Efficacy and safety of sulbactam-durlobactam versus colistin for the treatment of patients with serious infections caused by Acinetobacter baumannii-calcoaceticus complex: a multicentre, randomised, active-controlled, phase 3, non-inferiority clinical trial (ATTACK).

BACKGROUND: An urgent need exists for antibiotics to treat infections caused by carbapenem-resistant Acinetobacter baumannii-calcoaceticus complex (ABC). Sulbactam-durlobactam is a ß-lactam-ß-lactamase inhibitor combination with activity against Acinetobacter, including multidrug-resistant strains. In a phase 3, pathogen-specific, randomised controlled trial, we compared the efficacy and safety of sulbactam-durlobactam versus colistin, both in combination with imipenem-cilastatin as background therapy, in patients with serious infections caused by carbapenem-resistant ABC. METHODS: The ATTACK trial was done at 59 clinical sites in 16 countries. Adults aged 18 years or older with ABC-confirmed hospital-acquired bacterial pneumonia, ventilator-associated bacterial pneumonia, ventilated pneumonia, or bloodstream infections were randomised 1:1 using a block size of four to sulbactam-durlobactam (1·0 g of each drug in combination over 3 h every 6 h) or colistin (2·5 mg/kg over 30 min every 12 h) for 7-14 days. All patients received imipenem-cilastatin (1·0 g of each drug in combination over 1 h every 6 h) as background therapy. The primary efficacy endpoint was 28-day all-cause mortality in patients with laboratory-confirmed carbapenem-resistant ABC (the carbapenem-resistant ABC microbiologically modified intention-to-treat population). Non-inferiority was concluded if the upper bound of the 95% CI for the treatment difference was less than +20%. The primary safety endpoint was incidence of nephrotoxicity assessed using modified Risk, Injury, Failure, Loss, End-stage renal disease criteria measured by creatinine level or glomerular filtration rate through day 42. This trial is registered at ClinicalTrials.gov, NCT03894046. FINDINGS: Between Sep 5, 2019, and July 26, 2021, 181 patients were randomly assigned to sulbactam-durlobactam or colistin (176 hospital-acquired bacterial pneumonia, ventilator-associated bacterial pneumonia, or ventilated pneumonia; and five bloodstream infections); 125 patients with laboratory-confirmed carbapenem-resistant ABC isolates were included in the primary efficacy analysis. 28-day all-cause mortality was 12 (19%) of 63 in the sulbactam-durlobactam group and 20 (32%) of 62 in the colistin group, a difference of -13·2% (95% CI -30·0 to 3·5), which met criteria for non-inferiority. Incidence of nephrotoxicity was significantly (p<0·001) lower with sulbactam-durlobactam than colistin (12 [13%] of 91 vs 32 [38%] of 85). Serious adverse events were reported in 36 (40%) of 91 patients in the sulbactam-durlobactam group and 42 (49%) of 86 patients in the colistin group. Treatment-related adverse events leading to study drug discontinuation were reported in ten (11%) of 91 patients in the sulbactam-durlobactam group and 14 (16%) of 86 patients in the colistin group. INTERPRETATION: Our data show that sulbactam-durlobactam was non-inferior to colistin, both agents given in combination with imipenem-cilastatin, for the primary endpoint of 28-day all-cause mortality. Sulbactam-durlobactam was well tolerated and could be an effective intervention to reduce mortality from serious infections caused by carbapenem-resistant ABC, including multidrug-resistant strains. FUNDING: Entasis Therapeutics and Zai Lab.

Pharmacokinetics and Tolerability of Intravenous Sulbactam-Durlobactam with Imipenem-Cilastatin in Hospitalized Adults with Complicated Urinary Tract Infections, Including Acute Pyelonephritis.

