Bevacizumab plus irinotecan, fluorouracil, and leucovorin for metastatic colorectal cancer

BACKGROUND

Bevacizumab, a monoclonal antibody against vascular endothelial growth factor, has shown promising preclinical and clinical activity against metastatic colorectal cancer, particularly in combination with chemotherapy.

METHODS

Of 813 patients with previously untreated metastatic colorectal cancer, we randomly assigned 402 to receive irinotecan, bolus fluorouracil, and leucovorin (IFL) plus bevacizumab (5 mg per kilogram of body weight every two weeks) and 411 to receive IFL plus placebo. The primary end point was overall survival. Secondary end points were progression-free survival, the response rate, the duration of the response, safety, and the quality of life.

RESULTS

The median duration of survival was 20.3 months in the group given IFL plus bevacizumab, as compared with 15.6 months in the group given IFL plus placebo, corresponding to a hazard ratio for death of 0.66 (P<0.001). The median duration of progression-free survival was 10.6 months in the group given IFL plus bevacizumab, as compared with 6.2 months in the group given IFL plus placebo (hazard ratio for disease progression, 0.54; P<0.001); the corresponding rates of response were 44.8 percent and 34.8 percent (P=0.004). The median duration of the response was 10.4 months in the group given IFL plus bevacizumab, as compared with 7.1 months in the group given IFL plus placebo (hazard ratio for progression, 0.62; P=0.001). Grade 3 hypertension was more common during treatment with IFL plus bevacizumab than with IFL plus placebo (11.0 percent vs. 2.3 percent) but was easily managed.

CONCLUSIONS

The addition of bevacizumab to fluorouracil-based combination chemotherapy results in statistically significant and clinically meaningful improvement in survival among patients with metastatic colorectal cancer.

Randomized phase II trial comparing bevacizumab plus carboplatin and paclitaxel with carboplatin and paclitaxel alone in previously untreated locally advanced or metastatic non-small-cell lung cancer

PURPOSE

To investigate the efficacy and safety of bevacizumab plus carboplatin and paclitaxel in patients with advanced or recurrent non-small-cell lung cancer.

PATIENTS AND METHODS

In a phase II trial, 99 patients were randomly assigned to bevacizumab 7.5 (n = 32) or 15 mg/kg (n = 35) plus carboplatin (area under the curve = 6) and paclitaxel (200 mg/m(2)) every 3 weeks or carboplatin and paclitaxel alone (n = 32). Primary efficacy end points were time to disease progression and best confirmed response rate. On disease progression, patients in the control arm had the option to receive single-agent bevacizumab 15 mg/kg every 3 weeks.

RESULTS

Compared with the control arm, treatment with carboplatin and paclitaxel plus bevacizumab (15 mg/kg) resulted in a higher response rate (31.5% v 18.8%), longer median time to progression (7.4 v 4.2 months) and a modest increase in survival (17.7 v 14.9 months). Of the 19 control patients that crossed over to single-agent bevacizumab, five experienced stable disease, and 1-year survival was 47%. Bleeding was the most prominent adverse event and was manifested in two distinct clinical patterns; minor mucocutaneous hemorrhage and major hemoptysis. Major hemoptysis was associated with squamous cell histology, tumor necrosis and cavitation, and disease location close to major blood vessels.

CONCLUSION

Bevacizumab in combination with carboplatin and paclitaxel improved overall response and time to progression in patients with advanced or recurrent non-small-cell lung cancer. Patients with nonsquamous cell histology appear to be a subpopulation with improved outcome and acceptable safety risks.

Phase I safety and pharmacokinetic study of recombinant human anti-vascular endothelial growth factor in patients with advanced cancer

PURPOSE

We investigated the safety and pharmacokinetics of a recombinant human monoclonal antibody to vascular endothelial growth factor (rhuMAb VEGF) in patients with cancer.

PATIENTS AND METHODS

Cohorts of patients with metastatic cancer having failed prior therapy entered a phase I trial of rhuMAb VEGF administered by a 90-minute intravenous infusion at doses from 0.1 to 10.0 mg/kg on days 0, 28, 35, and 42. Patients underwent pharmacokinetic sampling on day 0 and had serum samples obtained during the subsequent 28 days. Response assessment was carried out on days 49 and 72.

