Search

Background Sulopenem is a thiopenem antibiotic being developed for the treatment of multidrug-resistant infections. The availability of both intravenous (IV) and oral formulations will facilitate earlier hospital discharge. Methods Hospitalized adults with pyuria, bacteriuria, and signs and symptoms of complicated urinary tract infection (cUTI) were randomized to 5 days of IV sulopenem followed by oral sulopenem etzadroxil/probenecid or 5 days of IV ertapenem followed by oral ciprofloxacin or amoxicillin-clavulanate, depending on uropathogen susceptibility. The primary end point was overall combined clinical and microbiologic response at the test-of-cure visit (day 21). Results Of 1392 treated patients, 444 and 440 treated with sulopenem and ertapenem, respectively, had a positive baseline urine culture and were eligible for the primary efficacy analyses. Extended-spectrum β-lactamase-producing organisms were identified in 26.6% of patients and fluoroquinolone-nonsusceptible pathogens in 38.6%. For the primary end point, noninferiority of sulopenem to the comparator regimen was not demonstrated, 67.8% vs 73.9% (difference, −6.1%; 95% confidence interval, −12.0 to −.1%). The difference was driven by a lower rate of asymptomatic bacteriuria in the subgroup of ertapenem-treated patients who stepped down to ciprofloxacin. No substantial difference in overall response was observed at any other time point. Both IV and oral formulations of sulopenem were well-tolerated and compared favorably to the comparator. Conclusions Sulopenem followed by oral sulopenem-etzadroxil/probenecid was not noninferior to ertapenem followed by oral step-down therapy for the treatment of cUTIs, driven by a lower rate of asymptomatic bacteriuria in those who received ciprofloxacin. Both formulations of sulopenem were well-tolerated. Clinical Trial Registration NCT03357614.

Item does not contain fulltext BACKGROUND: Rezafungin is a next-generation, once-a-week echinocandin in development for the treatment of candidaemia and invasive candidiasis and for the prevention of invasive fungal disease caused by Candida, Aspergillus, and Pneumocystis spp after blood and marrow transplantation. We aimed to compare the efficacy and safety of intravenous rezafungin versus intravenous caspofungin in patients with candidaemia and invasive candidiasis. METHODS: ReSTORE was a multicentre, double-blind, double-dummy, randomised phase 3 trial done at 66 tertiary care centres in 15 countries. Adults (≥18 years) with systemic signs and mycological confirmation of candidaemia or invasive candidiasis were eligible for inclusion and randomly assigned (1:1) to receive intravenous rezafungin once a week (400 mg in week 1, followed by 200 mg weekly, for a total of two to four doses) or intravenous caspofungin (70 mg loading dose on day 1, followed by 50 mg daily) for no more than 4 weeks. The primary endpoints were global cure (consisting of clinical cure, radiological cure, and mycological eradication) at day 14 for the European Medical Agency (EMA) and 30-day all-cause mortality for the US Food and Drug Administration (FDA), both with a target non-inferiority margin of 20%, assessed in the modified intention-to-treat population (all patients who received one or more doses of study drug and had documented Candida infection based on a culture from blood or another normally sterile site obtained within 96 h before randomisation). Safety was evaluated by the incidence and type of adverse events and deaths in the safety population, defined as all patients who received any amount of study drug. The trial is registered with ClinicalTrials.gov, NCT03667690, and is complete. FINDINGS: Between Oct 12, 2018, and Aug 29, 2021, 222 patients were screened for inclusion, and 199 patients (118 [59%] men; 81 [41%] women; mean age 61 years [SD 15·2]) were randomly assigned (100 [50%] patients to the rezafungin group and 99 [50%] patients to the caspofungin group). 55 (59%) of 93 patients in the rezafungin group and 57 (61%) of 94 patients in the caspofungin group had a global cure at day 14 (weighted treatment difference -1·1% [95% CI -14·9 to 12·7]; EMA primary endpoint). 22 (24%) of 93 patients in the rezafungin group and 20 (21%) of 94 patients in the caspofungin group died or had an unknown survival status at day 30 (treatment difference 2·4% [95% CI -9·7 to 14·4]; FDA primary endpoint). In the safety analysis, 89 (91%) of 98 patients in the rezafungin group and 83 (85%) of 98 patients in the caspofungin group had at least one treatment-emergent adverse event. The most common treatment-emergent adverse events that occurred in at least 5% of patients in either group were pyrexia, hypokalaemia, pneumonia, septic shock, and anaemia. 55 (56%) patients in the rezafungin group and 52 (53%) patients in the caspofungin group had serious adverse events. INTERPRETATION: Our data show that rezafungin was non-inferior to caspofungin for the primary endpoints of day-14 global cure (EMA) and 30-day all-cause mortality (FDA). Efficacy in the initial days of treatment warrants evaluation. There were no concerning trends in treatment-emergent or serious adverse events. These phase 3 results show the efficacy and safety of rezafungin and support its ongoing development. FUNDING: Cidara Therapeutics and Mundipharma.

