Publications

Aim To catalogue and compare the pattern of metastatic disease in germline BRCA1/2 pathogenic mutation carriers and non‐carriers with breast, ovarian and prostate cancer from a rapid autopsy programme. Methods and results The number of metastases in the major body systems and the proportion of participants with metastases were documented in 50 participants (19 germline mutation carriers). Analysis was conducted on the participants’ pattern of disease for the different cancers and mutation subgroups. The four commonly affected organ systems were the digestive (liver only) (82%), respiratory (76%), gastrointestinal (65%) and reticuloendothelial (42%). There were significant differences in the pattern of metastatic breast cancer in BRCA1/2 germline carriers compared with non‐carriers. Breast cancer carriers had significantly fewer organ systems involved (median n = 3, range = 1–3) compared with non‐carriers (median n = 9, range = 1–7) ( P = 0.03). BRCA1/2 carriers with ovarian carcinomas had significantly more organ systems with metastatic carcinoma (median n = 10, range = 3–8) than non‐carriers (median n = 5, range = 3–5) ( P < 0.001). There were no significant differences in the number of involved systems in BRCA2 carriers compared with non‐carriers with prostate cancer ( P = 1.0). There was an absence of locoregional disease (6.5%) compared with distant disease (93.5%) among the three cancer subtypes ( P < 0.001). The majority of metastatic deposits (97%) collected during the autopsy were identified by recent diagnostic imaging. Conclusion Even though a major limitation of this study is that our numbers are small, especially in the breast cancer carrier group, the metastatic patterns of breast and ovarian cancers may be impacted by BRCA1/2 carrier status, suggesting that tumours derived from patients with these mutations use different mechanisms of dissemination. The findings may focus clinical diagnostic imaging for monitoring metastases where whole‐body imaging resources are scant.

The genomics of primary prostate cancer differ from those of metastatic castration-resistant prostate cancer (mCRPC). We studied genomic aberrations in primary prostate cancer biopsies from patients who developed mCRPC, also studying matching, same-patient, diagnostic, and mCRPC biopsies following treatment. We profiled 470 treatment-naive prostate cancer diagnostic biopsies and, for 61 cases, mCRPC biopsies, using targeted and low-pass whole-genome sequencing (n = 52). Descriptive statistics were used to summarize mutation and copy number profile. Prevalence was compared using Fisher's exact test. Survival correlations were studied using log-rank test. TP53 (27%) and PTEN (12%) and DDR gene defects (BRCA2 7%; CDK12 5%; ATM 4%) were commonly detected. TP53, BRCA2, and CDK12 mutations were markedly more common than described in the TCGA cohort. Patients with RB1 loss in the primary tumor had a worse prognosis. Among 61 men with matched hormone-naive and mCRPC biopsies, differences were identified in AR, TP53, RB1, and PI3K/AKT mutational status between same-patient samples. In conclusion, the genomics of diagnostic prostatic biopsies acquired from men who develop mCRPC differ from those of the nonlethal primary prostatic cancers. RB1/TP53/AR aberrations are enriched in later stages, but the prevalence of DDR defects in diagnostic samples is similar to mCRPC.

