Kathleen M. Mullane

Fidaxomicin versus Vancomycin for Clostridium difficile Infection

BACKGROUND Clostridium difficile infection is a serious diarrheal illness associated with substantial morbidity and mortality. Patients generally have a response to oral vancomycin or metronidazole; however, the rate of recurrence is high. This phase 3 clinical trial compared the efficacy and safety of fidaxomicin with those of vancomycin in treating C. difficile infection. METHODS Adults with acute symptoms of C. difficile infection and a positive result on a stool toxin test were eligible for study entry. We randomly assigned patients to receive fidaxomicin (200 mg twice daily) or vancomycin (125 mg four times daily) orally for 10 days. The primary end point was clinical cure (resolution of symptoms and no need for further therapy for C. difficile infection as of the second day after the end of the course of therapy). The secondary end points were recurrence of C. difficile infection (diarrhea and a positive result on a stool toxin test within 4 weeks after treatment) and global cure (i.e., cure with no recurrence). RESULTS A total of 629 patients were enrolled, of whom 548 (87.1%) could be evaluated for the per-protocol analysis. The rates of clinical cure with fidaxomicin were noninferior to those with vancomycin in both the modified intention-to-treat analysis (88.2% with fidaxomicin and 85.8% with vancomycin) and the per-protocol analysis (92.1% and 89.8%, respectively). Significantly fewer patients in the fidaxomicin group than in the vancomycin group had a recurrence of the infection, in both the modified intention-to-treat analysis (15.4% vs. 25.3%, P=0.005) and the per-protocol analysis (13.3% vs. 24.0%, P=0.004). The lower rate of recurrence was seen in patients with non–North American Pulsed Field type 1 strains. The adverse-event profile was similar for the two therapies. CONCLUSIONS The rates of clinical cure after treatment with fidaxomicin were noninferior to those after treatment with vancomycin. Fidaxomicin was associated with a significantly lower rate of recurrence of C. difficile infection associated with non–North American Pulsed Field type 1 strains. (Funded by Optimer Pharmaceuticals; ClinicalTrials.gov number, NCT00314951.)

CMX001 to Prevent Cytomegalovirus Disease in Hematopoietic-Cell Transplantation

BACKGROUND The use of available antiviral agents for the prevention of cytomegalovirus (CMV) disease is limited by frequent toxic effects and the emergence of resistance. CMX001 has potent in vitro activity against CMV and other double-stranded DNA viruses. We evaluated the safety and anti-CMV activity of CMX001 in patients who had undergone allogeneic hematopoietic-cell transplantation. METHODS From December 2009 through June 2011, a total of 230 patients with data that could be evaluated were enrolled in the study. We randomly assigned these adult CMV-seropositive transplant recipients from 27 centers to oral administration of CMX001 or placebo. Patients were assigned in a 3:1 ratio to five sequential study cohorts according to a dose-escalating, double-blind design. Randomization was stratified according to the presence or absence of acute graft-versus-host disease and CMV DNA in plasma. Patients received the study drug after engraftment for 9 to 11 weeks, until week 13 after transplantation. Polymerase-chain-reaction analysis of CMV DNA in plasma was performed weekly. Patients in whom CMV DNA was detected at a level that required treatment discontinued the study drug and received preemptive treatment against CMV infection. The primary end point was a CMV event, defined as CMV disease or a plasma CMV DNA level greater than 200 copies per milliliter when the study drug was discontinued. The analysis was conducted in the intention-to-treat population. RESULTS The incidence of CMV events was significantly lower among patients who received CMX001 at a dose of 100 mg twice weekly than among patients who received placebo (10% vs. 37%; risk difference, -27 percentage points; 95% confidence interval, -42 to -12; P=0.002). Diarrhea was the most common adverse event in patients receiving CMX001 at doses of 200 mg weekly or higher and was dose-limiting at 200 mg twice weekly. Myelosuppression and nephrotoxicity were not observed. CONCLUSIONS Treatment with oral CMX001 at a dose of 100 mg twice weekly significantly reduced the incidence of CMV events in recipients of hematopoietic-cell transplants. Diarrhea was dose-limiting in this population at a dose of 200 mg twice weekly. (Funded by Chimerix; CMX001-201 ClinicalTrials.gov number, NCT00942305.).

