Background Nirmatrelvir is an orally administered severe acute respiratory syndrome coronavirus 2 main protease (M pro ) inhibitor with potent pan–human-coronavirus activity in vitro. Methods We conducted a phase 2–3 double-blind, randomized, controlled trial in which symptomatic, unvaccinated, nonhospitalized adults at high risk for progression to severe coronavirus disease 2019 (Covid-19) were assigned in a 1:1 ratio to receive either 300 mg of nirmatrelvir plus 100 mg of ritonavir (a pharmacokinetic enhancer) or placebo every 12 hours for 5 days. Covid-19–related hospitalization or death from any cause through day 28, viral load, and safety were evaluated. Results A total of 2246 patients underwent randomization; 1120 patients received nirmatrelvir plus ritonavir (nirmatrelvir group) and 1126 received placebo (placebo group). In the planned interim analysis of patients treated within 3 days after symptom onset (modified intention-to treat population, comprising 774 of the 1361 patients in the full analysis population), the incidence of Covid-19–related hospitalization or death by day 28 was lower in the nirmatrelvir group than in the placebo group by 6.32 percentage points (95% confidence interval [CI], −9.04 to −3.59; P<0.001; relative risk reduction, 89.1%); the incidence was 0.77% (3 of 389 patients) in the nirmatrelvir group, with 0 deaths, as compared with 7.01% (27 of 385 patients) in the placebo group, with 7 deaths. Efficacy was maintained in the final analysis involving the 1379 patients in the modified intention-to-treat population, with a difference of −5.81 percentage points (95% CI, −7.78 to −3.84; P<0.001; relative risk reduction, 88.9%). All 13 deaths occurred in the placebo group. The viral load was lower with nirmaltrelvir plus ritonavir than with placebo at day 5 of treatment, with an adjusted mean difference of −0.868 log 10 copies per milliliter when treatment was initiated within 3 days after the onset of symptoms. The incidence of adverse events that emerged during the treatment period was similar in the two groups (any adverse event, 22.6% with nirmatrelvir plus ritonavir vs. 23.9% with placebo; serious adverse events, 1.6% vs. 6.6%; and adverse events leading to discontinuation of the drugs or placebo, 2.1% vs. 4.2%). Dysgeusia (5.6% vs. 0.3%) and diarrhea (3.1% vs. 1.6%) occurred more frequently with nirmatrelvir plus ritonavir than with placebo. Conclusions Treatment of symptomatic Covid-19 with nirmatrelvir plus ritonavir resulted in a risk of progression to severe Covid-19 that was 89% lower than the risk with placebo, without evident safety concerns. (Supported by Pfizer; ClinicalTrials.gov number, NCT04960202 .)

Objectives: The aim of this analysis was to describe nirmatrelvir/ritonavir real-world effectiveness in preventing hospitalization among high-risk US COVID-19 patients during SARS-CoV-2 Omicron predominance. Design: An ongoing population-based cohort study with retrospective and prospective collection of electronic healthcare data in the United States. Methods: Data for this analysis were collected from the US Optum de-identified COVID-19 Electronic Health Record (EHR) dataset during December 22, 2021 to June 8, 2022. Key eligibility criteria for inclusion in the database analysis were at least 12-years-old; positive SARS-CoV-2 test, COVID-19 diagnosis, or nirmatrelvir/ritonavir prescription; and high risk of severe COVID-19 based on demographic/clinical characteristics. Potential confounders between groups were balanced using propensity score matching (PSM). Immortal time bias was addressed. Outcome measures: Hospitalization rates within 30 (primary analysis) or 15 (sensitivity analysis) days from COVID-19 diagnosis overall and within subgroups were evaluated. Results: Before PSM, the nirmatrelvir/ritonavir group (n=2811) was less racially diverse, older, and had higher COVID-19 vaccination rates and a greater number of comorbidities than the non-nirmatrelvir/ritonavir group (n=194,542). Baseline characteristics were well balanced across groups (n=2808 and n=10,849, respectively) after PSM. Incidence of hospitalization (95% CI) within 30 days was 1.21% (0.84%, 1.69%) for the nirmatrelvir/ritonavir group and 6.94% (6.03%, 7.94%) for the non-nirmatrelvir/ritonavir group, with a hazard ratio (95% CI) of 0.16 (0.11, 0.22; 84% relative risk reduction). Incidence within 15 days was 0.78% (0.49%, 1.18%) for the nirmatrelvir/ritonavir group and 6.54% (5.65%, 7.52%) for the non-nirmatrelvir/ritonavir group; hazard ratio 0.11 (0.07, 0.17; 89% relative risk reduction). Nirmatrelvir/ritonavir was effective in African American patients (hazard ratio, 0.35 [0.15, 0.83]; 65% relative risk reduction). Relative risk reductions were comparable with overall results across ages and among vaccinated patients. Conclusions: Real-world nirmatrelvir/ritonavir effectiveness against hospitalization during the Omicron era supports EPIC-HR efficacy among high-risk patients. Future research should confirm these early real-world results and address limitations.

Tigecycline was effective in the treatment of cIAI and was non-inferior to CTX/MET for the treatment of cIAI in hospitalized adults. Clinical Trials Identifier: NCT00230971.

