Neutralizing antiidiotypic antibodies to factor VIII inhibitors after desensitization in patients with hemophilia A.

Hemophilia A patients producing antibodies towards FVIII are usually treated with infusions of high doses of FVIII in an attempt to "desensitize" them. To examine the mechanisms by which such desensitization operates, sequential plasma samples of two unrelated inhibitor patients were analyzed for anti-FVIII and antiidiotypic antibodies before and during infusions of high doses of FVIII. Anti-FVIII antibodies were separated from antiidiotypic antibodies by immunoaffinity chromatography before analysis. We show in the present study that the concentration of anti-FVIII antibodies did not change during a successful desensitization and that antibodies maintained their capacity to inhibit the procoagulant function of FVIII, even though the number of Bethesda units in plasma was reduced to undetectable levels. Using a competition assay with mAbs, we further show that the specificity of human antibodies did not vary significantly during therapy. Finally, we show that the treatment elicited antiidiotypic antibodies, which neutralized the inhibitory capacity of anti-FVIII antibodies. Inhibitor antibodies can therefore not be accurately evaluated in plasma, as their function appears to be neutralized by antiidiotypic antibodies. These findings could have implications for the design of new therapies for hemophilia A patients with inhibitors.

Inhibitor development in patients with hemophilia A after continuous infusion of FVIII concentrates.

Continuous infusion (CI) of coagulation factor concentrates has been used since the early 1990s. Recent reports of the occurrence of an inhibitor after CI have raised concerns about this method of treatment. We conducted a retrospective study to investigate the development of inhibitors after CI of Factor VIII concentrates in Germany. So far, 13 hemophilia centers have been contacted, and data have been collected by a questionnaire. Of the 13 centers, CI had never been performed in three, no inhibitors had been detected in five, and inhibitor development after CI was recorded in 10 patients in the remaining five centers. Of these 10 patients (ages 7 months to 57 years), five were suffering from severe, one from moderate, and four from mild hemophilia. Indications for treatment were major bleeds and surgical procedures. Plasma-derived (6 cases) and recombinant (4 cases) factor concentrates were given in various infusion sets. Data concerning amount infused (4300 to > 100,000 IU), number of days of exposure to factor concentrates (1 to > 100), and inhibitor characteristics (alloantibodies, 3 LR, 7 HR) were collected. Regarding hemophilia genotype, we found missense mutations in four patients, intron-22 inversions in two, and one small deletion in one; the genotype in three was unknown. In conclusion, only 3 out of 10 patients who developed an inhibitor after CI showed the typical risk profile for inhibitor formation, which is severe hemophilia A with a severe gene defect and less than 50 days of exposure to coagulation factor concentrates. Especially striking was the finding that 50% of the patients who developed inhibitors had mild to moderate hemophilia A. Our data point to the existence of a so-far unknown factor, related to CI, that might lead to inhibitor formation.

Acute portal vein thrombosis after splenic embolization and splenectomy for autoimmune pancytopenia.

Postsplenectomy portal vein thrombosis for hematological diseases is uncommon in the pediatric population. The case summarized is, to our knowledge, the first manifestation of portal vein thrombosis in a child after preoperative splenic artery embolization and subsequent splenectomy for severe hypersplenism. We suggest that early routine diagnosis by Doppler ultrasonography and subcutaneous low molecular weight heparin therapy are useful steps for a successful outcome.

A phase II trial of interferon alpha-2b with folinic acid and 5-fluorouracil administered by 4-hour infusion in metastatic colorectal carcinoma.

Preclinical data suggest that folinic acid as well as interferon alpha-2b may enhance the antitumor activity of 5-fluorouracil (5-FU). In a phase I trial, we recently showed that interferon alpha-2b (IFN), folinic acid and 5-FU can be safely administered with a 4-hour infusion of 5-FU. We therefore initiated a phase II trial evaluating the efficacy and safety of these three drugs. Forty-five evaluable patients with advanced metastatic colorectal cancer, documented progressive disease, and previously unexposed to chemotherapy were treated with sequential IFN 5 MU/d subcutaneously and folinic acid 200 mg/m2/d as bolus on days 1 to 7 followed by 5-FU in a 4-hour infusion at a dose of 500 mg/m2/d, resulting in a total dose of 3,500 mg/m2/course. This schedule was repeated on day 21. A total of 204 courses of therapy were completed. One of 45 patients (2%) achieved a complete response, and 13 of 45 patients (29%) achieved a partial response. An additional 16 patients (36%) had stable disease. The median time to disease progression was seven months (2 to 24 months). Despite the relatively high-dose intensity of 5-FU, toxicity was very mild. Grade 3 or 4 myelosuppression, stomatitis, and nausea/vomiting occurred in only three of 45 patients (7%). Four of 45 patients (9%) suffered from severe (grade 3/4) diarrhea. Neurotoxicity and infections of grade 2 to 4 did not occur. From these data we conclude that modulation of 5-FU with both folinic acid and IFN induces an overall response rate of 31% in disseminated colorectal cancer. Using a 4-hour application schedule of 5-FU, the therapeutic index can be improved even for high-dose intensity and requires further evaluation in combination with other modulators.

