A Composite Decision Rule of CD8+ T-cell Density in Tumor Biopsies Predicts Efficacy in Early-stage, Immunotherapy Trials

PURPOSE

To examine whether CD8+ T-cell numbers in paired tumor biopsies in early-stage clinical trials can be used as an early indicator of clinical benefit for cancer immunotherapies.

EXPERIMENTAL DESIGN

Paraffin sections of tumor biopsies were stained immunohistochemically for CD8+ T cells, which were digitally enumerated. The tumor biopsies were from cancer patients in early-phase trials testing novel immunotherapeutic agents. Paired biopsies taken before the start of treatment and on-treatment were compared. A total of 155 patients were used as the training set and an additional 221 patients were used as the validation set.

RESULTS

Using the Cox proportional hazard model, a ≥0.9- increase in fold change (FC) on a ln scale in CD8+ T cells (corresponding to a 2.5-fold increase on the linear scale), from baseline, demonstrated a greater association with prolonged progression-free survival and allowed improved differentiation between groups above and below the threshold. Similarly, a ≥6.2 threshold in geometric mean of the on-treatment density (OTD) of T cells, which approximately corresponds to 500 cells/mm2, correlated with longer PFS. The combination of both criteria (FC and OTD) provided the best discrimination between clinically nonactive and active compounds.

CONCLUSIONS

We propose that a composite score of CD8+ T-cell density in paired biopsies taken before and on-treatment may be a new biomarker to inform on clinical outcomes in early immunotherapy clinical trials.

Support to early clinical decisions in drug development and personalised medicine with checkpoint inhibitors using dynamic biomarker-overall survival models

Longitudinal models of biomarkers such as tumour size dynamics capture treatment efficacy and predict treatment outcome (overall survival) of a variety of anticancer therapies, including chemotherapies, targeted therapies, immunotherapies and their combinations. These pharmacological endpoints like tumour dynamic (tumour growth inhibition) metrics have been proposed as alternative endpoints to complement the classical RECIST endpoints (objective response rate, progression-free survival) to support early decisions both at the study level in drug development as well as at the patients level in personalised therapy with checkpoint inhibitors. This perspective paper presents recent developments and future directions to enable wider and robust use of model-based decision frameworks based on pharmacological endpoints.

Multistate model for pharmacometric analyses of overall survival in HER2-negative breast cancer patients treated with docetaxel

The aim of this study was to develop a multistate model for overall survival (OS) analysis, based on parametric hazard functions and combined with an investigation of predictors derived from a longitudinal tumor size model on the transition hazards. Different states – stable disease, tumor response, progression, second‐line treatment, and death following docetaxel treatment initiation (stable state) in patients with HER2‐negative breast cancer (n = 183) were used in model building. Past changes in tumor size prospectively predicts the probability of state changes. The hazard of death after progression was lower for subjects who had longer treatment response (i.e., longer time‐to‐progression). Young age increased the probability of receiving second‐line treatment. The developed multistate model adequately described the transitions between different states and jointly the overall event and survival data. The multistate model allows for simultaneous estimation of transition rates along with their tumor model derived metrics. The metrics were evaluated in a prospective manner so not to cause immortal time bias. Investigation of predictors and characterization of the time to develop response, the duration of response, the progression‐free survival, and the OS can be performed in a single multistate modeling exercise. This modeling approach can be applied to other cancer types and therapies to provide a better understanding of efficacy of drug and characterizing different states, thereby facilitating early clinical interventions to improve anticancer therapy.

Rolling continual reassessment method with overdose control: An efficient and safe dose escalation design

In phase 1 dose escalation studies, dose limiting toxicities (DLTs) are defined as adverse events of concern occurring during a predefined time window after first dosing of patients. Standard dose escalation designs, such as the continual reassessment method (CRM), only utilize this binary DLT information. Thus, late-onset DLTs are usually not accounted for when CRM guiding the dose escalation and finally defining the maximum tolerated dose (MTD) of the drug, which brings safety concerns for patients. Previously, several extensions of CRMs, such as the time-to-event CRM (TITE-CRM), fractional CRM (fCRM) and the data augmented CRM (DA-CRM), have been proposed to handle this issue without prolonging trial duration. However, among the model-based designs, none of the designs have explicitly controlled the risk of overdosing as in the escalation with overdose control (EWOC) design. Here we propose a novel dose escalation with overdose control design using a two-parameter logistic regression model for the probability of DLT depending on the dose and a piecewise exponential model for the time to DLT distribution, which we call rolling-CRM design. A comprehensive simulation study has been conducted to compare the performance of the rolling-CRM design with other dose escalation designs. Of note, the trial duration is significantly shorter compared to traditional CRM designs. The proposed design also retains overdose control characteristics, but might require a larger sample size compared to traditional CRM designs.

Immune-Modified Response Evaluation Criteria In Solid Tumors (imRECIST): Refining Guidelines to Assess the Clinical Benefit of Cancer Immunotherapy

Purpose Treating solid tumors with cancer immunotherapy (CIT) can result in unconventional responses and overall survival (OS) benefits that are not adequately captured by Response Evaluation Criteria In Solid Tumors (RECIST) v1.1. We describe immune-modified RECIST (imRECIST) criteria, designed to better capture CIT responses. Patients and Methods Atezolizumab data from clinical trials in non-small-cell lung cancer, metastatic urothelial carcinoma, renal cell carcinoma, and melanoma were evaluated. Modifications to imRECIST versus RECIST v1.1 included allowance for best overall response after progressive disease (PD) and changes in PD definitions per new lesions (NLs) and nontarget lesions. imRECIST progression-free survival (PFS) did not count initial PD as an event if the subsequent scan showed disease control. OS was evaluated using conditional landmarks in patients whose PFS differed by imRECIST versus RECIST v1.1. Results The best overall response was 1% to 2% greater, the disease control rate was 8% to 13% greater, and the median PFS was 0.5 to 1.5 months longer per imRECIST versus RECIST v1.1. Extension of imRECIST PFS versus RECIST v1.1 PFS was associated with longer or similar OS. Patterns of progression analysis revealed that patients who developed NLs without target lesion (TL) progression had a similar or shorter OS compared with patients with RECIST v1.1 TL progression. Patients infrequently experienced a spike pattern (TLs increase, then decrease) but had longer OS than patients without TL reversion. Conclusion Evaluation of PFS and patterns of response and progression revealed that allowance for TL reversion from PD per imRECIST may better identify patients with OS benefit. Progression defined by the isolated appearance of NLs, however, is not associated with longer OS. These results may inform additional modifications to radiographic criteria (including imRECIST) to better reflect efficacy with CIT agents.