Durlobactam (DUR; ETX2514) is a novel ß-lactamase inhibitor with broad-spectrum activity against Ambler class A, C, and D ß-lactamases. Durlobactam restores the in vitro activity of sulbactam (SUL) against members of the Acinetobacter baumannii-A. calcoaceticus complex (ABC). Sulbactam (SUL)-durlobactam (SUL-DUR) is under development for the treatment of ABC infections. Eighty patients with complicated urinary tract infection (cUTI), including acute pyelonephritis (AP), were randomized 2:1 to receive SUL-DUR at 1 g/1 g intravenously (i.v.) or placebo every 6 h (q6h) for 7 days and background therapy with imipenem-cilastatin (IMI) at 500 mg i.v. q6h to evaluate the tolerability of SUL-DUR in hospitalized patients. Patients with bacteremia could receive up to 14 days of therapy. SUL-DUR tolerability and the values of various pharmacokinetic (PK) parameters were determined. Efficacy was recorded at the test-of-cure (TOC) visit. SUL-DUR was well tolerated, with no serious adverse events (AEs) being reported. Headache (5.7%), nausea (3.8%), diarrhea (3.8%), and vascular pain (3.8%) were the most common drug-related AEs with SUL-DUR and were mostly of mild or moderate severity. The PK profile of DUR and SUL in hospitalized patients was consistent with observations in healthy volunteers. Overall success in the microbiological modified intent-to-treat (m-MITT) population was similar between the groups, as would be expected with IMI background therapy in all patients (overall success at the TOC visit, 76.6% [n = 36] with SUL-DUR and 81.0% [n = 17] with placebo). SUL-DUR in combination with IMI was well tolerated in patients with cUTIs. The pharmacokinetics of SUL-DUR observed in hospitalized patients was similar to that observed in healthy volunteers. (This study has been registered at ClinicalTrials.gov under identifier NCT03445195.).

A Systematic Review and Pooled Analysis of Select Safety Parameters Among Normal Healthy Volunteers Taking Placebo in Phase 1 Clinical Trials.

A systematic review of the Bristol-Myers Squibb normal healthy volunteers (NHVs) database identified phase 1 trials that included NHVs administered placebo with the aim of characterizing normal inter- and intraindividual safety parameter variability. Twenty-five single and multiple ascending dose studies, median duration 28 (2 to 63) days, were included in the pooled analysis (355 NHVs). Laboratory evaluations, vital signs, electrocardiograms, and adverse events were assessed. The most commonly occurring adverse event was headache (28 [7.9%] NHVs; 519.5 events/100 person-years). During the dosing period (on placebo), evaluations showed 5.1 events/100 measures of alanine aminotransferase and 7.3 events/100 measures of creatine kinase 1× above the upper limit of normal. Alanine aminotransferase and creatine kinase elevations occurred in 28 (7.9%) and 39 (11.0%) NHVs, respectively; 105 (30.3%) NHVs had low and 46 (13.3%) had high diastolic blood pressure. This analysis may inform future study designs and provide a context for interpretation of safety signals in early phase clinical trials.

Safety and Efficacy of Pegylated Interferon Lambda, Ribavirin, and Daclatasvir in HCV and HIV-Coinfected Patients.

To evaluate the efficacy and safety of pegylated interferon-lambda-1a (Lambda)/ribavirin (RBV)/daclatasvir (DCV) for treatment of patients coinfected with chronic hepatitis C virus (HCV) and human immunodeficiency virus (HIV). Treatment-naive patients were assigned to cohort A [HCV genotype (GT)-2 or -3] or cohort B [HCV GT-1(a or b) or -4]. All patients received Lambda/RBV/DCV for the first 12 weeks; cohort A received Lambda/RBV for an additional 12 weeks, followed by 24 weeks of follow-up, and cohort B received response-guided therapy. The primary endpoint was the proportion of patients who achieved a sustained virologic response at post-treatment week 12 (SVR12). In cohort A (n = 104), 84.6% achieved SVR12 (95.0% in GT-2; 83.1% in GT-3). In cohort B (n = 196), 76.0% achieved SVR12 (71.7% in GT-1a; 86.0% in GT-1b; 70.7% in GT-4). Rates of discontinuation due to adverse events (AEs) (3.8% and 6.1%) and serious AEs (5.8% and 6.1%) were low in cohorts A and B, respectively. In addition, treatment with Lambda/RBV/DCV had little impact on CD4 counts. SVR12 rates with Lambda/RBV/DCV in an HCV/HIV-coinfected population ranged from 71.7% to 95.0%. Treatment was generally well tolerated, with a low proportion of patients discontinuing due to AEs. Clinical trial registration NCT01866930.