RESULTS

Twenty-five patients with a median Eastern Cooperative Oncology Group performance status of 0 were accrued. There were no grade III or IV adverse events definitely related to the antibody. There were three episodes of tumor-related bleeding. Infusions of rhuMAb VEGF were well tolerated without significant toxicity. Grades I and II adverse events possibly or probably related to study drug included asthenia, headache, and nausea. Pharmacokinetics revealed a linear profile with a half-life of 21 days. There were no objective responses, though 12 patients experienced stable disease over the duration of the study.

CONCLUSION

rhuMAb VEGF was safely administered without dose-limiting toxicity at doses ranging up to 10 mg/kg. Multiple doses of rhuMAb VEGF were well tolerated, and pharmacokinetic studies indicate that doses of > or = 0.3 mg/kg have a half-life similar to that of other humanized antibodies. Subsequent trials will explore rhuMAb VEGF alone and in combination chemotherapy.

Arterial thromboembolic events in patients with metastatic carcinoma treated with chemotherapy and bevacizumab

BACKGROUND

Although combination treatment with bevacizumab (humanized monoclonal antibody against vascular endothelial growth factor) and chemotherapy improves survival of patients with various metastatic carcinomas, an increased risk of arterial thromboembolic events has been observed in some trials. We characterized this risk by performing post hoc analyses of randomized controlled trials that evaluated combination treatment with bevacizumab and chemotherapy versus chemotherapy alone. Low-dose aspirin was permitted in these trials, and its safety was also analyzed.

METHODS

Data were pooled from five randomized controlled trials that included a total of 1745 patients with metastatic colorectal, breast, or non-small-cell lung carcinoma. The risk of an arterial or venous thromboembolic event was assessed by simple incidence rates, rates per 100 person-years, and/or hazard ratios (HRs). The association between patient characteristics and risk of an arterial thromboembolic event was investigated primarily by Cox proportional hazards regression. The relationship between low-dose aspirin and bleeding was explored by incidence rates and rates per 100 person-years.

RESULTS

Combined treatment with bevacizumab and chemotherapy, compared with chemotherapy alone, was associated with increased risk for an arterial thromboembolic event (HR = 2.0, 95% confidence interval [CI] = 1.05 to 3.75; P = .031) but not for a venous thromboembolic event (HR = 0.89, 95% CI = 0.66 to 1.20; P = .44). The absolute rate of developing an arterial thromboembolism was 5.5 events per 100 person-years for those receiving combination therapy and 3.1 events per 100 person-years for those receiving chemotherapy alone (ratio = 1.8, 95% CI = 0.94 to 3.33; P = .076). Development of an arterial thromboembolic event was associated with a prior arterial thromboembolic event (P<.001) or age of 65 years or older (P = .01). Baseline or on-study aspirin use was associated with modest increases in grade 3 and 4 bleeding events in both treatment groups, from 3.6% to 4.7% for bevacizumab-treated patients and from 1.7% to 2.2% for control subjects.

CONCLUSIONS

Combination treatment with bevacizumab and chemotherapy, compared with chemotherapy alone, was associated with an increased risk of arterial thromboembolism but not venous thromboembolism.

A synthetic IgG-binding domain based on staphylococcal protein A

A synthetic IgG-binding domain based on staphylococcal protein A was designed with the aid of sequence comparisons and computer graphic analysis. A strategy, utilizing non-palindromic restriction sites, was used to overcome the difficulties of introducing site-specific changes into the repetitive gene. A single mutagenized gene fragment was polymerized to different multiplicities, and the different gene products were expressed in Escherichia coli. Using this scheme, protein A-like proteins composed of different numbers of IgG-binding domains were produced. These domains were changed to lack asparagine--glycine dipeptide sequences as well as methionine residues and are thus, in contrast to native protein A, resistant to treatment with hydroxylamine and cyanogen bromide.

Bevacizumab in combination with fluorouracil and leucovorin: an active regimen for first-line metastatic colorectal cancer

PURPOSE

In a phase III trial, combining bevacizumab (BV)--a recombinant, humanized, monoclonal antibody targeting vascular endothelial growth factor--with irinotecan, bolus fluorouracil (FU), and leucovorin (LV; IFL) increased survival compared with IFL alone in first-line treatment of patients with metastatic colorectal cancer (CRC). Results for the parent study of IFL/BV versus IFL/placebo are reported elsewhere. Here, we describe efficacy and safety results for the third patient cohort in this trial, who received BV combined with FU/LV, and compare them with results for concurrently enrolled patients who received IFL.

