Cancer risk with alemtuzumab following kidney transplantation

Alemtuzumab has been employed for induction therapy in kidney transplantation with low rates of acute rejection and excellent graft and patient survival. Antibody induction therapy has been linked to increased vulnerability to cancer. Data regarding malignancy rates with alemtuzumab are limited. We studied 1350 kidney transplant recipients (between 2001 and 2009) at the University of Pittsburgh Starzl Transplant Institute, for post-transplant de novo and recurrent malignancy, excluding non-melanoma skin cancer, among patients receiving alemtuzumab, thymoglobulin, and no induction therapies. Of the 1350 patients, 1002 (74.2%) received alemtuzumab, 205 (15.2%) received thymoglobulin, and 122 (9%) received no induction therapy. After excluding cancers occurring within 60 d post-transplantation, 43 (3.25%) malignancies were observed during a median follow-up time of 4.0 yr. The incidence of malignancy was 5.4% (1.09 per 100 patient-years [PY]) with thymoglobulin, 2.8% (0.74 per 100 PY) with alemtuzumab, and 3.3% (0.66 per 100 PY) with no induction (across all groups; p = 0.2342, thymoglobulin vs. alemtuzumab; p = 0.008). Thus, with the exception of non-melanoma skin cancer which we did not evaluate, alemtuzumab induction was not associated with increased cancer incidence post-kidney transplantation when compared to no induction therapy and was associated with lower cancer incidence when compared to thymoglobulin.

In-vivo visualization of tumor microvessel density and response to anti-angiogenic treatment by high resolution MRI in mice

Purpose

Inhibition of angiogenesis has shown clinical success in patients with cancer. Thus, imaging approaches that allow for the identification of angiogenic tumors and the detection of response to anti-angiogenic treatment are of high clinical relevance.

Experimental Design

We established an in vivo magnetic resonance imaging (MRI) approach that allows us to simultaneously image tumor microvessel density and tumor vessel size in a NSCLC model in mice.

Results

Using microvessel density imaging we demonstrated an increase in microvessel density within 8 days after tumor implantation, while tumor vessel size decreased indicating a switch from macro- to microvessels during tumor growth. Moreover, we could monitor in vivo inhibition of angiogenesis induced by the angiogenesis inhibitor PTK787, resulting in a decrease of microvessel density and a slight increase in tumor vessel size.

Conclusions

We present an in vivo imaging approach that allows us to monitor both tumor microvessel density and tumor vessel size in the tumor. Moreover, this approach enables us to assess, early-on, treatment effects on tumor microvessel density as well as on tumor vessel size. Thus, this imaging-based strategy of validating anti-angiogenic treatment effects has high potential in applications to preclinical and clinical trials.

Two hundred living donor kidney transplantations under alemtuzumab induction and tacrolimus monotherapy: 3-year follow-up

Alemtuzumab has been used in off-label studies of solid organ transplantation. We extend our report of the first 200 consecutive living donor solitary kidney transplantations under alemtuzumab pretreatment with tacrolimus monotherapy and subsequent spaced weaning to 3 years of follow-up. We focused especially on the causes of recipient death and graft loss, and the characteristics of rejection. The actuarial 1-, 2- and 3-year patient and graft survivals were 99.0% and 98.0%, 96.4% and 90.8% and 93.3% and 86.3%, respectively. The cumulative incidence of acute cellular rejection (ACR) at the following months was 2%</=6, 9.0%</=12, 16.5%</=18, 19.5%</=24, 23.5%</=30, 24.0%</=36 and 25%</=42. The mean serum creatinine (mg/dL) and glomerular filtration rate (mL/min/1.73 m(2)) at 1 and 3 years were 1.4 +/- 0.6 and 58.7 +/- 21.6 and 1.5 +/- 0.7 and 54.9 +/- 20.9, respectively. Fifty (25%) recipients had a total of 89 episodes of ACR. About 88.7% of ACR episodes were Banff 1, and of those, 82% were steroid-sensitive. Nine (4.5%) recipients had antibody-mediated rejection (AMR). About 76.5% were weaned but only 46% are currently on spaced dose (qod or less) tacrolimus monotherapy, and 94.4% remained steroid-free from the time of transplantation. Infectious complications were uncommon. This experience suggests the 3-year efficacy of this approach.

Living donor renal transplantation using alemtuzumab induction and tacrolimus monotherapy

Alemtuzumab was used as an induction agent in 205 renal transplant recipients undergoing 207 living donor renal transplants. All donor kidneys were recovered laparoscopically. Postoperatively, patients were treated with tacrolimus monotherapy, and immunosuppression was weaned when possible. Forty-seven recipients of living donor renal transplants prior to the induction era who received conventional triple drug immunosuppression without antibody induction served as historic controls. The mean follow-up was 493 days in the alemtuzumab group and 2101 days in the historic control group. Actuarial 1-year patient and graft survival were 98.6% and 98.1% in the alemtuzumab group, compared to 93.6% and 91.5% in the control group, respectively. The incidence of acute cellular rejection (ACR) at 1 year was 6.8% in the alemtuzumab group and 17.0% (p < 0.05) in the historic control group. Most (81.3%) episodes of ACR in the alemtuzumab group were Banff 1 (a or b) and were sensitive to steroid pulses for the treatment of rejection. There was no cytomegalovirus disease or infection. The incidence of delayed graft function was 0%, and the incidence of posttransplant insulin-dependent diabetes mellitus was 0.5%. This study represents the largest series to date of live donor renal transplant recipients undergoing alemtuzumab induction, and confirms the short-term safety and efficacy of this approach.

