Targeting the endothelin axis with atrasentan, in combination with IFN-alpha, in metastatic renal cell carcinoma.

BACKGROUND: The endothelin system is involved in tumour growth. Atrasentan, a selective endothelin-A-receptor antagonist, blocks endothelin signalling. This phase I trial studied combining treatment of interferon-alpha (IFN-α) with atrasentan in renal cell carcinoma (RCC). PATIENTS AND METHODS: This study evaluated the safety and tolerance of IFN-α (9MU subcutaneously (s.c.) three times a week) in combination with atrasentan (2.5, 5 and 10 mg orally once daily) in untreated metastatic RCC. Cohort 10 mg was extended to obtain insights in efficacy and pharmacodynamics. RESULTS: Observed toxicities mainly consisted of known IFN-like toxicities (anorexia, chills, fever, fatigue and nausea), and of nasal congestion (associated to atrasentan). None of these toxicities were considered dose limiting. Cohort 10 mg was extended up to 32 patients; in a subset of patients treated according to the protocol (n=27), median overall survival (OS) was 17.3 months. One patient (3.1%) showed a partial response lasting 14.3 months. In an exploratory analysis, we observed that in the subset of patients with declining vascular endothelial growth factor (VEGF) levels (in combination with rising Endothelin-1 levels), median OS was 22.2 months compared with 2.2 months in patients with increasing VEGF levels. CONCLUSION: Combination treatment of IFN-α 9MU-α s.c. three times a week and atrasentan 10 mg once daily is tolerated. Clinical activity, especially OS, and biomarkers in our view warrant further studies targeting the endothelin axis.

Ancient Schwannoma of the Gallbladder.

Schwannomas are benign tumors which arise in the Schwann cells of the peripheral nerves. They develop anywhere in the human body but are less frequent found in the digestive tract. A 67-year-old female patient was referred to our tertiary HPB department with a asymptomatic mass of the gallbladder. Contrast-enhanced computed tomography revealed a rather homogeneous, well-circumscribed, high-density ovoid mural mass. An open cholecystectomy was performed. A final diagnosis of schwannoma with degenerative atypia, so-called "ancient schwannoma", was made. Clinical recovery and follow-up was uneventful, with no signs of recurrence.

International collaborative study for the calibration of a proposed international standard for thromboplastin, rabbit, plain.

BACKGROUND: A preparation of rabbit brain thromboplastin, provisionally coded 04/162, is proposed as a candidate for the World Health Organization (WHO) International Standard (IS) for thromboplastin (rabbit, plain), meant to replace the IS coded RBT/90 (rabbit, plain), stocks of which are now exhausted. RESULTS: The preparation was calibrated in an international collaborative study involving 21 laboratories from 13 countries and the calibration was performed against the existing WHO-IS (i.e. rTF/95 and OBT/79) and other Certified Reference Materials from the Institute for Reference Materials and Measurements of the European Commission (i.e. CRM149 S) and from the European Action on Anticoagulation (i.e. EUTHR-01). An additional candidate rabbit brain thromboplastin coded as 04/106 was also included in the study. On the basis of predefined criteria (the within- and between-laboratory precision of the calibration and the conformity to the calibration model), 04/162 was the preferred candidate. CONCLUSIONS: The assigned International Sensitivity Index value was 1.15 and the inter-laboratory SD and coefficient of variation were 0.057% and 4.9%, respectively.

Selective killing of malignant cells from leukemic patients by alkyl-lysophospholipid.

We studied the effects of the alkyl-lysophospholipid, 1-octadecyl-2-methyl-sn-glycerol-3-phosphocholine (ALP), on human leukemia cells from 56 patients with various leukemias and on normal bone marrow progenitors in order to assess the application of ALP as an in vitro marrow-purging agent. The tumoricidal activity was analyzed by the elimination of clonogenic leukemia cells (leukemic colony-forming cells), by the inhibition of the proliferative capacity [( 3H]thymidine incorporation) of leukemia cells, and by the elimination of viable leukemia cells measured with flow cytometry. The tumoricidal activity of ALP was dose and incubation time related, as, although to a lesser extent, held true for normal marrow progenitors. For some leukemias the ALP dose necessary for the elimination of 100% of the leukemic colony-forming cells is probably too toxic for normal marrow cells. The results of this study strongly support the possibility that ALP is a promising purging agent in the majority of patients with leukemias.