¹⁷⁷Lu-prostate-specific membrane antigen (PSMA)–617 enables targeted delivery of β-particle radiation to prostate cancer. We determined its radiation dosimetry and relationships to pretherapeutic imaging and outcomes. <b>Methods:</b> Thirty patients with prostate cancer receiving ¹⁷⁷Lu-PSMA-617 within a prospective clinical trial (ACTRN12615000912583) were studied. Screening ⁶⁸Ga-PSMA-11 PET/CT demonstrated high PSMA expression in all patients. After therapy, patients underwent quantitative SPECT/CT at 4, 24, and 96 h. Pharmacokinetic uptake and clearance at a voxel level were calculated and translated into absorbed dose using voxel S values. Volumes of interest were drawn on normal tissues and tumor to assess radiation dose, and a whole-body tumor dose was defined. Correlations between PSMA PET/CT parameters, dosimetry, and biochemical and therapeutic response were analyzed to identify relationships between absorbed dose, tumor burden, and patient physiology. <b>Results:</b> Mean absorbed dose to kidneys, submandibular and parotid glands, liver, spleen, and bone marrow was 0.39, 0.44, 0.58, 0.1, 0.06, and 0.11 Gy/MBq, respectively. Median whole-body tumor-absorbed dose was 11.55 Gy and correlated with prostate-specific antigen (PSA) response at 12 wk. A median dose of 14.1 Gy was observed in patients achieving a PSA decline of at least 50%, versus 9.6 Gy for those achieving a PSA decline of less than 50% (<i>P</i> &lt; 0.01). Of 11 patients receiving a tumor dose of less than 10 Gy, only one achieved a PSA response of at least 50%. On screening PSMA PET, whole-body tumor SUV_mean correlated with mean absorbed dose (<i>r</i> = 0.62), and SUV_max of the parotids correlated with absorbed dose (<i>r</i> = 0.67). There was an inverse correlation between tumor volume and mean dose to the parotids (<i>r</i> = −0.41) and kidneys (<i>r</i> = −0.43). The mean parotid dose was also reduced with increasing body mass (<i>r</i> = −0.41) and body surface area (<i>r</i> = −0.37). <b>Conclusion:</b>¹⁷⁷Lu-PSMA-617 delivers high absorbed doses to tumor, with a significant correlation between whole-body tumor dose and PSA response. Patients receiving less than 10 Gy were unlikely to achieve a fall in PSA of at least 50%. Significant correlations between aspects of screening ⁶⁸Ga-PET/CT and tumor and normal tissue dose were observed, providing a rationale for patient-specific dosing. Reduced salivary and kidney doses were observed in patients with a higher tumor burden. The parotid dose also reduced with increasing body mass and body surface area.

9583 Background: The efficacy of ICIs in metastatic melanoma is well-established. However, there is limited data regarding their efficacy in in-transit melanoma metastases (ITM). This study assessed the efficacy of ICI in patients with ITM. Methods: A multisite, retrospective review of patients with ITM treated with ICI from 2004-2018. Demographic and clinicopathological factors (age, sex, primary site, AJCC version 8 stage, BRAF status, prior locoregional therapies) were collected. Objective response rate (ORR) based on a clinician-assessed best overall response, progression free survival (PFS) and overall survival (OS) were analyzed by the Kaplan-Meier method. Results: Fifty-four patients were included: 27 (50%) female; median age 69 (range 19-89); 12 (22%) stage IIIB, 40 (74%) stage IIIC and 2 (4%) stage IIID; 10(19%) BRAF mutant. Forty (74%) received single agent PD-1 inhibitor (pembrolizumab or nivolumab), 8 (15%) single agent anti-CTLA-4 (ipilimumab), 5 (9%) combination anti-PD-1/anti-CTLA-4 (ipilimumab and nivolumab or pembrolizumab) and 1 (2%) combination anti-PDL-1/MEK inhibitor (atezolizumab and cobimetinib). ORR to ICI was 54%: 14 (26%) complete responses; 15 (28%) partial responses; 9 (17%) stable disease; 16 (30%) progressive disease. Thirteen (46%) responders had only one ITM lesion. ORR was 58% for single agent anti PD-1, 38% for single agent anti-CTLA4, and 40% for anti-PD-1/anti-CTLA-4 (Table). The median follow-up was 15 months (2-46). The median PFS was 11.7 months (6.6-N/A). PFS at 1 and 2 years were 48% and 39%. Fourteen (56%) progressed locoregionally and 11 (44%) progressed distantly. OS at 1 and 2 years were 85% and 63%; the median OS was not reached. No clinicopathological features were associated with ORR. Conclusions: ICI produces objective responses in ITM and should be considered in patients with unresectable ITM or disease recurrence despite locoregional therapies. [Table: see text]

