The Cox proportional hazards model with a partly linear relative risk function

The conventional Cox proportional hazards regression model contains a loglinear relative risk function, linking the covariate information to the hazard ratio with a finite number of parameters. A generalization, termed the partly linear Cox model, allows for both finite dimensional parameters and an infinite dimensional parameter in the relative risk function, providing a more robust specification of the relative risk function. In this work, a likelihood based inference procedure is developed for the finite dimensional parameters of the partly linear Cox model. To alleviate the problems associated with a likelihood approach in the presence of an infinite dimensional parameter, the relative risk is reparameterized such that the finite dimensional parameters of interest are orthogonal to the infinite dimensional parameter. Inference on the finite dimensional parameters is accomplished through maximization of the profile partial likelihood, profiling out the infinite dimensional nuisance parameter using a kernel function. The asymptotic distribution theory for the maximum profile partial likelihood estimate is established. It is determined that this estimate is asymptotically efficient; the orthogonal reparameterization enables employment of profile likelihood inference procedures without adjustment for estimation of the nuisance parameter. An example from a retrospective analysis in cancer demonstrates the methodology.

[Effect of modified labor posture on oxygenation of the fetus--a pulse oximetry study]

BACKGROUND

The evaluation of the birth position and its effects on maternal and fetal wellbeing has been a topic of perinatal research over the last decades. The aim of our observational study was to determine the effects of a modified and vertical maternal position on fetal oxygen saturation measured by pulse oximetry.

METHODS

Fetal oxygen saturation was measured by pulse oximetry in 56 labouring women randomly and successively adopting the supine position in 96.4%, the sitting position in 25.0%, the standing position in 14.3% and the prone position in 12.5%. The statistical analysis addressed the integrated 10 minutes period of SpO2 registrations before versus after adopting the modified position. Furthermore the mean values and the standard deviation (SD) for the total registration periods of different birth position was calculated.

RESULTS

While the supine position induced a reduction in oxygen saturation, sitting and prone position were favorable for fetal oxygenation as compared to horizontal position.

DISCUSSION

These findings implicate a clinical benefit of the modified birth position.

Platelet activation through triathlon competition in ultra-endurance trained athletes: impact of thrombin and plasmin generation and catecholamine release

The aims of this study were to evaluate whether platelets are activated during strenuous exercise in healthy athletes. Also, to determine the impact of plasmin and thrombin activity and catecholamine release. Previous studies have shown activation of the hemostatic system after competitive exercise, but platelet activation was thought to be absent in trained athletes. The impact of thrombin and other potent platelet activators is still a matter for debate. We examined 30 healthy triathletes during a triathlon competition. Flow cytometric detection of CD62p (P-selectin) was used to measure in vivo activation of platelets. Platelet-leukocyte aggregates were also determined. Thrombin concentration was assessed by the thrombin-antithrombin III complex (TAT) and the fibrinolytic state was characterised by the plasmin-alpha2-antiplasmin complex (PAP). Catecholamines were measured by means of high-pressure liquid chromatography. CD62p rose from baseline (2.3%) to 3.4% and was still elevated after 2 hours (3.1%, p = 0.0133). Platelet-leukocyte aggregates were elevated 30 min after exercise (4.3 % vs 3.6%) and decreased significantly after 60 min (2.9 %, p = 0.008). TAT increased from 3.9 microg/l to 8.3 microg/l after competition and to 5.4 microg/l 2 hours later (p < 0.001). PAP increased 10-fold from 350 microg/l to 3,267 microg/l after the triathlon and was still elevated after 2 hours (1,074 microg/l, p<0.001). No linear correlation was found between the hemostatic markers, catecholamines and platelet activation. Platelets, coagulation and fibrinolysis are activated by competitive exercise in athletes, whereby fibrinolytic changes are pronounced. Mechanisms of platelet activation during exercise include phenomena other than plasmatic hemostatic factors and catecholamines.

Hyperfractionated low-dose radiotherapy for high-risk neuroblastoma after intensive chemotherapy and surgery

PURPOSE

To assess prognostic factors for local control in high-risk neuroblastoma patients treated with hyperfractionated 21-Gy total dose to consolidate remission achieved by dose-intensive chemotherapy and surgery.

PATIENTS AND METHODS

Patients with high-risk neuroblastoma in first remission received local radiotherapy (RT) totaling 21 Gy in twice-daily 1.5-Gy fractions. RT to the primary site followed dose-intensive chemotherapy and tumor resection; the target field encompassed the extent of tumor at diagnosis, plus 3-cm margins and regional lymph nodes. RT to distant sites followed radiologic evidence of response. Local failure was correlated with clinical factors (including other consolidative treatments) and biologic findings.