Bayesian adaptive dose-escalation designs for simultaneously estimating the optimal and maximum safe dose based on safety and efficacy

The main purpose of dose-escalation trials is to identify the dose(s) that is/are safe and efficacious for further investigations in later studies. In this paper, we introduce dose-escalation designs that incorporate both the dose-limiting events and dose-limiting toxicities (DLTs) and indicative responses of efficacy into the procedure. A flexible nonparametric model is used for modelling the continuous efficacy responses while a logistic model is used for the binary DLTs. Escalation decisions are based on the combination of the probabilities of DLTs and expected efficacy through a gain function. On the basis of this setup, we then introduce 2 types of Bayesian adaptive dose-escalation strategies. The first type of procedures, called "single objective," aims to identify and recommend a single dose, either the maximum tolerated dose, the highest dose that is considered as safe, or the optimal dose, a safe dose that gives optimum benefit risk. The second type, called "dual objective," aims to jointly estimate both the maximum tolerated dose and the optimal dose accurately. The recommended doses obtained under these dose-escalation procedures provide information about the safety and efficacy profile of the novel drug to facilitate later studies. We evaluate different strategies via simulations based on an example constructed from a real trial on patients with type 2 diabetes, and the use of stopping rules is assessed. We find that the nonparametric model estimates the efficacy responses well for different underlying true shapes. The dual-objective designs give better results in terms of identifying the 2 real target doses compared to the single-objective designs.

Abstract 3597: Experiences and lessons from innovative dose escalation designs in early-phase oncology

Introduction: Since 2010, Roche-sponsored early development trials in oncology have successfully implemented innovative dose escalation (D/E) strategies including modified continual reassessment methods (CRM) and other Bayesian adaptive designs. Compared to standard 3+3 designs, these methods allow for flexibility to address a variety of clinical questions and to estimate more accurately a molecule’s maximum tolerated dose (MTD). However, CRM designs are sometimes considered as complex and difficult to implement and are not easily understood by clinicians (Le Tourneau et al., 2009, Iasonos et al. 2014). Here, we share our experiences and learnings from the initial exploration, introduction, and wide-spread implementation of CRM in early oncology clinical trials.

Methods: We conducted a thorough internal review of the current statistical methods and clinical strategies used in CRM designs. In addition, we systematically collected feedback on the internal experience through surveys and interviews of participating biostatisticians, pharmacologists, clinicians and operations managers.

Results: CRMs using two parameter logistic regression models and escalation with overdose control (Neuenschwander et al., 2008) are the most commonly used CRM designs in Roche-sponsored oncology D/E trials. Compared to trials in which 3+3 designs are used, we experienced significant advantages with CRM designs including: flexibility in cohort sizes; formal integration of relevant prior pre-clinical/clinical knowledge of the dose-toxicity relationship; and contribution of all dose limiting toxicities (DLTs) to an MTD determination. On the other hand, we learned about some limitations. The CRM designs modeled binary DLT events where the grade of an event was not considered. Thus, in a cohort where severe DLT event(s) were observed, clinical judgment typically superseded the CRM recommendation towards a lower dose; this decision rule was a priori defined in the protocol. In certain situations, inconsistent prior-information in the dose-toxicity relationship was observed. Therefore, prior assumptions had to be carefully assessed through simulations using multiple dose-toxicity scenarios.

Conclusions: Overall, utilization of CRM designs was considered beneficial to Roche early development trials. Based on our experience, CRM designs are flexible and can be tailored to address a variety of clinical research questions. Trial simulation analyses were critical for us to understand the performance of CRM designs, including the accuracy of estimated MTD, trial duration/sample size, and sensitivity to prior assumptions. Furthermore, the introduction and implementation of CRM designs required and promoted strong multidisciplinary collaborations, especially during the design and study protocol set-up phases and the D/E recommendation phase.

Citation Format: Jiawen Zhu, Ulrich Beyer, Somnath Sarkar, Gwen Nichols, William Pao, Daniel Sabanés Bové. Experiences and lessons from innovative dose escalation designs in early-phase oncology [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3597. doi:10.1158/1538-7445.AM2017-3597

Efficacy and Safety of Basimglurant as Adjunctive Therapy for Major Depression: A Randomized Clinical Trial

IMPORTANCE

Antagonism of the postsynaptic metabotropic glutamate subtype 5 receptor is a novel approach to modulate glutamatergic function and has proven efficacy in a number of preclinical behavioral models of depression.

OBJECTIVE

To evaluate the safety and efficacy of basimglurant modified-release (MR) vs placebo as adjunctive therapy to ongoing antidepressant medication therapy in patients with MDD who had inadequate response within the current episode.

DESIGN, SETTING, AND PARTICIPANTS

In this phase 2b, double blind, randomized clinical trial of 333 adult patients with a DSM-IV-TR diagnosis of MDD across 59 research clinics globally, patients were assigned to 1 of 2 doses of basimglurant MR (0.5 or 1.5 mg) or placebo once daily, adjunctive to ongoing antidepressant medication therapy (selective serotonin reuptake inhibitor or serotonin and norepinephrine reuptake inhibitor). Patients were enrolled from October 5, 2011, through July 26, 2013.

INTERVENTIONS

Six-week treatment with 0.5 mg of basimglurant MR, 1.5-mg basimglurant MR, or placebo once daily, adjunctive to ongoing antidepressant medication therapy.

MAIN OUTCOMES AND MEASURES

The primary end point was the mean change from baseline score on the Montgomery-Åsberg Depression Rating Scale (MADRS), as rated by the clinician at week 6. Other measures included patient-rated MADRS, Quick Inventory of Depressive Symptomatology-Self-Report, Clinical Global Impression-Improvement, Patient Global Impression-Improvement, and Clinical Global Impression-Severity Scales and adverse events.

RESULTS

A total of 596 patients were screened, and 333 were randomized into the study (mean [SD] age, 47 [11.2] years; 216 female [65.1%]). The primary end point (mean change in clinician-rated MADRS score from baseline to end of treatment) was not met (effect size [ES] = 0.16, P = .42; intent-to-treat [ITT] mixed-effects model for repeated measures [MMRM] analysis for comparing 1.5-mg basimglurant MR and placebo). Across secondary and exploratory end points, 1.5-mg basimglurant MR revealed larger improvements vs placebo on the patient-rated MADRS (-16.2 vs -13.3, ES = 0.28, nominal P = .04), Quick Inventory of Depressive Symptomatology-Self-Report (-7.5 vs -5.8; ES = 0.37, nominal P = .009), Clinical Global Impression-Improvement mean score, and Patient Global Impression-Improvement mean score. Improvements were also seen in the patient-rated MADRS remission rate (36.0% vs 22.0%; nominal P = .03) and response rate (50.5% vs 40.4%; nominal P = .13), A 0.5-mg dose of basimglurant MR had no benefit over placebo in any of these measures. The most common adverse event was dizziness, which was mostly transient and of mild intensity.

CONCLUSIONS AND RELEVANCE

No difference was observed on the study's primary outcome measure, the clinician-rated MADRS change from baseline to end of treatment, between adjunctive basimglurant MR vs placebo. Adjunctive 1.5-mg basimglurant MR daily revealed, however, an antidepressant effect across secondary end points, particularly in patient-rated measures. These findings combined with good tolerability warrant further investigation with this compound in depressive disorders.

TRIAL REGISTRATION

clinicaltrials.gov Identifier: NCT01437657.

