Preliminary time-of-flight neutron diffraction studies of Escherichia coli ABC transport receptor phosphate-binding protein at the Protein Crystallography Station.

Inorganic phosphate is an essential molecule for all known life. Organisms have developed many mechanisms to ensure an adequate supply, even in low-phosphate conditions. In prokaryotes phosphate transport is instigated by the phosphate-binding protein (PBP), the initial receptor for the ATP-binding cassette (ABC) phosphate transporter. In the crystal structure of the PBP-phosphate complex, the phosphate is completely desolvated and sequestered in a deep cleft and is bound by 13 hydrogen bonds: 12 to protein NH and OH donor groups and one to a carboxylate acceptor group. The carboxylate plays a key recognition role by accepting a phosphate hydrogen. PBP phosphate affinity is relatively consistent across a broad pH range, indicating the capacity to bind monobasic (H2PO4-) and dibasic (HPO4(2-)) phosphate; however, the mechanism by which it might accommodate the second hydrogen of monobasic phosphate is unclear. To answer this question, neutron diffraction studies were initiated. Large single crystals with a volume of 8 mm3 were grown and subjected to hydrogen/deuterium exchange. A 2.5 Šresolution data set was collected on the Protein Crystallography Station at the Los Alamos Neutron Science Center. Initial refinement of the neutron data shows significant nuclear density, and refinement is ongoing. This is the first report of a neutron study from this superfamily.

The functional assessment of cancer therapy-BRM (FACT-BRM): a new tool for the assessment of quality of life in patients treated with biologic response modifiers.

PURPOSE: This paper reports on the development and validation of two biologic response modifier (BRM) subscales for use with the Functional Assessment of Cancer Therapy-General (FACT-G) quality of life (QOL) questionnaire. METHODS: Using the FACT-G as a base, 17 additional questions related to symptoms common to interferon and retinoid therapy were developed. Data collected at baseline (n = 191) and week 2 (n = 168) in a randomized trial of interferon +/- 13-cis-retinoic acid in advanced renal cell carcinoma patients were used to validate this measure. RESULTS: Using a combined empirical and conceptual approach, the 17 questions were reduced to 13 questions consisting of two subscales: 'BRM-physical' (7 items; baseline coefficient alpha(alpha) = 0.70; week-2 alpha = 0.75) and 'BRM-mental' (6 items; baseline alpha = 0.79; week-2 alpha = 0.78). Internal consistency of the trial outcome index (TOI) combining physical well-being, functional well-being and the BRM subscales, was 0.91 for baseline assessments and 0.92 for week 2. Discriminant validity was demonstrated for the TOI by its ability to differentiate among prognostic risk groups, and for the total FACT-G, TOI and total FACT-BRM scores by their ability to distinguish between groups differing in performance, response and toxicity status. CONCLUSIONS: The 'BRM-physical' and 'BRM-mental' subscales can be combined with the FACT-G to form the 'FACT BRM' scale, useful for measuring QOL in cancer patients who are receiving treatment with biologic response modifiers.

Predicting outcome to chemotherapy in patients with germ cell tumors: the value of the rate of decline of human chorionic gonadotrophin and alpha-fetoprotein during therapy.

PURPOSE: The prognostic significance of the rate of decline of the serum tumor marker alpha-fetoprotein (AFP) and human chorionic gonadotrophin (HCG) during the first two cycles of chemotherapy in germ cell tumor (GCT) patients was initially reported by us, but its value has been debated. We re-examined this issue in the context of the International Germ Cell Cancer Collaborative Group (IGCCCG) risk classification system and investigated the role of including in the analysis patients whose markers normalized early. PATIENTS AND METHODS: One hundred eighty-nine GCT patients with elevated AFP/HCG marker values treated with platinum-based chemotherapy between 1986 and 1998 were included in this analysis. Patients were classified as good, intermediate, or poor risk by the IGCCCG criteria and as having satisfactory or unsatisfactory marker decline. Risk and marker decline were correlated with response, event-free survival, and overall survival. RESULTS: Satisfactory marker decline predicted improved complete response (CR) proportion and event-free and overall survival (P <.0001). The CR proportion, 2-year event-free, and 2-year overall survival rates for patients with a satisfactory and unsatisfactory marker decline were 92% versus 62%, 91% versus 69%, and 95% versus 72%, respectively. Marker decline remained a significant variable for all three end points when adjusted for risk (P <.01) with the outcome differences most pronounced in the poor-risk group. CONCLUSION: The rate of marker decline during chemotherapy has prognostic value independent of risk and may play a significant role in the management of poor-risk patients. It is appropriate to include patients whose markers normalized early.