RESULTS

Of 99 consecutively irradiated patients followed for a median of 21.1 months from RT, 10 relapsed in or at margins of RT fields at 1 to 27 months (median, 14 months). At 36 months after RT, the probability of primary-site failure was 10.1% +/- 5.3%. No primary-site relapses occurred among the 23 patients whose tumors were excised at diagnosis, but there were three such relapses among the seven patients who were irradiated with evidence of residual disease in the primary site. Four of 18 patients with MYCN-amplified disease and serum lactate dehydrogenase greater than 1,500 U/L had local failures (23.4% +/- 10.7% risk at 18 months). Acute radiotoxicities were insignificant, but three of 35 patients followed for > or = 36 months had short stature from decreased growth of irradiated vertebra.

CONCLUSION

Hyperfractionated 21-Gy RT is well tolerated and, together with dose-intensive chemotherapy and surgery, may help in local control of high-risk neuroblastoma. Extending the RT field to definitively encompass regional nodal groups may improve results. Visible residual disease may warrant higher RT dosing. Patients with biologically unfavorable disease may be at increased risk for local failure. RT to the primary site may not be necessary when tumors are excised at diagnosis.

The histone deacetylase inhibitor, CBHA, inhibits growth of human neuroblastoma xenografts in vivo, alone and synergistically with all-trans retinoic acid

Histone deacetylase inhibitors (HDACIs) inhibit the growth of a variety of transformed cells in culture. We demonstrated previously that the hybrid-polar HDACI m-carboxycinnamic acid bis-hydroxamide (CBHA) induces apoptosis of human neuroblastoma in vitro and is effective in lower doses when combined with retinoids. The current study investigates the effect of CBHA on the growth of human neuroblastoma in vivo, both alone and in combination with all-trans retinoic acid (atRA), using a severe combined immunodeficiency-mouse xenograft model. CBHA (50, 100, and 200 mg/kg/day) inhibited growth of SMS-KCN-69n tumor xenografts in a dose-dependent fashion, with 200 mg/kg CBHA resulting in a complete suppression of tumor growth. The efficacy of 50 and 100 mg/kg CBHA was enhanced by the addition of 2.5 mg/kg atRA. This dose of atRA was ineffective when administered alone. Treatment was accompanied by mild weight loss in all groups except the lowest dose of CBHA. Our results suggest HDACIs alone or combined with retinoids may have therapeutic utility for neuroblastoma.

Neuroblastoma metastatic to the central nervous system. The Memorial Sloan-kettering Cancer Center Experience and A Literature Review

BACKGROUND

The central nervous system (CNS) can be a sanctuary site for cancer cells, because the blood-brain barrier impedes penetration of most chemotherapeutic agents. The authors hypothesized that, with improved survival from childhood metastatic neuroblastoma (NB), the incidence of CNS (intraparenchymal and leptomeningeal) spread may increase. They undertook this study to assess the frequency of CNS NB, to analyze risk factors and treatment options, and to review the literature.

METHODS

The authors retrospectively analyzed all patients with metastatic NB who were treated on protocols N4, N5, N6, and N7 from 1980 to 1999 at Memorial Sloan-Kettering Cancer Center (MSKCC), during which time there was an increase in the overall survival rate.

RESULTS

Two hundred fifty-one patients with Stage 4 NB (Group 251) were studied, of which 127 (Group 127) were newly diagnosed patients who were treated initially at MSKCC. None had CNS NB at the time of diagnosis. Eleven patients developed documented CNS disease; 8 of these 11 recurrences were isolated in the CNS. For Group 127, the overall incidence rate of CNS NB was 6.3%, with an increase in incidence from N4-N5 to N6-N7 of from 1.7% to 11.7%. Seven patients had isolated CNS disease recurrences. Only lumbar punctures (LP) performed near the time of diagnosis in patients with known bone marrow involvement were associated with subsequent development of CNS disease. For the entire group of 251 patients, lumbar puncture at the time of diagnosis and elevated serum lactic dehydrogenase levels were prognostic. Among the larger series reported in the literature, CNS involvement from metastatic lesions was rare at the time of diagnosis and remained an uncommon complication.