METHODS

Patients (N = 923) were randomly assigned to receive IFL/placebo (control), IFL/BV, or FU/LV/BV. Bevacizumab (Avastin; Genentech Inc, South San Francisco, CA) 5 mg/kg was administered intravenously every 2 weeks. Before an interim analysis confirmed acceptable safety for IFL/BV, 313 patients were concurrently randomly assigned to these three arms; after this analysis, the FU/LV/BV arm was discontinued.

RESULTS

Median overall survivals were 18.3 and 15.1 months with FU/LV/BV (n = 110) and IFL/placebo (n = 100), respectively. Median progression-free survivals were 8.8 and 6.8 months, respectively. Overall response rates were 40.0% and 37.0%, and median response durations were 8.5 and 7.2 months, respectively. Adverse events consistent with those expected from FU/leucovorin- or IFL-based regimens were seen, as were modest increases in hypertension and bleeding in the bevacizumab arm, which were generally easily managed.

CONCLUSION

The FU/LV/BV regimen seems as effective as IFL and has an acceptable safety profile. FU/LV/BV is an active alternative treatment regimen for patients with previously untreated metastatic CRC.

Phase Ib trial of intravenous recombinant humanized monoclonal antibody to vascular endothelial growth factor in combination with chemotherapy in patients with advanced cancer: pharmacologic and long-term safety data

PURPOSE

Tumor angiogenesis mediated by vascular endothelial growth factor (VEGF) is inhibited by the recombinant humanized (rhu) monoclonal antibody (MAb) rhuMAbVEGF, which has synergy with chemotherapy in animal models. The present study was designed to assess the safety and pharmacokinetics of weekly intravenous (IV) rhuMAbVEGF with one of three standard chemotherapy regimens.

PATIENTS AND METHODS

Twelve adult patients were enrolled four on each combination. rhuMAbVEGF, 3 mg/kg IV, was administered weekly for 8 weeks with (1) doxorubicin 50 mg/m(2) every 4 weeks; (2) carboplatin at area under the curve of 6 plus paclitaxel 175 mg/m(2) every 4 weeks; and (3) fluorouracil (5-FU) 500 mg/m(2) with leucovorin 20 mg/m(2) weekly, weeks 1 to 6 every 8 weeks.

RESULTS

The median number of rhuMAbVEGF doses delivered was eight (range, four to eight doses). Grade 3 toxicities were diarrhea (one 5-FU patient), thrombocytopenia (two patients on carboplatin plus paclitaxel), and leukopenia (one patient on carboplatin plus paclitaxel). These toxicities were likely attributable to the chemotherapy component of the regimen. The mean (+/- SD) peak serum level of rhuMAbVEGF was 167 +/- 46 microg/mL, and the mean terminal half-life was 13 days. Total (free plus bound) serum VEGF levels increased from 51 +/- 39 pg/mL (day 0) to 211 +/- 112 (day 49) pg/mL. Three responding patients continued treatment with rhuMAbVEGF and chemotherapy, receiving the equivalent of 36, 20, and 40 total rhuMAbVEGF doses with no cumulative or late toxicities.

CONCLUSION

rhuMAbVEGF can be safely combined with chemotherapy at doses associated with VEGF blockade and without apparent synergistic toxicity. Its contribution to the treatment of advanced solid tumors should be evaluated in randomized treatment trials.

The Reaction Level Scale (RLS85). Manual and guidelines

The Reaction Level Scale (RLS85) is a "coma scale" for the direct assessment of overall reaction level in patients with acute brain disorders. It is devised for reliable use even in the management of patients who are difficult to assess, such as intubated patients and patients with swollen eyelids. We here present the manual of the RLS85 and the guidelines for its use. The underlying concepts as well as limitations are outlined. Condensed information of known reliability and validity is presented. A training scheme for presumed observers (doctors, nurses and assistant nurses) is outlined. It is suggested that users of the RLS85 refer to these guidelines and in scientific reports clearly state any deviations from this present manual in order to facilitate valid comparisons between different studies and different groups of patients.

