Janice M. Brown

Randomized, double-blind trial of fluconazole versus voriconazole for prevention of invasive fungal infection after allogeneic hematopoietic cell transplantation

Invasive fungal infection (IFI) is a serious threat after allogeneic hematopoietic cell transplant (HCT). This multicenter, randomized, double-blind trial compared fluconazole (N = 295) versus voriconazole (N = 305) for the prevention of IFI in the context of a structured fungal screening program. Patients undergoing myeloablative allogeneic HCT were randomized before HCT to receive study drugs for 100 days, or for 180 days in higher-risk patients. Serum galactomannan was assayed twice weekly for 60 days, then at least weekly until day 100. Positive galactomannan or suggestive signs triggered mandatory evaluation for IFI. The primary endpoint was freedom from IFI or death (fungal-free survival; FFS) at 180 days. Despite trends to fewer IFIs (7.3% vs 11.2%; P = .12), Aspergillus infections (9 vs 17; P = .09), and less frequent empiric antifungal therapy (24.1% vs 30.2%, P = .11) with voriconazole, FFS rates (75% vs 78%; P = .49) at 180 days were similar with fluconazole and voriconazole, respectively. Relapse-free and overall survival and the incidence of severe adverse events were also similar. This study demonstrates that in the context of intensive monitoring and structured empiric antifungal therapy, 6-month FFS and overall survival did not differ in allogeneic HCT recipients given prophylactic fluconazole or voriconazole. This trial was registered at www.clinicaltrials.gov as NCT00075803.

Development of a hypoxia-responsive vector for tumor-specific gene therapy

We are developing new gene therapy vectors whose expression is selectively activated by hypoxia, a unique feature of human solid tumors. As vascular endothelial growth factor (VEGF) is upregulated by hypoxia, such regulatory mechanisms would enable us to achieve hypoxia-inducible expression of therapeutic genes. Constructs with five copies of hypoxia-responsive elements (HREs) derived from the 5′-untranslated region (UTR) of the human VEGF showed excellent transcriptional activation at low oxygen tension relevant to tumor hypoxia. In an attempt to achieve higher responsiveness, various combinations of HREs and promoters were examined. In addition, we also investigated whether the 3′ UTR of the VEGF gene would confer increased post-transcriptional mRNA stability under hypoxic conditions. However, despite increases in the hypoxic/aerobic ratio of luciferase activity, gene expression with 3′ UTR was lower due to mRNA destabilization by AU-rich elements (AREs). Thus, we found no benefit from the inclusion of the 3′ UTR in our vectors. Of all the vectors tested, the combination of 5HRE and a CMV minimal promoter exhibited hypoxia responsiveness (over 500-fold) to the similar level to the intact CMV promoter. We propose that this vector would be useful for tumor selective gene therapy.

Anaerobic bacteria as a gene delivery system that is controlled by the tumor microenvironment

A fundamental obstacle in gene therapy for cancer treatment is the specific delivery of an anticancer gene product to a solid tumor. Although several strategies exist to control gene expression once a vector is directly introduced into a tumor, as yet no systemic delivery system exists that specifically targets solid tumors. Nonpathogenic, obligate anaerobic bacteria of the genus Clostridium have been used experimentally as anticancer agents because of their selective growth in the hypoxic regions of solid tumors after systemic application. In this report we further describe a novel approach to cancer gene therapy in which genetically engineered clostridia are used as tumor-specific vectors for the delivery of antitumor genes. We have introduced into a strain of C. beijerinckii the gene for an E. coli nitroreductase known to activate the nontoxic prodrug CB 1954 to a toxic anticancer drug. Nitroreductase produced by these clostridia enhanced the killing of tumor cells in vitro by CB 1954, by a factor of 22. To demonstrate the specificity of this approach for tumor targeting, we intravenously injected the inactive spore form of C. beijerinckii, which upon transition to a reproductive state will express the E. coli nitroreductase gene. Nitroreductase activity was detectable in 10 of 10 tumors during the first 5 days after intravenous injection of inactive clostridial spores, indicating a rapid transition from spore to reproductive state. Tumors harboring clostridial spores which did not possess the E. coli nitroreductase gene were devoid of nitroreductase activity. Most importantly, E. coli nitroreductase protein was not found in a large survey of normal mouse tissues following intravenous injection of nitroreductase containing clostridia, strongly suggesting that obligate anaerobic bacteria such as clostridia can be utilized as highly specific gene delivery vectors for cancer therapy.

Anticancer efficacy of systemically delivered anaerobic bacteria as gene therapy vectors targeting tumor hypoxia/necrosis.

