Public health case for microbiome-sparing antibiotics and new opportunities for drug development.

Although antibiotics remain a cornerstone of modern medicine, the issues of widespread antibiotic resistance and collateral damage to the microbiome from antibiotic use are driving a need for drug developers to consider more tailored, patient-directed products to avoid antibiotic-induced perturbations of the structure and function of the indigenous microbiota. This perspective summarizes a cascade of microbiome health effects that is initiated by antibiotic-mediated microbiome disruption at an individual level and ultimately leads to infection and transmission of multidrug-resistant pathogens across patient populations. The scientific evidence behind each of the key steps of this cascade is presented. The interruption of this cascade through the use of highly targeted, microbiome-sparing antibiotics aiming to improve health outcomes is discussed. Further, this perspective reflects on some key clinical trial design and reimbursement considerations to be addressed as part of the drug development path.

FDA, CDC, and NIH Co-sponsored Public Workshop Summary-Development Considerations of Antimicrobial Drugs for the Treatment of Gonorrhea.

There is an unmet need for developing drugs for the treatment of gonorrhea, due to rapidly evolving resistance of Neisseria gonorrhoeae against antimicrobial drugs used for empiric therapy, an increase in globally reported multidrug resistant cases, and the limited available therapeutic options. Furthermore, few drugs are under development. Development of antimicrobials is hampered by challenges in clinical trial design, limitations of available diagnostics, changes in and varying standards of care, lack of robust animal models, and clinically relevant pharmacodynamic targets. On April 23, 2021, the U.S. Food and Drug Administration; Centers for Disease Control and Prevention; and National Institute of Allergy and Infectious Diseases, National Institutes of Health co-sponsored a workshop with stakeholders from academia, industry, and regulatory agencies to discuss the challenges and strategies, including potential collaborations and incentives, to facilitate the development of drugs for the treatment of gonorrhea. This article provides a summary of the workshop.

Efficacy and safety of diclofenac in osteoarthritis: Results of a network meta-analysis of unpublished legacy studies.

BACKGROUND AND AIM: Diclofenac is widely prescribed for the treatment of pain. Several network meta-analyses (NMA), largely of published trials have evaluated the efficacy, tolerability, and safety of non-steroidal anti-inflammatory drugs (NSAIDs). The present NMA extends these analyses to unpublished older (legacy) diclofenac trials. METHODS: We identified randomised controlled trials (RCTs) of diclofenac with planned study duration of at least 4 weeks for the treatment of osteoarthritis (OA) from 'legacy' studies conducted by Novartis but not published in a peer reviewed journal or included in any previous pooled analyses. All studies reporting efficacy and/or safety of treatment with diclofenac or other active therapies or placebo were included. We used a Bayesian NMA model, and estimated relative treatment effects between pairwise treatments. Main outcomes included pain relief measured using visual analogue scale at 2, 4 and 12 weeks and patient global assessment (PGA) at 4 and 12 weeks for efficacy, all-cause withdrawals, and adverse events. RESULTS: A total of 19 RCTs (5030 patients) were included; 18 of which were double-blind and one single-blind. All studies were conducted before cyclooxygenase 2 inhibitors (COXIBs) became commercially available. Data permitted robust efficacy comparison between diclofenac and ibuprofen, but the amount of data for other comparators was limited. Diclofenac 150mg/day was more efficacious than ibuprofen 1200mg/day and had likely favourable outcomes for pain relief compared to ibuprofen 2400mg/day. Diclofenac 100mg/day had likely favourable outcomes compared to ibuprofen 1200mg/day in alleviating pain. Based on PGA, diclofenac 150mg/day was more efficacious and likely to be favourable than ibuprofen 1200mg/day and 2400mg/day, respectively. Risk of withdrawal due to all causes with diclofenac and ibuprofen were comparable. Diclofenac 150mg/day was likely to have favourable efficacy and comparable tolerability with diclofenac 100mg/day. Results comparing diclofenac and ibuprofen were similar to those from NMAs of published trials. CONCLUSIONS: Results from these unpublished 'legacy' studies were similar to those from NMAs of published trials. The favourable efficacy results of diclofenac compared to ibuprofen expand the amount of available evidence comparing these two NSAIDs. The overall benefit-risk profile of diclofenac was comparable to that of ibuprofen in OA. IMPLICATIONS: The present NMA results reassures that the older unpublished blinded trials have similar results compared to more recently published trials and also contributes to increase the transparency of clinical trials performed with diclofenac further back in the past.

