Unique genomic alterations in the circulating tumor DNA of patients with solid tumors brain metastases

Background

Although serum circulating tumor DNA (ctDNA) is routine, data from patients with brain metastases (BrMs) is limited. We assessed genomic alterations in ctDNA from patients with solid tumor BrMs in 3 groups: Isolated BrMs with stable extracranial disease (iCNS), concurrent brain and extracranial progression (cCNS), and extracranial progression with no active BrMs (eCNS). We also compared ctDNA alterations between patients with and without BrMs.

Methods

Patients with a Guardant360 ctDNA profile with (n = 253) and without BrMs (n = 449) from the Duke Molecular Registry between January 2014 and December 2020 were identified. Actionable alterations were defined as FDA-recognized or standard-of-care biomarkers. Disease status was determined via investigator assessment within 30 days of ctDNA collection.

Results

Among the 253 patients with BrMs: 29 (12%) had iCNS, 160 (63%) cCNS, and 64 (25%) eCNS. Breast (BC; 12.0%) and non-small cell lung cancer (NSCLC; 76.4%) were the most common tumor types. ESR1 (60% vs 25%, P < .001) and BRCA2 (17% vs 5%, P = .022) were more frequent in BC BrMs. In NSCLC BrMs, EGFR alterations were most frequent in the iCNS group (iCNS: 67%, cCNS: 40%, eCNS:37%, P = .08) and in patients with BrMs (36% vs 17%, P < .001). Sequencing from both brain tissue and ctDNA were available for 8 patients; 7 (87.5%) had identical alterations.

Conclusions

This study illustrates the feasibility of detecting alterations from ctDNA among patients with BrMs. A higher frequency of actionable mutations was observed in ctDNA in patients with BrMs. Additional studies comparing ctDNA and alterations in BrMs tissue are needed to determine if ctDNA can be considered a surrogate to support treatment decisions.

Long-term outcome analysis of Y90 radioembolization in hepatocellular carcinoma

Background

Yttrium-90 (Y90) radioembolization is a catheter-based therapy for hepatocellular carcinoma (HCC). Multiple trials have evaluated the efficacy of Y90 in HCC; however, few have assessed long-term hepatic function. This study aimed to evaluate a clinical real-world experience of Y90 effectiveness and long-term impact on hepatic function.

Methods

A single-center retrospective chart review was performed for patients with Child-Pugh (CP) class A or B who received Y90 for primary HCC between 2008 and 2016. Model for end-stage liver disease (MELD) and CP scores were calculated on the day of treatment and 1, 3, 6, 12, and 24 months post-procedure.

Results

Of the 134 patients included, the mean age was 60 years old and median overall survival (OS) from date of diagnosis was 28 months [95% confidence interval (CI): 22.21-38.05]. Patients with CP class A (85%) had a median progression-free survival (PFS) of 3 months (95% CI: 2.99-5.55) and median OS of 17 months (95% CI: 9.59-23.10) from date of Y90 treatment compared to a median PFS of 4 months (95% CI: 2.07-8.28) and OS of 8 months (95% CI: 4.60-15.64) for patients with CP class B. MELD scores were significantly higher post-treatment than pre-treatment, with significant recovery at 24 months. No significant differences were seen between cancer stage and OS, while PFS and cancer stage did show difference between cancer stage 1 and 3 with longer median PFS seen in stage 1.

Conclusions

While our study supports the literature for OS in Y90-treated patients, we found a shorter PFS in this population. This may reflect the differences between the utilization of RECIST in clinical trials and clinical radiology practice in determining progression. Significant factors associated with OS were age, MELD, CP scores and portal vein thrombosis (PVT). For PFS, CP score and stage at diagnosis were significant. Increasing MELD scores over time likely reflected a combination of radioembolization-induced liver disease, liver decompensation or progression of HCC. The downtrend at 24 months is likely due to long term survivors with significant benefit from therapy with no long-term complications from Y90.