Prognostic factors in intraoral squamous cell carcinoma: the influence of histologic grade

PURPOSE

The purpose of this retrospective study was to review the outcome of patients with oral cavity squamous cell carcinoma treated at a single institution by primary surgical resection with or without adjuvant radiotherapy or chemoradiotherapy and to identify factors affecting survival and locoregional control.

PATIENTS AND METHODS

The records of 233 patients with oral cavity squamous cell carcinoma treated at a single institution from 1993 to 2003 were identified from the Legacy Emanuel Hospital and Health Center's cancer registry (Portland, OR). All patients undergoing surgical resection as a primary treatment modality were included in the study. Patients with nonresectable disease, distant metastasis, and those with inadequate follow-up data were excluded from the study. Patients with positive surgical margins, high-grade histology, aggressive biologic behavior, or advanced staged disease underwent adjuvant radiotherapy or chemoradiotherapy. The data collected included age, gender, race, tumor site, margin status, grade, TNM stage, cancer therapies, and cancer status. Data were statistically analyzed in an attempt to identify predictors of locoregional control and disease-free survival. Descriptive statistics were calculated for each variable and survival was calculated using the Kaplan-Meier method. Prognostic factors were analyzed using the Cox proportional hazard model.

RESULTS

Two hundred fifteen patients consisting of 119 men (55%) and 123 females (52%), with an average age at diagnosis of 66 years (SD +/- 14), met the criteria for inclusion in the study. Average tumor size was 23.5 mm (SD +/- 14.1). Overall 5-year survival was 56% and disease-free survival at 5 years was 58%. Stage and grade were identified as having a statistically significant effect on survival (P = .014; likelihood ratio chi-square = 10.7, 3 degrees of freedom; and P = .026; likelihood ratio chi-square = 5, 1 degree of freedom, respectively). Neither age, gender, race, tumor site, nor positive margins showed a statistically significant effect on survival (P > .05).

CONCLUSION

This study highlights the importance of grade and stage as independent factors in predicting survival in patients with oral squamous cell carcinoma.

Independent adjudication of symptomatic heart failure with the use of doxorubicin and cyclophosphamide followed by trastuzumab adjuvant therapy: a combined review of cardiac data from the National Surgical Adjuvant breast and Bowel Project B-31 and the North Central Cancer Treatment Group N9831 clinical trials

PURPOSE

An independent Adjuvant Cardiac Review and Evaluation Committee (ACREC) systematically reviewed cases of symptomatic heart failure events to uniformly define the cardiac event rate across two large trials (National Surgical Adjuvant Breast and Bowel Project [NSABP] B-31 and North Central Cancer Treatment Group [NCCTG] N9831) that assessed the addition of trastuzumab to standard adjuvant chemotherapy.

PATIENTS AND METHODS

The committee was composed of six independent oncologists and cardiologists. A retrospective review of patients with a cardiac event was performed by the primary investigators of the trials. The ACREC prospectively established criteria for determining a symptomatic heart failure event. Recovery status was determined from documented resolution of signs and symptoms. Potential risk factors were also assessed.

RESULTS

Medical records for a total of 173 patients were reviewed: 40 in the chemotherapy-alone arm and 133 in the trastuzumab arm. Trastuzumab-treated patients had a 2.0% incidence of symptomatic heart failure events compared with 0.45% in the chemotherapy-alone arm. Complete or partial recovery was observed in 86.1% of trastuzumab-treated patients with symptomatic heart failure events. Of five patients who died, only one patient had received trastuzumab. Independent predictors for cardiac events were age older than 50 years, a low ejection fraction at the start of paclitaxel treatment, and trastuzumab treatment.

CONCLUSION

The incidence of symptomatic heart failure events is 2.0% in patients treated with adjuvant trastuzumab, and the majority of these patients recover with appropriate treatment.