Mechanisms of Hyperbilirubinemia During Peginterferon Lambda-1a Therapy for Chronic Hepatitis C Infection: A Retrospective Investigation.

The phase 2b EMERGE study compared the efficacy/safety of peginterferon lambda-1a (Lambda) and peginterferon alfa-2a (Alfa), both with ribavirin (RBV), for treatment of chronic hepatitis C virus (HCV) infection. A key safety finding was a higher frequency of hyperbilirubinemia with Lambda/RBV versus Alfa/RBV. To characterize mechanisms of hyperbilirubinemia associated with Lambda/RBV, we conducted a retrospective analysis of safety data from the HCV genotype 1 and genotype 4 cohort of the EMERGE study. Subjects were randomized to once-weekly Lambda (120/180/240 µg) or Alfa (180 µg), with daily RBV, for 48 weeks. Early-onset Lambda/RBV-related hyperbilirubinemia events (6-12 weeks) resulted mostly from RBV-induced hemolysis evidenced by sustained reticulocytosis and a predominantly unconjugated pattern of hyperbilirubinemia. The higher hyperbilirubinemia frequency with Lambda/RBV versus Alfa/RBV was attributed to bone marrow suppression known to occur with Alfa but not Lambda. Late-onset (>12 weeks) Lambda/RBV-related hyperbilirubinemia events occurred most frequently with higher Lambda doses and were associated with increased levels of hepatic transaminase and direct bilirubin fractions compared with early events. This dual pattern of hyperbilirubinemia observed while on Lambda/RBV treatment is thought to be caused by exaggerated RBV-induced hemolysis in early-onset events compared with possible direct Lambda-induced hepatocellular toxicity in late-onset events.

A Randomized Study of Peginterferon Lambda-1a Compared to Peginterferon Alfa-2a in Combination with Ribavirin and Telaprevir in Patients with Genotype-1 Chronic Hepatitis C.

BACKGROUND: A randomized, double-blind, multinational, phase 3 study was conducted comparing the efficacy and safety of peginterferon lambda-1a (Lambda)/ribavirin (RBV)/telaprevir (TVR) vs. peginterferon alfa-2a (Alfa)/RBV/TVR in patients with chronic hepatitis C virus (HCV) genotype-1 (GT-1) infection. METHODS: Patients (treatment-naïve or relapsers on prior Alfa/RBV treatment) were randomly assigned in a 2:1 ratio to receive Lambda/RBV/TVR or Alfa/RBV/TVR. Total duration of treatment was either 24 or 48 weeks (response-guided treatment), with TVR administered for the first 12 weeks. The primary endpoint was the proportion of patients who achieved a sustained virologic response at post treatment week 12 (SVR12), which was tested for noninferiority of Lambda/RBV/TVR. RESULTS: A total of 838 patients were enrolled, and 617 were treated; 411 and 206 patients received Lambda/RBV/TVR and Alfa/RBV/TVR, respectively. The majority of patients were treatment-naïve, with HCV GT-1b and a high baseline viral load (≥800,000 IU/mL). Less than 10% of patients had cirrhosis (Lambda, 7.5%; Alfa, 6.8%). Lambda/RBV/TVR did not meet the criterion for noninferiority (lower bound of the treatment difference interval was -12.3%); the SVR12 in all patients (modified intent-to-treat) was 76.2% in the Lambda arm and 82.0% in the Alfa arm. Overall, the frequency of adverse events in each arm was comparable (Lambda, 91.7%; Alfa, 97.1%). As expected based on the safety profile of the 2 interferons, there were more hepatobiliary events observed in the Lambda arm and more hematologic events in the Alfa arm. CONCLUSIONS: In this comparison of Lambda/RBV/TVR and Alfa/RBV/TVR in patients who were treatment-naïve or had relapsed on prior Alfa/RBV treatment, Lambda failed to demonstrate noninferiority based on SVR12 results. Treatment with Lambda/RBV/TVR was associated with a higher incidence of relapse. More patients discontinued Lambda/RBV/TVR treatment during the first 4 weeks of study treatment, mainly due to hepatobiliary-related events, and more Lambda patients were lost to follow-up.