Steroid-free tacrolimus monotherapy after pretransplantation thymoglobulin or Campath and laparoscopy in living donor renal transplantation

Living donor renal transplantation was performed under a regimen of recipient pretreatment and low-dose postoperative immunosuppression with subsequent weaning. From October 9, 2002, to December 31, 2004, 196 consecutive, unselected laparoscopic live donor nephrectomies resulting in 196 living donor renal transplantations were performed. Recipients were pretreated with rabbit antithymocyte globulin (thymoglobulin; 24 patients or [12%]) or Campath 1H (alemtuzumab; 166 patients [85%]), or were not in protocol (6 patients [3%]), and were given postoperative steroid-free low-dose tacrolimus immunosuppressive monotherapy with subsequent weaning. There was no donor mortality. Major and minor donor morbidities were 2.6% and 4.2%, respectively. Laparoscopic live donor nephrectomy recipient outcomes with a mean follow-up of 401 days included (1) recipient and graft survival of 99.0% and 97.4%, respectively; (2) no ureteral stenosis; (3) 0.5% delayed graft function, from recurrent focal segmental glomerulosclinosis; and (4) no vascular thrombosis. The incidence of acute rejection at 30, 90, and 401 days was 1.5%, 3.8%, and 11.2% (all 196 recipients), 0%, 25%, and 29.2% (thymoglobulin recipients), and 1.8%, 3.9%, and 8.4% (Campath 1H recipients), respectively. Sixty-six patients (33.7%) are receiving spaced-dose immunosuppressive monotherapy. The mean creatinine concentration in all recipients was 1.5 +/- 1.1 mg/dL. There were no instances of cytomegalovirus tissue invasive disease or posttransplantation lymphoproliferative disease. The incidence of new-onset posttransplantation insulin-dependent diabetes was 0.5%. At current follow-up, the use of Campath 1H rather than thymoglobulin for pretreatment seems to have significantly improved the efficacy of our regimen.

Systemic coagulation parameters in mice after treatment with vascular targeting agents

Background

Vascular targeting of malignant tumors has become a clinically validated new treatment approach with clear patient benefit. However clinical studies have also revealed that some types of vascular targeting agents (VTAs) are prone to coagulation system side effects. It is therefore essential to predetermine coagulation parameters in preclinical studies. As of to date, this has rarely been done, predominantly due to technical issues.

The goal of this study was to establish and apply a standardized process, whereby systemic coagulation activation can be routinely measured in mice.

Results

We have evaluated a number of sampling techniques and coagulation tests regarding their suitability for this purpose. We were able to adapt two assays measuring soluble fibrin, a marker for a prethrombotic status. Thus, soluble fibrin could be measured for the first time in mice. All assays were validated in a positive control model for systemic coagulation activation, i.e. lipopolysaccharide-induced endotoxemia.

Based on our results, we selected a panel of coagulation tests, which are both feasable and informative for preclinical testing of VTAs: soluble fibrin, thrombin-antithrombin complexes, free antithrombin III, white blood cell counts and platelet counts. The effect of tumor transplants on coagulation parameters was evaluated using this panel. We then applied this set of assays in treatment studies with a VTA developed in our laboratory to investigate a potential systemic coagulation activation.

Conclusion

We have established a standardized panel of assays that can be used to test murine blood samples for coagulation activation in preclinical studies. All tests are feasible to perform in any research laboratory without specialized equipment. In addition, this is the first report to measure soluble fibrin, an early marker of systemic coagulation activation, in mice. The panel was applied on tumor bearing mice and mice treated with a VTA. We suggest its general application for coagulation activation analyses in mice.

Specific Occlusion of Murine and Human Tumor Vasculature by VCAM-1–Targeted Recombinant Fusion Proteins

BACKGROUND

The tumor vasculature is increasingly recognized as a target for cancer therapy. We developed and evaluated recombinant fusion proteins targeting the coagulation-inducing protein soluble tissue factor (sTF) to the luminal tumor endothelial antigen vascular cell adhesion molecule 1 (VCAM-1, CD106).

METHODS

We generated fusion proteins consisting of sTF fused to antibody fragments directed against mouse or human VCAM-1 and characterized them in vitro by flow cytometry, surface plasmon resonance, and two-stage coagulation assays. Their therapeutic effects were tested in three human xenograft tumor models: L540rec Hodgkin lymphoma, Colo677 small-cell lung carcinoma, and Colo677/HDMEC small-cell lung carcinoma with human vasculature. Toxicity was analyzed by histologic examination of organs and determination of laboratory blood parameters.