A novel and selective sodium-glucose cotransporter-2 inhibitor, tofogliflozin, improves glycaemic control and lowers body weight in patients with type 2 diabetes mellitus

AIM

To assess the efficacy, safety and tolerability of different doses of tofogliflozin, a novel, highly selective sodium-glucose cotransporter 2 (SGLT2) inhibitor, in patients with type 2 diabetes mellitus (T2DM).

METHODS

In a 12-week, multicentre, multinational, randomized, double-blind, parallel-group, placebo-controlled, dose-finding study, patients with inadequate glycaemic control from diet and exercise alone, or from diet and exercise plus a stable dose of metformin, were randomized to one of five doses of tofogliflozin (2.5, 5, 10, 20, or 40 mg) or placebo. The primary efficacy endpoint was absolute change at week 12 from baseline in glycated haemoglobin (HbA1c), minus the change in the placebo group.

RESULTS

Statistically significant dose-dependent reductions in HbA1c were shown in all treated groups except the 2.5-mg dose group, with a maximum reduction of 0.56% (placebo-subtracted) at the 40-mg dose, along with increased urinary glucose excretion. Metformin treatment had no substantial influence on tofogliflozin efficacy. Dose-dependent reductions in fasting plasma glucose and body weight were observed, and glucose intolerance was improved, with a trend towards blood pressure reduction. Slight increases were observed for mean ketone bodies with no abnormal change in ketone body ratio. No deaths or treatment-related serious adverse events were reported. The incidence of adverse events was similar in the placebo (37.9%) to that in the tofogliflozin group (35.9-46.3%). Withdrawal because of adverse events was rare (≤2 patients per treatment group), with similar rates of withdrawal in the placebo and tofogliflozin groups.

CONCLUSIONS

A once-daily dose of tofogliflozin for 12 weeks was an effective, safe and well-tolerated treatment for T2DM.

Bayesian adaptive dose-escalation procedures for binary and continuous responses utilizing a gain function

One of the main aims of early phase clinical trials is to identify a safe dose with an indication of therapeutic benefit to administer to subjects in further studies. Ideally therefore, dose-limiting events (DLEs) and responses indicative of efficacy should be considered in the dose-escalation procedure. Several methods have been suggested for incorporating both DLEs and efficacy responses in early phase dose-escalation trials. In this paper, we describe and evaluate a Bayesian adaptive approach based on one binary response (occurrence of a DLE) and one continuous response (a measure of potential efficacy) per subject. A logistic regression and a linear log-log relationship are used respectively to model the binary DLEs and the continuous efficacy responses. A gain function concerning both the DLEs and efficacy responses is used to determine the dose to administer to the next cohort of subjects. Stopping rules are proposed to enable efficient decision making. Simulation results shows that our approach performs better than taking account of DLE responses alone. To assess the robustness of the approach, scenarios where the efficacy responses of subjects are generated from an Emax model, but modelled by the linear log-log model are also considered. This evaluation shows that the simpler log-log model leads to robust recommendations even under this model showing that it is a useful approximation to the difficulty in estimating Emax model. Additionally, we find comparable performance to alternative approaches using efficacy and safety for dose-finding.

Bayesian adaptive designs in single ascending dose trials in healthy volunteers

AIM

Recent publications indicate a strong interest in applying Bayesian adaptive designs in first time in humans (FTIH) studies outside of oncology. The objective of the present work was to assess the performance of a new approach that includes Bayesian adaptive design in single ascending dose (SAD) trials conducted in healthy volunteers, in comparison with a more traditional approach.

METHODS

A trial simulation approach was used and seven different scenarios of dose-response were tested.

RESULTS

The new approach provided less biased estimates of maximum tolerated dose (MTD). In all scenarios, the number of subjects needed to define a MTD was lower with the new approach than with the traditional approach. With respect to duration of the trials, the two approaches were comparable. In all scenarios, the number of subjects exposed to a dose greater than the actual MTD was lower with the new approach than with the traditional approach.

CONCLUSIONS

The new approach with Bayesian adaptive design shows a very good performance in the estimation of MTD and in reducing the total number of healthy subjects. It also reduces the number of subjects exposed to doses greater than the actual MTD.

C.E.R.A. once every 4 weeks corrects anaemia and maintains haemoglobin in patients with chronic kidney disease not on dialysis

Background. No previous randomized controlled studies have been reported examining de novo, once every 4 weeks (Q4W) administration of erythropoiesis-stimulating agents in chronic kidney disease (CKD) patients. We report results from a randomized multinational study that compared continuous erythropoietin receptor activator (C.E.R.A.) Q4W with darbepoetin alfa once weekly (QW) or every 2 weeks (Q2W) for the correction of anaemia in non-dialysis CKD patients.

Methods. Patients were randomized (1:1) to receive either 1.2 μg/kg C.E.R.A. Q4W or darbepoetin alfa QW/Q2W during a 20-week correction period and an 8-week evaluation period. Two primary end points were assessed: the haemoglobin (Hb) response rate and the change in average Hb concentration between baseline and evaluation.

Results. The Hb response rate for C.E.R.A. was 94.1%, significantly higher than the protocol-specified 60% response rate [95% confidence interval (CI): 89.1, 97.3; P < 0.0001] and comparable with darbepoetin alfa (93.5%; 95% CI: 88.4, 96.8; P < 0.0001). C.E.R.A. Q4W was non-inferior to darbepoetin alfa QW/Q2W, with similar mean Hb changes from baseline of 1.62 g/dL and 1.66 g/dL, respectively. Patients receiving C.E.R.A. showed a steady rise in Hb, with fewer patients above the target range during the first 8 weeks compared with darbepoetin alfa [39 patients (25.8%) versus 72 patients (47.7%); P < 0.0001]. Adverse event rates were comparable between the treatment groups.

Conclusion. C.E.R.A. Q4W successfully corrects anaemia and maintains stable Hb levels within the recommended target range in non-dialysis CKD patients.

Maintenance treatment of renal anaemia in haemodialysis patients with methoxy polyethylene glycol-epoetin beta versus darbepoetin alfa administered monthly: a randomized comparative trial

BACKGROUND

Several studies with erythropoiesis-stimulating agents claim that maintenance therapy of renal anaemia may be possible at extended dosing intervals; however, few studies were randomized, results varied, and comparisons between agents were absent. We report results of a multi-national, randomized, prospective trial comparing haemoglobin maintenance with methoxy polyethylene glycol-epoetin beta and darbepoetin alfa administered once monthly.

METHODS

Haemodialysis patients (n = 490) on stable once-weekly intravenous darbepoetin alfa were randomized to methoxy polyethylene glycol-epoetin beta once monthly or darbepoetin alfa every 2 weeks for 26 weeks, with dose adjustment for individual haemoglobin target (11-13 g/dL; maximum decrease from baseline 1 g/dL). Subsequently, patients entered a second 26-week period of once-monthly methoxy polyethylene glycol-epoetin beta and darbepoetin alfa. The primary endpoint was the proportion of patients who maintained average haemoglobin ≥10.5 g/dL, with a decrease from baseline ≤1 g/dL, in Weeks 50-53; the secondary endpoint was dose change over time. The trial is registered at www.ClinicalTrials.gov, number NCT00394953.