Current drug development and trial designs in neuro-oncology: report from the first American Society of Clinical Oncology and Society for Neuro-Oncology Clinical Trials Conference

Successful drug development for people with cancers of the CNS has been challenging. There are multiple barriers to successful drug development including biological factors, rarity of the disease, and ineffective use of clinical trials. Based upon a series of presentations at the First Central Nervous System Clinical Trials Conference hosted by the American Society of Clinical Oncology and the Society for Neuro-Oncology, we provide an overview on drug development and novel trial designs in neuro-oncology. This Review discusses the challenges of therapeutic development in neuro-oncology and proposes strategies to improve the drug discovery process by enriching the pipeline of promising therapies, optimising trial design, incorporating biomarkers, using external data, and maximising efficacy and reproducibility of clinical trials.

Durable responses in patients with HER2+ breast cancer and leptomeningeal metastases treated with trastuzumab deruxtecan

Leptomeningeal metastases (LM) are a devastating complication of HER2 + metastatic breast cancer (MBC), with no effective treatments. In a case series of 8 patients with heavily pretreated HER2 + MBC and progressing LM, all 8 patients (100%) derived clinical benefit from Trastuzumab deruxtecan (TDXd), and 4 patients (50%) had an objective partial response based on formal neuroradiology MRI reads using the EORTC/RANO-LM Revised-Scorecard. T-DXd warrants further study in LM in HER2 + MBC and solid tumors where T-DXd may be active.

Brain metastasis as the first and only metastatic relapse site portends worse survival in patients with advanced HER2 + breast cancer

PURPOSE

Current systemic therapy guidelines for patients with HER2 + breast cancer brain metastases (BCBrM) diverge based on the status of extracranial disease (ECD). An in-depth understanding of the impact of ECD on outcomes in HER2 + BCBrM has never been performed. Our study explores the implications of ECD status on intracranial progression-free survival (iPFS) and overall survival (OS) after first incidence of HER2 + BCBrM and radiation.

METHODS

A retrospective analysis was performed of 151 patients diagnosed with initial HER2 + BCBrM who received radiation therapy to the central nervous system (CNS) at Duke between 2008 and 2021. The primary endpoint was iPFS defined as the time from first CNS radiation treatment to intracranial progression or death. OS was defined as the time from first CNS radiation or first metastatic disease to death. Systemic staging scans within 30 days of initial BCBrM defined ECD status as progressive, stable/responding or none (isolated brain relapse).

RESULTS

In this cohort, > 70% of patients had controlled ECD with either isolated brain relapse (27%) or stable/responding ECD (44%). OS from initial metastatic disease to death was markedly worse for patients with isolated intracranial relapse (median = 28.4 m) compared to those with progressive or stable/responding ECD (48.8 m and 71.5 m, respectively, p = 0.0028). OS from first CNS radiation to death was significantly worse for patients with progressive ECD (16.9 m) versus stable/responding (36.6 m) or isolated intracranial relapse (28.4 m, p = 0.007). iPFS did not differ statistically based on ECD status. Receipt of systemic therapy after first BCBrM significantly improved iPFS (HR 0.45, 95% CI: 0.25-0.81, p = 0.008) and OS (HR: 0.43 (95% CI: 0.23-0.81); p = 0.001).

CONCLUSION

OS in patients with HER2 + isolated BCBrM was inferior to those with concurrent progressive or stable/responding ECD. Studies investigating initiation of brain-penetrable HER2-targeted therapies earlier in the disease course of isolated HER2 + intracranial relapse patients are warranted.

APOBEC Mutational Signatures in Hormone Receptor-Positive Human Epidermal Growth Factor Receptor 2-Negative Breast Cancers Are Associated With Poor Outcomes on CDK4/6 Inhibitors and Endocrine Therapy

PURPOSE

APOBEC mutagenesis underlies somatic evolution and accounts for tumor heterogeneity in several cancers, including breast cancer (BC). In this study, we evaluated the characteristics of a real-world cohort for time-to-treatment discontinuation (TTD) and overall survival on CDK4/6 inhibitors (CDK4/6i) plus endocrine therapy (ET) and immune checkpoint inhibitors.

METHODS

Comprehensive genomic profiling results from 29,833 BC samples were analyzed for tumor mutational burden and APOBEC signatures. For clinical outcomes, a deidentified nationwide (United States-based) BC Clinico-Genomic Database (CGDB) was evaluated with log-rank and Cox models. Patients with hormone receptor-positive (HR+) human epidermal growth factor receptor 2-negative (HER2-) BC who received first-line ET and CDK4/6i were included. Eligible patients from Mayo Clinic and Duke University were HR+ HER2- BC with sequencing data between September 2013 and July 2020.

