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 Å resolution 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.

A consensus prognostic factor model for survival in patients with metastatic renal cell carcinoma: A Kidney Cancer Association’s International Kidney Cancer Working Group (IKCWG) study

5109

Background: Numerous well-designed retrospective studies of prognostic factors (pf) for survival (S) in metastatic renal cell carcinoma (mRCC) patients (pts) have been conducted since 1986. However, no single model for describing S in this population has been universally accepted. Methods: Authors of several existing prognostic indices, and others, formed the IKCWG to develop a single validated S model. The IKCWG has established a comprehensive database of previously reported clinical pf from 3748 previously untreated mRCC pts entered on institution review board approved clinical trials conducted by 11 centers in Europe and the United States from 1975–2002. Results: Median age at study entry was 58, 70% of pts were male, 89% had ECOG performance status (PS) 0 or 1; 75% had prior nephrectomy. 72%, 30%, and 19% of pts had lung, bone, and liver metastases (mets), respectively. 72% received interferon-a and/or interleukin-2 based treatments (tx); 25% were txd with chemotherapy/hormones only; 3% received other tx. 88% of pts have died; median S was 11.1 months (m). All examined factors except sex, age, and histology impacted S at p<.001 in univariable analysis. Multivariable analysis using a log-logistic model stratified by center and multivariable fractional polynomials was performed to identify independent predictors of S. Missing data were handled using multiple imputation methods. Using p=.0044 as the criterion for variable selection to avoid overly complex models, a model comprising tx, PS, number of met sites, interval from diagnosis to tx, and pre-tx hemoglobin, WBC, LDH, alkaline phosphatase and calcium was identified. The 25th and 75th percentiles of the prognostic index formed by multiplying each factor by its regression coefficient were used as cutpoints to form three risk (r) groups with median S times (SE) of: favorable r (n=937; 27.8 (0.4) m), intermediate r (n=1874; 11.4 (0.2) m), and poor r (n=937; 4.1 (0.1) m). Conclusions: 9 clinical factors can be used to model S in mRCC and form 3 distinct prognostic groups. Additional model building to determine if model complexity can be reduced further, validation in independent data and comparison to existing prognostic models are underway.

No significant financial relationships to disclose.

A brief symptom index for renal cell carcinoma

4595

Background: Renal cell carcinoma (RCC) occurs in over 30,000 Americans each year. Since it is often diagnosed in later stages and metastatic sites are variable, an array of symptoms and concerns affect patients with this disease. Our objective was to test a brief, symptom index for advanced RCC. Methods: We conducted secondary data analyses on patient-reported outcomes from a completed Phase III trial of 284 patients with metastatic RCC treated with interferon + 13-cis-retinoic acid or interferon alone (Motzer et al., 2000). Patient-reported outcomes were collected using the FACT-Biological Response Modifier (FACT-BRM) module at baseline, 2 weeks, and 8 weeks. We analyzed data from eight FACT-BRM items that were previously identified by clinical experts to represent the most important symptoms of advanced RCC. Items comprising the proposed Kidney Cancer Symptom Index (KCSI) assess nausea, pain, appetite, perceived sickness, fatigue and weakness, with higher KCSI scores indicating fewer symptoms. We determined the reliability and concurrent validity of the KCSI and estimated a minimally important difference (MID). Results: The KCSI had excellent internal reliability at all three time points (alphas = 0.85). Baseline KCSI scores were able to discriminate patients across Karnofsky performance status (KPS 80–90 > KPS 70; F (2, 210) = 15.5, p < .001), number of identified metastatic sites (0–1 site > 2+ sites; t (211) = 3.2, p < .01), and risk group categories (favorable or intermediate risk > poor risk; F (2, 205) = 9.9, p < .001). No differences were observed in KCSI change scores over time across two objective clinical indicators: response to treatment and time to progression. All patients evidenced declines in scores from baseline likely indicative of the toxic nature of the treatments. Distribution- and anchor-based methods converged on an MID estimate of 2 to 3 points for the KCSI. Conclusions: The 8-item KCSI appears to be a psychometrically sound measure of patient-reported symptoms of RCC. It is a brief, reliable, and valid measure that can easily be adapted for use in clinical trials and observational studies.