Inhibitors in German hemophilia A patients treated with a double virus inactivated factor VIII concentrate bind to the C2 domain of FVIII light chain.

To reduce the risk of transmission of hepatitis A virus, an Octapharma produced factor VIII (fVIII) concentrate treated with solvent detergent (FVIII-SD) was further pasteurized after purification. This product, Octavi SDPlus (FVIII-SDP), was marketed in Europe in 1993 to 1995. Inhibitors appeared from September to October, 1995, in 12 of 109 previously treated German hemophilia A patients. A study of similarly treated Belgian patients, who also developed inhibitors, had shown antibodies to the fVIII light chain (domains A3-C1-C2) only. In the present study, the epitope specificity of 8 German inhibitor plasmas was also found to be restricted to the light chain. In radioimmunoprecipitation assays to localize the light chain epitope(s), antibody binding to heavy chain (domains A1-A2-B) was 11-148 fold lower than to the C2 domain, and binding to recombinant A3-C1 was barely detectable. These results were supported by >95% neutralization of a high responder inhibitor titer by the C2 domain.

Phase II clinical trial of high-dose recombinant human tumor necrosis factor.

Based on a phase I study in 1986, 22 patients have been entered in a phase II study of high-dose human tumor necrosis factor (rH-TNF) since May 1987. Of these patients, 18 are evaluable at present, 2 are still under investigation, and 2 have dropped out. All had advanced stages of cancer (9 soft-tissue sarcomas, 3 melanomas, 5 hypernephromas) and inclusion in the study was ethically acceptable (informed consent). The daily dose of rH-TNF was 15 x 10(5) units/m2, escalated to 21 x 10(5) units/m2 (683-956 micrograms/m2 every week; range 1-6 cycles). Additional prophylactic ketoprofen administration was carried out. Of the 18 evaluable patients, 4 responded with no change (2/4, clinical improvement) and 14 showed progressive disease. The main toxicities observed were hypotension (decrease in systolic blood pressure, 21-60 Torr), leukocytosis, increases in ALAT/ASAT (WHO grade 0-4), fever (WHO grade 1-2), chills (mild to moderate), neurotoxicity (WHO grade 0-2), and nausea/vomiting (WHO grade 0-3).

Mitoxantrone: mechanism of action, antitumor activity, pharmacokinetics, efficacy in the treatment of solid tumors and lymphomas, and toxicity.

Mitoxantrone is similar to Adriblastin in its mechanism of action and antitumor activity. Objective remissions were obtained in 20-30% pretreated patients and in 23-44% of untreated patients by single-drug treatment of patients suffering from metastatic breast cancer. The objective response rates to Mitoxantrone in combination with CTX, 5-FU, MTX, VCR, MMC. Prednimustine or Vindesine were 16-46% in treatment and 38-89% in primary treatment. Randomized studies comparing Mitoxantrone with Adriblastin in single-drug and combination treatment did not show any significant differences in efficacy. However, Mitoxantrone was significantly less toxic. Remission rates of between 24 and 54% were achieved by single-drug treatment in pretreated patients suffering from non-Hodgkin lymphoma. Mitoxantrone appears to be active in ovarian cancer, lung cancer and hepatocellular carcinoma.

[Haemophilia treatment centres in Germany]. / Register von Hämophilie-Zentren in Deutschland.