Population pharmacokinetics of daptomycin in adult patients undergoing continuous renal replacement therapy.

AIM: The objective of this population pharmacokinetic (PK) analysis was to provide guidance for the dosing interval of daptomycin in patients undergoing continuous renal replacement therapy (CRRT). METHODS: A previously published population PK model for daptomycin was updated with data from patients undergoing continuous veno-venous haemodialysis (CVVHD; n = 9) and continuous veno-venous haemodiafiltration (CVVHDF; n = 8). Model-based simulations were performed to compare the 24 h AUC, Cmax and Cmin of daptomycin following various dosing regimens (4, 6, 8, 10, and 12 mg kg-1 every [Q] 24 h and Q48 h), with the safety and efficacy exposure references for Staphylococcus aureus bacteraemia/right-sided infective endocarditis. RESULTS: The previously developed daptomycin structural population PK model could reasonably describe data from the patients on CRRT. The clearance in patients undergoing CVVHDF and CVVHD was estimated at 0.53 and 0.94 l h-1 , respectively, as compared with 0.75 l h-1 in patients with creatinine clearance (CrCl) ≥ 30 ml min-1 . Daptomycin Q24 h dosing in patients undergoing CRRT resulted in optimal exposure for efficacy, with AUC comparable to that in patients with CrCl ≥ 30 ml min-1 . In contrast, Q48 h dosing was associated with considerably lower AUC24-48h in all patients for doses up to 12 mg kg-1 and is therefore inappropriate. CONCLUSIONS: Q24 h dosing of daptomycin up to 12 mg kg-1 provides comparable drug exposure in patients on CVVHD and in those with CrCl ≥ 30 ml min-1 . Daily daptomycin use up to 8 mg kg-1 doses are appropriate for patients on CVVHDF, but higher doses may increase the risk of toxicity.

High correlation of VAS pain scores after 2 and 6 weeks of treatment with VAS pain scores at 12 weeks in randomised controlled trials in rheumatoid arthritis and osteoarthritis: meta-analysis and implications.

BACKGROUND: Researchers in clinical trials in rheumatoid arthritis (RA) and osteoarthritis (OA) often measure pain levels with a visual analogue scale (VAS). Of interest to clinical practice and future clinical trial design are associations of change from baseline (CFB) between time points with predictive ability of earlier response for long-term treatment benefit. We assessed the association and predictive ability of CFB in VAS pain between 2, 6 and 12 weeks in randomised controlled trials (RCTs) of non-steroidal anti-inflammatory drugs (NSAIDs). METHODS: Aggregated VAS pain data at baseline and CFB at 2, 6 and 12 weeks were collected from a systematic literature review of 176 RCTs in OA and RA. The predictive ability of earlier assessments for longer-term pain reduction was estimated using correlation and regression analyses. Analysis was performed using the R software package for statistical programming, version 3.1.1. RESULTS: Appropriate data were available from 50 RCTs (22,854 patients). Correlations between time points were high (weighted correlation coefficients between 2 and 6 weeks, 0.84; between 2 and 12 weeks, 0.79; and between 6 and 12 weeks, 0.96). CFB at 6 weeks was highly predictive and close to CFB at 12 weeks (regression coefficient 0.9, 95 % confidence interval 0.9-1.0). CFB at 2 weeks was significantly associated with CFB at 12 (0.8, 0.7-0.8) and 6 weeks (0.9, 0.8-1.0). CONCLUSIONS: The results showed that early analgesic response measured by VAS for pain beyond 2 weeks of treatment with a particular NSAID is likely to be predictive of response at 12 weeks. Failure to achieve desired pain relief in OA and RA after 2 weeks should trigger reassessment of dosage and/or analgesic.

Tipranavir/Ritonavir (500/200 mg and 500/100 mg) Was Virologically Non-Inferior to Lopinavir/Ritonavir (400/100 mg) at Week 48 in Treatment-Naïve HIV-1-Infected Patients: A Randomized, Multinational, Multicenter Trial.