CONCLUSIONS

The incidence of CNS NB may be increasing. Because it is the sole site of disease recurrence in 64% of patients, the CNS may represent a sanctuary site for NB. CNS NB is associated with diagnostic lumbar punctures in patients with known bone marrow disease, raising the possibility that circulating or epidural microscopic tumor cells may seed the craniospinal axis.

Visual loss in children with neurofibromatosis type 1 and optic pathway gliomas: relation to tumor location by magnetic resonance imaging

PURPOSE

To examine the potential for visual acuity loss, and its relation to extent and location of optic pathway gliomas in a cohort of children with neurofibromatosis type 1 studied with magnetic resonance imaging.

METHODS

We reviewed the neuro-ophthalmologic records and brain/orbital magnetic resonance imaging scans for 43 consecutive pediatric patients with neurofibromatosis type 1 and optic pathway gliomas who were followed at the Children's Hospital of Philadelphia. The presence of visual loss, defined as abnormal visual acuity for age in one or both eyes, was determined. Optic pathway gliomas were classified by tumor extent and location according to involvement of the optic nerves, chiasm, and postchiasmal structures by magnetic resonance imaging.

RESULTS

Involvement of the optic tracts and other postchiasmal structures at tumor diagnosis was associated with a significantly higher probability of visual acuity loss (P =.048, chi-square test). Visual loss was noted in 20 of 43 patients (47%) at a median age of 4 years; however, three patients developed visual acuity loss for the first time during adolescence.

CONCLUSIONS

In pediatric patients with neurofibromatosis type 1 and optic pathway gliomas, the likelihood of visual loss is dependent on the extent and location of the tumor by magnetic resonance imaging and is particularly associated with involvement of postchiasmal structures. Furthermore, older age during childhood (adolescence) does not preclude the occurrence of visual loss. Close follow-up beyond the early childhood years, particularly for those with postchiasmal tumor, is recommended.

All-trans retinoic acid significantly increases 5-year survival in patients with acute promyelocytic leukemia: long-term follow-up of the New York study

All-trans retinoic acid (ATRA) induces a high incidence of complete remission (CR) in patients with acute promyelocytic leukemia (APL); however, the magnitude of this agent's contribution to increased rates of cure of this disease has not yet been established. From 1990 to 1995 we used RA as remission induction therapy in 103 APL patients (73 newly diagnosed and 30 previously treated) who were retinoid-naive and were treated on the basis of initial morphology. Patients whose diagnosis was changed on the basis of the results of molecular testing (n = 13) were withdrawn from RA treatment and given chemotherapy alone. After achieving a CR, previously untreated patients received several cycles of consolidation chemotherapy, usually with idarubicin and cytosine arabinoside. Among individuals whose diagnosis was molecularly confirmed, 54 of 65 new patients (83%) and 25 of 30 previously treated patients (83%) achieved a CR. All induction failures in molecularly diagnosed cases were due either to early death or to premature withdrawal. Median disease-free and overall survival rates recorded for all newly diagnosed patients are currently > 40+ and > 43+ months, respectively. We subsequently examined a subset of 27 newly diagnosed patients treated during the first 2 years of this program whose actual median follow-up period is now > 5 years. Median disease-free and overall survival rates recorded for this group are > 57+ and > 58+ months, respectively; 56% of these patients are alive in first remission. These results significantly exceed those achieved using chemotherapy alone in a historical control group of 80 patients consecutively treated at this center from 1975 to 1990, whose median disease-free and overall survival rates were 11 and 19 months, respectively; only 22% of these patients were alive in first remission at 5 years. Although a high proportion of previously treated patients also achieved a CR after RA treatment, median disease-free and overall survival rates noted for that group were markedly lower (i.e., 7.5 and 10.9 months, respectively). Thus, data from patients whose median follow-up period is now > 5 years have confirmed earlier projections and indicate that the use of RA for remission induction yields an approximately 2.5-fold increase in the proportion of patients who have presumably been cured of this disease.

Quantitative effect of intravitreally injected tissue plasminogen activator and gas on subretinal hemorrhage

PURPOSE

To quantify the effect of intravitreally injected tissue plasminogen activator (TPA) and an expanding gas on freshly formed subretinal hemorrhage (SRH).

PATIENTS AND METHODS

Thirteen patients with acute (1 week or less) SRH due to age-related macular degeneration (ARMD) were treated with an intravitreal injection of 50 microg TPA, and 24 hours later, with an expanding gas. Fundus photographs taken before and 24 hours after each injection were digitized and calibrated. Area, geometric center, and shift of the SRH were measured at each time point using NIH image analysis software. Elevation of the SRH was assessed by echography.

