The protein-free surfactants showed only weak dose-dependent increase in PaO2 values at this time. This difference between the protein-containing and the protein-free surfactants was even more pronounced when comparing the PaO2 values at 120 min after treatment. Only rSP-C surfactant, bLES and Infasurf showed a dose-dependent increase in PaO2 at this time. 5. With this animal model of late treatment it is possible even to differentiate between bovine derived surfactants. The differences between protein-containing and protein-free surfactants become even more pronounced. From the comparison of rSP-C surfactant with bovine-derived surfactants and the PL surfactant without rSP-C, it can be concluded that addition of rSP-C is sufficient to achieve the same activity as that of natural surfactants.

Effects of rSP-C surfactant on oxygenation and histology in a rat-lung-lavage model of acute lung injury.

We have tested two surfactant preparations with the same phospholipid (PL) composition, containing recombinant surfactant protein-C (rSP-C surfactant) and without SP-C (plain PL surfactant). The effects of rSP-C surfactant were compared with the bovine-derived surfactant preparations Alveofact, bLES, and Infasurf in a lung lavage model, with surfactant given 1 h after the last lavage. The effects of surfactant treatment on histopathologic changes (e.g., hyaline-membrane formation) and improvement of oxygenation were compared with changes in untreated controls. The surfactants were given in doses of 25, 50, and 100 mg PL/kg body weight. At 120 min after treatment, only the protein-containing surfactants showed a statistically significant increasing dose dependence with respect to improving oxygenation. The values were 318 +/- 120 mm Hg, 443 +/- 58 mm Hg, and 480 +/- 43 mm Hg (mean +/- SD) for the three doses of rSP-C surfactant and 105 +/- 81 mm Hg, 100 +/- 69 mm Hg, and 131 +/- 108 mm Hg for the three doses of PL surfactant. The respective values for Alveofact were 104 +/- 81 mm Hg, 105 +/- 93 mm Hg, and 260 +/- 143 mm Hg; for bLES 373 +/- 138 mm Hg, 441 +/- 88 mm Hg, and 467 +/- 43 mm Hg; and for Infasurf 146 +/- 96 mm Hg, 284 +/- 178 mm Hg, and 436 +/- 70 mm Hg. The oxygen values of controls remained low, at 74 +/- 46 mm Hg. Only the protein-containing surfactants dose-dependently inhibited the formation of hyaline membranes. We conclude that rSP-C surfactant is at least as effective as bovine-derived surfactants. Furthermore, the data imply that the difference between plain PL surfactant preparations and bovine-derived surfactant preparations containing both SP-B and SP-C can be overcome by addition of SP-C.

Individual bioequivalence--a European perspective.

Regulatory requirements for average bioequivalence have been internationally harmonized, which is by no means the case for the more recent concept of individual bioequivalence. The main reason for introducing more complex replicate designs and bioequivalence criteria are the highly variable drugs, for which the setting of suitable bioequivalence ranges poses a major problem and scaling of the bioequivalence criteria by the intrasubject variability has been suggested. The shortcoming of the present two-treatment, two-period (2 x 2) crossover design to detect subject-by-formulation interaction provides a second argument in favor of the more complex replicate designs. A unified approach of proposed statistical procedures for the replicate design has been given by Schall. However, the availability of these methods and understanding of them seems to be limited to a small working group, so a broader international awareness of the problems and potentional solutions is desirable.

Choice of student's t- or Wilcoxon-based confidence intervals for assessment of average bioequivalence.

An open question in the analysis of average bioequivalence is whether the nonparametric (Wilcoxon) or parametric (t) approaches to two one-sided tests is preferable. Previous work has made particular distributional assumptions as to the distribution of AUC and C(max). Instead, we simulate data according to a pharmacokinetic model for an immediate-release formulation. We find that both approaches have estimated level consistent with the nominal 5%. The only concern is a possible anticonservativeness of the parametric approach for C(max). Further, the nonparametric approach is consistently less powerful than the parametric for the cases studied.