A randomized, controlled study of peginterferon lambda-1a/ribavirin ± daclatasvir for hepatitis C virus genotype 2 or 3.

BACKGROUND AND PURPOSE: Peginterferon Lambda was being developed as an alternative to alfa interferon for the treatment of chronic hepatitis C virus (HCV) infection. We compared peginterferon Lambda-1a plus ribavirin (Lambda/RBV) and Lambda/RBV plus daclatasvir (DCV; pangenotypic NS5A inhibitor) with peginterferon alfa-2a plus RBV (alfa/RBV) in treatment-naive patients with HCV genotype 2 or 3 infection. METHODS: In this multicenter, double-blind, phase 3 randomized controlled trial, patients were assigned 2:2:1 to receive 24 weeks of Lambda/RBV, 12 weeks of Lambda/RBV + DCV, or 24 weeks of alfa/RBV. The primary outcome measure was sustained virologic response at post-treatment Week 12 (SVR12). RESULTS: Overall, 874 patients were treated: Lambda/RBV, n = 353; Lambda/RBV + DCV, n = 349; alfa/RBV, n = 172. Patients were 65 % white and 33 % Asian, 57 % male, with a mean age of 47 years; 52 % were infected with genotype 2 (6 % cirrhotic) and 48 % with genotype 3 (9 % cirrhotic). In the Lambda/RBV + DCV group, 83 % (95 % confidence interval [CI] 78.5, 86.5) achieved SVR12 (90 % genotype 2, 75 % genotype 3) whereas SVR12 was achieved by 68 % (95 % CI 63.1, 72.9) with Lambda/RBV (72 % genotype 2, 64 % genotype 3) and 73 % (95 % CI 66.6, 79.9) with peginterferon alfa/RBV (74 % genotype 2, 73 % genotype 3). Lambda/RBV + DCV was associated with lower incidences of flu-like symptoms, hematological abnormalities, and discontinuations due to adverse events compared with alfa/RBV. CONCLUSION: The 12-week regimen of Lambda/RBV + DCV was superior to peginterferon alfa/RBV in the combined population of treatment-naive patients with genotype 2 or 3 infection, with an improved tolerability and safety profile compared with alfa/RBV.

Peginterferon Lambda-1a/Ribavirin with Daclatasvir or Peginterferon Alfa-2a/Ribavirin with Telaprevir for Chronic Hepatitis C Genotype 1b.