RESULTS

Baseline characteristics were similar between groups. One hundred and fifty-seven of 245 patients treated with methoxy polyethylene glycol-epoetin beta and 99 of 245 patients with darbepoetin alfa met the response definition (64.1% and 40.4%; P < 0.0001). Doses increased by 6.8% with methoxy polyethylene glycol-epoetin beta and 58.8% with darbepoetin alfa during once-monthly treatment. Death rates were equal between treatments (5.7%). Most common adverse events included hypertension, procedural hypotension, nasopharyngitis and muscle spasms, with no differences between groups.

CONCLUSIONS

Methoxy polyethylene glycol-epoetin beta maintained target haemoglobin more successfully than darbepoetin alfa at once-monthly dosing intervals despite dose increases with darbepoetin alfa.

Serum proteins as drug carriers of anticancer agents: a review

Targeted delivery of anticancer drugs is one of the most actively pursued goals in anticancer chemotherapy. Serum proteins such as transferrin, albumin, and low-density lipoprotein (LDL) offer promise for the selective delivery of antineoplastic agents due to their accumulation in tumor tissue. Uptake of these proteins in solid tumors is mediated by a number of factors, including an increased metabolic activity of tumors, an enhanced vascular permeability of tumor blood vessels for circulating macromolecules, and a lack of a functional lymphatic drainage system in tumor tissue. At the tumor site, transferrin, low-density lipoprotein, and albumin are taken up by the tumor cell through receptor-mediated and fluid phase endocytosis, respectively. Serum protein conjugates can be designed to release the bound antitumor drug after cellular uptake of the drug conjugate. This review covers the diagnostic evidence for tumor accumulation of serum proteins and the design, development, and biological evaluation of drug conjugates with transferrin, albumin, and low-density lipoprotein.

Hepcidin as a Predictor of Response to Epoetin Therapy in Anemic Cancer Patients

Background: Hepcidin is thought to be the central regulator of iron metabolism. Iron deficiency is associated with low hepcidin concentrations, and anemia in patients with cancer is associated with high concentrations of hepcidin.

Study objectives: Our main objective was to assess the potential role of hepcidin for predicting response to epoetin therapy in anemic cancer patients. We also aimed to identify a cutoff value for hepcidin as a potential predictive marker for response to epoetin therapy.

Methods: Using data from 525 anemic cancer patients enrolled in 5 studies, we assessed serum hepcidin concentrations in 408 of these patients at baseline and analyzed pooled data from the 408 patients. The analysis population was separated into 2 categories using a threshold hepcidin concentration of 13 nmol/L: low hepcidin (&lt;13 nmol/L) and high hepcidin (≥13 nmol/L).

Results: A significantly higher percentage of responders (defined as hemoglobin increase ≥10 g/L or ≥20 g/L from baseline) was observed in the low hepcidin group compared with the high hepcidin group (P = 0.04 for ≥10 g/L increase and P = 0.009 for ≥20 g/L from baseline). There was also a statistically significant difference between the 2 groups for hematopoietic response (hemoglobin rise at least once ≥20 g/L from baseline or at least once ≥120 g/L) to epoetin therapy (P = 0.0004).

Conclusions: The results of this analysis suggest a potential role of hepcidin serum concentrations in predicting the response to epoetin therapy.

Intravenous C.E.R.A. maintains stable haemoglobin levels in patients on dialysis previously treated with darbepoetin alfa: results from STRIATA, a randomized phase III study

Background. Extending the administration interval of erythropoiesis-stimulating agents (ESAs) represents an opportunity to improve the efficiency of anaemia management in patients with chronic kidney disease (CKD). However, effective haemoglobin (Hb) maintenance can be challenging with epoetin alfa and epoetin beta administered at extended intervals. C.E.R.A., a continuous erythropoietin receptor activator, has a unique pharmacologic profile and long half-life (∼130 h), allowing administration at extended intervals. Phase III results have demonstrated that C.E.R.A. administered once every 4 weeks effectively maintains stable Hb levels in patients with CKD on dialysis.

Methods. STRIATA (Stabilizing haemoglobin TaRgets in dialysis following IV C.E.R.A. Treatment for Anaemia) was a multicentre, open-label randomized phase III study to evaluate the efficacy and safety of intravenous C.E.R.A. administered once every 2 weeks (Q2W) for Hb maintenance following direct conversion from darbepoetin alfa (DA). Adult patients on dialysis receiving stable intravenous DA once weekly (QW) or Q2W were randomized (1:1) to continue their current DA regimen (n = 156) or receive intravenous C.E.R.A. Q2W (n = 157) for 52 weeks. Doses were adjusted to maintain Hb levels within ± 1.0 g/dl of baseline and between 10.0 and 13.5 g/dl. The primary endpoint was the mean Hb change between baseline and the evaluation period (weeks 29–36).

Results. Most patients (>80%) received DA QW before randomization. The mean (95% CI) difference between C.E.R.A. and DA in the primary endpoint was 0.18 g/dl (−0.05, 0.41), within a pre-defined non-inferiority limit. C.E.R.A. was clinically non-inferior to DA (P < 0.0001) in maintaining Hb levels. Both treatments were well tolerated.

Conclusions. Stable Hb levels were successfully maintained in patients on haemodialysis directly converted to Q2W intravenous C.E.R.A. from DA.

Mitomycin C in the treatment of gastrointestinal tumours: recent data and perspectives

Mitomycin C (MMC) is among the most effective anticancer drugs used for the treatment of a broad variety of tumours. This review summarises results of MMC-based chemotherapy in gastrointestinal tumours with special focus on current treatment options in gastric, pancreatic, biliary tract, colorectal, and anal cancer. In addition, these new developments are critically discussed with special attention to their potential clinical relevance.

C.E.R.A. corrects anemia in patients with chronic kidney disease not on dialysis: results of a randomized clinical trial

BACKGROUND AND OBJECTIVES

This study examined the efficacy of C.E.R.A., a continuous erythropoietin receptor activator, for correcting anemia in patients who had chronic kidney disease (CKD) and were not on dialysis.

DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS

In this open-label, randomized, parallel-group, Phase III study, 324 adult patients with CKD not on dialysis nor receiving treatment with erythropoiesis-stimulating agents (ESAs) were randomly assigned (1:1) to receive subcutaneous C.E.R.A. once every 2 wk or darbepoetin alfa once weekly during an 18-wk correction period and a 10-wk evaluation period. Thereafter, patients receiving C.E.R.A. were randomly assigned to C.E.R.A. once every 2 wk or once monthly, and patients receiving darbepoetin alfa could receive darbepoetin alfa once weekly or once every 2 wk for a 24-wk extension period. Dosage was adjusted to achieve a hemoglobin (Hb) response and to maintain Hb +/-1 g/dl of the response level and 11 to 13 g/dl. Primary end points were Hb response rate during correction and evaluation and change in Hb concentration between baseline and evaluation.