[Table: see text]

Pegylated interferon alpha-2B (PEG-Intron) for metastatic renal cell cancer (mRCC): Results of a phase II clinical trial and biologic correlates of response

4528

Background: PEG-Intron (PEG-I) is a pegylated derivative of interferon alpha-2b (IFN), recombinant, with a single molecule of mono methoxy polyethylene glycol which increases serum half-life. Methods: A single arm, one-stage phase II trial was conducted between 6/02 and 6/04 in 32 previously untreated patients (pts) with mRCC to assess time to progression and biologic correlates (primary and secondary endpoints). Eligibility included measurable disease and fresh tumor procured at surgery for genetic and immunohistochemical (vascular endothelial growth factor [VEGF] and carbonic anhydrase IX [CAIX]) studies. PEG-I was given SC at a weekly dose of 4.5 μg/kg until progression or intolerability. Quality of life (QOL) was assessed using the FACT-BRM. Results: All 32 were evaluable, 91% had prior nephrectomy, and MSKCC risk group (JCO 20:289–96, 2002) was: 41% good, 53% intermediate, 6% poor. 10 pts (31%; 95% CI: 16%-50%) achieved a partial response (PR). Median time to progression was 5.0 mos (95% C.I. [3, 7]); median survival was 31 mos (95% C.I. [18, not reached]). There were no grade IV toxicities; primary grade III toxicities were hematologic (6/32 pts; 19%) and fatigue (4/32 pts; 13%). FACT-BRM scores showed an initial decrease in QOL at 2 weeks followed by partial recovery. Genomic profiling of tumor samples identified four novel genes that correlated with IFN resistance: ABCD3, Hs.76704, Hs.11325, and Hs.94122. Change in serum VEGF levels did not correlate with response. Tumor tissue samples are being immunohistochemically stained for CAIX. Conclusions: PEG-I treatment results in a 31% response rate and similar median time to progression as standard IFN (JCO 18:2972–80, 2000) in this population with predominantly good and intermediate risk pts. Once weekly dosing was generally well tolerated. Future investigation of PEG-I in combination with novel targeted agents in mRCC is warranted. Further study of the four identified genes may provide insight into IFN resistance. Supported by Schering-Plough, Inc.

[Table: see text]

Phase III trial of conventional-dose chemotherapy alone or with high-dose chemotherapy for metastatic germ cell tumors (GCT) patients (PTS): A cooperative group trial by Memorial Sloan-Kettering Cancer Center, ECOG, SWOG, and CALGB

4510

Background: First-line high-dose chemotherapy (HDCT) for poor-prognosis GCT PTS demonstrated improved relapse-free and overall survival compared to historical controls receiving conventional-dose regimens (JCO 1996;14:2546). Retrospective studies also showed correlations between long-term outcome and initial declines of alpha-fetoprotein (AFP) and/or human chorionic gonadotropin (HCG). This trial sought to determine: 1) if early intervention with HDCT resulted in an outcome superior to standard-dose chemotherapy and 2) whether AFP and HCG declines during cycles 1 & 2 correlated with long-term treatment outcome. Methods: PTS with untreated intermediate- or poor-risk GCT by International criteria (IGCCCG) were randomized to either 2 cycles of standard BEP (bleomycin, etoposide & cisplatin) followed by 2 cycles of HDCT (cyclophosphamide, etoposide, carboplatin) plus stem-cell rescue (BEP + HDCT) or to 4 cycles of BEP. The primary endpoint was the percent of PTS in complete response at 1 year (CR-1 yr). Based on an historical CR-1 yr of 45% for BEP, targeted accrual was 109 PTS/arm to detect a 20% improvement in PTS receiving BEP + HDCT with an alpha of 5% and 80% power. Randomization used random permuted blocks; strata were risk status (poor/intermediate) and treatment center. An independent DSMB performed one interim analysis of CR-1yr and survival in May 2000. Results: 219 PTS were randomized; 108 to BEP + HDCT and 111 to BEP alone. Final analysis demonstrated a CR-1yr of 52% for BEP + HDCT and 48% for BEP alone (P = .53 via actuarial methods). Slow marker decline PTS (AFP and/or HCG) during cycles 1 & 2 of BEP had a shorter progression-free and overall survival compared to satisfactory decline PTS (P ≤ .02) Among 70 PTS with unsatisfactory marker decline in cycles 1 & 2, the CR-1 yr was 61% for PTS receiving HDCT for cycles 3 & 4 versus 31% for those receiving 2 more cycles of BEP (P = .008). Conclusions: The routine inclusion of HDCT for intermediate- and poor-risk GCT does not improve treatment outcome. Serum marker decline during the first 2 cycles of BEP chemotherapy provides a clinically useful estimate of outcome. Research support provided by the NIH.

[Table: see text]

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.