A comparison of the Glasgow Coma Scale and the Reaction Level Scale (RLS85)

The Glasgow Coma Scale (GCS) and the Reaction Level Scale (RLS85) were compared for rating neurosurgical patients in regard to ranking order of deficit severity, interobserver variability, and coverage for relevant factors. Four physicians, four registered nurses, and four assistant nurses performed 72 pairwise ratings on 47 neurosurgical patients. The rank correlation between the GCS sum score and the RLS85 was -0.94, suggesting the same ranking order of severity and indicating that the underlying concepts of somnolence, delirium, and motor responses in coma are evaluated in the same way. By the sign test, the RLS85 was shown to have better interobserver agreement than the GCS sum score and the eye-motor-verbal (EMV) profile. The interobserver grading disagreements in both scales were distributed over the entire range of responsiveness, and for the GCS sum score they were slanted to combined segments 9 to 15. The RLS85 showed full coverage of relevant factors, while 43 (60%) of the 72 test occasions in the GCS sum score and the EMV profiles showed untestable features, most often because of patient intubation. The pseudoscore (that is, the choice of value given to untestable features) affects interobserver agreement as well as the estimated overall patient responsiveness in the GCS sum score. Assessment by the order of applying the scales showed a significant effect on the GCS eye-opening scale (p = 0.01) and the GCS sum score (p = 0.03), indicating a sensitivity to environmental stimuli unrelated to the patient's status. This study demonstrates that basically the same information as that found in the separate eye, motor, and verbal scales of the GCS can be combined directly into the RLS85, which has better interobserver agreement and better coverage than the GCS sum score.

Minimally important differences were estimated for the Functional Assessment of Cancer Therapy–Colorectal (FACT-C) instrument using a combination of distribution- and anchor-based approaches

OBJECTIVE

To estimate minimally important differences (MIDs) on the Functional Assessment of Cancer Therapy-Colorectal (FACT-C) instrument using anchor- and distribution-based methods.

STUDY DESIGN AND SETTING

Preliminary MIDs were generated for FACT-C scores based on published results for two samples (n = 60 and n = 63) from the FACT-C validation study. Preliminary MIDs were confirmed using data from a Phase II randomized controlled clinical trial (n = 104) and a population-based observational study (n = 568). MIDs were estimated for the colorectal cancer subscale (CCS); the FACT-C Trial Outcome Index (TOI-C), which is the sum of the CCS, physical well-being, and functional well-being subscales; and the FACT-C total score. Both cross-sectional and longitudinal analyses were used.

RESULTS

MIDs were stable across the different patient samples. The recommended MIDs ranged from 2 to 3 points for the CCS, 4 to 6 points for the TOI-C, and 5 to 8 points for the FACT-C total score.

CONCLUSIONS

MIDs can enhance the interpretability of FACT-C scores, and they can be used to provide a basis for sample size estimation and to determine clinical benefit in combination with other measures of efficacy. General guidelines for estimating MIDs for other FACT instruments are suggested.

Application of a Facial Injury Severity Scale in Craniomaxillofacial Trauma

PURPOSE

To establish a Facial Injury Severity Scale (FISS) that correlates with patient outcome and provides a practical tool for communication between clinicians and healthcare personnel for management of facial trauma.

PATIENTS AND METHODS

All patients presenting to the Emergency Department (ED) at Legacy Emanuel Hospital (Level One Trauma Center) in Portland, Oregon between 01/1993 and 6/2003 with facial fractures with or without concomitant non-facial injuries where identified retrospectively. The diagnosis and treatment of all facial fractures were conducted by the Oral and Maxillofacial Surgery (OMFS) service. The following data were collected; age, gender, mechanism of injury, detailed diagnosis of facial fractures, disposition, and the length of hospital stay (LOS). The hospital operating room charges (ORC) for the treatment of each patient's facial fractures were also obtained. We designed the FISS to be a numeric value composed of the sum of the individual fractures and fracture patterns in a patient. Not all fractures of the face are weighted equally in the FISS because not all fracture patterns are equal in severity. Individual fracture points within the scale were optimized to result in the highest correlation.