Background Rezafungin is a next-generation, once-weekly echinocandin in development for treatment of candidemia and invasive candidiasis (IC), and for prevention of invasive fungal diseases caused by Candida, Aspergillus, and Pneumocystis in allogeneic blood and marrow transplant recipients (Fig 1). ReSTORE (NCT03667690) is a global, double-blind, double-dummy, 1:1 randomized, controlled, Phase 3 non-inferiority trial that evaluated the efficacy and safety of rezafungin once weekly (QWk) versus caspofungin once daily (QD) in patients with candidemia and/or IC. This analysis of the completed ReSTORE trial was conducted to evaluate outcomes by baseline pathogen and susceptibility. Methods In ReSTORE, adults (≥18 y) with systemic signs and mycological confirmation of candidemia and/or IC received either rezafungin QWk (400 mg Week 1, then 200 mg QWk) or caspofungin QD for ≥14 days (up to 4 weeks) with optional oral fluconazole step-down in the caspofungin arm. The primary endpoints were global cure at day (D) 14 (per Data Review Committee confirmation of investigator-assessed clinical cure [and radiological cure for IC) + mycological eradication]) and all-cause mortality (ACM) at D30 (Fig 2). Secondary endpoints included mycological eradication at D14. For this analysis, D14 global cure and mycological eradication by treatment group were analyzed by Candida species and in vitro susceptibility at baseline (CLSI broth microdilution MIC values; M27 Ed4) (Fig 3). Results A total of 204 Candida isolates were recovered in 187 patients across both treatment groups. Of the 204 isolates, C. albicans was the most common species, followed by C. glabrata, C. tropicalis, and C. parapsilosis; 61% of all baseline isolates were non-albicans Candida (Fig 3). The rates of D14 global cure and mycological eradication by pathogen are shown in Tables 1 and 2. Overall, outcomes by Candida species and MIC did not appear to be affected by MIC values for either rezafungin or caspofungin (Table 3). Conclusion Rezafungin was efficacious across multiple Candida species in the Phase 3 ReSTORE trial that demonstrated non-inferiority of rezafungin to caspofungin. There was no clear correlation between increased MIC values and clinical outcomes. Disclosures George R. Thompson, III, MD, Amplyx: Advisor/Consultant|Amplyx: Grant/Research Support|Astellas: Advisor/Consultant|Astellas: Grant/Research Support|Cidara: Advisor/Consultant|Cidara: Grant/Research Support|F2G: Advisor/Consultant|F2G: Grant/Research Support|Merck: Grant/Research Support|Pfizer: DSMB|Scynexis: Advisor/Consultant|Scynexis: Grant/Research Support Alex Soriano, MD, MSD, Pfizer, Shionogi, Angelini, Menarini, Gilead: Honoraria Oliver A. Cornely, Prof. Dr., Abbott: Honoraria|Abbvie: Advisor/Consultant|Actelion: Board Member|Al-Jazeera Pharmaceuticals: Honoraria|Allecra Therapeutics: Board Member|Amplyx: Advisor/Consultant|Amplyx: Grant/Research Support|Astellas: Honoraria|Basilea: Advisor/Consultant|Basilea: Grant/Research Support|Biocon: Advisor/Consultant|Biosys: Advisor/Consultant|BMBF: Grant/Research Support|Cidara: Advisor/Consultant|Cidara: Board Member|Cidara: Expert Testimony|Cidara: Grant/Research Support|CoRe Consulting: Stocks/Bonds|Da Volterra: Advisor/Consultant|DLR: Grant/Research Support|DZIF: Grant/Research Support|Entasis: Board Member|EU Directorate-General for Resarch and Innovation: Grant/Research Support|F2G: Grant/Research Support|German Patent and Trade Mark Office: German patent (DE 10 2021 113 007.7)|Gilead: Advisor/Consultant|Gilead: Grant/Research Support|Grupo Biotoscana/United Medical/Knight: Honoraria|Hikma: Honoraria|IQVIA: Board Member|Janssen: Board Member|Matinas: Advisor/Consultant|Matinas: Grant/Research Support|MedPace: Advisor/Consultant|MedPace: Grant/Research Support|MedScape: Honoraria|MedUpdate: Honoraria|Menarini: Advisor/Consultant|Merck/MSD: Grant/Research Support|Merck/MSD: Honoraria|Molecular Partners: Advisor/Consultant|MSG-ERC: Advisor/Consultant|Mundipharma: Grant/Research Support|Mylan: Honoraria|Noxxon: Advisor/Consultant|Octapharma: Advisor/Consultant|Octapharma: Grant/Research Support|Paratek: Board Member|Pardes: Advisor/Consultant|Pfizer: Grant/Research Support|Pfizer: Honoraria|Projektträger Jülich: Grant/Research Support|PSI: Advisor/Consultant|PSI: Board Member|Pulmocide: Board Member|Scynexis: Advisor/Consultant|Scynexis: Grant/Research Support|Seres: Advisor/Consultant|Shionogi: Board Member|Wiley (Blackwell): Editor-in-Chief, Mycoses Bart-Jan Kullberg, MD, FRCP, FIDSA, Cidara: Independent Data Review Committee Jeffrey B. Locke, PhD, Cidara Therapeutics: Employee|Cidara Therapeutics: Stocks/Bonds Taylor Sandison, MD, MPH, Cidara Therapeutics: Employee|Cidara Therapeutics: Stocks/Bonds.