RESULTS

Hb response rates were 97.5% for C.E.R.A. and 96.3% for darbepoetin alfa. Adjusted mean changes in Hb from baseline to evaluation were 2.15 g/dl (C.E.R.A.) and 2.00 g/dl (darbepoetin alfa). Analysis showed that C.E.R.A. once every 2 wk was as effective as darbepoetin alfa once weekly for correcting anemia. Hb levels remained stable in all groups during the extension period. C.E.R.A. and darbepoetin alfa were well tolerated.

CONCLUSIONS

Subcutaneous C.E.R.A. once every 2 wk corrects anemia in ESA-naïve patients who are not on dialysis.

C.E.R.A. maintains stable control of hemoglobin in patients with chronic kidney disease on dialysis when administered once every two weeks

BACKGROUND/AIMS

This Phase III study examined the efficacy and safety of C.E.R.A., a continuous erythropoietin receptor activator, given once every 2 weeks (Q2W) via subcutaneous or intravenous injection using pre-filled syringes, for maintaining hemoglobin (Hb) levels in patients with chronic kidney disease (CKD) on dialysis who converted directly from epoetin therapy.

METHODS

Patients (n = 336) were randomized 1:1 to continue epoetin at their current dose, route and administration interval (once to three times weekly (QW-TIW)), or receive C.E.R.A. Q2W by the same route as previous epoetin treatment for 36 weeks. Dosage was adjusted to maintain patients' Hb within +/-1.0 g/dl of baseline value and within 10.0-13.5 g/dl. Primary endpoint was mean change in Hb between baseline and the evaluation period (weeks 29-36).

RESULTS

Mean change in Hb for C.E.R.A. and epoetin was 0.088 and -0.030 g/dl, respectively (endpoint Hb 11.93 and 11.86 g/dl, respectively). Analysis showed that C.E.R.A. was as effective as epoetin in maintaining Hb (p < 0.0001), and was well tolerated. The administration route had no impact on primary endpoint.

CONCLUSION

Q2W C.E.R.A. administered using pre-filled syringes effectively maintains stable control of Hb in patients on dialysis who convert directly from epoetin QW-TIW.

Intravenous methoxy polyethylene glycol-epoetin beta for haemoglobin control in patients with chronic kidney disease who are on dialysis: a randomised non-inferiority trial (MAXIMA)

BACKGROUND

Conventional treatment with epoetin to manage anaemia in chronic kidney disease needs frequent administrations, changes of dose, and close monitoring of haemoglobin concentrations. We aimed to compare the effectiveness of methoxy polyethylene glycol-epoetin beta, given intravenously at 2-week or 4-week intervals, with epoetin treatment one to three times per week for haemoglobin control in haemodialysis patients.

METHODS

We screened 1115 adult patients from 96 centres who had stable chronic renal anaemia and were on dialysis treatment and intravenous maintenance epoetin. We did an open-label, parallel-group, non-inferiority trial to compare two dosing intervals of methoxy polyethylene glycol-epoetin beta with standard epoetin treatment. We established baseline haemoglobin concentration and eligibility over a 4-week run-in period. 223 patients were randomly assigned to receive methoxy polyethylene glycol-epoetin beta every 2 weeks, and 224 to receive it every 4 weeks. The initial dose was based on the average epoetin dose given during the week before the switch. The primary endpoint was change in haemoglobin concentration between baseline and the assessment period. We analysed patients both by intention to treat and per protocol. This study is registered with ClinicalTrials.gov, number NCT00077610.

FINDINGS

We excluded 133 of the 673 randomised patients from the per-protocol analysis because they had inadequate iron status or fewer than five haemoglobin measurements during the assessment period or needed red blood cell transfusions. The mean change from baseline haemoglobin for patients who had switched to intravenous methoxy polyethylene glycol-epoetin beta every 2 weeks (-0.71 g/L, 95% CI -2.20 to 0.77) or every 4 weeks (-0.25 g/L, -1.79 to 1.29) was non-inferior to the mean change for patients who continued treatment with epoetin (-0.75 g/L, -2.26 to 0.75) (p<0.0001 for both comparisons). Of the 666 patients who received at least one dose of study drug, the incidence of adverse events or serious adverse events did not differ between groups (p=0.30 and p=0.40, respectively).

INTERPRETATION

This long-acting erythropoiesis-stimulating agent is as safe as conventional epoetin treatment, and can maintain anaemia management in haemodialysis patients when given intravenously at 4-week dosing intervals.

Once-Monthly Subcutaneous C.E.R.A. Maintains Stable Hemoglobin Control in Patients with Chronic Kidney Disease on Dialysis and Converted Directly from Epoetin One to Three Times Weekly

BACKGROUND

C.E.R.A., a continuous erythropoietin receptor activator, is in development to provide anemia correction and stable maintenance of hemoglobin (Hb) levels at extended administration intervals in patients with chronic kidney disease (CKD). This study examined its efficacy and safety when administered up to once monthly in patients who have CKD and are on dialysis and randomly convert directly from epoetin alpha or beta one to three times weekly.

DESIGN, SETTING, PARTICIPANTS, AND MEASUREMENTS

In this three-arm, comparator-controlled, open-label, randomized, parallel-group, Phase III study, 572 dialysis patients (> or =18 yr) who were receiving stable subcutaneous epoetin one to three times weekly were randomly assigned (1:1:1) to continue epoetin or to receive subcutaneous C.E.R.A. once monthly or twice monthly for 52 wk. Dosage was adjusted to maintain Hb +/-1.0 g/dl of baseline level. Primary end point was mean change in Hb level between baseline and the evaluation period (weeks 29 to 36).

RESULTS

Mean Hb levels during the evaluation period were similar between groups (once-monthly C.E.R.A. 11.5 g/dl; twice-monthly C.E.R.A. 11.7 g/dl; epoetin 11.5 g/dl). The difference between C.E.R.A. and epoetin in mean change (97.5% confidence interval) in Hb concentration between baseline and evaluation was -0.022 g/dl (-0.262 to 0.217) for once monthly and 0.141 g/dl (-0.098 to 0.380) for twice monthly. Analysis demonstrated that C.E.R.A. was as effective as epoetin in maintaining Hb and was well tolerated.

CONCLUSIONS

Subcutaneous C.E.R.A. once or twice monthly successfully maintained tight and stable Hb levels in patients who were on dialysis and randomly converted directly from epoetin one to three times weekly.

Effect of a continuous erythropoietin receptor activator (C.E.R.A.) on stable haemoglobin in patients with CKD on dialysis: once monthly administration

AIMS

This Phase II study aimed to determine the optimal dose and administration schedule of continuous erythropoietin receptor activator (C.E.R.A.) given subcutaneously (s.c.) in patients receiving dialysis converting directly from s.c. epoetin therapy 1-3 times/week. An extension phase examined long-term safety and efficacy.