RESULTS

A total of 1,115 patient admissions to the ED with blunt or penetrating maxillofacial injuries were identified and reviewed. Full information on operating room charges (ORC) was available for 247 patients (average age: 32, SD +/- 17; range, 2 to 84; male:female, 3:1; blunt:penetrating, 232:15). The FISS scores were calculated for each patient (average FISS: 4.4, SD +/- 2.7; range, 1 to 13). Hospital ORC for the treatment of each patient's maxillofacial injuries were obtained from the hospital financial services (average ORC: 4,135 dollars, SD +/- 2,832 dollars; range, 845 dollars to 18,974 dollars). A significant correlation was identified between the FISS and the ORC (R value = .82). The length of stay was significantly associated with the FISS (t = 4.7, 245 degrees of freedom, P = .000004). Although the association was statistically significant, FISS is not a very good predictor of length of stay. The correlation between the predicted and observed values was 0.38. There were 3 deaths among the 247 entries. Those 3 deaths had higher than average FISS scores, but the difference between the scores of survivors and non-survivors was not significant (P = .08). The number of deaths was small and a larger study would be required to resolve this question.

CONCLUSIONS

We introduce a FISS that is easily calculated and reliably predicts the severity of maxillofacial injuries as measured by the operating room charges required to treat the facial injury. The scale is also an indicator of hospital length of stay. We anticipate this to be a valuable tool for assessment and management of maxillofacial trauma.

Expression of human insulin-like growth factor I in bacteria: use of optimized gene fusion vectors to facilitate protein purification

Several fusions between the gene for human insulin-like growth factor I (IGF-I) and the genes for different IgG-binding fragments of staphylococcal protein A were assembled and compared regarding expression, secretion, and purification of the peptide hormone. After IgG affinity purification of the fusion proteins from the growth medium of Staphylococcus aureus or Escherichia coli, native IGF-I was released by cleavage of an Asn-Gly peptide bond with hydroxylamine. An optimized expression system based on a modified synthetic IgG-binding domain (z), resistant to hydroxylamine, gave the highest yield of fusion protein. After cleavage, the hormone could be separated from the IgG-binding moiety and from noncleaved fusion protein by a second passage through the IgG affinity column. The biological activity and the purity of the IGF-I obtained were confirmed by a radioreceptor assay, N-terminal sequence analysis, polyacrylamide gel electrophoresis, isoelectric focusing, and high-performance liquid chromatography.

A gene fusion system for generating antibodies against short peptides

A novel method to obtain specific antibodies against short peptides is described, involving synthesis of the corresponding oligodeoxynucleotides followed by cloning into a new set of fusion vectors, pEZZ8 and pEZZ18, based on two synthetic IgG-binding domains (ZZ) of Staphylococcus aureus protein A. The soluble gene fusion product thus obtained, can be collected from the culture medium of Escherichia coli and rapidly recovered in a one-step procedure by IgG affinity chromatography. The system was used to express a fusion protein consisting of the two Z fragments and the C-terminal part [amino acids (aa) 57-70] of human insulin-like growth factor I (IGF-I). This 16-kDa protein was purified by affinity chromatography on IgG Sepharose and antibodies were raised in rabbits. The fusion protein elicited peptide-specific antibodies, as measured by solid-phase radioimmuno assay and Western blotting, reactive with both synthetic C-terminal peptide and the native human IGF-I protein. The results suggests that the gene fusion system can be used for efficient antibody production against short peptides encoded by synthetic oligodeoxynucleotides.

On acupuncture analgesia and the mechanism of pain

The effect on the experimental tooth pain threshold of conditioning electrical stimulation via needles or surface electrodes applied to the hands and cheeks was studied in 34 dental students. Conditioning stimulation with 2/sec. gave a slowly increasing pain threshold followed by a slow return to the control level in the post-conditioning period. In each individual the amplitude of the threshold increase was reproduceable. It was concluded that these effects are not due to motivational but to more basic neurophysiological mechanisms. The pain threshold was increased mainly by segmental conditioning stimulation; segmentally unrelated stimulation gave usually only small effects. Conditioning stimulation with 100/sec. produced only a strict segmental short-lasting effect. Effects with characteristics of both 2/sec. and 100/sec. were obtained by conditioning at 10/sec. It is suggested that the transmission of impulses from the pain afferents to ascending pathways is controlled at the segmental level by (a) presynaptic inhibition within the group of afferents giving rise to the flexion reflex of which the pain afferents are assumed to be a part; (b) postsynaptic inhibition between alternate pathway excited by flexion reflex afferents; and (c) descending control from supraspinal systems which may utilize similar segmental mechanisms as the primary afferents.

