Spores of Clostridium engineered for clinical efficacy and safety cause regression and cure of tumors in vivo.

Spores of some species of the strictly anaerobic bacteria Clostridium naturally target and partially lyse the hypoxic cores of tumors, which tend to be refractory to conventional therapies. The anti-tumor effect can be augmented by engineering strains to convert a non-toxic prodrug into a cytotoxic drug specifically at the tumor site by expressing a prodrug-converting enzyme (PCE). Safe doses of the favored prodrug CB1954 lead to peak concentrations of 6.3 μM in patient sera, but at these concentration(s) known nitroreductase (NTR) PCEs for this prodrug show low activity. Furthermore, efficacious and safe Clostridium strains that stably express a PCE have not been reported. Here we identify a novel nitroreductase from Neisseria meningitidis, NmeNTR, which is able to activate CB1954 at clinically-achievable serum concentrations. An NmeNTR expression cassette, which does not contain an antibiotic resistance marker, was stably localized to the chromosome of Clostridium sporogenes using a new integration method, and the strain was disabled for safety and containment by making it a uracil auxotroph. The efficacy of Clostridium-Directed Enzyme Prodrug Therapy (CDEPT) using this system was demonstrated in a mouse xenograft model of human colon carcinoma. Substantial tumor suppression was achieved, and several animals were cured. These encouraging data suggest that the novel enzyme and strain engineering approach represent a promising platform for the clinical development of CDEPT

Risk Assessment in Adult Cancer Patients with Febrile Neutropenia: A Review of Methods and of Risk-adapted Empiric Treatments

Febrile neutropenia is a common complication of antineoplasic chemotherapy. It is a potentially serious event, sometimes lethal. However, it is well recognized that the population of patients with febrile neutropenia is heterogeneous in terms of prognosis. Simplified therapy, for instance oral antibiotic empiric treatment or ambulatory treatment, in comparison to the classical management of intravenously administered empiric antibiotics and in-hospital surveillance, has been the purpose of research for patients predicted at low-risk for serious complications development. However, for such a strategy to be successful an accurate identification of patients at low-risk is required. The objective of the present review is to present the available tools for risk assessment, in adult patients populations and to review the status of our knowledge regarding the efficacy and the safety of risk-adapted therapy

Association between Antifungal Prophylaxis and Rate of Documented Bacteremia in Febrile Neutropenic Cancer Patients

Published data have suggested a correlation between antifungal prophylaxis and bacteremia in febrile neutropenia. This correlation was investigated among 3002 febrile neutropenic patients enrolled in 4 trials during 1986-1994. Globally, 1322 patients (44%) did not receive antifungal prophylaxis; 835 (28%) received poorly absorbable antifungal agents and 845 (28%) received absorbable antifungal agents. The rates of bacteremia for these groups were 20%, 26%, and 27%, respectively (P=.0001). In a multivariate model without including antifungal prophylaxis, factors associated with bacteremia were: age, duration of hospitalization, duration of neutropenia before enrollment, underlying disease, presence of an intravenous catheter, shock, antibacterial prophylaxis, temperature, and granulocyte count at onset of fever. When antifungal prophylaxis was included, the adjustment quality of the model improved slightly (P=.05), with an odds ratio of 1.19 (95% confidence interval [CI], 0.92-1.55) for patients receiving nonabsorbable and 1.42 (95% CI, 1.07-1.88) for those who were receiving absorbable antifungal agents. Antifungal prophylaxis with absorbable agents might have an impact on the rate of documented bacteremia in febrile neutropenia. This effect should be confirmed prospectivel

Invasive mechanical ventilation in cancer patients: prior non-invasive ventilation is a poor prognostic factor

info:eu-repo/semantics/publishe

A European Organization for Research and Treatment of Cancer-International Antimicrobial Therapy Group Study of secondary infections in febrile, neutropenic patients with cancer

BACKGROUND: Neutropenic patients with cancer may develop several episodes of fever and infection during chemotherapy-induced myeloaplasia. METHODS: To identify risk factors for secondary infectious episodes among patients who responded to initial antibiotic therapy, we retrospectively analyzed 2 consecutive, prospective, randomized clinical trials performed by the International Antimicrobial Therapy Group of the European Organization for Research and Treatment of Cancer during 1991-1994. RESULTS: Of 1720 patients with their first episode of febrile neutropenia, 836 responded to the initial antibiotic regimen and were therefore suitable for our analysis. A secondary infection was observed in 129 (15%) of 836 patients that occurred at a median of 10 days (range, 1-28 days) after the onset of the primary febrile episode. Factors at both baseline and day 4 were analyzed. Age of >16 years (odds ratio [OR], 3.46; P<.001), acute leukemia in first induction (OR, 3.17; P<.001), presence of intravenous line (OR, 1.88; P=.04), severe neutropenia (defined as an absolute granulocyte count of <100 cells/mm(3)) on day 4 (OR, 2.72; P<.001), and type of documentation of the primary episode (i.e., microbiologically documented cause or unexplained fever; OR, 2.56; P=.001) were found to be risk factors for secondary infection. The risk of death was higher among patients who developed a secondary infectious episode than among those who did not (5.4% vs. 1.4%; P<.01). CONCLUSIONS: The clinical parameters described above may help to identify neutropenic patients at risk of developing secondary infection