METHODS

Patients were assigned to one of three C.E.R.A. dose groups determined by multiplying the previous weekly dose of epoetin by one of three ratios (0.4/150, 0.8/150, 1.2/150 for groups A, B and C, respectively). Within each group, patients were randomized to once weekly (QW), once every 3 weeks (Q3W) and once monthly (Q4W) schedules. Dose adjustments were not permitted for the first 6 weeks. The core study period was 19 weeks (21 weeks in the Q4W cohorts). Patients could enter a 12-month extension period at the same schedule, aiming to maintain haemoglobin (Hb) at 11-12 g/dL.

RESULTS

137 patients entered the core period, and 62 continued into the extension period. A dose-dependent relationship was seen in the primary efficacy variable, change in Hb standardized to a 6 week period (p < 0.0001), but effect was independent of schedule. Hb levels were maintained throughout the study, with few dose changes. C.E.R.A. was generally well tolerated and the most frequent adverse event was hypotension.

CONCLUSION

The results suggest that s.c. C.E.R.A. at up to once monthly intervals provides stable maintenance of Hb levels in dialysis patients converting directly from epoetin 1-3 times/week. Achieving tight Hb control with few dose adjustments at extended administration intervals may offer health benefits and improvements in resource management.

Efficacy and tolerability of intravenous continuous erythropoietin receptor activator: A 19-week, phase ii, multicenter, randomized, open-label, dose-finding study with a 12-month extension phase in patients with chronic renal disease

BACKGROUND

A continuous erythropoietin receptor activator (C.E.R.A.) is currently in development for the treatment of anemia in patients with chronic renal disease (CRD) receiving or not receiving dialysis treatment.

OBJECTIVES

The objectives of this study were to determine the optimal dose and administration schedule for IV C.E.R.A. in patients with CRD previously treated with IV epoetin alfa TIW, and to assess its tolerability profile in these patients. In addition, a 12-month extension phase was used to assess the long-term efficacy and tolerability of C.E.R.A.

METHODS

This randomized, open-label, dose-finding study was conducted at 14 study centers across the United States. Male and female patients aged >/=18 years with CRD and CRD-related anemia and receiving treatment with IV epoetin alfa were enrolled. After a 2-week run-in period in which all patients continued to receive their previous epoetin treatment TIW, patients were switched to C.E.R.A. at 1 of 3 doses, determined by multiplying the previous weekly epoetin dose by 1 of 3 ratios (0.25 pg/150 IU, 0.4 pg/150 IU, or 0.6 pg/150 IU). Within each dose group, patients were randomized to 1 of 2 frequency subgroups: QW or Q2W Dose adjustments were not permitted during the first 6 weeks; the total dose during this period was the same for a particular dose group across the frequency subgroups. The primary efficacy parameter was change in hemoglobin (Hb) standardized to a 6-week period between baseline and the point when the patient had a dose change or blood transfusion, thus providing an estimate of Hb change based on starting dose. Following completion of a 19-week core period, patients could enter the 12-month extension period, aiming to maintain Hb concentrations between 11 and 12 g/dL. Adverse events (AEs) were recorded in the patients' case-report forms by the investigators throughout the study.

RESULTS

A total of 91 patients entered the core period (mean age, 58 years; 66% male); 10 patients withdrew prematurely during this period (4 owing to AEs and 6 for other reasons). Fifty-three patients continued into the extension period; 22 patients withdrew during this period (6 because of AEs, and 16 for other reasons). There was a significant dose-response effect (P < 0.001) and a significant effect of schedule (P < 0.002) for the primary efficacy end point. Stable Hb concentrations were maintained throughout the study (11-12 g/dL, with a narrow 95% CI). No significant difference between schedules was observed during the extension period, and few dose changes were required (mean, 4 and 2 per patient per year in the QW and Q2W groups, respectively). Nineteen and 22 patients experienced serious AEs during the core and extension periods, respectively, but only 1 event was considered related to study treatment. The most frequent AEs were headache and vomiting during the core study period and dizziness, fatigue, chest pain, and pyrexia during the extension period.

CONCLUSIONS

In this study, N C.E.R.A. provided effective maintenance of Hb concentrations in patients receiving dialysis treatment who were switched directly from N epoetin alfa TIW to N C.E.R.A. QW or Q2W C.E.R.A. was generally well tolerated.

Liposomal encapsulated anti-cancer drugs

Among several drug delivery systems, liposomal encapsulated anti-cancer agents represent an advanced and versatile technology. Several formulations of liposomal anthracyclines are approved, e.g. for the treatment of metastatic breast cancer (pegylated and non-pegylated liposomal doxorubicin) or AIDS-related Kaposi's sarcoma (pegylated liposomal doxorubicin and liposomal daunorubicin). Meanwhile, virtually all anti-cancer drugs have been encapsulated in liposomes using different technologies. This review will summarize preclinical and clinical data of approved and exemplary emerging liposomal anti-cancer agents.

Calibration of the viscometric glucose sensor before its use in physiological liquids--compensation for the colloid-osmotic effect

The function of the recently described viscometric affinity sensor (VAS), which measures glucose due to its strong effect on the viscosity of a sensitive liquid containing Concanavalin A (ConA) and dextran, was analysed for osmotic and colloid-osmotic effects on the glucose reading. The suction of low- and high-molecular weight osmotica on the membrane of the microdialysis fibre was measured using a membrane osmometer built from the microdialysis probe of the VAS. The reduction of the sensor read-out in blood plasma can be completely explained by a change in small osmotic volume fluxes through the dialysis membrane, which affect the ConA concentration and the viscosity after the flow of the sensitive liquid through the dialysis probe. The measuring error could be prevented by the presence of the polyethylene glycol 6000 at an isotonic concentration in the glucose standard solutions used for sensor calibration.

Ring-shaped vortex domain in type-II superconductors

We present results of experiments in superconducting niobium and numerical simulations showing the creation of a metastable ring-shaped vortex domain by heating. Such vortex rings, if pinned by structural defects, can exist forever.

Recording of subcutaneous glucose dynamics by a viscometric affinity sensor

AIMS/HYPOTHESIS

To provide a nonenzymatic sensor for glucose monitoring in subcutaneous tissue.

METHODS

A continuously working affinity sensor based on the glucose-dependent viscosity of a sensitive liquid containing dextran and concanavalin A has been designed by arranging a microdialysis probe, two flow-resisting capillaries and two pressure transducers in a linear flow system. It allows synchronous processing of the viscosity of the sensitive liquid at the standard glucose concentration and the glucose concentration to be measured. In preliminary human trials the sensor was implanted into the subcutaneous tissue of the forearm and its read-out was compared with capillary blood concentrations.