Ritonavir-boosted tipranavir (TPV/r) was evaluated as initial therapy in treatment-naïve HIV-1-infected patients because of its potency, unique resistance profile, and high genetic barrier. Trial 1182.33, an open-label, randomized trial, compared two TPV/r dose combinations versus ritonavir-boosted lopinavir (LPV/r). Eligible adults, who had no prior antiretroviral therapy were randomized to twice daily (BID) 500/100 mg TPV/r, 500/200 mg TPV/r, or 400/100 mg LPV/r. Each treatment group also received Tenofovir 300 mg + Lamivudine 300 mg QD. The primary endpoint was a confirmed viral load (VL) <50 copies/mL at week 48 without prior antiretroviral regimen changes. Primary analyses examined CD4-adjusted response rates for non-inferiority, using a 15% non-inferiority margin. At week 48, VL<50 copies/mL was 68.4%, 69.9%, and 72.4% in TPV/r100, TPV/r200, and LPV/r groups, respectively, and TPV/r groups showed non-inferiority to LPV/r. Discontinuation due to adverse events was higher in TPV/r100 (10.3%) and TPV/r200 (15.3%) recipients versus LPV/r (3.2%) recipients. The frequency of grade ≥3 transaminase elevations was higher in the TPV/r200 group than the other groups, leading to closure of this group. However, upon continued treatment or following re-introduction after treatment interruption, transaminase elevations returned to grade ≤2 in >65% of patients receiving either TPV/r200 or TPV/r100. The trial was subsequently discontinued; primary objectives were achieved and continuing TPV/r100 was less tolerable than standard of care for initial highly active antiretroviral therapy. All treatment groups had similar 48-week treatment responses. TPV/r100 and TPV/r200 regimens resulted in sustained treatment responses, which were non-inferior to LPV/r at 48 weeks. When compared with the LPV/r regimen and examined in the light of more current regimens, these TPV/r regimens do not appear to be the best options for treatment-naïve patients based on their safety profiles.

Daptomycin for methicillin-resistant Staphylococcus aureus diabetic foot infections.

BACKGROUND: Diabetic foot infection (DFI) is a serious, difficult-to-treat infection, especially when caused by methicillin-resistant Staphylococcus aureus (MRSA). Vancomycin has been the standard treatment for MRSA infection, but lower response rates in MRSA skin infections have been reported. This analysis assessed the outcome and safety of daptomycin therapy in patients with a DFI caused by MRSA. METHODS: Using the Cubicin Outcomes Registry and Experience and the European Cubicin Outcomes Registry and Experience (2006-2009), 79 patients with MRSA DFI were identified and included in this analysis. RESULTS: In the 74 evaluable patients, daptomycin was administered at a median dose of 4.8 mg/kg primarily every 24 hours (85.1%) and for a median of 15.0 days. Overall, 77.0% of the patients (57 of 74) received initial therapy with activity against MRSA; however, of patients receiving daptomycin as second-line therapy (n = 31), only 45.2% were treated with an antibiotic agent active against MRSA. The overall clinical success and treatment failure rates were 89.2% and 10.8%, respectively. Success with daptomycin therapy was higher in patients who had surgery and in those whose initial therapy was daptomycin. Eleven patients had 14 adverse events, two of which were possibly related to daptomycin use and led to discontinuation. CONCLUSIONS: In a large real-world cohort of patients with MRSA DFI, daptomycin therapy was shown to be generally well tolerated and effective. The use of an anti-MRSA antibiotic agent should be considered when implementing first-line antibiotic drug therapy for DFI in countries where MRSA is common to avoid inappropriate empirical treatment and potential negative effects on outcomes.

Clinical and pharmacokinetic considerations for the use of daptomycin in patients with Staphylococcus aureus bacteraemia and severe renal impairment.