RESULTS

Compared to the preoperative size, SRH enlarged significantly 24 hours after TPA injection (P < 0.001). A significant shift of the geometric center toward the inferior retinal periphery out of the macula was found after gas injection (P < 0.001). Significant horizontal displacement of the SRH was not noted after TPA or gas injection. More elevated subretinal blood clots showed a larger increase in size after TPA injection than flat clots (P < 0.05).

CONCLUSION

Enlargement of SRH in a gravity-dependent manner indicates subretinal liquefaction of the clot after TPA treatment. An intravitreal injection of gas 24 hours later can significantly displace the SRH inferiorly.

Clinical usefulness of pulse oximetry in the fetus with non-reassuring heart rate pattern?

The objective of this study was the evaluation of intrapartum pulse oximetry as an indicator of fetal distress and the condition of the newborn during clinical routine surveillance in an University Perinatal Center. Between 1998 and 1999 pulse oximetry (SpO2) was used additionally to routine fetal monitoring by electronic fetal heart rate tracing (CTG) and fetal blood sampling (FBA) in 128 cases with nonreassuring heart rate pattern. Cut off values were FIGO Score < 8 for the heart rate pattern and for fetal blood sampling during labor results of < 7.25 (preacidosis). The condition of the newborn was defined by the APGAR score with the cut off < 7 at 1 minute, while the biochemical status was evaluated by means of arterial blood sampling of the umbilical artery directly after birth using a pH of < 7.20 to verify acidosis. Predictive values of critically low SpO2 values (< 30%) for at least 10 minutes as well as corresponding sensitivities and specificities were calculated together with 95% confidence intervals to identify fetal distress or a depressed condition of the newborns. Of 128 fetuses included in this study 66 (52%) were born spontaneously, 23 (18%) were born by operative vaginal delivery and 39 (31%) by means of cesarean section. The high rate of cesarean section was due to cephalopelvic disproportion in 29 cases. Fetal outcome was evaluated with a clinical score: mean APGAR score value 8.5 SD +/- 1. The mean value of the pH in the umbilical artery was 7.23 +/- 0.04. During a SpO2 monitoring period of 18,381 minutes we analyzed a contact time of 63%. Comparing SpO2 values of < 30% with preacidosis in the fetal blood sampling, we found a positive predictive value of merely 0.17 (95% CI: 0.00-0.64). Of 9 preacidotic cases during delivery only 1 was indicated by a saturation value below 30% (sensitivity 0.11, 95% CI: 0.00-0.48). The specificity and negative predictive value were calculated as 0.83 (95% CI: 0.65-0.94) and 0.76 (95% CI: 0.58-0.89) respectively. Of eleven cases with acidosis in the blood of the umbilical cord artery, pH < 7.20, only 2 were indicated by a SpO2 values below 30%. Which is equivalent to a sensitivity of 0.18 (95% CI: 0.03-0.52). Results of a receiver operator curve analysis showed no substantial deviation from the diagonal. The area under the curve was 0.62, the 95% CI (0.47-0.76) indicating no significant discrimination. Three of 49 fetuses with SpO2 recording during the last 10 minutes were born in clinical depressed status (APGAR < 7). None was indicated by a SpO2 value below 30%.

CONCLUSION

Fetal distress and impaired condition of the newborn are not identified or predicted during routine application of SpO2 monitoring in the fetus during labor with adequate safety.

Paclitaxel, estramustine phosphate, and carboplatin in patients with advanced prostate cancer

PURPOSE

To determine the safety and activity of weekly paclitaxel in combination with estramustine and carboplatin (TEC) in patients with advanced prostate cancer.

PATIENTS AND METHODS

In a dose-escalation study, patients with advanced prostate cancer were administered paclitaxel (weekly 1-hour infusions of 60 to 100 mg/m(2)), oral estramustine (10 mg/kg), and carboplatin (area under the curve, 6 mg/mL-min every 4 weeks). Paclitaxel levels were determined 0, 30, 60, 90, and 120 minutes and 18 hours after infusion, and a concentration-time curve was estimated. Once a safe dose was established, a multi-institutional phase II trial was conducted in patients with progressive androgen-independent disease.

