1122. Effect of Aluminum Hydroxide/Magnesium Hydroxide/Simethicone and Omeprazole on the Pharmacokinetics of Tebipenem Pivoxil Hydrobromide (TBP-PI-HBr) in Healthy Adult Subjects

Background Tebipenem pivoxil hydrobromide (TBP-PI-HBr) is an oral prodrug that is converted to tebipenem (TBP), the active moiety being developed for treating complication urinary tract infections. Antacids and proton pump inhibitors are known to change gastric pH after administration, which could affect the absorption of oral medications. This study evaluated the effect of a single dose of aluminum hydroxide/magnesium hydroxide/simethicone and the effect of multiple doses of omeprazole on the PK of TBP, following a single dose of TBP-PI-HBr. Methods This was an open-label, 3-period, fixed sequence drug-drug interaction study. On Day 1, Period 1, subjects received a single oral dose of TBP-PI-HBr 600 mg (2 x 300 mg tablets) at Hour 0. On Day 1, Period 2, subjects received a single oral 20 mL dose of aluminum hydroxide 800 mg/magnesium hydroxide 800 mg/simethicone 80 mg suspension per 10 mL (Maalox® Advanced Maximum Strength oral suspension) with a single oral dose of TBP-PI-HBr 600 mg at Hour 0. In Period 3, on Days 1 through 5, subjects received a single oral dose of omeprazole 40 mg (Prilosec®) once daily (QD), at Hour -2. On Day 5, a single oral dose of 600 mg TBP-PI-HBr was administered at Hour 0. Whole blood sampling for TBP PK occurred pre-dose and up to 24 hours post dose. Whole blood samples were assayed for TBP by liquid chromatography-tandem mass spectrometry. Results Twenty subject were enrolled and completed the study. Geometric mean ratios for AUC indicated mean TBP exposure (AUC) was approximately 11% lower and mean Cmax was 22% lower for TBP-PI-HBr combined with aluminum hydroxide/magnesium hydroxide/simethicone vs. TBP-PI-HBr alone (Figure). Similarly, geometric mean ratios for AUC indicated mean TBP exposure (AUC) was approximately 11% lower and mean Cmax was 43% lower for TBP-PI-HBr in combination with omeprazole vs. TBP-PI-HBr alone. Because the PK/PD driver for TBP efficacy is AUC dependent, concomitant administration is not expected to impact the efficacy of oral TBP-PI-HBr. Figure 1. Arithmetic mean plasma TBP concentrations following a 600 mg dose of clinical study drug product (A1 and A2) and registrational drug product (B) – PK population. Conclusion Administration of TBP-PI-HBr combined with aluminum hydroxide/magnesium hydroxide/simethicone or omeprazole QD had no meaningful effect on plasma TBP exposure; Cmax decreased with both agents. Co-administration was generally safe and well tolerated. Disclosures Vipul K. Gupta, Ph.D., Spero Therapeutics (Employee, Shareholder) Gina Patel, PhD, Spero Therapeutics, Inc. (Consultant) Leanne Gasink, MD, Spero Therapeutics, Inc. (Consultant) Floni Bajraktari, MSc, Spero Therapeutics, Inc. (Employee) Yang Lei, PhD, Spero Therapeutics, Inc. (Employee) Akash Jain, PhD, Spero Therapeutics, Inc. (Employee) Praveen Srivastava, MS, BS, Spero Therapeutics, Inc. (Employee) Angela Talley, MD, Spero Therapeutics, Inc. (Employee)

