Publications

Abstract [177Lu]Lu-PSMA-617 (LuPSMA) radionuclide therapy improves overall survival in mCRPC, and was recently approved by the FDA. Nevertheless, owing to the heterogeneous nature of mCRPC, responses to LuPSMA therapy can be variable, and resistance is inevitable. As a result, biomarkers linked to clinical outcome with LuPSMA are urgently required. Using plasma ctDNA, we present the first comprehensive genomic analysis of a prospective cohort of mCRPC patients treated with LuPSMA. Targeted sequencing of 78 genes was performed on baseline plasma and matched buffy coat samples from patients who received LuPSMA on a prospective registry (NCT04769817). Reportable alterations included pathogenic single-nucleotide and copy number variants. Association between alterations and clinical outcomes were assessed using log rank, cox proportional, and chi-squared analyses. Clinical data collected included PSA decline by ≥50% or ≥90% (PSA50-response rate, PSA50-RR; and PSA90-RR), and PSA progression free survival (PSA-PFS). In total, 100 patients (median age 74 years, range 52-90) received a median of 4 cycles of LuPSMA. 83 patients had detectable ctDNA (median fraction 17%, range 0-94%) with PSA50-RR 50%, PSA90-RR 22%, and a median PSA-PFS of 7.2 months. Patients with an AR or PTEN aberration had significantly shorter PSA-PFS (HR 0.50 and 0.59, respectively; Table), as did patients with any PI3K pathway aberration (HR 0.56). Additionally, patients with a high ctDNA burden had significantly worse PSA-PFS (HR 0.42, Table). There were no significant differences in PSA-RR based on deleterious genomic changes. Our data reveal that aberrations in the AR and PI3K pathways, along with pre-treatment ctDNA fraction, whilst not linked to PSA-RR, are prognostic for durability of response to LuPSMA. If validated in larger cohorts, these data will help to optimise the use of LuPSMA by improving patient selection and enhancing prognostication. Analysis of clinical endpoints based on deleterious genomic changes in ctDNA n PSA-PFS (months, wild type (wt) vs variant) PSA-PFS HR (95% CI, wt vs variant) PSA50-RR (wt vs variant) PSA90-RR (wt vs variant) Exonic AR variants 47 8.1 vs 6.0 p=0.005 0.50 (0.30-0.83) p=0.006 58% vs 40% p=0.09 23% vs 21% p=0.8 Any AR variant (intronic and upstream enhancer regions included) 49 8.1 vs 6.0 p=0.007 0.53 (0.31-0.83) p=0.008 60% vs 41% p=0.09 24% vs 20% p=0.7 RB1 variant 19 7.9 vs 5.5 p=0.2 0.67 (0.39-1.2) p=0.2 51% vs 42% p=0.5 23% vs 21% p=0.9 PTEN variant 25 7.8 vs 6.3 p=0.04 0.59 (0.36-1.00) p=0.045 50% vs 48% p=0.9 22% vs 24% p=0.8 TP53 variant 43 8.1 vs 6.7 p=0.1 0.67 (0.42-1.1) p=0.1 52% vs 47% p=0.6 20% vs 26% p=0.5 BRCA2 variant 10 7.7 vs 5.1 p=0.2 0.63 (0.29-1.30) p=0.2 51% vs 40% p=0.7 20% vs 40% p=0.1 PIK3CA variant 8 7.7 vs 4.1 p=0.08 0.48 (0.20-1.1) p=0.09 52% vs 13% p=0.06 23% vs 13% p=0.5 PI3K pathway variant 35 7.8 vs 5.5 p= 0.02 0.56 (0.34-0.91) p=0.02 55% vs 40% p=0.2 22% vs 23% p=0.9 ctDNA fraction ≥20% 43 9.0 vs 5.1 p=0.0002 0.42 (0.26-0.67) p<0.001 55% vs 42% p=0.2 21% vs 23% p=0.8 Citation Format: Heidi Fettke, Louise Kostos, James Buteau, Jason A. Steen, Elizabeth Medhurst, Mo B. Haskali, Declan Murphy, Maria Docanto, Patricia Bukczynska, Nicole Ng, Shahneen Sandhu, Siavash Foroughi, Luc Furic, Tu Nguyen-Dumont, Michael S. Hofman, Arun A. Azad. Genomic aberrations in circulating tumor DNA (ctDNA) and clinical outcomes from [177Lu]Lu-PSMA-617 in metastatic castration-resistant prostate cancer (mCRPC). [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 5614.