RESULTS

Fifty-six patients with progressive androgen-independent disease were treated for a median of four cycles. The dose of paclitaxel was escalated from 60 to 100 mg/m(2) without the occurrence of DLT. Posttherapy decreases in serum prostate-specific antigen levels of 50%, 80%, and 90% were seen in 67%, 48%, and 39% (95% confidence interval, 55% to 79%, 35% to 61%, 26% to 52%) of the patients, respectively. Of the 33 patients with measurable disease, two (6%) had a complete response and 13 (39%) had a partial response. The overall median time to progression was 21 weeks, and the median survival time for all patients was 19.9 months. Major grade 3 or 4 adverse effects were thromboembolic disease (in 25% of patients), hyperglycemia (in 38%), and hypophosphatemia (in 42%). Significant leukopenia, thrombocytopenia, and peripheral neuropathy were not observed.

CONCLUSION

TEC has significant antitumor activity and is well tolerated in patients with progressive androgen-independent prostate cancer.

Validation of NACB and IFCC guidelines for the use of cardiac markers for early diagnosis and risk assessment in patients with acute coronary syndromes

BACKGROUND

International guidelines have been established for the use of cardiac markers in the early diagnosis and risk assessment of patients with acute coronary syndromes.

METHODS

A single center, prospective observational study was conducted in a tertiary care university hospital on 200 consecutive patients with suspected acute myocardial infarction (AMI). Blood was drawn on admission and after 2, 4, 8, 12 and 24 h for the measurement of CK-MB/CK activity, myoglobin, CK-MB mass and troponin I. A 6-week follow-up was undertaken for the combined end point of acute coronary syndrome and death.

RESULTS

Myoglobin showed an early diagnostic sensitivity of 0.65 on admission, 0.90 after 2 h and 0.92 after 4 h compared with 0.46, 0.74 and 0.88 for CK-MB/CK activity. The combination of myoglobin and cTnI increased the diagnostic value compared with myoglobin alone on admission, 2 and 4 h later. In multivariate analysis, cTnI and CK-MB/CK mass, but not myoglobin and CK-MB/CK activity, were shown to be independent predictors on the 6-week follow-up.

CONCLUSIONS

Repetitive myoglobin measurements within 4 h of admission, combined with at least one early troponin test, was shown to be the strategy of choice in early AMI diagnosis and prognosis assessment.

N7: a novel multi-modality therapy of high risk neuroblastoma (NB) in children diagnosed over 1 year of age

BACKGROUND

The N7 protocol for poor-risk neuroblastoma uses dose-intensive chemotherapy (as in N6 protocol [Kushner et al.: J Clin Oncol 12:2607-2613, 1994] but with lower dosing of vincristine) for induction, surgical resection and 2100 cGy hyperfractionated radiotherapy for local control, and for consolidation, targeted radioimmunotherapy with 131I-labeled anti-GD2 3F8 monoclonal antibody and immunotherapy with unlabeled/unmodified 3F8 (400 mg/m2).

PROCEDURE

The chemotherapy consists of: cyclophosphamide 70 mg/kg/d x 2 and a 72-hr infusion of doxorubicin 75 mg/m2 plus vincristine 2 mg/m2, for courses 1, 2, 4, and 6; and cisplatin 50 mg/m2/d x 4 and etoposide 200 mg/m2/d x 3, for courses 3, 5, and 7. 131I-3F8 is dosed at 20 mCi/kg, which is myeloablative and therefore necessitates stem-cell support.

RESULTS

Of the first 24 consecutive previously untreated patients more than 1 year old at diagnosis, 22 were stage 4 and two were unresectable stage 3 with MYCN amplification. Chemotherapy achieved CR/VGPR in 21 of 24 patients. Twenty patients to date have completed treatment with 131I-3F8, and 15 patients have completed all treatment. With a median follow-up of 19 months, 18 of 24 patients remain progression-free.

CONCLUSIONS

Major toxicities were grade 4 myelosuppression and mucositis during chemotherapy, and self-limited pain and urticaria during antibody treatment. Late effects include hearing deficits and hypothyroidism.