RESULTS

Of 29,833 samples sequenced, 7.9% were APOBEC+ with a high rate in invasive lobular carcinoma (16.7%) and in metastatic tumors (9.7%) relative to locally biopsied BC (4.3%; P < .001). In CGDB, 857 patients with HR+ HER2- BC received ET plus CDK4/6i in the first line. APOBEC+ patients had significantly shorter TTD on ET plus CDK4/6i than APOBEC- patients, 7.8 (95% CI, 4.3 to 14.6) versus 12.4 months (95% CI, 11.2 to 14.1; hazard ratio, 1.6; 95% CI, 1.03 to 2.39; P = .0036). Clinical benefit to immune checkpoint inhibitors was observed in HR+ HER2-, APOBEC+, tumor mutational burden-high patients, with four of nine CGDB patients (TTD 0.3-11.3 months) and four of six patients in Duke/Mayo cohorts (TTD 0.9-40.5 months) with a TTD of ≥ 3 months.

CONCLUSION

APOBEC+ HR+ HER2- patients had shorter TTD on first-line ET plus CDK4/6i relative to APOBEC- patients. Further research is needed to optimize the treatment of APOBEC+ HR+ HER2- BC and to investigate the efficacy of immunotherapeutic strategies in this population.

How to Manage and Monitor Cardiac Dysfunction in Patients With Metastatic HER2-Positive Breast Cancer

•

Targeted therapies improve clinical outcomes in HER2+ metastatic breast cancer.

•

There is thus far minimal signal of increased risk of cardiotoxicity from novel HER2 targeted therapies.

•

Cancer therapy benefit drives clinical decision-making with LV dysfunction.

•

The frequency of cardiac monitoring should be based on a risk-benefit approach.

Abstract 5257: Durable clinical and radiographic responses in a series of patients with HER2+ Breast Cancer (BC) Leptomeningeal Disease (LMD) treated with trastuzumab deruxtecan (T-DXd)

Background: LMD is a devastating clinical outcome of advanced BC with a median survival of 4.4 months for the HER2+ subtype. There are few effective treatments for LMD. T-DXd has shown excellent extracranial efficacy in the DESTINY-Breast01/03 trials for metastatic HER2+ BC, including the stable brain metastases (BrM) subgroups. The efficacy of T-DXd in HER2+ untreated BrM and LMD is unknown. We present a case series of 6 patients with HER2+ LMD treated with T-DXd.

Methods: Six patients with HER2+ BC with LMD (based on imaging +/- positive cytology) who had received T-DXd prior to 10/18/21 and had undergone at least 1 restaging evaluation were identified at Duke Cancer Institute and Dana Farber Cancer Institute. Data was extracted from patients’ electronic medical records and entered into a secure, patient de-identified database. Objective MRI response was defined as neuroimaging with definitive improvement assessed by neuroradiologist review without signs of clinical progression. Clinical benefit (CB) is defined as stable disease or objective response by neuroimaging without clinical progression.

Results: Of the 6 patients included, median age was 42.5 years with 5 median lines of prior therapy. All 6 patients (100%) derived CB and 5/6 (83.3%) had objective response on MRI. Patients were treated with a median 6.5 (5-23) cycles. Median duration of T-DXd therapy was 5.3 months (4.1-16.9) with 4/6 patients receiving ongoing treatment. The median survival from initial diagnosis of LMD to death or last follow-up was 12.5 months. Results are summarized in Table 1.

Conclusion: In this case series, 5/6 patients had radiographic responses without clinical progression, with median duration of treatment nearing 6 months and 4/6 patients continuing T-DXd at data cutoff. This series provides rationale for prospective evaluation of T-DXd in HER2+ LMD patients across tumor types.