1121. Bioequivalence of Two Formulations of Oral Tebipenem-Pivoxil Hydrobromide in Healthy Subjects

Background Tebipenem-pivoxil-hydrobromide (TBP-PI-HBr) is a novel oral carbapenem being developed to treat serious bacterial infections including complicated urinary tract infection. The objectives of this study were to assess the bioequivalence (BE) of two tablet formulations of TBP-PI-HBr in healthy adult subjects under fasted conditions and to evaluate the food-drug interactions of the registration drug product. Methods This was an open-label, randomized, single-dose, semi-replicate, 3-sequence, 4-period crossover, BE, and food effect study. Subjects were randomized to one of three sequences where they received a single 600 mg oral dose of TBP-PI-HBr, as either the reference clinical study drug product (Treatment A) or the registration drug product (Treatment B) under fasted conditions. Subsequently, all subjects received a single 600 mg oral dose of TBP-PI-HBr as the registration drug product under fed conditions. There was by a 7-day washout between each period. Whole blood sampling to determine TBP pharmacokinetics (PK) was conducted predose and up to 24 hours post dose in each period. Safety and tolerability were monitored throughout the study. Results Thirty-six healthy, adult male and female subjects were enrolled and completed the study. The TBP-PI-HBr registration product was bioequivalent to the clinical study product (Figure 1). For TBP, 90% confidence intervals (CIs) for AUC0-t, AUC0-inf, and Cmax were within the 80% to 125% BE limits when administered under fasted conditions. A standard high-fat/high-calorie meal had no meaningful effect on the total plasma exposure of TBP after administration of the registration product, thus, overall exposure based on AUC0-t and AUC0-inf was comparable under fed and fasted conditions (Figure 2). Five (14%) subjects reported adverse events of mild severity. No deaths, serious AEs or discontinuations due to AEs were reported, and no clinically relevant ECGs, vital signs or safety laboratory findings were observed. Figure 1. Arithmetic mean plasma TBP concentrations following a 600 mg dose of clinical study drug product (A1 and A2) and registrational drug product (B) – PK population. Figure 2. Arithmetic mean plasma TBP concentrations following a 600 mg dose of registrational drug product (B) under fasted and fed conditions – PK population. Conclusion The TBP-PI-HBr registration product was bioequivalent to the clinical study product under fasted conditions, and no meaningful effect of a high fat meal on TBP PK was observed. Disclosures Vipul K. Gupta, Ph.D., Spero Therapeutics (Employee, Shareholder) Gina Patel, PhD, Spero Therapeutics, Inc. (Consultant) Leanne Gasink, MD, Spero Therapeutics, Inc. (Consultant) Floni Bajraktari, MSc, Spero Therapeutics, Inc. (Employee) Yang Lei, PhD, Spero Therapeutics, Inc. (Employee) Akash Jain, PhD, Spero Therapeutics, Inc. (Employee) Praveen Srivastava, MS, BS, Spero Therapeutics, Inc. (Employee) Angela Talley, MD, Spero Therapeutics, Inc. (Employee)

1120. Absorption, Metabolism, and Excretion of [14C]-Tebipenem Pivoxil Hydrobromide (TBP-PI-HBr) Following a Single Oral Dose in Healthy Male Subjects

Background Tebipenem pivoxil hydrobromide (TBP-PI-HBr) is an oral prodrug that is converted to tebipenem (TBP), the active moiety, with activity against multidrug-resistant gram-negative pathogens, including extended-spectrum-β-lactamase (ESBL)-producing Enterobacterales. TBP-PI-HBr is the first oral carbapenem intended for treating complicated urinary tract infections and acute pyelonephritis. This study evaluated the absorption, metabolism, and excretion (AME) of TBP-PI-HBr following a single oral dose of [14C]-TBP-PI-HBr to healthy males and characterized metabolites in plasma, urine, and feces. Methods This was a Phase 1, open-label, single-dose study in healthy subjects. Study drug was provided as radiolabeled and non-radiolabeled active pharmaceutical ingredient containing approximately 150 μCi of [14C]-TBP-PI-HBr. On Day 1, each subject received a 600 mg dose of TBP-PI-HBr. administered with 240 mL of water and fasted overnight for at least 10 hours. Blood samples were collected to determine TBP concentrations (whole blood), total radioactivity (whole blood and plasma), and metabolite profiling and identification were determined from plasma, urine, and feces. For mass balance, total radioactivity derived from urine and feces collections were determined. PK parameters were calculated using noncompartmental methods. Results Total radioactivity in plasma and whole blood decreased rapidly with geometric mean t½ values of 6.0 hours and 3.5 hours, respectively and Tmax of 1 hour. The cumulative mean recovery of radioactivity was 38.7% in urine and 44.6% in feces. Most of the administered radioactivity was recovered in the first 144 hours post dose in urine and feces (80.0%). Six of 8 subjects achieved a mass balance recovery ranging from 80.1% to 85.0%. The TBP plasma to total radioactivity ratio of 0.536 indicated that other metabolites contribute to the total radioactivity AUC in plasma. Metabolite profiling and identification results indicated that TBP was the major component in plasma and urine. The inactive ring open metabolite of TBP (LJC 11,562) was also found in plasma ( >10%), urine (5.27%), and feces ( >10%) as a secondary metabolite. Conclusion This study adequately characterized the AME of TBP-PI-HBr in humans. Disclosures Vipul K. Gupta, Ph.D., Spero Therapeutics (Employee, Shareholder) Gary Maier, PhD, Spero Therapeutics, Inc. (Consultant) Leanne Gasink, MD, Spero Therapeutics, Inc. (Consultant) Amanda Ek, MS, Spero Therapeutics, Inc. (Employee) Mary Fudeman, BA, MBA, Spero Therapeutics, Inc. (Employee) Praveen Srivastava, MS, BS, Spero Therapeutics, Inc. (Employee) Angela Talley, MD, Spero Therapeutics, Inc. (Employee)