Human epidermal growth factor receptor 2 as a prognostic indicator in osteogenic sarcoma

Prognostic biologic factors that can be assessed at the time of diagnosis for patients with osteogenic sarcoma have not been identified. The current study was designed to evaluate the prognostic significance of the human epidermal growth factor receptor 2 as it relates to histologic response to preoperative chemotherapy and event-free survival. A retrospective immunohistochemical study was performed on material from patients who were newly diagnosed with osteogenic sarcoma who were treated according to the T12 protocol from the authors' institution between 1986 to 1993. Staining for HER2/erbB-2 was accomplished using standard monoclonal antibodies and methods. At the time of initial biopsy, 42.6% of the samples showed HER2/erbB-2 overexpression. Higher levels of expression were observed in samples from patients with clinically detectable metastases at initial presentation and at relapse. Expression of HER2/erbB-2 correlated with inferior event-free survival in patients with nonmetastatic disease (47% versus 79% at 5 years). In addition, HER2/erbB-2 expression was associated with significantly less tumor necrosis after preoperative chemotherapy as determined by the Huvos grading system. These data suggest that HER2/erbB-2 should be evaluated prospectively as a prognostic indicator and clinical trials using antibodies that target this receptor should be considered for the treatment of patients with osteogenic sarcoma.

Granulocyte-colony stimulating factor and multiple cycles of strongly myelosuppressive alkylator-based combination chemotherapy in children with neuroblastoma

BACKGROUND

The authors assessed key effects of granulocyte-colony stimulating factor (G-CSF) used prophylactically with multiple cycles of strongly myelosuppressive alkylator-based combination chemotherapy. To the authors' knowledge, no large study has focused on G-CSF in this setting, yet this kind of treatment has recently become standard for poor risk pediatric solid tumors such as neuroblastoma. PATIENTS AND METHODS. Children with neuroblastoma received cyclophosphamide 140 mg/kg (i.e., 4200 mg/m(2)), doxorubicin 75 mg/m(2), and vincristine (CAV) in cycles 1, 2, 4, and 6 and cisplatin 200 mg/m(2) and etoposide 600 mg/m(2) (P/VP) in cycles 3, 5, and 7. To maximize dose intensity, chemotherapy was begun as soon as the absolute neutrophil count (ANC) was > or = 500/microL and platelet count was > or = 100,000/microL. No cytokines were used during 1990-1994 (control group; n = 28), but G-CSF was used from 1995 to 1998 (G-CSF group; n = 30) at 5 microg/kg/day subcutaneously from 1 day after chemotherapy until the ANC was > or = 500/microL on 2 successive days or was > or = 1000/microL.

RESULTS

Each cycle of CAV decreased ANCs to < 200/microL in all 58 patients; recovery to 200/microL and to 500/microL was significantly sooner with G-CSF. In contrast, P/VP did not invariably cause severe neutropenia: similar numbers of patients in each group maintained ANCs > or = 200/microL and > or = 500/microL; recovery to 500/microL (but not to 200/microL) was significantly faster in the G-CSF group. G-CSF had no impact on rates of febrile episodes. Bacterial/fungal infections were slightly less frequent in the G-CSF group with CAV (P = 0.11) but not with P/VP. Dose intensity through cycle 4 was the same in both groups. Beginning with cycle 3, G-CSF patients had slower recovery to platelet counts > or = 100,000/microL. Response rates were similar in the two groups.

CONCLUSIONS

With multiple cycles of strongly myelosuppressive alkylator-based combination chemotherapy, prophylactic use of G-CSF hastened ANC recovery but did not reduce the incidence of febrile episodes, had little impact on infection rates, did not yield augmented dose intensity, was associated with prolonged thrombocytopenia, and had no effect on response rates of neuroblastoma. The data support more limited use of G-CSF.

The phase II/III transition. Toward the proof of efficacy in cancer clinical trials

Few phase III investigations show a benefit for an experimental treatment when compared to a standard therapy or placebo. This illustrates the need for more reliable estimates of treatment effects from the phase II investigations used to design the more definitive phase III trials. In this manuscript, we examine four aspects of phase II clinical trial designs: (1) selecting endpoints; (2) defining the patient population for evaluation; (3) determining a level of activity that would justify a phase III trial; and (4) estimating sample sizes. In each area, problems with the conventional approaches are discussed and alternatives for the successful transition of phase II results to a phase III setting are suggested. An application of the design for patients with androgen-independent prostate cancer is illustrated.

[C-reactive protein as an independent marker of prognosis in acute coronary syndrome: comparison with troponin T]

BACKGROUND

It has been suggested that inflammatory processes play a role in the pathogenesis of acute coronary syndromes (ACS). C-reactive protein (CRP) is a classic acute phase protein. It is yet unclear whether, in addition to established markers as troponin T (TnT), determination of CRP in patients admitted for ACS contributes significantly to the diagnosis and prognosis of ACS.