Cooperative effects by the initiation codon and its flanking regions on translation initiation

The purine-rich Shine-Dalgarno (SD) sequence located a few bases upstream of the mRNA initiation codon supports translation initiation by complementary binding to the anti-SD in the 16S rRNA, close to its 3' end. AUG is the canonical initiation codon but the weaker UUG and GUG codons are also used for a minority of genes. The codon sequence of the downstream region (DR), including the +2 codon immediately following the initiation codon, is also important for initiation efficiency. We have studied the interplay between these three initiation determinants on gene expression in growing Escherichia coli. One optimal SD sequence (SD(+)) and one lacking any apparent complementarity to the anti-SD in 16S rRNA (SD(-)) were analyzed. The SD(+) and DR sequences affected initiation in a synergistic manner and large differences in the effects were found. The gene expression level associated with the most efficient of these DRs together with SD(-) was comparable to that of other DRs together with SD(+). The otherwise weak initiation codon UUG, but not GUG, was comparable with AUG in strength, if placed in the context of two of the DRs. The +2 codon was one, but not the only, determinant for this unexpectedly high efficiency of UUG.

Efficient secretion and purification of human insulin-like growth factor I with a gene fusion vector in Staphylococci

A novel approach for production of small polypeptides, using a staphylococcal protein A vector, is described. This system is used to express, secrete and purify human insulin-like growth factor I (IGF-I). A fusion protein consisting of protein A and IGF-I is recovered in high yield by passing the culture medium through an IgG affinity column. Using site-specific mutagenesis an acid labile asp-pro cleavage site was introduced at the fusion point between the two proteins. The protein A "tail" can thereby be removed from the affinity purified fusion protein by chemical cleavage releasing biologically active IGF-I molecules.

A randomized phase II trial of nab-paclitaxel and gemcitabine with tarextumab or placebo in patients with untreated metastatic pancreatic cancer

Purpose

Notch signaling dysregulation is implicated in the development of pancreatic adenocarcinoma (PDAC). Tarextumab is a fully human IgG2 antibody that inhibits Notch2/3 receptors.

Patients and Methods

Aphase 2, randomized, placebo‐controlled, multicenter trial evaluated the activity of tarextumab in combination with nab‐paclitaxel and gemcitabine in patients with metastatic PDAC. Patients were stratified based on ECOG performance score and Ca 19‐9 level and randomized 1:1 to nab‐paclitaxel, gemcitabine with either tarextumab or placebo. Based on preclinical and phase Ib results suggesting a positive correlation between Notch3 gene expression and tarextumab anti‐tumor activity, patients were also divided into subgroups of low, intermediate, and high Notch3 gene expression. Primary endpoint was overall survival (OS) in all and in patients with the three Notch3 gene expression subgroups (≥25th, ≥50% and ≥75% percentiles); secondary end points included progression‐free survival (PFS), 12‐month OS, overall response rate (ORR), and safety and biomarker investigation.

Results

Median OS was 6.4 months in the tarextumab group vs 7.9 months in the placebo group (HR = 1.34 [95% CI = 0.95, 1.89], P = .0985). No difference observed in OS in the Notch3 gene expression subgroups. PFS in the tarextumab‐treated group (3.7 months) was significantly shorter compared with the placebo group (5.5 months) (hazard ratio was 1.43 [95% CI = 1.01, 2.01]; P = .04). Grade 3 diarrhea and thrombocytopenia were more common in the tarextumab group.

Conclusions

The addition of tarextumab to nab‐paclitaxel and gemcitabine did not improve OS, PFS, or ORR in first‐line metastatic PDAC, and PFS was specifically statistically worse in the tarextumab‐treated patients.

Clinical trial registry no

NCT01647828.

Post-operative thromboembolism in neurosurgery. A study on the prophylactic effect of calf muscle stimulation plus dextran compared to low-dose heparin