9508 Background: Preliminary data from the ABC (76 pts) and CheckMate 204 (94 pts) trials showed that nivo and nivo+ipi have activity in active melanoma brain metastases, with durable responses in a subset of pts. Here, we report updated 5-yr data from all pts enrolled on the ABC trial (NCT02374242). Methods: This open-label ph2 trial enrolled 3 cohorts of pts with active melanoma brain mets naïve to anti-PD1/PDL1/PDL2/CTLA4 from Nov 2014-Apr 2017. Pts with asymptomatic brain mets with no prior local brain therapy were randomised to cohort A (nivo 1mg/kg + ipi 3mg/kg, Q3Wx4, then nivo 3mg/kg Q2W) or cohort B (nivo 3mg/kg Q2W). Cohort C (nivo 3mg/kg Q2W) had brain mets i) that failed local therapy, ii) with neuro symptoms and/or iii) with leptomeningeal disease. Prior BRAF inhibitor (BRAFi) was allowed. The primary endpoint was best intracranial response (ICR) ≥wk12. Key secondary endpoints were IC PFS, overall PFS, OS, &amp; safety. Results: A total of 76 pts (med f/u 54 mo) were enrolled; median age 59y, 78% male. For cohorts A, B and C: elevated LDH 51%, 58% and 19%; V600BRAF 54%, 56% and 81%; prior BRAFi 23%, 24%, 75%. Efficacy and toxicity are shown in the table. There were no treatment-related deaths. 1/17 deaths in cohort A &amp; 4/16 in cohort B were due to IC progression only. Conclusions: Nivo monotherapy and ipi+nivo are active in melanoma brain mets, with durable responses in the majority of patients who received ipi+nivo upfront. A study of upfront ipi+nivo+/-SRS is underway (NCT03340129). Clinical trial information: NCT02374242. [Table: see text]

Abstract BACKGROUND: Distinct metastatic prostate cancer lesions within the same patient can show a range of responses to targeted therapy. These variations in response present a challenge for the interpretation of predictive biomarkers derived from a single lesion. The influence of tumor evolution on how lesions respond to Androgen Signaling Inhibitor (ASI) or PARP inhibitor therapy has been difficulty to study, because few autopsy studies have been performed in heavily treated patients with DNA repair defects. METHODS: In this study, we analyzed an autopsy cohort of 54 tumors from six men with DNA repair-deficient metastatic prostate cancer using whole genome, exome, and targeted DNA sequencing as well as RNA-sequencing. Observations were validated in an independent cohort of 135 mCRPC biopsies with whole genome and transcriptome sequencing. To automate the analysis of mutations conferring resistance to PARP inhibitor therapy, we developed a tool (AARDVARK) that detects and annotates PARP inhibitor resistance mutations. RESULTS: Patients harboring germline inactivation of the DNA repair gene BRCA2 showed consistent BRCA2 biallelic inactivation, while somatic BRCA2 inactivation was not always associated with biallelic deletion and genomic scars of DNA repair inactivation. AARDVARK identified numerous identical resistance mutations in physically distinct tumors in the same individual, consistent with dissemination of these mutations prior to later targeted therapy. We identified DNA structural variations linked to extra-chromosomal DNA (ecDNA) in 52% of mCRPC biopsies, and ecDNA amplified an oncogene 28% of the time. Extensive heterogeneity of structural variants was present at the Androgen Receptor locus, which was the most frequent target of ecDNA amplification (15% of tumors). Cyclins CCND1 and CCNE1 were amplified in 3% of cases, and a long tail of oncogenes were also targeted. Phylogenetic analysis was consistent with AR amplification by ecDNA in response to both androgen deprivation therapy and second-generation ASI. The presence of ecDNA was significantly associated with overall genomic instability, aneuploidy, whole genome doubling, chromothripsis, and with inactivating PTEN alterations. CONCLUSIONS: This study demonstrated that mCRPC lesions continue to evolve on therapy, and their varied responses can be influenced by shared genetic backgrounds. Oncogene amplification by ecDNA is common in mCRPC, particularly at the AR locus, and is linked to genomic instability. Alterations conferring resistance to ASI and PARP inhibitor therapy can be present in individual lesions before metastatic dissemination, and the evolutionary history of tumors plays an important role in their tumor response to targeted therapy. Citation Format: Thaidy Moreno, Meng Zhang, Arian Lundberg, Raunak Shrestha, Martin Sjöström, Anu Pasam, Adam Foye, Anna Trigos, Felix Feng, Shahneen Sandhu, David A. Quigley. Convergent evolution in DNA repair-deficient mCRPC in response to targeted therapy [abstract]. In: Proceedings of the AACR Special Conference: Advances in Prostate Cancer Research; 2023 Mar 15-18; Denver, Colorado. Philadelphia (PA): AACR; Cancer Res 2023;83(11 Suppl):Abstract nr PR003.

