Transcriptomic signature, bioactivity and safety of a non-hepatotoxic analgesic generating AM404 in the midbrain PAG region

Abstract Safe and effective pain management is a critical healthcare and societal need. The potential for acute liver injury from paracetamol (ApAP) overdose; nephrotoxicity and gastrointestinal damage from chronic non-steroidal anti-inflammatory drug (NSAID) use; and opioids’ addiction are unresolved challenges. We developed SRP-001, a non-opioid and non-hepatotoxic small molecule that, unlike ApAP, does not produce the hepatotoxic metabolite N-acetyl-p-benzoquinone-imine (NAPQI) and preserves hepatic tight junction integrity at high doses. CD-1 mice exposed to SRP-001 showed no mortality, unlike a 70% mortality observed with increasing equimolar doses of ApAP within 72 h. SRP-001 and ApAP have comparable antinociceptive effects, including the complete Freund’s adjuvant-induced inflammatory von Frey model. Both induce analgesia via N-arachidonoylphenolamine (AM404) formation in the midbrain periaqueductal grey (PAG) nociception region, with SRP-001 generating higher amounts of AM404 than ApAP. Single-cell transcriptomics of PAG uncovered that SRP-001 and ApAP also share modulation of pain-related gene expression and cell signaling pathways/networks, including endocannabinoid signaling, genes pertaining to mechanical nociception, and fatty acid amide hydrolase (FAAH). Both regulate the expression of key genes encoding FAAH, 2-arachidonoylglycerol (2-AG), cannabinoid receptor 1 (CNR1), CNR2, transient receptor potential vanilloid type 4 (TRPV4), and voltage-gated Ca2+ channel. Phase 1 trial (NCT05484414) (02/08/2022) demonstrates SRP-001’s safety, tolerability, and favorable pharmacokinetics, including a half-life from 4.9 to 9.8 h. Given its non-hepatotoxicity and clinically validated analgesic mechanisms, SRP-001 offers a promising alternative to ApAP, NSAIDs, and opioids for safer pain treatment

1109. A multicenter, observational study to compare the effectiveness of C eftazidime- A vibactam versus C eftolozane- T azobactam for multidrug-resistant Pseudomonas aeruginosa infections in the U nited S tates (CACTUS)