Role of postchemotherapy adjunctive surgery in the management of patients with nonseminoma arising from the mediastinum.

PURPOSE: To evaluate the role of postchemotherapy surgery in patients with nonseminomatous germ cell tumors arising from the anterior mediastinum. PATIENTS AND METHODS: Thirty-two patients with nonseminoma arising from a mediastinal primary site were treated on a clinical trial at our center, and they underwent postchemotherapy surgery. The results of postchemotherapy surgical resection, frequency of viable tumor found during postchemotherapy surgery, and prognostic factors for survival were assessed. RESULTS: Complete resection of all gross residual disease was achieved in 27 patients (84%). Histologic analysis of resected residua postchemotherapy revealed viable tumor in 66%, teratoma in 22%, and necrosis in 12% of the specimens. Viable tumor included embryonal carcinoma, choriocarcinoma, yolk sac carcinoma, seminoma, and teratoma with malignant transformation to nongerm cell histology (eg, sarcoma). Clinical characteristics associated with a shorter survival after surgery included the presence of viable tumor in a resected specimen (P =.003) and more than one site resected during surgery (P =.06). There were no statistically significant differences in survival for patients who underwent surgical resection with normal markers compared with patients with elevated serum tumor markers (P =.33). A trend toward shorter survival was found in patients with increasing tumor markers before surgery compared with patients with normal and declining serum tumor markers (P =.09). CONCLUSION: Surgical resection of residual mass after chemotherapy plays an integral role in the management of patients with primary mediastinal nonseminoma. Teratoma and viable tumor were found in the majority of resected residua after chemotherapy. Because patients who undergo conventional salvage chemotherapy programs rarely achieve long-term disease-free status, selected patients with elevated markers after chemotherapy are considered candidates for surgical resection.

Phase III trial of interferon alfa-2a with or without 13-cis-retinoic acid for patients with advanced renal cell carcinoma.

PURPOSE: A randomized phase III trial was conducted to determine whether combination therapy with 13-cis-retinoic acid (13-CRA) plus interferon alfa-2a (IFNalpha2a) is superior to IFNalpha2a alone in patients with advanced renal cell carcinoma (RCC). PATIENTS AND METHODS: Two hundred eighty-four patients were randomized to treatment with IFNalpha2a plus 13-CRA or treatment with IFNalpha2a alone. IFNalpha2a was given daily subcutaneously, starting at a dose of 3 million units (MU). The dose was escalated every 7 days from 3 to 9 MU (by increments of 3 MU), unless >/= grade 2 toxicity occurred, in which case dose escalation was stopped. Patients randomized to combination therapy were given oral 13-CRA 1 mg/kg/d plus IFNalpha2a. Quality of life (QOL) was assessed. RESULTS: Complete or partial responses were achieved by 12% of patients treated with IFNalpha2a plus 13-CRA and 6% of patients treated with IFNalpha2a (P =.14). Median duration of response (complete and partial combined) in the group treated with the combination was 33 months (range, 9 to 50 months), versus 22 months (range, 5 to 38 months) for the second group (P =.03). Nineteen percent of patients treated with IFNalpha2a plus 13-CRA were progression-free at 24 months, compared with 10% of patients treated with IFNalpha2a alone (P =.05). Median survival time for all patients was 15 months, with no difference in survival between the two treatment arms (P =.26). QOL decreased during the first 8 weeks of treatment, and a partial recovery followed. Lower scores were associated with the combination therapy. CONCLUSION: Response proportion and survival did not improve significantly with the addition of 13-CRA to IFNalpha2a therapy in patients with advanced RCC. 13-CRA may lengthen response to IFNalpha2a therapy in patients with IFNalpha2a-sensitive tumors. Treatment, particularly the combination therapy, was associated with a decrease in QOL.