Breakthrough zygomycosis after voriconazole administration among patients with hematologic malignancies who receive hematopoietic stem-cell transplants or intensive chemotherapy

Zygomycosis is increasingly reported as a cause of life-threatening fungal infections. A higher proportion of cases reported over the last decades have been in cancer patients, with or without hematopoietic stem cell transplantation (HSCT). The new anti-fungal agent voriconazole is a recently identified risk factor for developing zygomycosis. We reviewed the clinical characteristics and outcomes of a large cohort of cancer patients who developed zygomycosis after exposure to voriconazole. Health care professionals at 13 large cancer centers provided clinical information on cancer patients with zygomycosis and prior exposure to voriconazole. Criteria for inclusion were 5 days or more of voriconazole use and diagnostic confirmation with tissue or histology. Fifty-eight cases were identified among patients with hematologic malignancies, 62% including patients who underwent a HSCT procedure. Fifty-six patients received voriconazole for primary or secondary prophylaxis against fungal infection. In addition to prior exposure to voriconazole, patients also had several of the previously established risk factors for zygomycosis. Amphotericin B was the most commonly prescribed anti-fungal therapy. Overall mortality was 73%. We conclude that zygomycosis after exposure to voriconazole is a recently described entity that is frequently fatal, despite treatment with currently available anti-fungal agents and surgery.

Efficacy of Fidaxomicin Versus Vancomycin as Therapy for Clostridium difficile Infection in Individuals Taking Concomitant Antibiotics for Other Concurrent Infections

Concomitant antibiotic (CA) use compromised initial response to Clostridium difficile infection therapy and durability of that response. Fidaxomicin was significantly more effective than vancomycin in achieving clinical cure in the presence of CAs and preventing recurrence regardless of CA use.

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.).

Accelerated neutrophil apoptosis in the acquired immunodeficiency syndrome.

Neutrophil (PMNL) function defects occur as a consequence of HIV infection. This study examined PMNL apoptosis in patients with the acquired immunodeficiency syndrome (AIDS) to determine if accelerated apoptosis contributes to impaired function. PMNL were isolated from 10 HIV-infected patients with CD4+ lymphocyte counts < 200/mm3 without signs of active infection and 7 healthy volunteers. PMNL were stained with acridine orange and ethidium bromide after 0, 3, 6, and 18 h in culture, and examined for the morphologic changes of apoptosis and viability by fluorescent microscopy. Apoptosis was also demonstrated by electron microscopy, flow cytometry, and DNA gel electrophoresis. Apoptosis was minimal at 0 h, but PMNL from AIDS patients exhibited significantly greater apoptosis than controls at 3 h (22.5+/-11.5 vs. 8.9+/-6.9%, P = 0.015), 6 h (38.1+/-14.2 vs. 18.1+/-4.5%, P = 0.003), and 18 h (71.3+/-19.0 vs. 38.8+/-16.7%, P = 0.002). Viabilities were > or = 88.0% for both groups from 0-6 h, but by 18 h viability was significantly decreased for the HIV group (58.8+/-12.4 vs. 83.5+/-10.4%, P = 0.001) due to an increase in non-viable apoptotic cells. Incubation with serum from AIDS patients had no effect on control PMNL, and incubation with control serum did not reduce the rate of apoptosis of PMNL from AIDS patients. Incubation with granulocyte colony-stimulating factor (G-CSF) in vitro significantly decreased apoptosis for PMNL from AIDS patients. PMNL from patients with AIDS exhibit markedly accelerated apoptosis ex vivo. In vivo, apoptosis and functional impairment of PMNL may contribute to the risk of secondary infections, and cytokine therapy may be of potential clinical benefit in this circumstance.

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.

Clinical Outcomes, Safety, and Pharmacokinetics of OPT-80 in a Phase 2 Trial with Patients with Clostridium difficile Infection