BACKGROUND: Preterm birth is a global health priority. Using a progestogen during high-risk pregnancy could reduce preterm birth and adverse neonatal outcomes.METHODS: We did a systematic review of randomised trials comparing vaginal progesterone, intramuscular 17-hydroxyprogesterone caproate (17-OHPC), or oral progesterone with control, or with each other, in asymptomatic women at risk of preterm birth. We identified published and unpublished trials that completed primary data collection before July 30, 2016, (12 months before data collection began), by searching MEDLINE, Embase, CINAHL, the Maternity and Infant Care Database, and relevant trial registers between inception and July 30, 2019. Trials of progestogen to prevent early miscarriage or immediately-threatened preterm birth were excluded. Individual participant data were requested from investigators of eligible trials. Outcomes included preterm birth, early preterm birth, and mid-trimester birth. Adverse neonatal sequelae associated with early births were assessed using a composite of serious neonatal complications, and individually. Adverse maternal outcomes were investigated as a composite and individually. Individual participant data were checked and risk of bias assessed independently by two researchers. Primary meta-analyses used one-stage generalised linear mixed models that incorporated random effects to allow for heterogeneity across trials. This meta-analysis is registered with PROSPERO, CRD42017068299.FINDINGS: Initial searches identified 47 eligible trials. Individual participant data were available for 30 of these trials. An additional trial was later included in a targeted update. Data were therefore available from a total of 31 trials (11 644 women and 16185 offspring). Trials in singleton pregnancies included mostly women with previous spontaneous preterm birth or short cervix. Preterm birth before 34 weeks was reduced in such women who received vaginal progesterone (nine trials, 3769 women; relative risk [RR] 0·78, 95% CI 0·68-0·90), 17-OHPC (five trials, 3053 women; 0·83, 0·68-1·01), and oral progesterone (two trials, 181 women; 0·60, 0·40-0·90). Results for other birth and neonatal outcomes were consistently favourable, but less certain. A possible increase in maternal complications was suggested, but this was uncertain. We identified no consistent evidence of treatment interaction with any participant characteristics examined, although analyses within subpopulations questioned efficacy in women who did not have a short cervix. Trials in multifetal pregnancies mostly included women without additional risk factors. For twins, vaginal progesterone did not reduce preterm birth before 34 weeks (eight trials, 2046 women: RR 1·01, 95% CI 0·84-1·20) nor did 17-OHPC for twins or triplets (eight trials, 2253 women: 1·04, 0·92-1·18). Preterm premature rupture of membranes was increased with 17-OHPC exposure in multifetal gestations (rupture INTERPRETATION: Vaginal progesterone and 17-OHPC both reduced birth before 34 weeks' gestation in high-risk singleton pregnancies. Given increased underlying risk, absolute risk reduction is greater for women with a short cervix, hence treatment might be most useful for these women. Evidence for oral progesterone is insufficient to support its use. Shared decision making with woman with high-risk singleton pregnancies should discuss an individual's risk, potential benefits, harms and practicalities of intervention. Treatment of unselected multifetal pregnancies with a progestogen is not supported by the evidence.FUNDING: Patient-Centered Outcomes Research Institute.