This study compares the safety and effectiveness of two methods for the prophylaxis of post-operative thromboembolism in neurosurgical patients: A: low-dose heparin (5,000 IU X 2 s.c.) started preoperatively and continued daily for one week post-operatively, and B: per-operative electrical calf muscle stimulation with groups of impulses plus post-operative dextran infusions every other day for one week. Neurosurgical patients aged 40 years or more with normal laboratory coagulation values and operated under general anaesthesia were included. The 125:I-fibrinogen uptake test (FUT) was used for screening and phlebography for verification of deep venous thrombosis (DVT). 122 patients entered the study and 104 completed the prophylactic protocol, 58 in group A and 46 in group B. The two groups were comparable according to pre-operative data and distribution of diagnoses. 89 patients completed screening for post-operative DVT. We found an overall incidence of 5/49 (10 percent) DVT in group A and 5/40 (13 percent) in group B, compared to a frequency of 32-50 percent for controls without prophylaxis reported in the literature, In spite of prophylaxis our patients with intracranial neoplasms and intracranial vascular disease showed a relatively higher incidence of DVT, 4/23 (17 percent) and 4/14 (29 percent) respectively, compared to patients with spinal diagnoses 2/25 (8 percent). In combination with cranial diagnoses paretic lower limbs meant an apparent risk factor, 4/7 (57 percent). However, paretic limbs appearing in cases with spinal disorders did not predetermine an unsuccessful prophylaxis, 2/14 (14 percent). Blood loss, transfusion requirements and post-operative complications did not differ significantly between the two prophylactic groups.(ABSTRACT TRUNCATED AT 250 WORDS)

Production of specific antibodies against protein A fusion proteins

The gene for Staphylococcal protein A was fused to the coding sequence of bacterial beta-galactosidase, alkaline phosphatase and human insulin-like growth factor I (IGF-I). The fusion proteins, expressed in bacteria, were purified by affinity chromatography on IgG-Sepharose and antibodies were raised in rabbits. All three fusion proteins elicited specific antibodies against both the inserted protein sequences and the protein A moiety. In the case of IGF-I, the protein A moiety in the fusion protein may act as an adjuvant since native IGF-I alone is a poor immunogen. The results suggest that the protein A fusion system can be used for efficient antibody production against peptides or proteins expressed from cloned or synthetic genes. To facilitate such gene fusions a set of optimized vectors have been constructed.

Characterization of a succinate dehydrogenase complex solubilized from the cytoplasmic membrane of Bacillus subtilis with the nonionic detergent Triton X-100

A succinic dehydrogenase (SDH) complex has been purified from Triton X-100-solubilized membranes from Bacillus subtilis by precipitation with specific antibody. Radioactively labeled precipitated complex was analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis followed by autoradiography of the gels. The complex contained equimolar amounts of three polypeptides with approximate molecular weights of 65,000, 28,000, and 19,000. Five succinic dehydrogenase-negative mutants, belonging to the citF group, contained the 65,000-dalton polypeptide in a soluble form in the cytoplasm. Each 65,000-dalton polypeptide had about one molecule of flavin bound. Another citF mutant, citF11, which lacks the 65,000-dalton polypeptide, contained a membrane-bound 28,000-dalton polypeptide. The wild-type succinic dehydrogenase complex contained cytochrome, probably a cytochrome b. The 19,000-dalton polypeptide is suggested to represent the apoprotein of this cytochrome. The 65,000-dalton and the 28,000-dalton polypeptides are thought to constitute succinic dehydrogenase and to correspond to the flavoprotein and the ironprotein, respectively, as described for succinic dehydrogenase isolated from beef heart mitochondria or Rhodospirillum rubrum chromatophores. The results presented suggest that in B. subtilis succinic dehydrogenase is attached to a cytochrome b in the membrane via the 28,000-dalton (ironprotein) polypeptide.

Evaluation of the pain suppressive effect of different frequencies of peripheral electrical stimulation in chronic pain conditions

The pain suppressive effect of low (2/s) and high (50-100/s) frequency electrical stimulation was studied in 12 patients with severe chronic pain in the back and/or the legs. All patients were subjected to a thorough physical examination before and 2-3 weeks after a series of stimulation sessions. The stimulation was applied via surface electrodes to areas both segmentally related and segmentally unrelated to the regions of chronic pain. Low frequency stimulation induced a partial pain relief in only one patient whereas stimulation with high frequency gave a suppression of pain in seven patients. The effect was short-lasting in most cases and the pain started to increase usually within 30 min. It is concluded that the observed pain suppression is not due to psychological factors but to more basic neurophysiological mechanisms. Augmentation of the effect after repeated stimulation sessions was not observed, neither was there any alteration in the neuro-orthopedic status nor any lasting pain relief in any patient.