The study objective was to compare the efficacy and safety of peginterferon lambda-1a combined with ribavirin/daclatasvir (Lambda/RBV/DCV), versus peginterferon alfa-2a combined with ribavirin/telaprevir (Alfa/RBV/TVR), in patients chronically infected with hepatitis C virus (HCV), genotype 1b. This was a prospective, randomized, open-label, phase 3 study (NCT01718158) in adults (aged ≥18 years) who were treatment naïve or prior relapsers to peginterferon alfa/ribavirin therapy. The primary endpoint was sustained virologic response at post-treatment follow-up week 12 (SVR12). Patients were randomized in a 2:1 ratio to receive 24 weeks of Lambda/RBV/DCV or response-guided 24 or 48 weeks of Alfa/RBV/TVR. Overall, 440 patients were treated (294 with Lambda/RBV/DCV; 146 with Alfa/RBV/TVR). The proportion of patients achieving SVR12 was 88.8% in the Lambda/RBV/DCV arm and 70.5% in the Alfa/RBV/TVR arm (difference between arms: 18.3%; 95% confidence interval: 9.9-25.7; P < 0.0001). Patients in the Lambda/RBV/DCV group had fewer rash-related adverse events (AEs), cytopenic abnormalities, flu-like symptoms, serious AEs, and discontinuations due to AEs, but more liver abnormalities than those in the Alfa/RBV/TVR group. In conclusion, treatment with Lambda/RBV/DCV led to higher SVR12 rates and a more favorable safety profile than Alfa/RBV/TVR in patients with chronic HCV, genotype 1b infection.

Peginterferon Lambda-1a Is Associated with a Low Incidence of Autoimmune Thyroid Disease in Chronic Hepatitis C.

Peginterferon alfa (alfa) increases the risk of autoimmune disease. Peginterferon lambda-1a (Lambda) acts through a receptor with a more liver-specific distribution compared to the alfa receptor. In a phase-2b study, 525 treatment-naive patients with chronic hepatitis C virus (HCV) infection received ribavirin and Lambda interferon (120, 180, or 240 µg) or alfa interferon (180 µg) for 24 (genotypes 2 and 3) or 48 (genotypes 1 and 4) weeks. Retrospective analysis found that adverse events of MedDRA-coded thyroid dysfunction and abnormal levels of thyroid-stimulating hormone (TSH) were significantly more frequent with alfa versus Lambda (12% versus 2.6% and 15.2% versus 3.4%, respectively, both P<0.0001). Most Lambda recipients with abnormal TSH had levels below the lower limit of normal; the frequency of low and high TSH was similar in alfa recipients with abnormal TSH. Blinded review by an endocrinologist found that new-onset primary hypothyroidism or painless thyroiditis was less frequent with Lambda versus alfa (0.5% and 1.8% versus 5.3% and 7.5%, respectively, P<0.0001). Most TSH elevations reflected new-onset hypothyroidism requiring treatment, while most markedly suppressed TSH values reflected probable painless thyroiditis and resolved without sequelae. In conclusion, HCV-infected patients treated with Lambda/ribavirin experienced fewer adverse events of thyroid dysfunction compared with patients treated with alfa/ribavirin.

Anti-PEG antibody bioanalysis: a clinical case study with PEG-IFN-λ-1a and PEG-IFN-α2a in naive patients.

BACKGROUND: Extensive use of polyethylene glycol (PEG) in consumer products necessitates the assessment of anti-PEG antibodies (APAb). METHODS: In clinical trials comparing PEG-IFN-λ to PEG-IFN-α, conventional bridge and direct assays were assessed. RESULTS & CONCLUSION: The bridge assay detected IgM and IgG APAb reactive with common PEG sizes and derivatives at sufficient sensitivity, 15-500 ng/ml. Of subjects evaluated, 6% of PEG-IFN-λ and 9% of PEG-IFN-α subjects had persistent APAb while 60% of PEG-IFN-λ and 33% of PEG-IFN-α subjects had persistent anti-interferon antibodies (AIAb). Pre-existing APAb and AIAb prevalence was comparable (approximately 10% of subjects). APAb were earlier onset, less frequent, less persistent and lower titer than AIAb. No associated hypersensitivity events were reported.

A randomized phase 2b study of peginterferon lambda-1a for the treatment of chronic HCV infection.