Background There are limited treatment options for uncomplicated urinary tract infection (uUTI) caused by resistant pathogens. Sulopenem etzadroxil/probenecid (sulopenem) is an oral thiopenem antibiotic active against multidrug-resistant pathogens that cause uUTIs. Methods Patients with uUTI were randomized to 5 days of sulopenem or 3 days of ciprofloxacin. The primary endpoint was overall success, defined as both clinical and microbiologic response at day 12. In patients with ciprofloxacin-nonsusceptible baseline pathogens, sulopenem was compared for superiority over ciprofloxacin; in patients with ciprofloxacin-susceptible pathogens, the agents were compared for noninferiority. Using prespecified hierarchical statistical testing, the primary endpoint was tested in the combined population if either superiority or noninferiority was declared in the nonsusceptible or susceptible population, respectively. Results In the nonsusceptible population, sulopenem was superior to ciprofloxacin, 62.6% vs 36.0% (difference, 26.6%; 95% confidence interval [CI], 15.1 to 7.4; P Conclusions Sulopenem was noninferior to ciprofloxacin in the treatment of uUTIs. Sulopenem was superior to ciprofloxacin in patients with uUTIs due to ciprofloxacin-nonsusceptible pathogens. Sulopenem was not noninferior in patients with ciprofloxacin-susceptible pathogens, driven largely by a lower rate of ASB in those who received ciprofloxacin. Clinical Trial Registration NCT03354598.

Lefamulin was the first systemic pleuromutilin antibiotic approved for intravenous and oral use in adults with community-acquired bacterial pneumonia based on two phase 3 trials (Lefamulin Evaluation Against Pneumonia [LEAP]-1 and LEAP-2). This pooled analysis evaluated lefamulin efficacy and safety in adults with community-acquired bacterial pneumonia caused by atypical pathogens (Mycoplasma pneumoniae, Legionella pneumophila, and Chlamydia pneumoniae). In LEAP-1, participants received intravenous lefamulin 150 mg every 12 h for 5–7 days or moxifloxacin 400 mg every 24 h for 7 days, with optional intravenous-to-oral switch. In LEAP-2, participants received oral lefamulin 600 mg every 12 h for 5 days or moxifloxacin 400 mg every 24 h for 7 days. Primary outcomes were early clinical response at 96 ± 24 h after first dose and investigator assessment of clinical response at test of cure (5–10 days after last dose). Atypical pathogens were identified in 25.0% (91/364) of lefamulin-treated patients and 25.2% (87/345) of moxifloxacin-treated patients; most were identified by ≥1 standard diagnostic modality (M. pneumoniae 71.2% [52/73]; L.pneumophila 96.9% [63/65]; C. pneumoniae 79.3% [46/58]); the most common standard diagnostic modality was serology. In terms of disease severity, more than 90% of patients had CURB-65 (confusion of new onset, blood urea nitrogen > 19 mg/dL, respiratory rate ≥ 30 breaths/min, blood pressure

Background ADG20 is a fully human IgG1 monoclonal antibody engineered to have high potency and broad neutralization against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) and other SARS-like CoVs with pandemic potential by binding to a highly conserved epitope in the receptor-binding domain (RBD) of the spike protein. The Fc region of ADG20 has been modified to provide an extended half-life. ADG20 is in clinical development for the treatment and prevention of COVID-19. Methods This is an ongoing Phase 1, randomized, placebo (PBO)-controlled, single ascending-dose study of ADG20 administered intramuscularly (IM) or intravenously (IV) to healthy adults aged 18–50 years with no evidence of prior or current SARS-CoV-2 infection. Participants were randomized 8:2 in 3 cohorts (N=10/cohort: n=8 ADG20, n=2 PBO): ADG20 300 mg IM, 500 mg IV, and 600 mg IM. Safety, tolerability, PK, and sVNA titers were assessed up to 3 months post dose. Serum ADG20 concentrations were measured with a validated hybrid ligand binding liquid chromatography–mass spectrometry (MS)/MS assay. sVNA titers against authentic SARS-CoV-2 were determined by a plaque reduction neutralization assay. Results Overall, 30 participants received ADG20 (n=24) or PBO (n=6). Blinded safety data for all cohorts