Effect of magnesium contamination in evacuated blood collection tubes on the prothrombin time test and ISI calibration using recombinant human thromboplastin and different types of coagulometer.

UNLABELLED: The purpose of the present study was to assess the effect of two types of evacuated blood collection tube on the prothrombin time and international sensitivity index (ISI) of Recombiplastin, a recombinant human thromboplastin. Vacutainer tubes were compared with Venoject II tubes. Magnesium contamination was detected in the sodium citrate solutions contained in the Vacutainer tubes with concentrations ranging from 1.1 to 1.5 mmol/l. In contrast, magnesium ions could not be detected in the Venoject II tubes. The prothrombin ratio was decreased by contamination with magnesium ions and, hence, the ISI was increased. The magnitude of the effect of magnesium contamination on the ISI was influenced by the type of coagulometer and increased in the order: ACL Advance (3%), ACL-300 (4%), Electra-1000 (6%). The ISI bias is transmitted to the international normalized ratio (INR). In the case of the Electra-1000, the INR bias would be approximately 6% at INR 3.0 if the two types of blood collection tubes would be used without distinction. In a secondary study, the effect of magnesium contamination on the prothrombin time was assessed with the current World Health Organization international reference preparation for recombinant human thromboplastin (rTF/95). Magnesium chloride added to patients' blood (0.2 mmol/l) induced 2.3% reduction of the INR determined with rTF/95 and the manual technique. CONCLUSION: The magnitude of the influence of blood collection tubes contaminated with magnesium on ISI and INR determined with recombinant human thromboplastin depends on the coagulometer.

Analytical accuracy and precision of two novel Point-of-Care systems for INR determination.

BACKGROUND: Portable point-of-care (POC) instruments for determination of the whole blood prothrombin time (PT) have been available for the last three decades. Recently, two novel POC instruments for PT and International Normalized Ratio (INR) determination in whole blood have been manufactured. The purpose of this study was to compare INR values obtained with the novel instruments (microINR® and ProTime InRhythm™) to the INR determined with the international standard for thromboplastin rTF/09. MATERIALS AND METHODS: In 60 patients treated with vitamin K-antagonists, venous whole blood was analysed with four different types of POC instruments including the novel ones. In the same patients, citrated plasma was analysed with the international standard rTF/09 and the manual tilt tube technique for clotting time determination. We assessed the bias of the INR read from the POC instruments relative to the international standard. To study the imprecision of the two novel POC instruments, duplicate INR determinations were performed. RESULTS: The results obtained with the two novel POC instruments were positively correlated with those of the international standard rTF/09. However, there was a significant bias between INR read from the novel instruments and the INR determined with rTF/09 (P < 0.001). The mean bias was -13.7% (MicroINR) and -9.3% (InRhythm). The imprecision coefficient of variation in venous blood was 5.0% and 5.1%, respectively. CONCLUSION: The imprecision of the two novel instruments is acceptable with respect to the average within-subject variation of the INR. The accuracy of the systems is borderline and should be improved by the manufacturers.

Accelerated degradation test of lyophilized recombinant tissue factor-liposome preparations.

Accelerated degradation experiments were performed to assess the heat stability of lyophilized recombinant tissue factor-liposome preparations from two different manufacturers. When stored at 4 degrees C, these preparations did not show a significant change of the prothrombin time (PT). Two preparations (coded rTF-2 and rTF-a) showed a progressive prolongation of the PT on storage at 30 degrees C, 37 degrees C, and 44 degrees C. The third preparation showed an initial decrease of the PT at 37 degrees C and 44 degrees C followed by a progressive prolongation. Although none of the three preparations was absolutely stable at 30 degrees C, 37 degrees C and 44 degrees C, rTF-2 had the advantage that its PT-ratio (and hence its International Sensitivity Index) did not change under the conditions used in this study. The PT-ratio with a reference material for rabbit brain tissue factor (CRM149S) stored under similar conditions, did not change either.

A comparison between capillary and venous blood international normalized ratio determinations in a portable prothrombin time device.