RESULTS

In vitro, the viscometric sensor shows a linear and long-term stable dependence on the glucose concentration without detectable drift. At the applied flow rate of the sensitive liquid (about 5 microliters/h) the technical delay is 5 to 10 min. The read-out of the implanted sensor followed the dynamics of the capillary blood glucose concentrations with a time-shift of 10 to 15 min but showed a systematic error when based on precalibration with polymer-free glucose solutions. After appropriate in vivo calibration, the read-out was in good or acceptable coincidence with capillary blood concentrations according to the error grid method and did not show any detectable reduction of sensitivity during the periods of measurement (up to 44 h). CONCLUSION/INTERPRETION: The viscometric-affinity sensor is an efficient tool for current research on glucose monitoring in the subcutaneous tissue and can potentially be further developed for routine clinical use.

Differences in the intracellular distribution of acid-sensitive doxorubicin-protein conjugates in comparison to free and liposomal formulated doxorubicin as shown by confocal microscopy

PURPOSE

To investigate differences in the cellular uptake and intracellular distribution of protein-bound doxorubicin in comparison to free doxorubicin and a liposomal formulation (CAELYX) METHODS: LXFL 529 lung carcinoma cells were incubated with an acid-sensitive transferrin and albumin conjugate of doxorubicin, a stable albumin doxorubicin conjugate, and free and liposomal doxorubicin for up to 24 h. The uptake of doxorubicin was detected with confocal laser scanning microscopy (CLSM). To investigate the intracellular localization of the anticancer drug, lysosomes, Golgi apparatus, and mitochondria were also stained by various organelle-specific fluorescent markers. In vitro efficacy of the doxorubicin derivatives was examined with the BrdU incorporation assay.

RESULTS

The acid-sensitive albumin and transferrin doxorubicin conjugates showed enhanced cytotoxicity in comparison to liposomal doxorubicin, whereas the stable albumin-doxorubicin conjugate showed only marginal activity. Of all compounds tested, doxorubicin showed the highest cytotoxicity. CLSM studies with specific markers for lysosomes, mitochondria, and the Golgi apparatus demonstrated that protein-bound doxorubicin or liberated doxorubicin was accumulated in the mitochondria and Golgi compartments, but not in the lysosomes after 24 h. Free doxorubicin showed a time-dependent intracellular shift from the nucleus to the mitochondria and Golgi apparatus. Fluorescence resulting from incubation with CAELYX was primarily detected in the nucleus.

CONCLUSIONS

Our results indicate that other organelles in addition to the cell nucleus are important sites of accumulation and interaction for protein-bound doxorubicin or intracellularly released doxorubicin as well as for free doxorubicin.

Compensation of temperature and concanavalin A concentratration effects for glucose determination by the viscometric affinity assay

A viscometer suitable for rapid measurements in small volumes of highly viscous liquids is described. Using this device the viscometric affinity assay for glucose was studied under variable conditions in order to obtain basic information for the design of a viscometric glucose sensor. The viscosity of the dextran/Concanavalin A (ConA) solution is sensitive to glucose in a broad range of the shear stress. However, for measuring the glucose concentration with this sensitive liquid the strong dependence of the absolute viscosity on temperature and ConA concentration has to be taken into account. For the purpose of calibration a parameter more suitable than the absolute viscosity is the relative fluidity (F(r)) that is defined by the actual measured viscosity at a given glucose concentration, the reference viscosity at a standard glucose concentration, and a constant linearization coefficient. F(r) shows a linear dependence on the glucose concentration in the therapeutically interesting range up to 30 mM and is not significantly changed by moderate variations of the ConA concentration or temperature.

Drug-polymer conjugates containing acid-cleavable bonds

Drug-polymer conjugates are potential candidates for the selective delivery of anticancer agents to tumor tissue. Incorporating acid-sensitive bonds between the drug and the polymer is an attractive approach because it ensures effective release of the polymer-bound drug at the tumor site. This release is either extracellular, resulting from the slightly acidic pH in tumor tissue, or intracellular, in acidic endosomes or lysosomes after cellular uptake of the drug-polymer conjugate. This paper reviews acid-sensitive drug-polymer conjugates developed during the past 20 years and outlines aspects for further development in this research field.

Acid-sensitive polyethylene glycol conjugates of doxorubicin: preparation, in vitro efficacy and intracellular distribution

Coupling anticancer drugs to synthetic polymers is a promising approach of enhancing the antitumor efficacy and reducing the side-effects of these agents. Doxorubicin maleimide derivatives containing an amide or acid-sensitive hydrazone linker were therefore coupled to alpha-methoxy-poly(ethylene glycol)-thiopropionic acid amide (MW 20000 Da), alpha,omega-bis-thiopropionic acid amide poly(ethylene glycol) (MW 20000 Da) or alpha-tert-butoxy-poly(ethylene glycol)-thiopropionic acid amide (MW 70000 Da) and the resulting polyethylene glycol (PEG) conjugates isolated through size-exclusion chromatography. The polymer drug derivatives were designed as to release doxorubicin inside the tumor cell by acid-cleavage of the hydrazone bond after uptake of the conjugate by endocytosis. The acid-sensitive PEG conjugates containing the carboxylic hydrazone bonds exhibited in vitro activity against human BXF T24 bladder carcinoma and LXFL 529L lung cancer cells with IC70 values in the range 0.02-1.5 microm (cell culture assay: propidium iodide fluorescence or colony forming assay). In contrast, PEG doxorubicin conjugates containing an amide bond between the drug and the polymer showed no in vitro activity. Fluorescence microscopy studies in LXFL 529 lung cancer cells revealed that free doxorubicin accumulates in the cell nucleus whereas doxorubicin of the acid-sensitive PEG doxorubicin conjugates is primarily localized in the cytoplasm. Nevertheless, the acid-sensitive PEG doxorubicin conjugates retain their ability to bind to calf thymus DNA as shown by fluorescence and visible spectroscopy studies. Results regarding the effect of an acid-sensitive PEG conjugate of molecular weight 20000 in the chorioallantoic membrane (CAM) assay indicate that this conjugate is significantly less embryotoxic than free doxorubicin although antiangiogenic effects were not observed.

Synthesis and in vitro efficacy of transferrin conjugates of the anticancer drug chlorambucil

One strategy for improving the selectivity and toxicity profile of antitumor agents is to design drug carrier systems employing soluble macromolecules or carrier proteins. Thus, five maleimide derivatives of chlorambucil were bound to thiolated human serum transferrin which differ in the stability of the chemical link between drug and spacer. The maleimide ester derivatives 1 and 2 were prepared by reacting 2-hydroxyethylmaleimide or 3-maleimidophenol with the carboxyl group of chlorambucil, and the carboxylic hydrazone derivatives 5-7 were obtained through reaction of 2-maleimidoacetaldehyde, 3-maleimidoacetophenone, or 3-maleimidobenzaldehyde with the carboxylic acid hydrazide derivative of chlorambucil. The alkylating activity of transferrin-bound chlorambucil was determined with the aid of 4-(4-nitrobenzyl)pyridine (NBP) demonstrating that on average 3 equivalents were protein-bound. Evaluation of the cytotoxicity of free chlorambucil and the respective transferrin conjugates in the MCF7 mammary carcinoma and MOLT4 leukemia cell line employing a propidium iodide fluorescence assay demonstrated that the conjugates in which chlorambucil was bound to transferrin through non-acid-sensitive linkers, i.e., an ester or benzaldehyde carboxylic hydrazone bond, were not, on the whole, as active as chlorambucil. In contrast, the two conjugates in which chlorambucil was bound to transferrin through acid-sensitive carboxylic hydrazone bonds were as active as or more active than chlorambucil in both cell lines. Especially, the conjugate in which chlorambucil was bound to transferrin through an acetaldehyde carboxylic hydrazone bond exhibited IC50 values which were approximately 3-18-fold lower than those of chlorambucil. Preliminary toxicity studies in mice showed that this conjugate can be administered at higher doses in comparison to unbound chlorambucil. The structure-activity relationships of the transferrin conjugates are discussed with respect to their pH-dependent acid sensitivity, their serum stability, and their cytotoxicity.