A major obstacle in cancer gene therapy is selective tumor delivery. Previous studies have suggested that genetically engineered anaerobes of the genus Clostridium might be gene therapy vectors because of their ability to proliferate selectively in the hypoxic/necrotic regions common to solid tumors. However, the tumor colonization efficiency of the strain previously used was insufficient to produce any antitumor effect. Here we describe for the first time the successful transformation of C. sporogenes, a clostridial strain with the highest reported tumor colonization efficiency, with the E. coli cytosine deaminase (CD) gene and show that systemically injected spores of these bacteria express CD only in the tumor. This enzyme can convert the nontoxic prodrug 5-fluorocytosine (5-FC) to the anticancer drug 5-fluorouracil (5-FU). Furthermore, systemic delivery of 5-FC into mice previously injected with CD-transformed spores of C. sporogenes produced greater antitumor effect than maximally tolerated doses of 5-FU. Since most human solid tumors have hypoxic and necrotic areas this vector system has considerable promise for tumor-selective gene therapy.

Letermovir for Cytomegalovirus Prophylaxis in Hematopoietic-Cell Transplantation

BACKGROUND Cytomegalovirus (CMV) infection is a leading cause of illness and death in patients who have undergone allogeneic hematopoietic-cell transplantation. Available treatments are restricted by clinically significant toxic effects and drug resistance. METHODS In this phase 2 study, we evaluated the effect of letermovir (also known as AIC246), a new anti-CMV drug with a novel mechanism of action, on the incidence and time to onset of prophylaxis failure in CMV-seropositive recipients of allogeneic hematopoietic-cell transplants from matched related or unrelated donors. From March 2010 through October 2011, we randomly assigned 131 transplant recipients in a 3:1 ratio to three sequential study cohorts according to a double-blind design. Patients received oral letermovir (at a dose of 60, 120, or 240 mg per day, or matching placebo) for 12 weeks after engraftment. The primary end point was all-cause prophylaxis failure, defined as discontinuation of the study drug because of CMV antigen or DNA detection, end-organ disease, or any other cause. Patients underwent weekly surveillance for CMV infection. RESULTS The reduction in the incidence of all-cause prophylaxis failure was dose-dependent. The incidence of prophylaxis failure with letermovir, as compared with placebo, was 48% versus 64% at a daily letermovir dose of 60 mg (P=0.32), 32% at a dose of 120 mg (P=0.01), and 29% at a dose of 240 mg (P=0.007). Kaplan-Meier time-to-onset profiles for prophylaxis failure showed a significant difference in the comparison of letermovir at a dose of 240 mg per day with placebo (P=0.002). The safety profile of letermovir was similar to placebo, with no indication of hematologic toxicity or nephrotoxicity. CONCLUSIONS Letermovir, as compared with placebo, was effective in reducing the incidence of CMV infection in recipients of allogeneic hematopoietic-cell transplants. The highest dose (240 mg per day) had the greatest anti-CMV activity, with an acceptable safety profile. (Funded by AiCuris; ClinicalTrials.gov number, NCT01063829.).

Invasive Non-Aspergillus Mold Infections in Transplant Recipients, United States, 2001-2006

Recent reports describe increasing incidence of non-Aspergillus mold infections in hematopoietic cell transplant (HCT) and solid organ transplant (SOT) recipients. To investigate the epidemiology of infections with Mucorales, Fusarium spp., and Scedosporium spp. molds, we analyzed data from the Transplant-Associated Infection Surveillance Network, 23 transplant centers that conducted prospective surveillance for invasive fungal infections during 2001-2006. We identified 169 infections (105 Mucorales, 37 Fusarium spp., and 27 Scedosporium spp.) in 169 patients; 124 (73.4%) were in HCT recipients, and 45 (26.6%) were in SOT recipients. The crude 90-day mortality rate was 56.6%. The 12-month mucormycosis cumulative incidence was 0.29% for HCT and 0.07% for SOT. Mucormycosis incidence among HCT recipients varied widely, from 0.08% to 0.69%, with higher incidence in cohorts receiving transplants during 2003 and 2004. Non-Aspergillus mold infections continue to be associated with high mortality rates. The incidence of mucormycosis in HCT recipients increased substantially during the surveillance period.

Isavuconazole treatment for mucormycosis: a single-arm open-label trial and case-control analysis