Metastatic renal carcinoma comprehensive prognostic system

The purpose of the study was to identify a comprehensive prognostic system of pretreatment clinical parameters in 425 patients (pts) with metastatic renal-cell carcinoma treated with different subcutaneous (s.c.) recombinant cytokine-based home therapies in consecutive trials. Treatment consisted of (A) s.c. interferon-α2a (INF-α), s.c. interleukin-2 (IL-2) (n=102 pts), (B) s.c. IFN-α2a, s.c. IL-2, and i.v. 5-fluorouracil (5-FU) (n=235 pts) or (C) s.c. IFN-α2a, s.c. IL-2, and i.v. 5-FU combined with p.o. 13-cis-retinoic acid (13cRA) (n=88 pts). Kaplan–Meier survival analysis, log-rank statistics, and Cox regression analysis were employed to identify risk factors and to create a multiple risk factor model. The following pretreatment risk factors were identified by univariate analysis: (1) three and more metastatic sites, (2) presence of liver, lymph node or bone metastases, (3) neutrophil count ⩾6500 cells μl−1, (4) serum lactate dehydrogenase level (LDH) ⩾220 U l−1, and (5) serum C-reactive protein level (CRP) ⩾11 mg l−1. Cox regression analysis with forward stepwise variable selection identified neutrophil count as the major prognostic factor (hazard ratio=1.9, P<0.001), while serum levels of LDH and CRP, time between diagnosis of tumour and onset of metastatic disease, number of metastatic sites, and bone metastases were significant but somewhat less important prognostic variables within the multiple risk factor model (hazard ratio ⩽1.5). Patients were assigned to one of the three risk groups according to cumulative risk defined as the sum of simplified risk s.c.ores for six pretreatment variables. Low-, intermediate-, and high-risk patients achieved a median overall survival of 32+ months (95% CI 24, 43; 5-year survival of 27%), 18+ months (95% CI 15, 20; 5-year survival of 11%), and 8+ months (95% CI 6, 10; 5-year survival of 5%), respectively. These prognostic categories are helpful both in individual patient care and in the assessment of patients entering prospective clinical trials

Epidemiology and Outcome of Fungemia in a Cancer Cohort of the Infectious Diseases Group (IDG) of the European Organization for Research and Treatment of Cancer (EORTC 65031)

In a prospective cohort study of 145 030 admissions of cancer patients from 13 European Organisation for Research and Treatment of Cancer centers fungemia occurred in 0.23%. Candida albicans was the predominant pathogen. Fungemia was associated with substantial mortality. Antifungal prophylaxis and remission of cancer predicted better surviva

Low Mannose-Binding Lectin Concentration Is Associated with Severe Infection in Patients with Hematological Cancer Who Are Undergoing Chemotherapy

Background. Mannose-binding lectin (MBL) is a serum lectin involved in innate immune response. Low serum MBL concentration may constitute a risk factor for infection in patients receiving myelosuppressive chemotherapy. Methods. We conducted a prospective, observational study that assessed MBL concentration as a risk factor for infection in patients with hematological malignancy who were hospitalized to undergo at least 1 chemotherapy cycle. MBL deficiency was defined using an algorithm that considered the serum MBL concentration and the MBL genotype. The primary end point was the ratio of duration of febrile neutropenia to the duration of neutropenia. Secondary end points included the incidence of severe infection (e.g., sepsis, pneumonia, bacteremia, and invasive fungal infection). Logistic regression analysis was conducted, and Fisher's exact test was used to analyze binary outcomes, and Kaplan-Meier estimates and log rank tests were used for time-to-event variables. Results. We analyzed 255 patients who received 569 cycles of chemotherapy. The median duration of neutropenia per cycle was 7 days (interquartile range, 0-13 days). Sixty-two patients (24%) were found to have MBL deficiency. Febrile neutropenia occurred at least once in 200 patients. No difference in the primary outcome was seen. The incidence of severe infection was higher among MBL-deficient patients than among non-MBL-deficient patients (1.96 vs. 1.34 cases per 100 days for analysis of all patients [P = .008] and 1.85 vs. 0.94 cases per 100 days excluding patients with acute leukemia [P < .001]). Conclusions. MBL deficiency does not predispose adults with hematological cancer to more-frequent or more-prolonged febrile episodes during myelosuppressive chemotherapy, but MBL-deficient patients have a greater number of severe infections and experience their first severe infection earlier, compared with nondeficient patient

Allosteric modulation of the GTPase activity of a bacterial LRRK2 homolog by conformation-specific Nanobodies

Mutations in the Parkinson's disease (PD)-associated protein leucine-rich repeat kinase 2 (LRRK2) commonly lead to a reduction of GTPase activity and increase in kinase activity. Therefore, strategies for drug development have mainly been focusing on the design of LRRK2 kinase inhibitors. We recently showed that the central RocCOR domains (Roc: Ras of complex proteins; COR: C-terminal of Roc) of a bacterial LRRK2 homolog cycle between a dimeric and monomeric form concomitant with GTP binding and hydrolysis. PD-associated mutations can slow down GTP hydrolysis by stabilizing the protein in its dimeric form. Here, we report the identification of two Nanobodies (NbRoco1 and NbRoco2) that bind the bacterial Roco protein (CtRoco) in a conformation-specific way, with a preference for the GTP-bound state. NbRoco1 considerably increases the GTP turnover rate of CtRoco and reverts the decrease in GTPase activity caused by a PD-analogous mutation. We show that NbRoco1 exerts its effect by allosterically interfering with the CtRoco dimer–monomer cycle through the destabilization of the dimeric form. Hence, we provide the first proof of principle that allosteric modulation of the RocCOR dimer–monomer cycle can alter its GTPase activity, which might present a potential novel strategy to overcome the effect of LRRK2 PD mutations