Paclitaxel, ifosfamide, and cisplatin second-line therapy for patients with relapsed testicular germ cell cancer.

PURPOSE: To evaluate the dose, toxicity, and efficacy of paclitaxel in combination with ifosfamide and cisplatin as salvage therapy for patients with relapsed testicular germ cell tumors (GCTs). PATIENTS AND METHODS: Thirty patients with previously treated GCTs were treated with paclitaxel and ifosfamide plus cisplatin (TIP) as second-line therapy. All had favorable prognostic features for response (testis primary tumor site and prior complete response to first-line chemotherapy program). Four cycles of paclitaxel, ifosfamide 5 g/m(2), and cisplatin 100 mg/m(2) were given 21 days apart with granulocyte colony-stimulating factor support, followed by resection of radiographic residua. The dose of paclitaxel was increased among cohorts with dose levels of 175, 215, and 250 mg/m(2); the largest dose was selected for the phase II part of the trial. RESULTS: Twenty-three (77%) of 30 patients achieved a complete response to chemotherapy alone, and one patient achieved a durable partial response with normal tumor markers. Therefore, 24 (80%) achieved a favorable response. Eleven patients with normalized markers after chemotherapy underwent resection of residual tissue, with only necrosis found in 10 and mature teratoma in one. Two patients relapsed, and 22 (73%) of the favorable responses remain durable at a median follow-up duration of 33 months. Myelosuppression was the major toxicity, and two patients had grade 3 neurotoxicity. CONCLUSION: Four cycles of TIP was associated with a high proportion of patients who achieved a complete response, a lack of relapse, and relative tolerability as an ifosfamide-containing salvage regimen for testicular GCTs. The high durable complete response proportion emphasizes the importance of patient selection according to prognostic factors for a favorable outcome to conventional-dose salvage therapy.

Effect of cytokine therapy on survival for patients with advanced renal cell carcinoma.

PURPOSE: To evaluate the relationship between treatment with cytokine therapy and survival, investigate the effect of nephrectomy on survival, and identify long-term survivors among a cohort of 670 patients with advanced renal cell carcinoma (RCC). PATIENTS AND METHODS: A total of 670 patients with advanced RCC treated on 24 clinical trials of systemic chemotherapy or cytokine therapy were the subjects of this retrospective analysis. Treatment was categorized as cytokine (containing interferon alfa and/or interleukin-2) in 396 patients (59%) and as chemotherapy (cytotoxic or hormonal therapy) in 274 (41%). Among the 670 patients, those with survival times of greater than 5 years were identified as long-term survivors. RESULTS: Patients treated with cytokine therapy had a longer survival time than did those treated with chemotherapy, regardless of the year of treatment or risk category based on pretreatment features. The median survival times for favorable-, intermediate-, and poor-risk patients were 27, 12, and 6 months for those treated with cytokines and 15, 7, and 3 months for those treated with chemotherapy, respectively. The magnitude of difference in median survival was greater in the favorable- and intermediate-risk groups. The median survival time was less than 6 months in the poor-risk group for both treatment programs. Median survival time was 14 months among patients with prior nephrectomy plus time from diagnosis to treatment greater than 1 year versus 8 months among those with time from diagnosis to treatment less than 1 year, regardless of pretreatment nephrectomy status. Thirty patients (4.5%) among the 670 patients were identified as long-term survivors; 12 were free of disease after nephrectomy and treatment with interferon alfa, interleukin-2, or surgical resection of metastasis. CONCLUSION: The low proportion of patients with advanced RCC who achieve long-term survival emphasizes the need for clinical investigation to identify more effective therapy.