PATIENTS AND METHODS

We investigated 50 patients with ACS (59.4 SD 13.9 years) in the first hour after admission and 4-24 h later with respect to TnT (Elecsys, Roche Diagnostics) and CRP (biokit, modified Quantex CRP plus, analytical sensitivity 0.02 mg/dL). Fifty percent of the patients were classified as having unstable angina retrospectively. All patients were followed in the 6 weeks post discharge regarding death and recurrent ACS.

RESULTS

The cumulative event rate at 6 weeks after discharge was 62.5% for patients being CRP and TnT positive compared to 35.3% in TnT positive and CRP negative patients. In TnT negative patients a positive CRP test predicted 33.3% of events and 28.8% of patients negative for CRP and TnT had events at 42 days post discharge. Logistic regression analysis regarding the primary endpoint including TnT and CRP (4-24 h values), age, gender and diagnosis resulted in independent prediction of ACS or death by TnT (cutoff 0.1 microgram/L, p = 0.048, odds ratio = 7.5) and CRP (cutoff 0.862 mg/dL, p = 0.026, odds ratio = 5.3). Sensitivity/specificity for AMI diagnosis were 69.6%/75% for TnT and 12%/72% for CRP in the first hour and 91.3%/68.2% for TnT and 68%/72% for CRP 4-24 h later.

CONCLUSIONS

Besides TnT, high sensitivity CRP determination has no additional value for early AMI diagnosis. The prognosis of these patients during the first 24 hours is significantly and independently predicted by CRP measurements in addition to troponin T.

Therapeutic haemoglobin synthesis in beta-thalassaemic mice expressing lentivirus-encoded human beta-globin

The stable introduction of a functional beta-globin gene in haematopoietic stem cells could be a powerful approach to treat beta-thalassaemia and sickle-cell disease. Genetic approaches aiming to increase normal beta-globin expression in the progeny of autologous haematopoietic stem cells might circumvent the limitations and risks of allogeneic cell transplants. However, low-level expression, position effects and transcriptional silencing hampered the effectiveness of viral transduction of the human beta-globin gene when it was linked to minimal regulatory sequences. Here we show that the use of recombinant lentiviruses enables efficient transfer and faithful integration of the human beta-globin gene together with large segments of its locus control region. In long-term recipients of unselected transduced bone marrow cells, tetramers of two murine alpha-globin and two human betaA-globin molecules account for up to 13% of total haemoglobin in mature red cells of normal mice. In beta-thalassaemic heterozygous mice higher percentages are obtained (17% to 24%), which are sufficient to ameliorate anaemia and red cell morphology. Such levels should be of therapeutic benefit in patients with severe defects in haemoglobin production.

Leukocytosis and the retinoic acid syndrome in patients with acute promyelocytic leukemia treated with arsenic trioxide

PURPOSE

Arsenic trioxide, like all-trans-retinoic acid (RA), induces differentiation of acute promyelocytic leukemia (APL) cells in vivo. Treatment of APL patients with all-trans RA is commonly associated with leukocytosis, and approximately 50% of patients develop the RA syndrome. We reviewed our clinical experience with arsenic trioxide to determine the incidence of these two phenomena.

PATIENTS AND METHODS

Twenty-six patients with relapsed or refractory APL were treated with arsenic trioxide for remission induction at daily doses that ranged from 0.06 to 0.17 mg/kg.

RESULTS

Twenty-three patients (88%) achieved complete remission. Leukocytosis was observed in 15 patients (58%). The median baseline leukocyte count for patients with leukocytosis was 3,900 cells/microL (range, 1,200 to 72,300 cells/microL), which was higher than that for patients who did not develop leukocytosis (2,100 cells/microL; range, 500 to 5,400 cells/microL; P =.01). No other cytotoxic therapy was administered, and the leukocytosis resolved in all cases. The RA syndrome was observed in eight patients (31%). Patients who developed leukocytosis were significantly more likely to develop the RA syndrome (P <.001), and no patient without a peak leukocyte count greater than 10,000 cells/microL developed the syndrome. Among the patients with leukocytosis, there was no observed relation between the leukocyte peak and the probability of developing the syndrome (P =.37).

CONCLUSION

Induction therapy of APL with all-trans RA and arsenic trioxide is associated with leukocytosis and the RA syndrome. These clinical effects seem to be intrinsically related to the biologic responsiveness and the differentiation process induced by these new agents.