ABSTRACT OPT-80, a novel, minimally absorbed macrocycle, is a candidate treatment option for Clostridium difficile infection (CDI) based on cure without recurrence of CDI in the hamster challenge model, good in vitro activity against C. difficile, and relative sparing of commensal gram-negative anaerobes. In this open-label, dose-ranging clinical trial, 48 evaluable subjects were randomized to receive either 50, 100, or 200 mg of OPT-80 orally every 12 h for 10 days as treatment for mild to moderately severe CDI. OPT-80 was well tolerated by all subjects. Plasma concentrations were below the lower limit of quantitation in almost one-half of patients and typically ≤20 ng/ml across the dose range; the mean fecal concentrations exceeded the MIC at which 90% of the isolates tested are inhibited by 2,000- to 10,000-fold with increasing dosages. Resolution of diarrhea within 10 days was achieved in 10/14 patients (71%), 12/15 patients (80%), and 15/16 patients (94%), and the median time to resolution of diarrhea was reduced from 5.5 to 3.0 days with increasing dosages. Across all groups, the clinical cure rate, which was defined as resolution of diarrheal disease without the need for further treatment, was 41/45 patients (91%). Recurrence of CDI at ∼1 month after treatment was observed in two (5%) patients, one each in the 100-mg and 400-mg groups. The apparent high clinical response, good tolerance, low recurrence rate, and more-complete and rapid symptom control with the highest dosage support the selection of the 200-mg twice-daily dose for further clinical development of OPT-80 for treatment of CDI.

Reduced Acquisition and Overgrowth of Vancomycin-Resistant Enterococci and Candida Species in Patients Treated With Fidaxomicin Versus Vancomycin for Clostridium difficile Infection

Fidaxomicin causes less disruption of anaerobic microbiota during treatment of Clostridium difficile infection (CDI) than vancomycin and has activity against many vancomycin-resistant enterococci (VRE). In conjunction with a multicenter randomized trial of fidaxomicin versus vancomycin for CDI treatment, we tested the hypothesis that fidaxomicin promotes VRE and Candida species colonization less than vancomycin. Stool was cultured for VRE and Candida species before and after therapy. For patients with negative pretreatment cultures, the incidence of VRE and Candida species acquisition was compared. For those with preexisting VRE, the change in concentration during treatment was compared. The susceptibility of VRE isolates to fidaxomicin was assessed. Of 301 patients, 247 (82%) had negative VRE cultures and 252 (84%) had negative Candida species cultures before treatment. In comparison with vancomycin-treated patients, fidaxomicin-treated patients had reduced acquisition of VRE (7% vs 31%, respectively; P < .001) and Candida species (19% vs 29%, respectively; P = .03). For patients with preexisting VRE, the mean concentration decreased significantly in the fidaxomicin group (5.9 vs 3.8 log10 VRE/g stool; P = .01) but not the vancomycin group (5.3 vs 4.2 log10 VRE/g stool; P = .20). Most VRE isolates recovered after fidaxomicin treatment had elevated fidaxomicin minimum inhibitory concentrations (MICs; MIC90, 256 µg/mL), and subpopulations of VRE with elevated fidaxomicin MICs were common before therapy. Fidaxomicin was less likely than vancomycin to promote acquisition of VRE and Candida species during CDI treatment. However, selection of preexisting subpopulations of VRE with elevated fidaxomicin MICs was common during fidaxomicin therapy. Clinical Trials Registration. NCT00314951.

Histoplasmosis After Solid Organ Transplant

BACKGROUND To improve our understanding of risk factors, management, diagnosis, and outcomes associated with histoplasmosis after solid organ transplant (SOT), we report a large series of histoplasmosis occurring after SOT. METHODS All cases of histoplasmosis in SOT recipients diagnosed between 1 January 2003 and 31 December 2010 at 24 institutions were identified. Demographic, clinical, and laboratory data were collected. RESULTS One hundred fifty-two cases were identified: kidney (51%), liver (16%), kidney/pancreas (14%), heart (9%), lung (5%), pancreas (2%), and other (2%). The median time from transplant to diagnosis was 27 months, but 34% were diagnosed in the first year after transplant. Twenty-eight percent of patients had severe disease (requiring intensive care unit admission); 81% had disseminated disease. Urine Histoplasma antigen detection was the most sensitive diagnostic method, positive in 132 of 142 patients (93%). An amphotericin formulation was administered initially to 73% of patients for a median duration of 2 weeks; step-down therapy with an azole was continued for a median duration of 12 months. Ten percent of patients died due to histoplasmosis with 72% of deaths occurring in the first month after diagnosis; older age and severe disease were risk factors for death from histoplasmosis. Relapse occurred in 6% of patients. CONCLUSIONS Although late cases occur, the first year after SOT is the period of highest risk for histoplasmosis. In patients who survive the first month after diagnosis, treatment with an amphotericin formulation followed by an azole for 12 months is usually successful, with only rare relapse.