UNLABELLED: An adequate number of qualified haemophilia centres is an essential requirement for effective and cost-efficient haemophilia care. During a reassessment of the delivery of haemophilia care in Germany a broad range of criteria relating to structure and quality of the centres were defined and a questionnaire was developed. RESULTS: Of 137 doctors who received the questionnaire, 113 (82%) replied. Based on data related to diagnostic and treatment services, together with voluntary information from PEI forms (Paul Ehrlich Institut, Germany), 72 haemophilia centres were established. Three levels of haemophilia care were defined by the Medical Advisory Council of the German Haemophilia Society. This is in accordance with criteria defined by European working parties. 17 haemophilia centres were designated CCC (Comprehensive Care Centre), 24 were designated HTC (Haemophilia Treatment Centre) and 31 smallest centres were allocated the status HTR (Haemophilia Treatment Regional). In comparison to the survey in 2007, there was only slight variance in the CCC centres (+ 2 centres/-1 centre). From the previous HTC centres, 7 have withdrawn from this treatment level: 4 maintain treatment on the lower level HTR, and 3 centres had ceased treatment. On the HTR level of treatment, 6 of 29 (21%) had ceased to offer treatment. 9 had been able to increase the number of patients and were designated HTC. 5404 patients with haemophilia and 3047 with the severe form of haemophilia were reported. 67% were treated in CCC, 25% in haemophilia treatment centres and 8% in the 31 smallest centres. 13 of the adult CCC are situated in the department of internal medicine and 4 in the section of transfusion medicine. CONCLUSIONS: The survey and analysis of the haemophilia treatment centres in Germany show that the delivery of haemophilia care through 17 CCC, 24 HCT and 31 HTR appears to be adequately structured. But it is noticeable and alarming, however, that on both HTC and HTR levels of treatment, 32% and 21%, respectively, have left their treatment level. 9 centres (12.5%) have finished working in haemophilia care in the last four years. On the strength of these results, endeavours to maintain haemophilia centres must be intensified. A high level of effective care can be guaranteed only through continued existence of the centres.

Efficacy, safety and tolerability of recombinant factor VIII (REFACTO) in patients with haemophilia A: interim data from a postmarketing surveillance study in Germany and Austria.

An open-label, multicentre, postmarketing surveillance study conducted in Germany and Austria with recombinant factor VIII (REFACTO) has enrolled 217 patients (mean age 26.3 years) from 38 haemophilia centres during the first 4.8 years. Most patients (188/217; 86.6%) had severe to moderately severe haemophilia A, of whom 153 completed sufficient diary information for the main efficacy analysis. These 153 patients experienced a median of 6.6 (interquartile range 1.4-18.6) bleeding episodes per year. Patients treated with prophylaxis experienced a median of 4.4 (1.1-9.3) bleeds per year, while patients treated on-demand experienced a median of 22.8 (11.3-29.0) bleeds per year. Overall, most physicians (41/43 [95.3%]) were 'very satisfied' or 'satisfied' with the efficacy of REFACTO in the treatment of bleeding episodes. A total of 137 non-serious adverse events have been reported in 52/217 patients (24.0%) to date. In addition, 129 serious adverse events in 87 patients (40%) were reported, including 41 cases of 'less than expected therapeutic effect' (LETE). Of these, 39 LETE cases were reported in one centre; however, patients in this centre experienced considerably fewer bleeding episodes per year than patients outside this centre. Overall, six patients (2.8%) have developed de novo inhibitors, three of which were considered high titre. Four of these patients were at high risk (0-50 exposure days [ED]) of inhibitor formation, one was at intermediate risk (51-100 ED) and one was at low risk (>100 ED). These results emphasize the benefit of postmarketing surveillance and, overall, this study confirms the efficacy, safety and tolerability of REFACTO in the treatment of patients with haemophilia A.

The German Registry of immune tolerance treatment in hemophilia--1999 update.

As of 1999, the German registry of immune tolerance treatment in hemophilia has received reports on 146 patients who have undergone this therapy from 25 hemophilia centers. In 16 of the reported patients treatment is ongoing. Therapy has been completed in 126 patients of all groups with hemophilia A; most of them are children. In 78.6% of hemophilia A patients full success was achieved, 8.7% finished with partial success, and in 12.7% ITT failed. Statistical analysis demonstrates that interruptions of therapy have a negative influence on success. The inhibitor titer has the highest predictive value for success or failure of therapy. A high maximum titer as well as a high titer at start of treatment were related to a low success rate. Other variables such as exposure days and time interval between inhibitor detection and start of ITT were not statistically significant. Four patients with hemophilia B have also completed therapy, only one of them with success.

[The differential diagnosis of hemarthrosis--septic arthritis in patients with hemophilia]. / Beitrag zur Differentialdiagnose Hämarthros--septische Arthritis bei Patienten mit Hämophilie.