Abstract Background Ceftolozane-tazobactam (CT) and ceftazidime-avibactam (CZA) are front-line agents for treatment of multidrug-resistant (MDR) Pseudomonas aeruginosa; however, real-world comparative-effectiveness data are lacking. Methods CACTUS is a retrospective, matched, multicenter study to compare the efficacy of CT and CZA among patients with bacteremia or pneumonia due to MDR P. aeruginosa. CT and CZA patients were matched 1:1 within each study site by the presence/absence of septic shock/severe sepsis, infection site, and time to treatment initiation. The primary outcome was clinical success at day 30 defined as survival, resolution of signs/symptoms with the intended treatment course, and absence of recurrent infections. Patients with cystic fibrosis or COVID-19 infection within 90 days were excluded. Results 234 patients were included from 20 sites. Patient demographics, severity of illness, infection types, and treatment durations were similar for patients treated with CT or CZA (Table 1). The overall median age was 61 years, 61% were male, and the median Charlson score was 5. At study drug initiation, 77% of patients were in the ICU, 67% received mechanical ventilation and the median SOFA score was 7. 79% of patients were treated for pneumonia; 72% of which occurred in ventilated patients. The median time from index culture to treatment initiation was 72 hours in both groups; CT patients were more likely to receive a prolonged infusion of ≥3 hours (36% vs 19%; P=0.005). Clinical success occurred in 62% and 55% of patients receiving CT and CZA, respectively (P=0.35; Table 1). Corresponding rates of success for pneumonia were 63% and 52%, respectively (P=0.13; Figure 1). All-cause, 30-day mortality rate was 20% and 19%, respectively. Microbiologic failures, recurrent infections, and development of resistance within 90 days were similar between groups. Time to a composite endpoint of recurrent infection or death within 90 days was similar between groups in the overall analysis and the subgroup of patients with pneumonia (Figure 2). Conclusion In this interim analysis of the CACTUS study, patients treated with CT and CZA had similar clinical outcomes. We plan to continue enrollment up to 420 patients to detect if any differences exist in the efficacy of CT and CZA for MDR P. aeruginosa infections. Disclosures Ryan K. Shields, PharmD, MS, Allergan: Advisor/Consultant|Cidara: Advisor/Consultant|Entasis: Advisor/Consultant|GSK: Advisor/Consultant|Melinta: Advisor/Consultant|Melinta: Grant/Research Support|Menarini: Advisor/Consultant|Merck: Advisor/Consultant|Merck: Grant/Research Support|Pfizer: Advisor/Consultant|Roche: Grant/Research Support|Shionogi: Advisor/Consultant|Shionogi: Grant/Research Support|Utility: Advisor/Consultant|Venatorx: Advisor/Consultant|Venatorx: Grant/Research Support Lilian M. Abbo, MD, MBA, Ferring: Advisor/Consultant|Pfizer: Advisor/Consultant|Regeneron: Grant/Research Support|Shionogi: Advisor/Consultant Ahmed Babiker, MBBS, Roche: Advisor/Consultant Kimberly C. Claeys, PharmD, Abbvie: Advisor/Consultant|bioMérieux Inc.: Advisor/Consultant|bioMérieux Inc.: Speaker|La Jolla Pharmaceuticals: Advisor/Consultant|Melinta Therapeutics: Advisor/Consultant Jason C. Gallagher, PharmD, Entasis: Advisor/Consultant|Merck: Advisor/Consultant|Merck: Grant/Research Support|Qpex: Advisor/Consultant|Shionogi: Advisor/Consultant|Spero: Advisor/Consultant Emily L. Heil, PharmD, MS, Wolters Kluwer-LexiComp: Advisor/Consultant Wesley D. Kufel, PharmD, BCPS, BCIDP, AAHIVP, Merck and Co: Grant/Research Support Amy Mathers, MD, D(ABMM), Merck: Advisor/Consultant Erin K. McCreary, PharmD, Abbvie: Advisor/Consultant|Ferring: Advisor/Consultant|GSK: Honoraria|La Jolla (Entasis): Advisor/Consultant|LabSimply: Advisor/Consultant|Merck: Advisor/Consultant|Shionogi: Advisor/Consultant|Shionogi: Honoraria Christopher Polk, MD, ViiVHealthcare: Job change to work for ViiV as Medical Director Michael J. Satlin, MD, AbbVie: IDMC member|Biomerieux: Grant/Research Support|Merck: Grant/Research Support|SNIPRBiome: Grant/Research Support Michael Veve, PharmD, MPH, National Institutes of Health: Grant/Research Support|Paratek Pharmaceuticals: Grant/Research Support jason M. Pogue, PharmD, AbbVie: Advisor/Consultant|Entasis: Advisor/Consultant|Ferring: Advisor/Consultant|GSK: Advisor/Consultant|Merck: Advisor/Consultant|Merck: Grant/Research Support|Qpex: Advisor/Consultant|Shionogi: Advisor/Consultan

\u3ci\u3eDrosophila\u3c/i\u3e Muller F Elements Maintain a Distinct Set of Genomic Properties Over 40 Million Years of Evolution

The Muller F element (4.2 Mb, ~80 protein-coding genes) is an unusual autosome of Drosophila melanogaster; it is mostly heterochromatic with a low recombination rate. To investigate how these properties impact the evolution of repeats and genes, we manually improved the sequence and annotated the genes on the D. erecta, D. mojavensis, and D. grimshawi F elements and euchromatic domains from the Muller D element. We find that F elements have greater transposon density (25–50%) than euchromatic reference regions (3–11%). Among the F elements, D. grimshawi has the lowest transposon density (particularly DINE-1: 2% vs. 11–27%). F element genes have larger coding spans, more coding exons, larger introns, and lower codon bias. Comparison of the Effective Number of Codons with the Codon Adaptation Index shows that, in contrast to the other species, codon bias in D. grimshawi F element genes can be attributed primarily to selection instead of mutational biases, suggesting that density and types of transposons affect the degree of local heterochromatin formation. F element genes have lower estimated DNA melting temperatures than D element genes, potentially facilitating transcription through heterochromatin. Most F element genes (~90%) have remained on that element, but the F element has smaller syntenic blocks than genome averages (3.4–3.6 vs. 8.4–8.8 genes per block), indicating greater rates of inversion despite lower rates of recombination. Overall, the F element has maintained characteristics that are distinct from other autosomes in the Drosophila lineage, illuminating the constraints imposed by a heterochromatic milieu