Pharmacokinetics, Urinary Excretion, and Pharmaco-Metabolomic Study of Tebipenem Pivoxil Granules After Single Escalating Oral Dose in Healthy Chinese Volunteers

Tebipenem pivoxil (TBPM-PI), an oral carbapenem antibiotic, has shown special advantages in pediatric infections and was in urgent need in China. Although pharmacokinetics, urinary excretion, and metabolite information of its active form tebipenem (TBPM) has been reported, ethnic differences may exist among the Chinese and Japanese population. By now, no systematic pharmacokinetics, urinary excretion, metabolites, or safety information has been revealed to the Chinese population. The purpose of the present work was to investigate abovementioned information of TBPM-PI granules after oral single ascending doses of 100, 200, and 400 mg in Chinese volunteers. Based on the pharmacokinetic study, the urine pharmaco-metabolomic analysis was conducted to reveal metabolomic interruptions and metabolite information. The study design was a single-center, open-label, randomized, single-dose pharmacokinetic study of 36 healthy volunteers (with half of them being male and the other half female). Time to maximum concentration (Tmax) was reached at 0.50, 0.50, or 0.67 h for 100, 200, or 400 mg, respectively. The linear pharmacokinetic characteristic of maximum plasma concentration (Cmax) was detected over 100–200 mg. The area under the concentration time curve (AUC) was proportional to the dose in the range of 100–400 mg. The maximum urinary excretion rate was detected at 0–1 or 1–2 h for dose of 100 or 200–400 mg. Cumulative amount of TBPM excreted in urine by 24 h accounted up to 90, 95, and 80% of dose administered for three groups, respectively. The pharmaco-metabolomic analysis revealed urine metabolic trajectory of deviation at 0–1 or 1–2 h and gradually regressing back to the pre-dose group at the following time periods. Urine metabolites from M1 to M4 were identified, indicating ethnic difference in metabolites among the Chinese or Japanese population. The current work proved safety and tolerance of single-dose administration of oral TBPM-PI in Chinese healthy volunteers over doses of 100–400 mg. All these results provide pharmacokinetics, urine excretion, urine metabolomics, urine metabolites, and safety information in healthy Chinese volunteers after oral single ascending doses of TBPM-PI, benefitting further development and clinical utilities.

A Randomized, Double-blind, Placebo- and Positive-controlled Crossover Study of the Effects of Tebipenem Pivoxil Hydrobromide on QT/QTc Intervals in Healthy Subjects

Tebipenem pivoxil hydrobromide (TBP-PI-HBr) is an orally available prodrug of TBP, a carbapenem with in vitro activity against multidrug-resistant gram-negative pathogens. This study evaluated the effects of single therapeutic and supratherapeutic doses of TBP-PI-HBr on the heart rate corrected QT interval (QTc) by assessing the concentration-QT (C-QT) relationship using exposure-response modeling. This was a randomized, double-blind, placebo- and active-controlled, single dose, 4-way, crossover study. Subjects received single oral doses of TBP-PI-HBr 600 and 1200 mg, placebo, and positive control, moxifloxacin 400 mg. Cardiodynamic electrocardiograms (ECGs) and blood samples were collected in each period. Twenty-four subjects were enrolled. TBP-PI-HBr had no clinically significant adverse effects on heart rate or ECG parameters. The model-predicted slope suggests that ddHR was not importantly affected by plasma tebipenem concentrations, supporting the use of QTcF as an appropriate correction method. The model predicted difference in corrected QT interval (ddQTcF) at mean peak concentration (Cmax) for TBP had negative predicted values for each dose, and no QTc prolongation was detected following TBP-PI-HBr 600 mg or 1200 mg. Assay sensitivity was established following moxifloxacin 400 mg. Exposure to TBP increased in a dose-dependent manner with 600 and 1200 mg doses. TBP area under the concentration curve from time 0 to infinity (AUC0-inf) and Cmax at the 1200 mg dose level were 1.8- and 1.3-fold higher than with the 600 mg dose. TBP-PI-HBr was generally safe and well tolerated with no effect on QT prolongation.