A 12-year-old boy with severe hemophilia A fell ill with high fever and painful swelling of joints. There was a delay of four days in the diagnosis of septic arthritis. The course of the disease shows some important distinguishing criteria, speaking in favour of septic arthritis: 1. longlasting temperature above 39 degree C; 2. an elevated peripheral leukocyte count; 3. increasing complaints despite normalisation of the coagulation defect.

[Chemotherapy alternatives, problems and outlook in testicular tumors]. / Alternativen, Probleme und Perspektiven der Chemotherapie bei Hodentumoren.

The treatment of testicular tumors is among the most impressive examples of progress in tumor chemotherapy. At present, a complete remission can be achieved with the world-wide adopted standard therapy Cisplatinum/Vinblastine/Bleomycin in 50-80% of the cases. Whether these remissions are equivalent to healing remains to be established in long-term studies; at any rate, they are long-term palliations. Main problems of further research are the high-risk patients. Approaches to reach complete remissions and thus long-term palliations or healing, consist in increase of combination, dose escalation with Cisplatinum, introduction of novel substances (Etoposide, Ifosfamide etc.). The latter field is scientifically underdeveloped, as is the field of second- and third-order therapy. After all, chemotherapy of testicular tumors--similarly as treatment of leukemia--is an oncological intensive therapy that should be restricted to specialized centers.

[Integration of medical responsibility]. / Zur Integration der ärztlichen Verantwortungen.

The article describes responsibility as a term with six relations and four different levels. It analyses the conflicts between different addresses, levels and values and emphasizes the need to integrate the responsibilities of the physician. The term "responsibility" provides a more differentiating analytical tool for conflicts in medical acting than the so-called "principles of biomedical ethics".

[Genetic questions of hemophilia]. / Genetische Fragen der Hämophilie.

Haemophilia A and B are X-chromosomally recessively inherited. In the GDR the frequency of these genuine haemophilias is 1 to 6,500 male births. The frequency of sporadic haemophilias is still in dispute and certainly depends on the intensity of genealogic examinations. The mutation rate for haemophilia A is estimated to 1.3 to 3.6 x 10(-5). In secure female conductors the lyonisation evokes a considerable dispersion of the factor VIII coagulation activity, wherefore this is able to prove also only a small proportion, about 20-50%. The lyonisation apparently takes place in a critical anlage of less than 32 cells. Bleeding female conductors are in the first place the sequel of extreme lyonisation, more infrequently homozygotes or such ones with anomalies of the X-chromosomes. The state of female conductors is best characterized by th discrepancy between decreased factor VIII coagulation activity and the normal factor VIII associated antigen. At present numerous variants of this female conductor test are used, particularly concerning its calculatory evaluation. In many places only quotients from the two parameters are formed. Discriminancy-analytical methods brings without doubt better results. They allow to coordinate a certain probability to each result, which with the help of genealogic criteria may be combined to an evidence. Immunochemical determinations of the factor IX are certainly not of value for the proof of the state of female conductors of haemophilia B. The prenatal diagnostics of sex is recommended for pregnant conductors by amniocentesis in the 14th week of pregnancy. Only in few countries the prenatal diagnostics of haemophilia is possible. In blood tests taken by means of fetoscopy beginning with the 18th week of pregnancy the factor VIII coagulation property is determined by immunoradiometrical methods or recently even by means of a coagulation method. Though for the genetic consultation only female conductors in the reproductive phase are of importance, for the search of female conductors the whole lineage must be worked up genealogically, at least over four generations and with the help of archives material. The genetic consultation of haemophils and female conductors should be performed early and directedly, for important reasons also repeatedly.

[An inhibitor in the Willebrand-Jürgens syndrome and its effect on the factor VIII molecule properties]. / Ein Hemmkörper bei von Willebrand-Jürgens-Syndrom und seine Wirkung auf die Eigenschaften des Faktor VIII-moleküls.

In a patient with a clinically serious Willebrand-Jürgen's syndrome an inhibitor appeared at the age of 1 1/2 years, which, contrary to inhibitors in haemophilia A, was directed against all properties of factor VIII molecule. In a quantitative test the height of the inhibitor level to factor VIIIag was determined. Administrations of plasma concentrate resulted in a titre increase which could not be suppressed even by an immunosuppressive therapy with cyclophosphamide. After a long break in the substitution a severe bleeding could be successfully treated and the substitution effect for factor VIIIc, factor VIIIag and Ristocetin co-factor could be identified for several days.

[Hemostasis disorders after transfusions]. / Hämostasestörungen nach Transfusionen.