Transferrin conjugates of doxorubicin: synthesis, characterization, cellular uptake, and in vitro efficacy

One strategy for improving the antitumor selectivity and toxicity profile of antitumor agents is to design drug carrier systems employing suitable carrier proteins. Thus, thiolated human serum transferrin was conjugated with four maleimide derivatives of doxorubicin that differed in the stability of the chemical link between drug and spacer. Of the maleimide derivatives, 3-maleimidobenzoic or 4-maleimidophenylacetic acid was bound to the 3'-amino position of doxorubicin through a benzoyl or phenylacetyl amide bond, and 3-maleimidobenzoic acid hydrazide or 4-maleimidophenylacetic acid hydrazide was bound to the 13-keto position through a benzoyl hydrazone or phenylacetyl hydrazone bond. The acid-sensitive transferrin conjugates prepared with the carboxylic hydrazone doxorubicin derivatives exhibited an inhibitory efficacy in the MDA-MB-468 breast cancer cell line and U937 leukemia cell line comparable to that of the free drug (employing the BrdU (5-bromo-2'-deoxyuridine) incorporation assay and tritiated thymidine incorporation assay, respectively, IC50 approximately 0.1-1 mM), whereas conjugates with the amide derivatives showed no activity. Furthermore, antiproliferative activity of the most active transferrin conjugate (i.e. the conjugate containing a benzoyl hydrazone link) was demonstrated in the LXFL 529 lung carcinoma cell line employing a sulforhodamine B assay. In contrast to in vitro studies in tumor cells, cell culture experiments performed with human endothelial cells (HUVEC) showed that the acid-sensitive transferrin conjugates of doxorubicin were significantly less active than free doxorubicin (IC50 values approximately 10-40 higher by the BrdU incorporation assay), indicating selectivity of the doxorubicin-transferrin conjugates for tumor cells. Fluorescence microscopy studies in the MDA-MB-468 breast cancer cell showed that free doxorubicin accumulates in the cell nucleus, whereas doxorubicin of the transferrin conjugates is found localized primarily in the cytoplasm. The differences in the intracellular distribution between transferrin-doxorubicin conjugates and doxorubicin were confirmed by laser scanning confocal microscopy in LXFL 529 cells after a 24 h incubation that revealed an uptake and mode of action other than intercalation with DNA. The relationship between stability, cellular uptake, and cytotoxicity of the conjugates is discussed.

Systemic Fusarium oxysporum infection in an immunocompetent patient with an adult respiratory distress syndrome (ARDS) and extracorporal membrane oxygenation (ECMO)

We report a case of disseminated fusariosis in a 42-year-old patient with adult respiratory distress syndrome (ARDS) and extracorporal membrane oxygenation (ECMO), but without definite immunosuppression. Fusarium oxysporum was isolated from a bronchial lavage taken 6 days ante mortem. Despite antifungal treatment with amphotericin B and flucytosine the patient died in septic multiorgan failure. A post-mortem examination was performed. The patient's liver was found to contain fungus cells and F. oxysporum could be cultured from ascites.

Albumin conjugates of the anticancer drug chlorambucil: synthesis, characterization, and in vitro efficacy

In our efforts to improve the selectivity and toxicity profile of antitumor agents, four maleimide derivatives of chlorambucil (1-4) were bound to thiolated human serum albumin which differ in the stability of the chemical link between drug and spacer. 1 is an aliphatic maleimide ester derivative of chlorambucil, whereas 2-4 are acetaldehyde, acetophenone, and benzaldehyde carboxylic hydrazone derivatives. HPLC stability studies at pH 5.0 with the related model compounds 5, 7, 8, and 9, in which chlorambucil was substituted by 4-phenylbutyric acid, demonstrated that the carboxylic hydrazone derivatives have acid-sensitive properties; the acid lability of 7 was particular prominent with a half-life of only a few hours. The alkylating activity of albumin-bound chlorambucil was determined with the aid of 4-(4-nitrobenzyl)-pyridine (NBP), demonstrating that on average three equivalents were protein-bound. Evaluation of the cytotoxicity of free chlorambucil and the respective albumin conjugates in the MCF7 mamma carcinoma and MOLT4 leukemia cell line employing a propidium iodide fluorescence assay demonstrated that the conjugate in which chlorambucil was bound to albumin through an ester bond was not as active as chlorambucil. In contrast, the conjugates in which chlorambucil was bound to albumin through carboxylic hydrazone bonds were as or more active than chlorambucil in both cell lines. In particular, the conjugate in which chlorambucil was bound to albumin through an acetaldehyde carboxylic hydrazone bond exhibited IC50 values which were approximately 4-fold (MCF7) to 13-fold (MOLT4) lower than those of chlorambucil. Preliminary toxicity studies in mice showed that this conjugate can be administered at higher doses in comparison to unbound chlorambucil.

Preparation, characterization and in vitro efficacy of albumin conjugates of doxorubicin

One strategy for improving the antitumor selectivity and toxicity profile of antitumor agents is to design drug carrier systems with suitable transport proteins. Thus, four maleimide derivatives of doxorubicin were bound to thiolated human serum albumin which differed in the stability of the chemical link between drug and spacer. In the maleimide derivatives, 3-maleimidobenzoic or 4-maleimidophenylacetic acid was bound to the 3'-amino position of doxorubicin through a benzoyl or phenylacetyl amide bond and 3-maleimidobenzoic acid hydrazide or 4-maleimidophenylacetic acid hydrazide was bound to the 13-keto position through a benzoyl hydrazone or phenylacetyl hydrazone bond. The acid-sensitive albumin conjugates prepared with the carboxylic hydrazone doxorubicin derivatives exhibited an inhibitory efficacy in the MDA-MB-468 breast cancer cell line and U937 leukemia cell line comparable with that of the free drug (using the BrdU-(5-bromo-2'-deoxyuridine)-incorporation assay and tritiated thymidine incorporation assay respectively, IC50 approximately 0.1-1 microM) whereas conjugates with the amide derivatives showed no or only marginal activity. These results demonstrate that antiproliferative activity depends on the nature of the chemical bond between doxorubicin and carrier protein. Acid-sensitive albumin conjugates are suitable candidates for further in vitro and in vivo assessment.