Repurposing tebipenem pivoxil as alternative therapy for severe gastrointestinal infections caused by extensively-drug resistant (XDR) Shigella spp.

Diarrhoea remains one of the leading causes of childhood mortality globally. Recent epidemiological studies conducted in low-middle income countries (LMICs) identified Shigella spp. as the first and second most predominant agent of dysentery and moderate diarrhoea, respectively. Antimicrobial therapy is often necessary for Shigella infections; however, we are reaching a crisis point with efficacious antimicrobials. The rapid emergence of resistance against existing antimicrobials in Shigella spp. poses a serious global health problem. Here, aiming to identify alternative antimicrobial chemicals with activity against multi-drug resistant (MDR) Shigella, we initiated a collaborative academia-industry drug discovery project, applying high throughput phenotypic screening across broad chemical diversity. We identified several suitable compounds with antibacterial activity against Shigella. These compounds included the oral carbapenem tebipenem, which was found to be highly potent against broadly susceptible Shigella and contemporary MDR variants. Additional in vitro screening demonstrated that tebipenem had activity against a wide range of other non-Shigella enteric bacteria. Cognisant of the risk for the development of resistance against monotherapy, we identified synergistic behaviour of two different drug combinations incorporating tebipenem. The orally bioavailable prodrug (tebipenem pivoxil) effectively cleared the gut of infecting organisms when administered in physiological doses to Shigella-infected mice and gnotobiotic piglets. Our data highlight the utility of broad compound screening for tackling the emerging antimicrobial resistance crisis and shows that tebipenem pivoxil (licenced for paediatric respiratory tract infections in Japan) could be repurposed as an effective treatment for severe diarrhoea caused by MDR Shigella and other enteric pathogens in LMICs.

In Vitro and In Vivo Characterization of Tebipenem (TBP), an Orally Active Carbapenem, against Biothreat Pathogens

Bacillus anthracis and Yersinia pestis, causative pathogens for anthrax and plague, respectively, along with Burkholderia mallei and B. pseudomallei are potential bioterrorism threats. Tebipenem pivoxil hydrobromide (TBP HBr, formerly SPR994), is an orally available prodrug of tebipenem, a carbapenem with activity versus multidrug-resistant (MDR) gram-negative pathogens, including quinolone-resistant and extended-spectrum-β-lactamase-producing Enterobacterales. We evaluated the in vitro activity and in vivo efficacy of tebipenem against biothreat pathogens. Tebipenem was active in vitro against 30-strain diversity sets of B. anthracis, Y. pestis, B. mallei, and B. pseudomallei with minimum inhibitory concentration (MIC) values of 0.001 – 0.008 μg/ml for B. anthracis, ≤0.0005 – 0.03 μg/ml for Y. pestis, 0.25 – 1 μg/ml for B. mallei, and 1 – 4 μg/ml for B. pseudomallei. In a B. anthracis murine model, all control animals died within 52 h post challenge. The survival rates in the groups treated with tebipenem were 75% and 73% when dosed at 12 h and 24 h post challenge, respectively. The survival rates in the positive control groups treated with ciprofloxacin were 75% and when dosed 12 h and 25% when dosed 24 h post challenge, respectively. Survival rates were significantly (p=0.0009) greater in tebipenem groups treated at 12 h and 24 h post challenge and in the ciprofloxacin group 12 h post-challenge vs. the vehicle-control group. For Y. pestis, survival rates for all animals in the tebipenem and ciprofloxacin groups were significantly (p<0.0001) greater than the vehicle-control group. These results support further development of tebipenem for treating biothreat pathogens.