The CoaguChek PT system is a portable point-of-care device for prothrombin time testing that can be used with capillary and venous whole blood. This system had been calibrated by the manufacturer in terms of the international normalized ratio (INR) for monitoring oral anticoagulant therapy. The purpose of the present study was to compare capillary blood with venous blood INRs from healthy volunteers and patients treated with oral anticoagulants using the same CoaguChek PT system. Two different CoaguChek PT strip formulations [international sensitivity index (ISI), 1.5 and 1.1] were used in separate test series. The differences between capillary and venous blood INRs were statistically significant (P < 0.001) but the magnitude of the differences was small. The mean relative deviations of the INR were 5.8 and 2.8% for the strips with ISI 1.5 and 1.1, respectively. These deviations are clinically acceptable. It is concluded that capillary blood can be replaced by venous blood for the calibration of the CoaguChek PT system.

Influence of plasma volumetric errors on the prothrombin time ratio and International Sensitivity Index.

The International Sensitivity Index (ISI) for prothrombin time systems depends on the thromboplastin manufacturer's recommended method for use. The purpose of the present study was to investigate the influence of small deviations from the recommended sample volume on the prothrombin time ratio and ISI. Four commercial reagents were studied; three with low ISI and one with high ISI. The effects of volumetric errors on the ISI were used to assess the associated effects on the International Normalized Ratio (INR). The effect of 10% volume error on the INR was not greater than 5%. The effects with the three low-ISI reagents were slightly greater than those with the high-ISI reagent. It is recommended that each laboratory should check the volumes of sample and reagent used for the prothrombin time test.

Effect of plasma pooling on the International Sensitivity Index of prothrombin time systems.

Guidelines set by the World Health Organization (WHO) state that in order to calibrate a prothrombin time system for International Sensitivity Index (ISI), freshly prepared specimens from 20 normal individuals and 60 patients receiving coumarin are required. These numbers are required to obtain a precise value of the calibration line slope when there is considerable scatter of individual data about the regression line. The scatter can be reduced by pooling individual plasma samples. In the present study, four pooled plasmas were prepared, one from 20 normal individuals and three from three groups of 30 patients receiving treatment with long-term oral anticoagulants. Prothrombin times were determined with four thromboplastins, HepatoQuick (rabbit thromboplastin combined with adsorbed plasma), Recombiplastin (recombinant human thromboplastin), Thromborel-S (human placenta), and Thromboplastin-C Plus (rabbit brain). Calibration line slopes were calculated for the six possible combinations of thromboplastins using the set of all individual plasma samples and the set of four pooled plasmas. In most comparisons, the WHO calibration model was appropriate, i.e. the line calculated for the patients' samples passed through the mean of the normals. The calibration line slopes obtained with the set of four pooled plasmas did not differ by more than 5% from the corresponding slopes calculated with the original individual plasmas. For some combinations of thromboplastins non-linear relations were observed both with the individual plasmas and with the pooled plasmas. We conclude that pooling individual plasmas does not significantly change the calibration relation between prothrombin times determined with the original individual plasmas. Freshly pooled plasmas can be used to determine the ISI of prothrombin time systems with an acceptable degree of precision.

Phase II study of the combination of pegylated liposomal doxorubicin and topotecan in platinum-resistant ovarian cancer.

The combination of liposomal doxorubicin and topotecan was evaluated in a phase II study in patients with platinum-resistant ovarian cancer. Twenty-seven patients received liposomal doxorubicin (30 mg/m(2)) infused at day 1, followed by topotecan (1 mg/m(2)) infusion daily for 5 days. Cycles were repeated every 21 days. This combination regimen showed an overall response rate of 28%. Median time to progression was 30 weeks, with a median overall survival of 40 weeks. Grade 3/4 neutropenia was shown in 70% of patients and grade 3/4 thrombopenia in 41% of patients. Neutropenic fever was reported in 11% of patients. After reviewing the first 12 patients, the internal review board decided to administer topotecan at a dose of 0.75 mg/m(2) and liposomal doxorubicin at 40 mg/m(2) for the remainder of the study. However, this adjustment did not lead to reduction in bone marrow toxicity nor to an improvement in dose intensity. Palmar-plantar erythrodysesthesia and mucositis were more reported in the second cohort but usually mild. The combination of liposomal doxorubicin and topotecan demonstrates favorable response data in platinum-resistant ovarian cancer. However, substantial bone marrow toxicity limits further clinical use.