Sir, We thank Shamash and Sarker for their interest in our recent article (Omlin et al, 2013). They make three comments: first, that the activity of diethylstilboestrol (DES) when combined with a corticosteroid such as dexamethasone (D) is increased compared to DES alone; second, that chemotherapy may re-induce sensitivity to a hormonal agent; finally, their experience in 11 patients who received the sequence of docetaxel followed by DES and D and then abiraterone acetate (AA) and prednisone. In this setting the activity of AA was limited, as indicated by a median progression-free survival (PFS) of 1.8 months (range 0.6–8.1). We wish to clarify that we did not report any data on DES activity prior to treatment with AA because it was not possible to get complete DES activity data for patients treated outside of our institution. We therefore only reported duration of DES treatment. Our large institutional experience with single-agent DES and aspirin in 231 men with castration resistant prostate cancer (CRPC) showed a median time to PSA progression of 4.6 months, ⩾50% PSA declines in 28.9% of patients and a VTE rate of 9.9% (Wilkins et al, 2012). We acknowledge that the activity of DES may be modestly higher when it is combined with D, which has been shown to have single-agent anti-tumour activity in men with castration-resistant prostate cancer, although there is little evidence that this therapeutic manoeuvre imparts significant clinical benefit (Venkitaraman et al, 2008). The comparison of DES plus D with D alone by Shamash et al (2011) is interesting but raised concerns that DES is associated with a major risk of serious toxicity, unlike AA, with veno-thromboembolic events (VTEs) in 22% of patients despite prophylactic treatment with aspirin. Given that AA provides overall survival benefit in Phase III trials, AA is a preferable treatment to DES for CRPC (de Bono et al, 2011; Ryan et al, 2013). Indeed we believe that there may now be little merit in administering DES to patients suffering from CRPC. The hypothesis that chemotherapy may induce sensitivity to endocrine agents is also intriguing. However, clinical trials of AA and enzalutamide have all reported higher response rates pre-chemotherapy than afterwards, suggesting overlapping mechanisms of resistance (Scher et al, 2010, 2012; de Bono et al, 2011; Ryan et al, 2013). The study referenced by Shamash et al (2008) did not utilise taxanes (that through their postulated disruption of AR signalling may be associated with cross-resistance with endocrine treatments) and allowed cessation of androgen deprivation with 49% of patients having non-castrate levels of testosterone at the completion of chemotherapy (Shamash et al, 2008). The responses observed could therefore be related to re-initiation of castration. Nevertheless, we too envision that in the future we will be able to interrogate the evolution – emergence, disappearance and possibly re-emergence – of different CRPC clones/sub-clones following different therapeutic pressures. We believe that the pursuit of translational studies of circulating biomarkers and CRPC tissue urgently need to be prioritised to address these issues. Finally, Shamash et al (2008) report minimal activity in 11 patients who received AA after docetaxel followed by DES given with D. Recently published case series have similarly indicated that the activity of AA is reduced when administered after docetaxel and enzalutamide (Loriot et al, 2013; Noonan et al, 2013). Our report observed PSA declines ⩾50% in 28.4% of 81 patients treated with AA after DES and docetaxel and radiological responses in 25% of patients (Omlin et al, 2013). The differences of these two reports could be explained by the post hoc nature of the analyses and the differences in use of steroids. As AA is now commonly used pre-chemotherapy and prior to DES, the latter is often an option of last resort. Overall, however, our report indicates that the limited activity and the significant toxicity of DES should limit its use in patients who have previously progressed on AA and docetaxel, and that patients should be offered agents with a proven survival benefit or clinical trials in this situation.