Abstract The laboratorial mouse harbors a unique gut microbiota with potential value for human microbiota-associated studies. Mouse gut microbiota has been explored at the genus and species levels, but features rarely been showed at the strain level. The identification of 833,051 and 658,438 nonredundant genes of faeces and gut content samples from the laboratorial C57/BL mice showed over half of these genes were newly found compared to the previous mouse gut microbial gene catalogue. Metagenome-assembled genomes (MAGs) was used to reconstruct 46 nonredundant MAGs belonging to uncultured specieses. These MAGs included members across all phyla in mouse gut (i.e. Firmicutes, Bacteroidetes, Proteobacteria, Deferribacteres, Verrucomicrobia, and Tenericutes) and allowed a strain-level delineating of the mouse gut microbiota. Comparison of MAGs with human gut colonies revealed distinctive genomic and functional characteristics of mouse’s Bacteroidetes and Firmicutes strains. Genomic characteristics of rare phyla in mouse gut microbiota were demonstrated by MAG approach, including strains of Mucispirillum schaedleri, Parasutterella excrementihominis, Helicobacter typhlonius , and Akkermansia muciniphila . Importance The identification of nonredundant genes suggested the existence of unknown microbes in the mouse gut samples. The metagenome-assembled genomes (MAGs) instantiated the specificity of mouse gut species and revealed an intestinal microbial correlation between mouse and human. The cultivation of faeces and gut contents sample validated the existence of MAGs and estimate their accuracy. Full-length 16S ribosomal RNA gene sequencing enabled taxonomic characterization. This study highlighted a unique ecosystem in the gut of laboratorial mice that obviously differed with the human gut flora at the strain level. The outcomes may be beneficial to researches based on laboratorial mouse models.

<p>Supplementary Figure 3. Pano induced pancreatic tumor cell apoptosis.</p>

The mycophenolate mofetil (MMF) dose management for optimization of post-transplant treatment especially the early postoperative phase has been well recognized. MMF is a pro-drug of mycophenolic acid (MPA) and is widely used in Chinese renal transplant patients. Until now, the pharmacokinetic (PK) characteristics and model for the area under the concentration–time curve for the 12-hour (h) of exposure (AUC0-12h) of MPA (MPA-AUC0-12h) estimation were lacking for the new formulation of MMF dispersible tablet in renal transplant patients. The aims of the study were to investigate the PK characteristics of MMF dispersible tablet by detecting the active metabolite of MPA and to establish an accuracy and precision equation for calculating MPA-AUC0-12h by limited sampling strategy (LSS) in Chinese kidney transplant patients. A total of 60 postoperative kidney transplant recipients were given a multiple-dose of MMF dispersible tablet twice daily combination with tacrolimus (Tac) and steroids. On the fifth day post-transplantation, blood specimens were collected before drug administration and up to 12 h after MMF dispersible tablet administration. Non-compartmental PK analysis was used to determine the data obtained from individual patients. Multivariate stepwise regression analysis was used to develop models for predicting MPA-AUC0-12h. The 3- and 4-point sampling models using 2h, 4h, 8h and 1h, 2h, 4h and 8h, respectively, allowed accurate estimation of MPA-AUC0-12h. PK parameters of MMF dispersible tablet were obtained and the 4-point LSS is the best model for accurate and precise estimation of MPA-AUC0-12h.