BACKGROUND Mucormycosis is an uncommon invasive fungal disease with high mortality and few treatment options. Isavuconazole is a triazole active in vitro and in animal models against moulds of the order Mucorales. We assessed the efficacy and safety of isavuconazole for treatment of mucormycosis and compared its efficacy with amphotericin B in a matched case-control analysis. METHODS In a single-arm open-label trial (VITAL study), adult patients (≥18 years) with invasive fungal disease caused by rare fungi, including mucormycosis, were recruited from 34 centres worldwide. Patients were given isavuconazole 200 mg (as its intravenous or oral water-soluble prodrug, isavuconazonium sulfate) three times daily for six doses, followed by 200 mg/day until invasive fungal disease resolution, failure, or for 180 days or more. The primary endpoint was independent data review committee-determined overall response-ie, complete or partial response (treatment success) or stable or progressive disease (treatment failure)-according to prespecified criteria. Mucormycosis cases treated with isavuconazole as primary treatment were matched with controls from the FungiScope Registry, recruited from 17 centres worldwide, who received primary amphotericin B-based treatment, and were analysed for day-42 all-cause mortality. VITAL is registered with ClinicalTrials.gov, number NCT00634049. FungiScope is registered with ClinicalTrials.gov, number NCT01731353. FINDINGS Within the VITAL study, from April 22, 2008, to June 21, 2013, 37 patients with mucormycosis received isavuconazole for a median of 84 days (IQR 19-179, range 2-882). By day 42, four patients (11%) had a partial response, 16 (43%) had stable invasive fungal disease, one (3%) had invasive fungal disease progression, three (8%) had missing assessments, and 13 (35%) had died. 35 patients (95%) had adverse events (28 [76%] serious). Day-42 crude all-cause mortality in seven (33%) of 21 primary-treatment isavuconazole cases was similar to 13 (39%) of 33 amphotericin B-treated matched controls (weighted all-cause mortality: 33% vs 41%; p=0·595). INTERPRETATION Isavuconazole showed activity against mucormycosis with efficacy similar to amphotericin B. Isavuconazole can be used for treatment of mucormycosis and is well tolerated. FUNDING Astellas Pharma Global Development, Basilea Pharmaceutica International.

Safety and immunogenicity of a bivalent cytomegalovirus DNA vaccine in healthy adult subjects.

BACKGROUND VCL-CB01, a candidate cytomegalovirus (CMV) DNA vaccine that contains plasmids encoding CMV phosphoprotein 65 (pp65) and glycoprotein B (gB) to induce cellular and humoral immune responses and that is formulated with poloxamer CRL1005 and benzalkonium chloride to enhance immune responses, was evaluated in a phase 1 clinical trial. METHODS VCL-CB01 was evaluated in 44 healthy adult subjects (22 CMV seronegative and 22 CMV seropositive) 18-43 years old. Thirty-two subjects received 1- or 5-mg doses of vaccine on a 0-, 2-, and 8-week schedule, and 12 subjects received 5-mg doses of vaccine on a 0-, 3-, 7-, and 28-day schedule. RESULTS Overall, the vaccine was well tolerated, with no serious adverse events. Local reactions included mild to moderate injection site pain and tenderness, induration, and erythema. Systemic reactions included mild to moderate malaise and myalgia. All reactions resolved without sequelae. Through week 16 of the study, immunogenicity, as measured by enzyme-linked immunosorbant assay and/or ex vivo interferon (IFN)-gamma enzyme-linked immunospot assay, was documented in 45.5% of CMV-seronegative subjects and in 25.0% of CMV-seropositive subjects who received the full vaccine series, and 68.1% of CMV-seronegative subjects had memory IFN-gamma T cell responses at week 32. CONCLUSION The safety and immunogenicity data from this trial support further evaluation of VCL-CB01.

Risks and outcomes of invasive fungal infections in pediatric patients undergoing allogeneic hematopoietic cell transplantation.

Summary:Invasive fungal infections (IFI) are the leading cause of infectious mortality in adult patients undergoing hematopoietic cell transplantation (HCT) after myeloablative conditioning, but the extent of this problem in the pediatric population is unclear. We retrospectively examined risk factors for IFI among 120 consecutive pediatric patients undergoing allogeneic HCT at a single center. The incidence of proven or probable IFI in pediatric patients during the first year after allogeneic HCT was 13%, comparable to the rate reported in adult patients; however, unlike IFI in adult patients, the majority of IFI in children occurred within the first month after transplantation. The primary risk factors for IFI were duration of neutropenia, age greater than 10 years, transplant for severe aplastic anemia or Fanconi anemia, and high-dose corticosteroid administration for 10 days or longer. IFI were more likely to be successfully treated (42%, 5/12 patients) in pediatric HCT recipients when compared to previous reports of adult recipients. Nonrelapse mortality was estimated at 17% (20/120 patients) after allogeneic HCT, of which 35% (seven patients) were directly attributed to IFI. Thus, IFI is a significant cause of nonrelapse mortality in children undergoing allogeneic HCT and more effective strategies are needed to prevent and treat IFI.

Utility of influenza vaccination for oncology patients.

Every fall and winter, patients with cancer and their families ask oncologists whether they should be vaccinated for influenza. This season, with escalating concerns regarding the novel H1N1 influenza virus and its recently approved vaccine, this question has become more frequent and increasingly urgent. The purpose of this article is to review evidence related to the ability of patients with cancer to mount protective immunological responses to influenza vaccination. The literature on immunogenicity in pediatric and adult patients, those with solid tumors and hematologic malignancies, untreated and actively treated patients, and patients receiving biologic agents is summarized and reviewed. In addition, we report on potential strategies to improve the efficacy of influenza vaccination in patients with cancer, such as the timing of vaccination, use of more than a one-shot series, increasing the antigen dose, and the use of adjuvant therapies. We conclude that there is evidence that patients with cancer receiving chemotherapy are able to respond to influenza vaccination, and because this intervention is safe, inexpensive, and widely available, vaccination for seasonal influenza and the novel H1N1 strain is indicated.