Table 1. Demographic and clinical information T-DXd in HER2+ BC LMD - Demographic and Clinical Information*Data cut-off: 10/18/21 Demographic Characteristic (n=6) # (%) or median (range) Median age at T-DXd, years (range) 42.5 (37 - 56) ER Status Positive Negative 4 (66.7%)2 (33.3%) Site DFCI Duke 4 (66.7%)2 (33.3%) Clinical Information (n=6) # (%) or median (range) Median # of therapies prior to T-DXd Prior HER2 TKI 5 (4-6)6 (100%) T-DXd Treatment Median # cycles Total time on DS-8201 (months) 6.5 (5-23)5.3 (4.1-16.9) Response on first MRI post-C1D1 T-DXd Yes No 5 (83.3%)1 (16.6%) Still on T-DXd Treatment Yes No 4 (66.7%)2 (33.3%) Median survival since LMD diagnosis (months) 12.5 (6.8 - 20.6)

Citation Format: Laura Alder, Dario Trapani, Amanda Van Swearingen, Mustafa Khasraw, Carey Anders, Nancy Lin, Sarah Sammons. Durable clinical and radiographic responses in a series of patients with HER2+ Breast Cancer (BC) Leptomeningeal Disease (LMD) treated with trastuzumab deruxtecan (T-DXd) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5257.

Brain metastasis as first and only metastatic relapse site portends poor outcomes in patients with advanced HER2+ breast cancer

1045

Background: In patients (pts) with stable or no extracranial disease (ECD) presenting with breast cancer brain metastases (BCBrMs), current guidelines recommend pts receive local therapy with radiation +/- surgery, without changing systemic therapy. However, preliminary studies suggest that pts with isolated HER2+ BCBrM without ECD have inferior overall survival (OS) compared to pts with concurrent ECD. Our study further explores the implications of ECD status on intracranial progression free survival (iPFS) and OS. Methods: Retrospective analysis was performed on data from 153 pts diagnosed with initial HER2+ BCBrM who received CNS radiation at Duke between 2008 and 2020. Demographics, dates of metastatic and BCBrM diagnosis, ECD status at first CNS event, systemic therapy, and outcomes were collected. The primary endpoint was iPFS defined as the time from first CNS radiation to the subsequent documentation of intracranial progression (RANO-BM). OS was defined as time from first CNS radiation and first metastatic disease to date of death or last known contact. ECD status was defined by RECIST1.1 from systemic staging scans within 30 days of first CNS event. Results: In this cohort of 153 pts with HER2+ BCBrMs undergoing CNS radiation, > 70% of pts with known ECD status had controlled systemic disease: either no ECD (27%) or stable/responding disease (44%). 64% of pts’ tumors were ER+. Median age was 50 years (range 24 – 75). Most pts (59%) developed first CNS event during adjuvant or 1st/2nd line metastatic therapy. CNS radiation treatment included 48% of pts receiving SRS only, 9% WBRT only, and 43% SRS and WBRT. All pts with no ECD presented with isolated BCBrMs as first metastatic disease. Among pts with known ECD status, OS from initial metastatic disease to death was markedly worse for pts with isolated brain metastases or no ECD (median = 28.4m, 95% CI: 18.1 to not reached) compared to those with progressive or stable/responding ECD (48.8m, 95% CI: 40.5 to 65.0; and 68.1m, 95% CI: 55.2 to 85.7, respectively; log-rank p = 0.004). OS from first CNS involvement to death was significantly worse for pts with progressive ECD (17.8m, 95% CI: 13.7 to 28.8) versus stable/responding (36.6m, 95% CI: 29.7 to 45.2) or no ECD (28.4m, 95% CI: 18.1 to not reached; log-rank p = 0.008). iPFS did not differ statistically among subgroups of pts with known ECD status: progressive ECD (median = 7.7m), no ECD (8.3m), or stable/responding ECD (11.2m) (log-rank p = 0.15). Conclusions: Overall survival in pts with HER2+ isolated BCBrM was markedly inferior to that of pts with progressive or stable/responding ECD. Studies investigating initiation of brain penetrable HER2-targeted therapies earlier in the disease course of isolated HER2+ BCBrMs pts are warranted.