Cyclic dimeric adenosine monophosphate (c-di-AMP) is a ubiquitous second messenger of bacteria involved in diverse physiological processes as well as host immune responses. MSMEG_2630 is a c-di-AMP phosphodiesterase (cnpB) of Mycobacterium smegmatis, which is homologous to Mycobacterium tuberculosis Rv2837c. In this study, cnpB-deleted (ΔcnpB), -complemented (ΔcnpB::C), and -overexpressed (ΔcnpB::O) strains of M. smegmatis were constructed to investigate the role of c-di-AMP in regulating mycobacterial physiology and immunogenicity. This study provides more precise evidence that elevated c-di-AMP level resulted in smaller colonies, shorter bacteria length, impaired growth, and inhibition of potassium transporter in M. smegmatis. This is the first study to report that elevated c-di-AMP level could inhibit biofilm formation and induce porphyrin accumulation in M. smegmatis by regulating associated gene expressions, which may have effects on drug resistance and virulence of mycobacterium. Moreover, the cnpB-deleted strain with an elevated c-di-AMP level could induce enhanced Th1 immune responses after M. tuberculosis infection. Further, the pathological changes and the bacteria burden in ΔcnpB group were comparable with the wild-type M. smegmatis group against M. tuberculosis venous infection in the mouse model. Our findings enhanced the understanding of the physiological role of c-di-AMP in mycobacterium, and M. smegmatis cnpB-deleted strain with elevated c-di-AMP level showed the potential for a vaccine against tuberculosis.

The incidence of cerebral ischemic stroke characterized by high mortality is increasing every year. Danshen Chuanxiongqin Injection (DSCXQ), a traditional Chinese medicine (TCM) preparation, is often applied to treat cerebral apoplexy and its related sequelae. However, there is a lack of systematic research on how DSCXQ mediates its protective effects against cerebral ischemia stroke. Metabolomic analysis based on UHPLC-Q-Orbitrap HRMS was employed to explore the potential mechanisms of DSCXQ on ischemic stroke induced by transient middle cerebral artery occlusion (MCAO). Pattern analysis and metabolomic profiling, combined by multivariate analysis disclosed that 55 differential metabolites were identified between Sham group and Model group, involving sphingolipid metabolism, glycerophospholipid metabolism, phenylalanine, tyrosine and tryptophan biosynthesis, primary bile acid biosynthesis, pantothenate and CoA synthesis and valine, leucine and isoleucine biosynthesis pathways. DSCXQ could reverse brain metabolic deviations in stroke by significantly upregulating the levels of L-tryptophan, Lyso (18:0/0:0), LPC (18:2), Indole-3-methyl acetate, and downregulating the levels of sphinganine 1-phosphate, L-threonic acid, glutaconic acid and N6,N6,N6-Trimethyl-L-lysine. In our study, we focused on the neuroprotective effects of DSCXQ against neuroinflammatory responses and neuronal apoptosis on a stroke model based on sphingolipid metabolism. The expressions of Sphk1, S1PR1, CD62P, Bcl-2, Bax, and cleaved Caspase-3 in brain tissue were evaluated. The neurological deficit, cerebral infarct size and behavioral abnormality were estimated. Results showed that DSCXQ intervention significantly reduced cerebral infarct size, ameliorated behavioral abnormality, inhibited the expression of Sphk1, S1PR1, CD62P, Bax, Cleaved Caspase-3, while increased the level of Bcl-2, and prevented neuronal apoptosis. The limitations are that our study mainly focused on the verification of sphingolipid metabolism pathway in stroke, and while other metabolic pathways left unverified. Our study indicates that SphK1-SIP axis may potentiate neuroinflammatory responses and mediate brain damage through neuronal apoptosis, and DSCXQ could suppress the activity of SphK1-SIP axis to protect brain tissue in cerebral ischemia. In conclusion, this study facilitates our understanding of metabolic changes in ischemia stroke and the underlying mechanisms related to the clinical application of DSCXQ.