Disturbances of haemostasis caused immunologically and non-immunologically were observed after transfusion of blood and blood derivatives. Transfusion of heparin blood increased the bleeding susceptibility only in case of pre-existing high-degree defects of haemostasis or if they were performed as massive or exchange transfusions. Massive transfusions with blood stored for a long time will induce complex defects. Under intensive substitution therapy of haemophilia A the so-called paradoxical bleeding will occur in spite of a high factor VIII level. These bleedings are supposed to be disturbances of the thrombocyte function and are caused by fibrin(ogen) derivatives. Post-transfusional thrombocytopenias may be brought to remission by repeated plasmapheresis. Factor specific inhibitory bodies will appear after substitution in a small percentage of haemophilic patients. 5 to 7 days after the onset of therapy an anamnestic reaction can be observed as a titre increase by leaps. Usually, the inhibitory titre will decrease to a mostly low basal value in the course of three to five months. The therapy with cyclophosphamide simultaneously started with the substitution will more frequently prevent the anamnestic reaction or reduce it. Titres with more than 5 units cannot be overcome at the beginning even by higher concentrations of preparations. The substitution therapy should be preceded by exchange transfusions or plasmapheresis of up to 25 units. With still higher titres only procedures of inhibitor-bypassing are possible with factor VIII preparations of animal origin or better with activated prothrombin complex preparations, such as FEIBA. Recent reports give evidence that permanent substitution with factor VIII concentrates at a highest dosage can eliminate the production of inhibitors completely.

[Elimination of inhibitors in children with hemophilia A]. / Uber die Austilgung von Hemmkörpern bei Kindern mit Hämophilie A.

In five hemophilic children an attempt was made to eradicate inhibitors by continuous treatment with low doses of cryoprecipitate. All patients were high responders with maximum titers of 25 and 600 U. In four patients the anamnestic response was prevented or diminished by simultaneous treatment with cyclophosphamide. In these patients the inhibitor did not return during the continuous replacement therapy, even not after cessation of cyclophosphamide administration and in three of them not after intensive substitution. In the other child the titer decreased continuously in the beginning, but only to values unsuitable for replacement effects. Attempts to exterminate the inhibitor should be occasionally made by continuous low dose substitution therapy. The importance of the combination with cyclophosphamide cannot be decided until now because of the small number of observations.

[Blood coagulation tests in children with cyanotic heart defects]. / Gerinnungsuntersuchungen an Kindern mit zyanotischen Herzfehlern

In 57 children with congenital cyanotic heart disease coagulation analyses were performed before operation. The patients with low haematocrit only sometimes exhibited defects of low degree. In patients with haematocrit values of more than 60% were increasingly found complex coagulation disturbances. Many correlations could be proved between the coagulation parameters. Thrombocytopenia, plasmatic defects and hyperfibrinolysis were parallel. The cause of the changes is to be seen in chronic disseminated intravasal coagulation processes. The results of investigations presented confirm the necessity of preoperative coagulation analyses especially in patients with high haematocrit values. Larger disturbances of coagulation may influence the decision between a palliative intervention or immediate causal operation.

Human pharmacological investigation of a human recombinant tumor necrosis factor preparation (PAC-4D) a phase-I trial.

15 patients aged between 24 and 66 years with 10 different malignant tumor diseases were treated with a recombinant human tumor necrosis factor preparation PAC-4D in a phase-I trial. The starting dose was 10(5) U PAC-4D as an intravenous short infusion. The maximally tolerable dose is around 18 X 10(5) U/m2. As the main clinical side effects were observed: fever, chills, hypertension with subsequent hypotension, lethargy, transient somnolence, headache, neurological deficiency symptoms, nausea and vomiting. Important laboratory-chemical parameters were the increase in transaminases and, in higher dose levels, leukocytosis with the left shift and lymphopenia in the differential blood picture. As dose-limiting toxicity are estimated hypotension, and neurological side effects and hepatotoxicity. In one female patient who received 27 X 10(5) U PAC-4D there appeared pronounced, histologically verified necroses in the metastases of a malignant fibrous histiocytoma.

Frequency of different types of von Willebrand's disease in the GDR.

The frequency of different types of von Willebrand's disease (vWD) was studied in the southern part of the GDR and during investigations of relatives of already diagnosed patients. Among 111 patients diagnosed, vWD was found to be type I in 85 cases, type II in 13 cases and severe recessive type in 13 cases. The patients with type I belonged to 46 different families. Two families with type II had the II A variant and another a variant similar to II C. No patients with type II B were diagnosed. The incidence of severe recessive vWD was estimated to be lower than in Sweden but higher than in Italy and France.