OBJECTIVES: To support daptomycin dosing recommendations in patients with Staphylococcus aureus bacteraemia (SAB) and severe renal impairment using simulations from a population pharmacokinetic model for daptomycin. METHODS: A population pharmacokinetic model was developed using 4875 daptomycin plasma concentrations from 442 subjects. Daptomycin 24 h AUC and Cmax were then simulated for subjects with a CL(CR) < 30 mL/min [with or without haemodialysis (HD) or continuous ambulatory peritoneal dialysis (CAPD)] for different dosing frequencies (every 24 h, every 48 h and three times weekly) with doses of 4 mg/kg and 6 mg/kg. These results were compared with efficacy and safety exposure references based on daily dosing to understand the implications of less frequent dosing (for example, higher exposures on day 1 versus day 2) and to evaluate the 4 mg/kg versus 6 mg/kg regimens. RESULTS: Substantially more patients with SAB and severe renal impairment were underexposed (24 h AUCs compared with an efficacy reference of 6 mg/kg/day, CLCR ≥ 30 mL/min, pivotal trial population) at 4 mg/kg every 48 h compared with 6 mg/kg. Cmax results also favoured 6 mg/kg every 48 h over 4 mg/kg every 48 h. Both exposure metrics at 6 mg/kg every 48 h also stayed below the defined safety limits (based on 12 mg/kg/day, CL(CR) >80 mL/min, the highest dose in controlled clinical trials). CONCLUSIONS: For patients with SAB and CLCR <30 mL/min, or receiving HD or CAPD, the dose recommendation of 6 mg/kg every 48 h provides appropriate daptomycin exposure for this indication; this will not be the case for patients receiving 4 mg/kg every 48 h.

Safety and efficacy of daptomycin as first-line treatment for complicated skin and soft tissue infections in elderly patients: an open-label, multicentre, randomized phase IIIb trial.

BACKGROUND: Daptomycin has proven efficacy in patients with Gram-positive complicated skin and soft tissue infections (cSSTIs), including those caused by Staphylococcus aureus, regardless of methicillin susceptibility. OBJECTIVE: This study was undertaken to evaluate the efficacy and safety of daptomycin in elderly patients. STUDY DESIGN: This was an open-label, multicentre, randomized phase IIIb study conducted in hospitalized patients PATIENTS: Patients aged ≥65 years with a diagnosis of Gram-positive cSSTIs with or without bacteraemia were included. In addition, infections were required to be of sufficient severity to require inpatient hospitalization and treatment with parenteral antibiotics for at least 96 h. The main exclusion criterion was the presence of a non-complicated SSTI that could heal by itself or be cured by surgical removal of the site of infection. INTERVENTION: Patients were randomized (2:1) to intravenous daptomycin or pooled intravenous standard therapies (semi-synthetic penicillin or vancomycin, referred to as the 'comparator'). Duration of treatment was between 5 and 14 days for cSSTIs without bacteraemia and between 10 and 28 days for cSSTIs with bacteraemia. MAIN OUTCOME MEASURE: The primary objective was descriptive comparison of clinical success in clinically evaluable patients at test of cure, 7-14 days post treatment. Secondary objectives were microbiological outcome, duration of treatment and safety. RESULTS: In total, 120 patients were randomized (81 to daptomycin; 39 to the comparator) and 102 patients completed the study. Baseline characteristics were similar between the two groups. Common infections included cellulitis, ulcers and abscesses; six patients had bacteraemia [five documented (daptomycin, n = 3; comparator, n = 2); and one suspected (daptomycin, n = 1)]. Test-of-cure clinical success rates were numerically higher for daptomycin than for the comparator [89.0 % (65/73) vs. 83.3 % (25/30); odds ratio 1.65 (95 % confidence interval 0.49-5.54)]. For patients with S. aureus infections, cure rates were 89.7 % (35/39) versus 69.2 % (9/13), respectively; percentage points difference, 20.5 (95 % confidence interval -12.2 to 50.9)]. Rates of adverse events (AEs) and serious AEs were similar in both treatment arms; however, discontinuation rates for AEs/serious AEs were lower for daptomycin than for the comparator (3.8 % vs. 10.0 %). Three serious AEs were considered to be related to the study drug: one case each of pancytopenia (semi-synthetic penicillin), renal failure (vancomycin) and asymptomatic increase in creatine phosphokinase concentrations (daptomycin). CONCLUSION: In elderly patients, for whom data were previously limited, the efficacy and safety of daptomycin have been confirmed, including for infections caused by S. aureus, regardless of methicillin susceptibility.

Daptomycin for outpatient parenteral antibiotic therapy: a European registry experience.