BACKGROUND & AIMS: Peginterferon lambda-1a (Lambda) is a type-III interferon with similar antiviral activity to alfa interferons but with a diminished extrahepatic receptor distribution, reducing the risk for extrahepatic adverse events. METHODS: This was a randomized, blinded, actively-controlled, multicentre phase 2b dose-ranging study in patients chronically infected with HCV genotypes 1-4. Treatment-naive patients received Lambda (120/180/240 µg) or peginterferon alfa-2a (alfa; 180 µg) once-weekly with ribavirin for 24 (genotypes [GT] 2,3) or 48 (GT1,4) weeks. RESULTS: Rates of undetectable HCV-RNA at week 12 (complete early virologic response [cEVR]; primary end point) were significantly higher in GT1,4 patients receiving Lambda vs. alfa (170/304, 56% vs. 38/103, 37%); with similar cEVR rates for GT2,3 (80/88, 91% vs. 26/30, 87%). Rates of undetectable HCV-RNA at week 4 were significantly higher on 180 µg (15/102, 15% GT1,4; 22/29, 76% GT2,3) and 240 µg (17/104, 16% GT1,4; 20/30, 67% GT2,3) Lambda than alfa (6/103, 6% GT1,4; 9/30, 30% GT2,3). Sustained virologic responses (post-treatment week 24) were comparable between Lambda and alfa for GT1,4 (37-46% Lambda; 37% alfa) and GT2,3 (60-76% Lambda; 53% alfa). Aminotransferase and/or bilirubin elevations were the primary dose-limiting abnormalities for Lambda; a sponsor-mandated 240 to 180 µg dose reduction was therefore implemented. Serious adverse events were comparable (3-13% Lambda; 3-7% alfa). Grade 3-4 haemoglobin, neutrophil, and platelet reductions were lower on Lambda than alfa. Among alfa patients, 28/133 (21%) had peginterferon and 31/133 (23%) had ribavirin dose reductions for haematologic abnormalities vs. 0/392 and 8/392 (2%) on Lambda. Lambda demonstrated fewer musculoskeletal (16-28% vs. 47-63%) and influenza-like events (8-23% vs. 40-46%) than alfa. CONCLUSION: Lambda was associated with improved or similar rates of virologic response with fewer extrahepatic adverse events than alfa in chronic HCV infection.

A phase 2 study of filibuvir in combination with pegylated IFN alfa and ribavirin for chronic HCV.

OBJECTIVES: Filibuvir is a non-nucleoside inhibitor of hepatitis C virus (HCV) polymerase. This study evaluated the safety and efficacy of filibuvir plus pegylated interferon alfa-2a (pegIFN)/ribavirin. MATERIAL AND METHODS: Treatment-naïve, HCV genotype-1 patients were randomized to receive filibuvir 300 or 600 mg twice daily (BID) or placebo plus pegIFN (180 µg/wk) and ribavirin (1,000/1,200 mg BID) for 24 weeks. Filibuvir patients who achieved defined response through week 24 discontinued therapy at week 24. All other patients continued on open-label pegIFN/ribavirin through week 48. The primary endpoint was the proportion of patients who achieved sustained virologic response (SVR) defined as HCV RNA < 15 IU/mL at end of treatment (weeks 24 or 48) and week 72. RESULTS: Overall, 288 patients were randomized and treated. SVR was achieved by 41.7, 39.6, and 45.8% of patients in the filibuvir 300 mg, 600 mg, and placebo arms, respectively. While the addition of filibuvir to pegIFN/ribavirin improved on-treatment virologic response parameters, this did not translate into improved SVR rates due to a high rate of virologic relapse following completion of therapy (300 mg: 35.9%; 600 mg: 42.9%; placebo: 25.4%). The most commonly reported adverse events were nausea, fatigue, headache, and insomnia, and were reported at similar rates across arms. CONCLUSIONS: Filibuvir plus pegIFN/ribavirin did not improve the percentage of patients achieving SVR compared with administration of pegIFN/ribavirin alone. However, the agent was well tolerated and was associated with higher on-treatment virologic response parameters. Further evaluation of filibuvir in combination with other direct-acting antiviral agents may be considered.