Systemic management of brain metastases in HER2+ breast cancer in 2022

Up to half of all patients with metastatic human epidermal growth factor receptor 2-positive (HER2+) breast cancer will eventually acquire brain metastases (BrMs), which are associated with reduced overall survival and decreased quality of life. Although the median overall survival was previously less than a year, novel systemic treatments have significantly extended life expectancy in patients with HER2+ breast cancer BrMs. The current first-line standard of care for all patients with HER2+ metastatic breast cancer, regardless of BrMs status, is dual HER2 antibody therapy with pertuzumab/trastuzumab plus a taxane. Second-line systemic therapy has recently evolved, with the option of trastuzumab deruxtecan (T-DXd) or tucatinib in combination with trastuzumab and capecitabine. T-DXd has shown dramatically superior progression-free survival in comparison with trastuzumab emtansine (T-DM1) in patients with stable BrMs in the second-line setting. Patients who have untreated or locally treated/progressive BrMs may benefit from a regimen with robust intracranial response rates, such as tucatinib in combination with trastuzumab and capecitabine. Third-line therapy and beyond includes multiple options that require careful selection, with the patient's BrMs status, comorbidities, and performance status taken into account. In this review, we focus on current management and evolving strategies for the treatment of patients with HER2+ breast cancer BrMs.

Abstract PD14-09: APOBEC signature, clinical characteristics, and outcome in hormone receptor-positive (HR+) HER2-negative (HER2-) breast cancer (BC) patients (pts) in real-world data (RWD)

Background: APOBEC mutagenesis underlies somatic evolution and accounts for tumor heterogeneity in several cancers, including BC. In our clinical experience, HR+HER2- BC with an APOBEC signature do poorly on standard of care (SOC) first line endocrine therapy (ET) + CDK4/6 inhibitor (CDK4/6i) and need additional treatment options. Here we evaluated the characteristics of a real-world cohort for time-to-treatment discontinuation (TTD) and overall survival (OS) on SOC and immune checkpoint inhibitors (ICI).Methods: Hybrid capture-based comprehensive genomic profiling (CGP) results from 29,833 formalin-fixed paraffin-embedded tissue biopsies of all BC subtypes were analyzed. For outcomes (TTD and OS), this study used a de-identified nationwide (US-based) BC clinico-genomic database (CGDB, ~800 sites of care, 1/2011 - 12/2020). HR+HER2- metastatic BC pts who received first line ET + CDK4/6i were included (CGDB cohort).TTD was defined as the difference between the first and last drug episode within a given line of treatment (LOT). LOT were derived based on FH algorithms. OS was defined as the time from LOT start to the date of death or data cutoff. Log-rank test and Cox model were used to evaluate the difference in outcomes. To reduce the impact of confounding variables (Age at Dx, Stage at Dx, Tumor Type, Metastases sites, TMB group (≥10 vs &lt;10), SOC treatment group, PIK3CA), inverse probability of treatment weighting (IPTW) was used. Eligible pts from Mayo Clinic and Duke University were HR+HER2- mBC with sequencing data from FMI between 9/2013-7/2020. Clinical data were manually extracted from Mayo and Duke EHR. Results: Of all 29,833 BC samples in the CGP cohort, 7.9% were APOBEC+ with high rate in invasive lobular carcinoma (ILC) 16.7% vs. 4.9% in invasive ductal carcinoma (IDC) and metastatic lesions 9.7% vs. 4.3% from breast. APOBEC+ samples had a higher median TMB 12.5 vs. 2.5 mut/Mb. In CGDB, 857 HR+HER2- BC met inclusion criteria; 69 (8%) pts were APOBEC+ and 788 (9.2%) were APOBEC-. APOBEC+ pts had significantly shorter TTD on SOC ET+CDK4/6i than APOBEC- pts, 7.8 (95% CI 4.3-14.6) vs. 12.4 (95% CI 11.2-14.1) months (p=0.0036). APOBEC+ pts also had noticeably shorter OS compared to APOBEC- pts, 32.4 (95%CI 19.8-47.4) vs. 40.5 (95%CI 36.9-45.7) months (p=0.06).Cox regression results indicate that the relative risk of shorter TTD for the APOBEC+ vs the APOBEC- was 1.6 (95%CI 1.03-2.39). Also, APOBEC+ pts had almost twice the risk that APOBEC- pts had of death (HR=1.96, 95%CI 1.2-3.3). In CGDB, there were 10 APOBEC+ pts who received ICI, 9/10 had evaluable TTD data, 4/9 were still on treatment as of Dec 2020. 5/9 received ICI monotherapy, 4 pts received ICI + chemotherapy. TTD ranged from 0.3 to 11.3 mo, 1 pt’s TTD was &gt; 6 mo. In Mayo and Duke cohort, there were 6 pts, 5/6 received ICI + chemotherapy. The TTD was 0.9-40.5 months with longest 2 pts receiving 5-FU plus ICI (11 and 40.5 months). To better understand the ICI treatment landscape, TTD in HR+HER2- hTMB MSS APOBEC- CGDB cohort (N=6) was analyzed: 5/6 had evaluable treatment data, 4/5 finished ICI treatment, 1 pt’s TTD was &gt; 3 mo, 0/5 had TTD &gt; 6 mo. Conclusions: APOBEC+ occurs in ~7% of BC and is more common in ILC and metastatic lesions. APOBEC+ HR+HER2- pts had shorter TTD and OS on SOC ET+CDK4/6i relative to APOBEC- pts. However, TTD on ICI tended to be longer in APOBEC+ pts, but our data is limited, and more research is needed.