A retrospective analysis of data from patients receiving daptomycin as outpatient parenteral antimicrobial therapy (OPAT) within the European Cubicin Outcomes Registry and Experience (EU-CORE(SM)) was performed. Of 4592 enrolled patients in 15 countries, 550 (12%) received daptomycin OPAT. Of these, 149 (27%) received daptomycin without hospital admission, 84% had significant underlying diseases and 44% were ≥65 years of age. Most frequently treated infections were complicated skin and soft-tissue infections (28%), osteomyelitis (17%), foreign body/prosthetic infections (15%) and endocarditis (14%). In patients with culture results available, Staphylococcus aureus and coagulase-negative staphylococci were the most commonly isolated primary pathogens [n = 218 (46%) and n = 102 (21%), respectively]. Daptomycin was typically used at doses of 6 mg/kg (n = 210; 38%) and 4 mg/kg (n = 160; 29%), with concomitant antibiotics used in 41%. The median treatment duration was 22 days (range 1-300 days), with a median of 13 OPAT days (range 1-290 days). Overall clinical success was observed in 89%, with high success rates across the wide range of infections, including those caused by meticillin-resistant and meticillin-susceptible S. aureus (88% and 90%, respectively). Daptomycin exhibited a favourable safety profile; 3.1% of patients discontinued treatment owing to an adverse event. These data demonstrate that daptomycin is effective and well tolerated in the treatment of a wide range of Gram-positive infections in the outpatient setting. Ease of administration of daptomycin, via a daily 2-min injection, and its efficacy and safety combine to make it an attractive treatment option for OPAT.

Effectiveness and safety of daptomycin in complicated skin and soft-tissue infections and bacteraemia in clinical practice: results of a large non-interventional study.

This retrospective analysis of patients from eight countries included in the European Cubicin(®) Outcomes Registry and Experience (EU-CORE(SM)) captures the first post-approval years of clinical experience with daptomycin in its licensed indications. Of the total 1127 patients enrolled in EU-CORE between 2006 and 2008, 373 had a primary complicated skin and soft-tissue infection (cSSTI), most commonly surgical-site infection (48%), and 244 had bacteraemia, 55% of which were catheter-related. The most common pathogens were Staphylococcus aureus in cSSTIs (43%) and coagulase-negative staphylococci in bacteraemia (36%). The most frequently prescribed daptomycin doses were 4 mg/kg and 6 mg/kg for cSSTIs, and 6 mg/kg for bacteraemia. The median duration of inpatient and outpatient treatment, respectively, was 13 days and 8 days for cSSTIs and 8 days and 10 days for bacteraemia. Clinical success was reported for 81% of patients with cSSTIs and 77% with bacteraemia, with 82% success overall for infections caused by S. aureus. A trend towards higher clinical success was noted with higher daptomycin doses in bacteraemia (78% for 6 mg/kg vs. 90% for doses >6 mg/kg). Daptomycin demonstrated a favourable safety profile. Adverse events regardless of relationship to study drug were reported for 11% of patients with cSSTIs and 24% with bacteraemia, most commonly septic shock [7 patients (2%) with cSSTIs and 5 patients (2%) with bacteraemia]. These results demonstrate that daptomycin is effective and well tolerated in the treatment of cSSTIs and bacteraemia caused by Gram-positive bacteria in clinical practice.

Daptomycin use in patients with osteomyelitis: a preliminary report from the EU-CORE(SM) database.

BACKGROUND: Osteomyelitis is a complex and heterogeneous group of infections that require surgical and antimicrobial interventions. Because treatment failure or intolerance is common, new treatment options are needed. Daptomycin has broad Gram-positive activity, penetrates bone effectively and has bactericidal activity within biofilms. This is the first report on clinical outcomes in patients with osteomyelitis from the multicentre, retrospective, non-interventional European Cubicin(®) Outcomes Registry and Experience (EU-CORE(SM)), a large database on real-world daptomycin use. PATIENTS AND METHODS: In total, 220 patients were treated for osteomyelitis; the population was predominantly elderly, with predisposing baseline conditions such as diabetes and chronic renal/cardiac diseases. RESULTS: Most patients (76%) received prior antibiotic treatment, and first-line treatment failure was the most frequent reason to start daptomycin. Common sites of infection were the knee (22%) or hip (21%), and the most frequently isolated pathogens were Staphylococcus aureus (33%) and coagulase-negative staphylococci (32%). Overall, 52% of patients had surgery, 55% received concomitant antibiotics and 29% received a proportion of daptomycin therapy as outpatients. Clinical success was achieved in 75% of patients. Among patients with prosthetic device-related osteomyelitis, there was a trend towards higher success rates if the device was removed. Daptomycin was generally well tolerated. CONCLUSIONS: This analysis suggests that daptomycin is an effective and well-tolerated treatment option for osteomyelitis and highlights the importance of optimal surgical intervention and appropriate microbiological diagnosis for clinical outcomes.