Survival and prognostic stratification of 670 patients with advanced renal cell carcinoma.

PURPOSE: To identify prognostic factors and a model predictive for survival in patients with metastatic renal-cell carcinoma (RCC). PATIENTS AND METHODS: The relationship between pretreatment clinical features and survival was studied in 670 patients with advanced RCC treated in 24 Memorial Sloan-Kettering Cancer Center clinical trials between 1975 and 1996. Clinical features were first examined univariately. A stepwise modeling approach based on Cox proportional hazards regression was then used to form a multivariate model. The predictive performance of the model was internally validated through a two-step nonparametric bootstrapping process. RESULTS: The median survival time was 10 months (95% confidence interval [CI], 9 to 11 months). Fifty-seven of 670 patients remain alive, and the median follow-up time for survivors was 33 months. Pretreatment features associated with a shorter survival in the multivariate analysis were low Karnofsky performance status (<80%), high serum lactate dehydrogenase (> 1.5 times upper limit of normal), low hemoglobin (< lower limit of normal), high "corrected" serum calcium (> 10 mg/dL), and absence of prior nephrectomy. These were used as risk factors to categorize patients into three different groups. The median time to death in the 25% of patients with zero risk factors (favorable-risk) was 20 months. Fifty-three percent of the patients had one or two risk factors (intermediate-risk), and the median survival time in this group was 10 months. Patients with three or more risk factors (poor-risk), who comprised 22% of the patients, had a median survival time of 4 months. CONCLUSIONS: Five prognostic factors for predicting survival were identified and used to categorize patients with metastatic RCC into three risk groups, for which the median survival times were separated by 6 months or more. These risk categories can be used in clinical trial design and interpretation and in patient management. The low long-term survival rate emphasizes the priority of clinical investigation to identify more effective therapy.

Outcome of postchemotherapy surgery after treatment with methotrexate, vinblastine, doxorubicin, and cisplatin in patients with unresectable or metastatic transitional cell carcinoma.

PURPOSE: The role of postchemotherapy surgery for patients with metastatic transitional cell carcinoma (TCC) is controversial. We retrospectively analyzed our experience with patients who underwent postchemotherapy surgery after methotrexate, vinblastine, doxorubicin, and cisplatin (M-VAC) chemotherapy to assess an impact on long-term survival. PATIENTS AND METHODS: This report is based on the retrospective analysis of 203 patients with unresectable primary tumors or metastatic TCC, previously reported in five trials of M-VAC chemotherapy. Fifty patients underwent postchemotherapy surgery for suspected or known residual disease. Characteristics of patients selected for surgery, results of surgery, and the impact of surgery on survival were assessed. RESULTS: In 17 patients, no viable tumor was found at postchemotherapy surgery, pathologically confirming a complete response to chemotherapy. Three patients had unresectable residual TCC. In 30 patients, residual, viable TCC was completely resected, which resulted in a complete response to chemotherapy plus surgery. Ten (33%) of these 30 patients remained alive at 5 years, similar to results observed for patients who attained a complete response to chemotherapy alone (41%). Analysis by baseline extent of disease suggested that patients with unresectable primary tumors or with metastases restricted to lymph node sites were most likely to survive for 5 years. CONCLUSION: Postchemotherapy surgical resection of residual cancer may result in 5-year disease-free survival in some patients who would otherwise succumb to disease. Optimal candidates include patients whose prechemotherapy sites of disease are restricted to the primary or lymph node sites and who have a major response to chemotherapy.

Drug Use Prevention Data, Missed Assessments and Survival Analysis.

In prevention studies, researchers often investigate the incidence of initial drug experimentation or other drug use milestones and its relationship to individual attributes such as the level of parental monitoring or rebelliousness. In this case, survival analysis is the methodology of choice. Survival analysis methods deal efficiently with data from individuals who leave the study prematurely and do not return. However often individuals do return to the study. The application of survival analysis to a situation in which individuals miss assessments and later return is nonstandard. This article examines the use of multiple imputation as a methodology for utilizing information from all assessments.