CGDB APOBEC+ vs. APOBEC- with SOC 1st lineAPOBEC+ (N=69)APOBEC- (N=788)p adjusted (FDR)*Age at Dx, Median (IQR)59.0 (53.0, 65.0)56.0 (47.0, 65.0)0.102Stage at Dx0.067- 0-III52 (75.4%)505 (64.1%)- IV11 (15.9%)245 (31.1%)- Not documented6 (8.7%)38 (4.8%)Metastasis free interval, yrs, Median (IQR)5.2 (3.0, 10.5)5.1 (2.8, 9.3)0.734Tumor Grade0.104- Grade 12 (2.9%)49 (6.2%)- Grade 234 (49.3%)259 (32.9%)- Grade 311 (15.9%)163 (20.7%)- Not documented22 (31.9%)317 (40.2%)Tumor Type0*- IDC7 (10.1%)251 (31.9%)- ILC30 (43.5%)138 (17.5%)- Other /Not documented32 (46.4%)399 (50.6%)Metastases sites0.734- Bone-only17 (24.6%)169 (21.5%)- CNS11 (15.9%)104 (13.2%)- Visceral41 (59.4%)514 (65.3%)TMB, Median (IQR)11.3 (8.8, 18.8)2.5 (1.3, 3.8)0*MSI0.946- MSI-H0 (0.0%)4 (0.5%)- MSI-I0 (0.0%)1 (0.1%)- MSS68 (98.6%)728 (97.2%)- Not documented1 (1.4%)16 (2.1%)BRCA5 (7.2%)45 (5.7%)0.734PIK3CA46 (66.7%)341 (43.3%)0.001*Treatments0.005*- AI + CDK4/6i31 (44.9%)510 (64.7%)- Fulvestrant + CDK4/6i38 (55.1%)278 (35.3%)

Citation Format: Saranya Chumsri, Kira Raskina, Sarah Sammons, Laura Alder, Natalie Danziger, Alexa B Schrock, Kim McGregor, Ethan Sokol. APOBEC signature, clinical characteristics, and outcome in hormone receptor-positive (HR+) HER2-negative (HER2-) breast cancer (BC) patients (pts) in real-world data (RWD) [abstract]. In: Proceedings of the 2021 San Antonio Breast Cancer Symposium; 2021 Dec 7-10; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2022;82(4 Suppl):Abstract nr PD14-09.

Advanced breast conservation and partial breast reconstruction - a review of current available options for oncoplastic breast surgery

Breast cancer is the most common cancer affecting one in three women with new cancer diagnosis in England. Breast-conserving surgery is the primary surgical option in a vast majority of these patients. Use of oncoplastic techniques in breast conservation surgery has significantly improved the aesthetic outcomes without compromising the oncological safety of cancer resections. Oncoplastic breast-conserving surgery (OPBCS) has transformed the specialty with a paradigm shift in ideology and the recognition that aesthetic and oncological resections are synonymous when planning surgical intervention for patients with breast cancer. The two main options for OPBCS are therapeutic mammoplasty and partial beast reconstruction using pedicle-based flaps. This review aims to highlight key concepts in OPBCS demonstrating an overview of these surgical techniques, their safety, outcomes and the emergence of extreme oncoplastic breast surgery.

OTHR-10. Diverse survival outcomes of HER2+ Breast Cancer Brain Metastases (BrCBM) presenting with isolated brain relapse compared to those with concurrent extracranial disease

Background

In patients with isolated HER2+ BrCBM and no extracranial disease (ECD), there are no consensus guidelines on optimal treatment approaches following CNS-directed therapy. Our goal was to determine the implications of ECD at time of first HER2+ BrCBM on intracranial progression-free survival (PFS1) and overall survival (OS).