and PK/sVNA titer data for the 300 mg IM cohort are reported. Through a minimum of 10 weeks post dose, no study drug-related adverse events (AEs), serious AEs, injection site reactions, or hypersensitivity reactions were reported. The observed preliminary PK profile was dose proportional, consistent with an extended half-life monoclonal antibody, and well predicted by translational physiologically-based PK modeling. The measured 50% sVNA titer (MN50; geometric mean [coefficient of variation, %]) was 1382 (32.7%) 13 days after a single 300 mg IM dose. These values are within the range of peak serum neutralizing antibody titers reported for COVID-19 mRNA vaccines. Conclusion A single dose of ADG20, up to 600 mg IM, was well tolerated. Preliminary PK and sVNA titer profiles support the ongoing Phase 2/3 trials of ADG20 at a 300 mg IM dose for the prevention of COVID-19 (EVADE: NCT04859517) and treatment of ambulatory patients with mild to moderate COVID-19 (STAMP: NCT04805671). Disclosures Helen Paguntalan, MD, Adagio Therapeutics, Inc. (Scientific Research Study Investigator) Zoltán Magyarics, MD, PhD, Adagio Therapeutics, Inc. (Consultant) Lynn E. Connolly, MD, PhD, Adagio Therapeutics, Inc. (Employee) Ellie Hershberger, PharmD, Adagio Therapeutics, Inc. (Employee) Kristin Narayan, PhD, Adagio Therapeutics, Inc. (Employee) Deepali Gupta, BS, Adagio Therapeutics, Inc. (Employee) Paul G. Ambrose, PharmD, Adagio Therapeutics, Inc. (Employee) Frank Engler, PhD, Adagio Therapeutics, Inc. (Independent Contractor) Ed Campanaro, BSN, MSHS, Adagio Therapeutics, Inc. (Employee) Anita F. Das, PhD, Adagio Therapeutics, Inc. (Consultant) Pete Schmidt, MD, Adagio Therapeutics, Inc. (Employee)

Background Exebacase (EXB), a recombinantly-produced lysin (cell wall hydrolase), is the first direct lytic agent to advance into Phase 3 of clinical development for the treatment of bacteremia including infective endocarditis due to Staphylococcus aureus. The microbiologic attributes of EXB, including pathogen-targeted rapid bacteriolysis, and biofilm eradication are distinct from and synergistic with those of traditional antibiotics and underpin the therapeutic potential for EXB. Methods The Phase 2 trial was a randomized, double-blind, placebo-controlled multinational study. Patients were randomized (2:1) to receive a single 2-hour infusion of EXB or placebo (PBO) in addition to standard of care antibiotics. Time to resolution of symptoms (shortness of breath, sweating, fatigue and confusion) attributable to the bacteremia was analyzed using Kaplan-Meier methods. Time to resolution was defined as the number of days until all attributable symptoms were absent. If a new (not present at baseline) attributable symptom was present before the baseline symptoms resolved, this new symptom also had to be absent for symptoms to be considered resolved. Results A total of 86 patients (53 EXB and 33 PBO) had at least one attributable symptom present at baseline. Of these, symptoms resolved in 94.3% and 87.9% of EXB and PBO patients, respectively. The median time to resolution was 3 days for EXB and 6 days for PBO patients. Median days to symptom resolution in the MRSA group was 3 and 7 days for EXB and PBO patients, respectively, and 3 and 5 days for EXB and PBO patients in the MSSA group, respectively. Time to symptom resolution in MRSA patients in presented in Figure 1. Figure 1. Time to Resolution of Symptoms in Patients with MRSA Bacteremia including Infective Endocarditis Conclusion The majority of EXB and PBO patients had symptom resolution. However, EXE patients achieved symptom resolution in 3 days compared with 6 days for PBO patients overall, and 7 days for PBO patients with MRSA. These data suggest that rapid bacteriolysis may translate to a clinical benefit for patients receiving EXB and aligns with a median length of hospital stay of 6 and 10 days among US MRSA patients that received EXE and PBO patients, respectively. (Fowler, et al, 2020). Disclosures Cara Cassino, MD, ContraFect Corporation (Employee) Anita F. Das, PhD, Adagio (Consultant)AN2 (Consultant)Cidara (Consultant)ContraFect (Consultant)Iterum (Consultant)MicuRx (Consultant)Paratek (Consultant)Union (Consultant) Joy Lipka, MS, ContraFect Corporation (Consultant)