Daptomycin for the treatment of infective endocarditis: results from a European registry.

OBJECTIVES: Infective endocarditis (IE) is a complex infection associated with high mortality. Daptomycin, a cyclic lipopeptide antibiotic highly active against Gram-positive bacteria, has recently been incorporated into IE treatment guidelines. This retrospective analysis provides insights into the use of daptomycin in IE in the European Cubicin(®) Outcomes Registry Experience (EU-CORE(SM)) between 2006 and 2010. PATIENTS AND METHODS: Three hundred and seventy-eight (10%) of 3621 enrolled patients received daptomycin for treatment of IE. Two hundred and fifty-nine (69%) had left-sided IE (LIE) and 182 patients (48%) underwent concomitant surgery. RESULTS: Staphylococcus aureus was the most frequently identified pathogen (n=92; methicillin susceptible, n=50) and daptomycin was used empirically in 134 patients. Among cases of second-line therapy (n=312), the most common reason for switching to daptomycin was failure of the previous regimen (including glycopeptides and penicillins). Daptomycin was administered at 6 mg/kg in 224 patients and at ≥ 8 mg/kg in 72 patients. Clinical success rates were 80% overall, 91% for right-sided IE (RIE) and 76% for LIE, with similar rates seen for infections caused by methicillin-susceptible S. aureus (84%) and methicillin-resistant S. aureus (81%). The clinical success rate in patients treated with ≥ 8 mg/kg daptomycin was 90% [n=72 (RIE, 91%; LIE, 89%)]. No new safety signals were observed. CONCLUSIONS: In patients with IE registered in EU-CORE, daptomycin was most frequently used as second-line treatment after treatment failure. The majority of patients had LIE and most commonly received daptomycin for the treatment of staphylococcal infections. Clinical success was high in this difficult-to-treat population. The role of doses ≥ 8 mg/kg per day in the empirical treatment of IE deserves further investigation.

Clinical experience with daptomycin in Europe: the first 2.5 years.

OBJECTIVES: To describe the patient populations and infections being treated with daptomycin, as well as the efficacy and safety outcomes. PATIENTS AND METHODS: Data from the European Cubicin Outcomes Registry and Experience (EU-CORESM), retrospectively collected at 118 institutions between January 2006 and August 2008, were analysed. RESULTS: Daptomycin treatment was documented in 1127 patients with diverse infections, including complicated skin and soft tissue infections (33%), bacteraemia (22%), endocarditis (12%) and osteomyelitis (6%). It was used empirically, before microbiological results became available, in 53% of patients. Staphylococcus aureus was the most common pathogen (34%), with 52% of isolates resistant to methicillin; coagulase-negative staphylococci and enterococci were also frequent, with 22% of Enterococcus faecium isolates resistant to vancomycin. Daptomycin was used as first-line therapy in 302 (27%) patients. When used second line, the most common reasons for discontinuation of previous antibiotic were treatment failure and toxicity or intolerance. The use of concomitant antibiotics was reported in 65% of patients. Most frequent doses were 6 mg/kg (47%) and 4 mg/kg (32%). The median duration of daptomycin therapy was 10 days (range 1-246 days) in the inpatient setting and 13 days (range 2-189 days) in the outpatient setting. The overall clinical success rate was 79%, with a clinical failure rate of <10% for all infection types. Low failure rates were observed in first- and second-line therapy (6% and 8%, respectively). Daptomycin demonstrated a favourable safety and tolerability profile regardless of treatment duration. CONCLUSIONS: Daptomycin has a relevant role in the treatment of Gram-positive infections.

A potential role for daptomycin in enterococcal infections: what is the evidence?