Methods

Retrospective analysis was performed on 77 patients with HER2+ BrCBM who received 1^st CNS radiation from 2006–2020. Demographics, dates of metastatic and intracranial diagnosis, ECD status at 1st BrCBM, and outcomes were collected. The primary endpoint was PFS1 defined as time from first CNS radiation to the subsequent documentation of intracranial progression (RANO-BM). OS was defined as time from 1^st CNS radiation and 1^st metastatic disease to date of death/last known alive. ECD status was defined by RECIST1.1 from staging scans within 30 days of 1^st BrCBM.

Results

In this patient cohort, 25% (19/77) had isolated brain relapse/no ECD. Median age was 50 years. Most patients (58%) developed first BrCBM during adjuvant or early-line metastatic therapy. All patients with no ECD presented with isolated brain relapse as first metastatic presentation. Patients with concurrent ECD presented with first BrCBM at a median of 16.6m (95% CI: 10.5 to 25.3) after initial metastatic presentation. Median OS from initial metastatic presentation to death was worse for patients with isolated brain relapse (25.3m, 95% CI: 16.8 to 35.3) compared to those with concurrent ECD (49.7m, 95% CI: 43.2 to 62; p=0.01). Median OS from first CNS involvement to death was not statistically different amongst groups.

Conclusions

Patients with isolated HER2+ BrCBM as their initial metastatic event have substantially worse OS compared to patients with concurrent ECD developing CNS metastases later in their disease course. This population with isolated brain relapse deserves investigation of novel treatment algorithms, including earlier introduction of brain-penetrable HER2-targeted agents.

Clinical frailty and its effect on the septuagenarian population after emergency laparotomy

INTRODUCTION

The UK has an ageing population with an increased prevalence of frailty in the over 70s. Emergency laparotomy for acute intra-abdominal pathology is increasingly offered to this population. This can challenge decision making and information given to patients should not only be based on mortality outcomes but on relative expected quality of life and change to frailty syndromes.

MATERIALS AND METHODS

This was a single site National Emergency Laparotomy Audit (NELA)-based retrospective cohort audit for consecutive cases in the septuagenarian population assessing mortality, length of stay outcome and subjective postoperative functioning. Follow-up was conducted between one and two years postoperatively to determine this.

RESULTS

Some 153 patients were identified throughout the single site NELA database. Median age was 79 years with a ratio of 1.7 men to women. Median rate of all-cause mortality was 35.3% at the median follow-up of 19 months. Median time from admission to death was 120 days. Of those who had died by the time of follow-up, significant preoperative indicators included clinical frailty scale (p < 0.0001), preoperative P-POSSUM (mortality). At follow-up, 35% responded to a quality of life follow-up. This revealed a decline in mid-term physical functioning, lower energy, higher fatigue and reduction in social functioning. There was also an increase in pre- and postoperative clinical frailty scale score.

CONCLUSION

In the septuagenarian-plus population it is important to consider not only risk stratification with mortality scoring (P-POSSUM or NELA-adjusted risk), but to take into account frailty. Postoperative rehabilitation and careful recovery is paramount. Where possible, during the counselling and consent for emergency laparotomy, significant postoperative long-term deterioration in physical, emotional and social function should be considered.