Background: Treatment with an echinocandin is recommended as first-line therapy for patients with invasive candidiasis (ICC) including candidemia. Little is known about the efficacy and safety of anidulafungin in children with ICC. Methods: Eligible patients with ICC 2 to <18 years old were enrolled into this prospective, open-label, noncomparative, international study (NCT00761267) and received anidulafungin for 10–35 days (3 mg/kg on day 1, 1.5 mg/kg daily thereafter). Safety was assessed through week 6 follow-up. Efficacy, measured by global response (based on clinical and microbiologic responses), was assessed at end of intravenous treatment (EOIVT), end of treatment, weeks 2 and 6 follow-up. Results: Forty-nine patients (n = 19, 2 to <5 years; n = 30, 5 to <18 years) received ≥1 dose of anidulafungin (median 11 days; range 1–35 days) and were assessed for safety. Among 48 patients with a Candida species isolated, C. albicans (37.5%), C. parapsilosis (25.0%), C. tropicalis (14.6%) and C. lusitaniae (10.4%) were the most frequent Candida spp. All patients reported ≥1 treatment-emergent adverse event, with diarrhea (22.4%), vomiting (24.5%) and pyrexia (18.4%) being most frequent. Five patients discontinued treatment because of adverse events, of which 4 discontinuations were considered related to anidulafungin. All-cause mortality was 8.2% (4/49) by EOIVT and 14.3% (7/49) by week 6 follow-up. None of 7 deaths during the study period were considered treatment related. Global response success rate was 70.8% at EOIVT. Conclusions: These data support the use of anidulafungin as a treatment option for ICC in children 2 to <18 years old at the studied dose.

Background: With increasing antimicrobial resistance, antibiotic treatment options for neonatal late-onset sepsis (LOS) are becoming limited. Primary objective of this study was assessment of the safety of ceftaroline fosamil in LOS. Methods: Eligible neonates and very young infants 7 to <60 days of age with LOS were enrolled in this phase 2, open-label, multicenter study (NCT02424734) and received ceftaroline fosamil 4 or 6 mg/kg every 8 hours by 1-hour intravenous infusion plus intravenous ampicillin and optional aminoglycoside for 48 hours−14 days. Safety was assessed through the final study visit (21–35 days after the last study therapy dose). Efficacy, assessed as clinical and microbiologic response, was evaluated at end-of-treatment and test-of-cure. Pharmacokinetic samples were collected via sparse-sampling protocol. Results: Eleven patients [54.5% male, median (range) age 24 (12–53) days] were enrolled and received ceftaroline fosamil for a median (range) duration of 8 (3–15) days. Ten adverse events (AEs) occurred in 5 (45.5%) patients (safety population); most frequent AE was diarrhea (n = 2). All except 1 AE (diarrhea) were nontreatment-related. Predominant baseline pathogen was Escherichia coli. No patients were clinical failures at end-of-treatment/test-of-cure. Observed sparse steady-state pharmacokinetics data (19 samples) were comparable to previous pediatric data and generally within 90% model prediction intervals; neonatal probability of target attainment was >95% based on established pharmacokinetic/pharmacodynamic targets. Conclusions: Safety in neonates and very young infants was consistent with the known ceftaroline fosamil safety profile. These results support the use of ceftaroline fosamil (6 mg/kg every 8 hours) as a potential treatment option for LOS.

Nineteen patients 1 month to <2 years of age with (n = 16) or at high risk of (n = 3) invasive candidiasis received anidulafungin for 5-35 days (3 mg/kg day 1, 1.5 mg/kg daily thereafter) followed by optional fluconazole (NCT00761267). Most treatment-emergent adverse events were mild/moderate, and no treatment-related deaths occurred. End of intravenous therapy global response success rate was 68.8%. Pharmacokinetics were similar to adult patients.

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Nirmatrelvir-ritonavir was developed for the treatment of COVID-19 and has shown efficacy in a Phase 2/3 study of high risk patients (EPIC-HR1). Monitoring for the emergence of viral resistance and recurrence of symptoms is a critical component of any antiviral drug development. As part of the study of viral resistance, a sub-analysis was conducted to examine viral load rebound (VLR) following nirmatrelvir-ritonavir treatment in the EPIC-HR study. Nasopharyngeal or nasal swabs were collected from all study participants at Day 1, Day 3, Day 5, Day 10, and Day 14, and analyzed for viral RNA load and next generation viral sequencing. Two categories of viral load rebound were considered including present/persistent and transient. In EPIC-HR, the proportion of present/persistent VLR was low, occurring at 1.73% (17/980) vs 2.32% (23/990) and for transient VLR 2.35% (23/980) vs 4.65% (46/990) in placebo vs nirmatrelvir-ritonavir participants, respectively. VLR occurred in both treatment arms and was not associated with low nirmatrelvir exposure, hospitalization or death, severe symptom relapse, serological status, or Mpro gene/cleavage treatment emergent mutations. In summary, viral load rebounds are likely a phenomena COVID-19 disease course and nirmatrelvir-ritonavir continue to be an important treatment option for high risk COVID-19 patients.