Background Exebacase, a lysin (cell wall hydrolase), is the first direct lytic agent to report Phase 2 study results in Staphylococcus aureus bacteremia including endocarditis. Among MRSA patients enrolled in this randomized, double-blind, placebo, controlled study, EXE used in addition to standard of care antibiotics (SoC), had 42.8% higher clinical responder rates (CRRs) compared SoC alone. We sought to determine whether these differences in CRRs translated into reductions in health resource utilization (HRU) in this population of critically ill, hospitalized patients. Methods The microbiological intent-to-treat population included 116 patients (71 EXE, 45 SoC) with documented S. aureus who received a single 2-hour infusion of blinded study drug dosed based on target attainment. The primary efficacy endpoint was CRR at Day 14. Diagnoses and clinical outcomes were determined by a blinded Adjudication Committee. HRU including length of stay (LOS), and 30-day hospital readmission rates (HRR) for all causes (AC) and for S. aureus (SA) were evaluated in MRSA patients who were alive at the time of discharge. Results The average patient was white, male and ~56 years old (67.8%). Twenty-seven EXe patients (38.0%) and 16 SoC patients (35.6%) had MRSA. All but 2 MRSA patients (1 EXE, 1 SoC) were enrolled in the United States. The Day 14 CRR were 70.4% for EXE and 60.0% for SoC groups (p=0.314) overall. In a prespecified analysis of MRSA patients, the CRR with EXE was 74.1% vs. 31.3% with SoC (P = 0.010). Among MRSA patients who received study drug, incidence of treatment emergent adverse events (TEAEs) was balanced between groups (24 (88.9%) in EXE and 15 (98.3%) in SoC) as were serious TEAEs (17(63.0%) in EXE, 12 (75%) in SoC). 1 EXE and 2 SoC US MRSA patients died in hospital. Among US MRSA patients discharged alive from the hospital, the median LOS after study drug was 6 vs. 10 days for EXE and SoC, respectively. Thirty-day AC HRR were 16% vs. 30.8%, for EXE vs. SoC, respectively, and 30-day SA HRR were 8% vs. 15.4%, respectively. Conclusions Exebacase used in addition to SoC was associated with a reduction in length of hospital stay and 30-day readmission rates for all causes and for S. aureus compared with SoC alone in patients being treated for MRSA bacteremia/endocarditis. Disclosures Cara Cassino, MD, ContraFect Corporation (Employee), Hemal Shah, PharmD, Boehringer Ingelheim (Consultant), ContraFect Corp (Consultant), DBV Technologies (Consultant), Mylan specialty (Consultant), Nabriva (Consultant), Joy Lipka-Diamond, MS, ContraFect Corporation (Consultant), Anita F. Das, PhD, Achaogen (Consultant), AntiobioTx (Consultant), Boston Pharmaceuticals (Consultant), Cempra (Consultant), ContraFect Corporation (Consultant), Iterum Therapeutics (Consultant), Nabriva (Consultant), Paratek (Consultant), Tetraphase (Consultant), UTILITY (Consultant), Wockhardt (Consultant).

Background In high-risk pregnant women, noninvasive prenatal testing with the use of massively parallel sequencing of maternal plasma cell-free DNA (cfDNA testing) accurately detects fetal autosomal aneuploidy. Its performance in low-risk women is unclear. Methods At 21 centers in the United States, we collected blood samples from women with singleton pregnancies who were undergoing standard aneuploidy screening (serum biochemical assays with or without nuchal translucency measurement). We performed massively parallel sequencing in a blinded fashion to determine the chromosome dosage for each sample. The primary end point was a comparison of the false positive rates of detection of fetal trisomies 21 and 18 with the use of standard screening and cf DNA testing. Birth outcomes or karyotypes were the reference standard. Results The primary series included 1914 women (mean age, 29.6 years) with an eligible sample, a singleton fetus without aneuploidy, results from cfDNA testing, and a risk classification based on standard screening. For trisomies 21 and 18, the false positive rates with cfDNA testing were significantly lower than those with standard screening (0.3% vs. 3.6% for trisomy 21, P