Induction of Ab3 and Ab3' antibody was associated with long-term survival after anti-G(D2) antibody therapy of stage 4 neuroblastoma

Treatment with anti-G(D2) monoclonal antibody 3F8 (Ab1) at the time of remission may prolong survival for children with stage 4 neuroblastoma. A transient human antimouse antibody (HAMA) response was associated with significantly longer survival (Cheung et al., J. Clin. Oncol., 16: 3053-3060, 1998). Because this response was primarily anti-idiotypic (Ab2), we postulate that the subsequent induction of an idiotype network that included an elevation of anti-anti-idiotypic (Ab3) and anti-G(D2) (Ab3') antibody titers may be responsible for tumor control. Thirty-four patients with stage 4 neuroblastoma diagnosed at >1 year of age were treated with 3F8 at the end of chemotherapy. Most had either bone marrow (31 of 34) or distant bony (29 of 34) metastases at diagnosis. Thirteen patients were treated at second or subsequent remission, and 12 patients in this group had a history of progressive/persistent disease after bone marrow transplantation; 21 patients were treated in the first remission after N6 chemotherapy. Their serum HAMA, Ab3, and Ab3' titers prior to, at 6, and at 14 months after antibody treatment were measured by ELISA. Among these 34 patients, 14 are alive, and 13 (1.8-7.4 years at diagnosis) are progression free (53-143 months from the initiation of 3F8 treatment) without further systemic therapy. Long-term progression-free survival (PFS) and survival correlated significantly with Ab3' (anti-G(D2)) response at 6 months and with Ab3 response at 6 and 14 months. By defining Ab3 threshold ranging from the ratio of 1.1 to 2.6 above pretreatment level, the difference in PFS and survival between the high-Ab3 and low-Ab3 groups became markedly widened. Similarly, increasing the Ab3' threshold at either 6 or 14 months to 300% above pre-3F8 levels also increased the spread between the high versus low Ab3' groups for both PFS and survival curves. Non-idiotype antibody responses (anti-mouse-IgG3 or anti-tumor nuclear HUD antigen) had no apparent impact on PFS or survival. In conclusion, despite the high-risk nature of stage 4 neuroblastoma, long-term remission without myeloablative therapy can be achieved with 3F8 treatment. Ab3 and Ab3' antibody response correlated with prolonged PFS and survival. We postulate that successful induction of an idiotype network in patients may be responsible for long-term tumor control.

[Management concept for acute traumatic aortic rupture based on a case report]

Acute traumatic rupture of the thoracic aorta (ATRRA) is mainly a consequence of high-speed travel or fall from great altitude. Most of the victims die at the accident scene. Only 10-20% reach the hospital alive. Because of the extremely high mortality, emergency repair seems to be indicated. Taking into consideration that the hemorrhage into the mediastinum may remain constained and the patient usually suffers from a wide variety of life-threatening causes of injury the aforementioned option is probably not the best one. We report on a patient whose "stable" aortic rupture was surgically corrected after stablization of the circulation, coagulation and respiratory problems.

The acute coronary syndrome diagnosis and prognostic evaluation by troponin I is influenced by the test system affinity to different troponin complexes

It was suggested recently that cardiac troponins are released as T-I-C complexes and then further degraded to T and I-C. It is not known whether the various affinity to the T-I-C and I-C complex of different troponin I test systems influence the diagnostic and prognostic value of the test results in clinical practice. We studied 162 patients (61.3 S.D. 11.1 years) with suspected acute myocardial infarction (AMI) in a single center study. AMI was confirmed in 109 patients. Blood samples were taken at admission, after 1, 2, 4, 8, 12 and 24 h. Troponin I (TnI) was measured using the OPUS plus (TnI-O, cut-off 1.6 microg/l) and the Stratus II (TnI-S, cut-off 1.5 microg/l) analyzers. TnI-O has high affinity to the binary (I-C) and TnI-S to the ternary (T-I-C) troponin complex. A 6-month follow-up with respect to death and recurrent AMI was performed. The sensitivity (SE) and specificity (SP) for AMI diagnosis were 82.6 and 86.8% for TnI-S; 75.2 and 92.5% for TnI-O 0-2 h after admission. The ROC analysis showed a slightly better curve for TnI-S at 4 h (P<0.05). Logistic regression analysis shows prediction of 6 months outcome by 0-24 h serial TnI-S measurements (odds ratio 5.21, P=0.0356), and serial TnI-O measurements (odds ratio 4.92, P=0.0186). High affinity to the ternary troponin complex enhances the diagnostic but not the prognostic value of a test system. Indeed, the resulting differences are small but underline the need for standardization of biochemical markers.