Nosocomial infections caused by enterococci present a challenge for clinicians because treatment options are often limited due to the widespread occurrence of strains resistant to multiple antibiotics, including vancomycin. Daptomycin is a first-in-class cyclic lipopeptide that has proven efficacy for the treatment of Gram-positive infections. Although methicillin-resistant Staphylococcus aureus has been the most prominent target in the clinical development of daptomycin, this agent has demonstrated potent bactericidal activity in enterococcal infection models and has been used for the treatment of enterococcal infections in humans. In recent years, large-scale susceptibility studies have shown that daptomycin is active against >98% of enterococci tested, irrespective of their susceptibility to other antibacterial agents. This lack of cross-resistance reflects the fact that daptomycin has a mode of action distinct from those of other antibiotics, including glycopeptides. While there are limited data available from randomized controlled trials, extensive clinical experience with daptomycin in enterococcal infections (including bacteraemia, endocarditis, skin and soft tissue infections, bone and joint infections and urinary tract infections) has been reported. This growing body of evidence provides useful insights regarding the efficacy of daptomycin against enterococci in clinical settings.

Comparison of the pharmacokinetics, safety and tolerability of daptomycin in healthy adult volunteers following intravenous administration by 30 min infusion or 2 min injection.

OBJECTIVES: Two randomized Phase I studies in separate populations of healthy adult volunteers investigated the pharmacokinetics, safety and tolerability of daptomycin (Cubicin; Novartis Pharma AG, Basel, Switzerland) administered as a 2 min intravenous (iv) injection, relative to the currently licensed 30 min iv infusion. METHODS: Study 1 was an open-label, single-dose, two-period, crossover study in which each subject received 6 mg/kg daptomycin administered as a 30 min iv infusion (n = 15) and as a 2 min iv injection (n = 16). In Study 2, a single-blind, multiple-dose, parallel-group study, subjects received a once-daily 2 min iv injection of 6 mg/kg daptomycin (n = 12), 4 mg/kg daptomycin (n = 8) or placebo (n = 4) for 7 days. Single-dose pharmacokinetics were assessed at various timepoints up to 36 and 24 h post-dose in Study 1 and Study 2, respectively, and multiple-dose pharmacokinetics were assessed in Study 2 at day 7 for 48 h post-dose. RESULTS: In Study 1, pharmacokinetic comparability between the two administration regimens was demonstrated by meeting the bioequivalence criteria for the exposure parameters, AUC(0-t), AUC(0-infinity) and C(max). In Study 2, time-invariant pharmacokinetic properties as well as dose-proportional pharmacokinetics were demonstrated for the daptomycin 2 min iv injection regimen. In both studies, daptomycin was well tolerated and the majority of treatment-emergent adverse events were of mild intensity and considered to be unrelated to daptomycin. CONCLUSIONS: The similar pharmacokinetic and safety profiles of the two administration regimens suggest that the 2 min iv injection may be a convenient treatment option for both patients and healthcare professionals.

Short-term antiviral efficacy of BILN 2061, a hepatitis C virus serine protease inhibitor, in hepatitis C genotype 1 patients.

BACKGROUND AND AIMS: Novel, potent, and well-tolerated hepatitis C virus (HCV) drugs are needed. BILN 2061 is a potent and specific inhibitor of HCV serine protease in vitro. Preclinical toxicology data and studies in healthy volunteers supported the administration of BILN 2061 to patients with HCV infection. METHODS: The antiviral efficacy, pharmacokinetics, and tolerability of 25, 200, and 500 mg BILN 2061 twice daily given as monotherapy for 2 days in 31 patients infected with chronic genotype 1 HCV infection and with minimal liver fibrosis (Ishak score of 0-2) were assessed in a placebo-controlled, double-blind pilot study. In 2 subsequent placebo-controlled studies of similar design, 200 mg BILN 2061 twice daily was administered for 2 days to 10 patients with advanced liver fibrosis (Ishak score of 3 or 4) and to 10 patients with compensated cirrhosis (Ishak score of 5 or 6). RESULTS: Viral RNA reductions of 2-3 log 10 copies/mL were achieved in most of the patients. There was a trend toward a higher number of patients receiving 500 mg BILN 2061 achieving a viral RNA reduction > or =3 log(10) copies/mL as compared with patients receiving 25 mg BILN 2061. Advanced fibrosis or compensated cirrhosis did not affect the antiviral efficacy of BILN 2061. BILN 2061 was well tolerated in all studies. CONCLUSIONS: BILN 2061 is a well-tolerated and very active compound that reduced serum viral RNA concentrations after 2 days of treatment in patients infected with genotype 1 HCV independent of the degree of fibrosis. Nevertheless, further clinical trials are on hold pending resolution of animal toxicity issues.