RESULTS

The fusion proteins bound VCAM-1 with nanomolar affinities and had the same coagulation activity as an sTF standard. Xenograft tumor-bearing mice treated with fusion protein (FP) alone or in combination with lipopolysaccharide (FP/L) or doxorubicin (FP/D) exhibited tumor-selective necrosis (L540rec tumors: 74% tumor necrosis [95% confidence interval {CI} = 55% to 93%] with FP/L versus 13% tumor necrosis [95% CI = 4% to 22%] with vehicle; Colo677 tumors: 26% [95% CI = 16% to 36%] with FP versus 8% [95% CI = 2% to 14%] with vehicle); tumor growth delay (Colo677/HDMEC: mean tumor weights after 3 days = 42 mg in FP-treated mice versus 71 mg in vehicle-treated mice, difference = 29 mg, 95% CI = 8 to 100, Mann-Whitney P = .008); and some tumor regressions (one of seven FP-treated Colo677 tumor-bearing mice and two of seven FP/D-treated mice). The fusion protein was well tolerated.

CONCLUSIONS

Recombinant tissue factor-based fusion proteins directed against an intraluminal tumor endothelial cell marker induce tumor-selective intravascular coagulation, tumor tissue necrosis, and tumor growth delay.

Soluble tissue factor induces coagulation on tumor endothelial cells in vivo if coadministered with low-dose lipopolysaccharides

OBJECTIVE

This study was performed to evaluate the mechanisms leading to tumor vessel occlusion by tissue factor-based drugs, which are used in vascular targeting approaches for the treatment of malignant tumors.

METHODS AND RESULTS

The effects of nontargeted soluble tissue factor were evaluated in vitro and in vivo. Tumor-bearing mice were treated with (1) the extracellular portion of tissue factor (soluble tissue factor), (2) low nontoxic doses of lipopolysaccharides, or (3) a combination thereof. The combination treatment showed the best effects and resulted in selective thrombosis of tumor vessels. On the basis of our data from subsequent in vitro analyses, including surface plasmon resonance measurements and endothelial cell based coagulation assays, we propose a model on how soluble tissue factor, although lacking its membrane anchor, can promote selective tumor vessel occlusion.

CONCLUSIONS

To our knowledge, this is the first report to describe the molecular mechanisms of coagulation induction by untargeted soluble tissue factor in vivo. Combination treatments including soluble tissue factor might represent an alternative vascular targeting approach for the treatment of malignant tumors.

A comparison of the residual effects of zaleplon and zolpidem following administration 5 to 2 h before awakening

AIMS

To compare the duration of the residual hypnotic and sedative effects of zaleplon with those of zolpidem and placebo following nocturnal administration at various times before morning awakening.

METHODS

Zaleplon 10 mg, zolpidem 10 mg, or placebo was administered double-blind to 36 healthy subjects under standardized conditions in a six-period, incomplete-block, crossover study. Subjects were gently awakened and given medication at predetermined times 5, 4, 3, or 2 h before morning awakening, which occurred 8 h after bedtime. When the subjects awoke in the morning, a battery of subjective and objective assessments of residual effects of hypnotics was administered.

RESULTS

No residual effects were demonstrated after zaleplon 10 mg, when administered as little as 2 h before waking, on either subjective or objective assessments, whereas zolpidem 10 mg showed significant residual effects on DSST and memory (immediate and delayed free recall) after administration up to 5 h before waking and choice reaction time, critical flicker fusion threshold and Sternberg memory scanning after administration up to 4 h before waking. Residual effects of zolpidem were apparent in all objective and subjective measurements when the drug was administered later in the night.

CONCLUSIONS

The present results demonstrate that zaleplon at the dose of 10 mg is free of residual hypnotic or sedative effects when administered nocturnally as little as 2 h before waking in normal subjects. In contrast, residual effects of zolpidem are still apparent on objective assessments up to 5 h after nocturnal administration, longer than has been reported from studies involving daytime administration.

Pharmacokinetic and pharmacodynamic evaluation of the potential drug interaction between venlafaxine and ethanol

Venlafaxine is a new antidepressant with a unique mode of action. Because many patients taking antidepressant therapy may self-medicate with ethanol, this study was undertaken to assess the possible pharmacokinetic and pharmacodynamic interactions between venlafaxine and ethanol. This randomized, double-blind, placebo-controlled, two-period crossover study was conducted with 16 healthy men. Multiple doses of venlafaxine (50 mg every 8 hours) or placebo were administered for 7 days. On days 5 and 7 a single dose of 0.5 g/kg of ethanol or a placebo solution was administered in a randomized fashion. Pharmacokinetic data indicated that ethanol administration did not affect the disposition of venlafaxine or O-desmethylvenlafaxine. Similarly, venlafaxine administration did not affect the pharmacokinetic disposition of ethanol. Ethanol produced its expected effects on the eight psychometric tests administered. Venlafaxine produced small effects on the results of the Digit Symbol Substitution Test, the Divided Attention Reaction Time, and the Profile of Mood States. No pharmacodynamic interaction was detected between venlafaxine and ethanol.