To assess the activity and safety of sequential lutetium-177 (177 Lu)-PSMA-617 and docetaxel vs docetaxel on a background of androgen deprivation therapy (ADT) in men with de novo metastatic hormone-naïve prostate cancer (mHNPC).UpFrontPSMA (NCT04343885) is an open-label, randomized, multicentre, phase 2 trial, recruiting 140 patients at 12 Australian centres. Key eligibility criteria include: prostate cancer with a histological diagnosis within 12 weeks of screening commencement; prostate-specific antigen (PSA) >10 ng/mL at diagnosis; ≤4 weeks on ADT; evidence of metastatic disease on computed tomography (CT) and/or bone scan; high-volume prostate-specific membrane antigen (PSMA)-avid disease with a maximum standardized uptake value >15; and absence of extensive discordant fluorodeoxyglcuose (FDG)-positive, PSMA-negative disease. 68 Ga-PSMA-11 and 18 F-FDG positron-emission tomography (PET)/CT undergo central review to determine eligibility. Patients are randomized 1:1 to experimental treatment, Arm A (177 Lu-PSMA-617 7.5GBq q6w × 2 cycles followed by docetaxel 75 mg/m2 q3w × 6 cycles), or standard-of-care treatment, Arm B (docetaxel 75 mg/m2 q3w × 6 cycles). All patients receive continuous ADT. Patients are stratified based on disease volume on conventional imaging and duration of ADT at time of registration. The primary endpoint is the proportion of patients with undetectable PSA (≤0.2 ng/L) at 12 months after study treatment commencement. Secondary endpoints include safety, time to castration resistance, overall survival, PSA and radiographic progression-free survival, objective tumour response rate, early PSMA PET response, health-related quality of life, and frequency and severity of adverse events. Enrolment commenced in April 2020.The results of this trial will generate data on the activity and safety of 177 Lu-PSMA-617 in men with de novo mHNPC in a randomized phase 2 design.

Background Melanoma brain metastases (MBMs) are a challenging clinical problem with high morbidity and mortality. Although first-line dabrafenib–trametinib and ipilimumab–nivolumab have similar intracranial response rates (50%–55%), central nervous system (CNS) resistance to BRAF-MEK inhibitors (BRAF-MEKi) usually occurs around 6 months, and durable responses are only seen with combination immunotherapy. We sought to investigate the utility of ipilimumab–nivolumab after MBM progression on BRAF-MEKi and identify mechanisms of resistance. Methods Patients who received first-line ipilimumab–nivolumab for MBMs or second/third line ipilimumab–nivolumab for intracranial metastases with BRAF V600 mutations with prior progression on BRAF-MEKi and MRI brain staging from March 1, 2015 to June 30, 2018 were included. Modified intracranial RECIST was used to assess response. Formalin-fixed paraffin-embedded samples of BRAF V600 mutant MBMs that were naïve to systemic treatment (n=18) or excised after progression on BRAF-MEKi (n=14) underwent whole transcriptome sequencing. Comparative analyses of MBMs naïve to systemic treatment versus BRAF-MEKi progression were performed. Results Twenty-five and 30 patients who received first and second/third line ipilimumab–nivolumab, were included respectively. Median sum of MBM diameters was 13 and 20.5 mm for the first and second/third line ipilimumab–nivolumab groups, respectively. Intracranial response rate was 75.0% (12/16), and median progression-free survival (PFS) was 41.6 months for first-line ipilimumab–nivolumab. Efficacy of second/third line ipilimumab-nivolumab after BRAF-MEKi progression was poor with an intracranial response rate of 4.8% (1/21) and median PFS of 1.3 months. Given the poor activity of ipilimumab–nivolumab after BRAF-MEKi MBM progression, we performed whole transcriptome sequencing to identify mechanisms of drug resistance. We identified a set of 178 differentially expressed genes (DEGs) between naïve and MBMs with progression on BRAF-MEKi treatment (p value <0.05, false discovery rate (FDR) <0.1). No distinct pathways were identified from gene set enrichment analyses using Kyoto Encyclopedia of Genes and Genomes, Gene Ontogeny or Hallmark libraries; however, enrichment of DEG from the Innate Anti-PD1 Resistance Signature (IPRES) was identified (p value=0.007, FDR=0.03). Conclusions Second-line ipilimumab–nivolumab for MBMs after BRAF-MEKi progression has poor activity. MBMs that are resistant to BRAF-MEKi that also conferred resistance to second-line ipilimumab–nivolumab showed enrichment of the IPRES gene signature.