Long-term outcome analysis of Y90 radioembolization in hepatocellular carcinoma

e16633

Background: Yttrium-90 (Y90) radioembolization is a catheter-based therapy utilized in the treatment of hepatic tumors such as hepatocellular carcinoma (HCC). Multiple trials have evaluated the efficacy of Y90 in HCC; few have assessed long term hepatic function. These studies reported PFS ranging from 7.9 to 18 months (m), and median OS of 17.2 to 18 m for Child-Pugh (CP) Class A and 6.0 to 7.7 m for CP Class B. This study aimed to evaluate a clinical real-world experience of Y90 therapeutic effectiveness and long-term impact on hepatic function. Methods: A single-center retrospective chart review was performed for patients with a CP score of A or B who received Y90 for primary HCC between 2008 and 2016. Model for end stage liver disease (MELD) and CP scores were calculated for the day of treatment and at 1, 3, 6, 12, and 24 m post procedure. OS and PFS were characterized using a Kaplan-Meier survival analysis and a multivariate model. Results: 134 patients were included. Mean age was 60 years old, ranging from 44-90. Underlying liver disease included HCV – 66%, ETOH cirrhosis – 23%, NAFLD – 19%, HBV – 5%. CP Class A patients (79%) had a median OS of 16.59 m (95% CI: 8.90 to 23.10m) from date of Y90 treatment compared to a median of 7.90 m (95% CI: 4.60 to 15.64 m) for CP Class B. CP Class A patients had a median PFS of 3.45 m (95% CI: 2.99 to 5.55 m) from date of Y90 treatment compared to a median of 3.71 m (95% CI: 2.07 to 8.28 m) for CP Class B patients. These differences were not statistically significant. Median OS from date of diagnosis for the entire study population was 29.37 m (95% CI: 23.00 to 38.77 m). MELD scores were statistically significantly higher at 1, 3, 6 and 12 m post-treatment than on Day 0, with significant recovery at 24 vs 3 m. Older age, higher T stage, higher MELD and CP scores, and patients with a history of portal vein thrombosis (PVT) had significantly lower OS. PFS was significantly shorter in those with advanced stage at diagnosis and higher CP score. Conclusions: While our study supports the literature for OS in Y90 patients, we found a shorter PFS in this population. This may reflect the utilization of RECIST in clinical trials vs clinical radiology practice in determining progression. Over time, the most significant factors associated with OS were age, MELD and CP scores and PVT. For PFS, CP score and stage at diagnosis were significant. The increasing MELD and CP scores over time reflect a possible mix of radio embolization‐induced liver disease and progression of HCC. The downtrend at 24 m is likely due to durable survivors with significant benefit from therapy and no long-term complications from Y90.

Racial disparities in utilization of gene expression testing in breast cancer patients at an academic medical center

142

Background: Gene expression profiling of breast cancers, such as the OncotypeDx (ODX) test, PAM 50 and Mammaprint, can define the risk of distant recurrence and assist with decisions about adjuvant chemotherapy. A recent study of all breast cancer patients in Virginia found that only 11.7 % of Caucasian Americans (CA) and 5.1% of African Americans (AA) received genomic testing. Methods: We utilized the Virginia Commonwealth University Health System (VCUHS) Tumor Registry and billing data from 2010-2017 to identify all patients that met the following criteria per NCCN guidelines for genomic testing: early stage (stage I or II) breast cancer, estrogen and/or progesterone receptor positive and lymph node-negative breast cancer. We also obtained records from Genomic Health on ODX testing ordered through VCU Health. Additionally, ODX utilization was stratified by race. We then performed Chi Square analysis. Results: 1080 patients were eligible per NCCN Guidelines. Of these, 248 were eliminated due to having only radiation performed at VCU. 39 were eliminated because initial treatments were at outside hospitals. Of the remaining 793, 536 were CA, 232 AA, 9 Asian and 16 other. Among the patients for whom a genomic test was appropriate, the proportion who actually had such a test performed were: 83.4% for CA, 71.98% for AA, 55.56% for Asians, 81.25 % for Others and 79.7% overall. There was a significant difference between utilization in CAs and AAs (p < 0.001). Conclusions: Breast cancer patients at VCU Health are far more likely to receive gene expression profiling overall compared to the Commonwealth of VA as a whole. This may reflect more equitable and guideline-compliant care in an academic/safety net health system.

Testicular Swelling as an Initial Presentation of a Patient With Metastatic Gastric Cancer

While signet-ring cell morphology in the testes might represent metastatic spread from an extragonadal adenocarcinoma, a rare variant of primary testicular neoplasms should be considered in a differential diagnoses as was seen in this rare occurrence of a testicular swelling as an initial presentation for a patient with metastatic gastric cancer.

Initial Match Rates of an Innovative International Partnership: The Ochsner Clinical School Experience

BACKGROUND

Ochsner Clinical School (OCS) is a unique partnership between Ochsner Health System in New Orleans, LA, and The University of Queensland (UQ) School of Medicine in Brisbane, Australia. OCS trains physicians in global medicine and promotes careers in primary care through its unique structure. The purpose of this study was to determine how OCS graduates perform in the National Resident Matching Program (NRMP)-The Match-compared to applicants from other types of medical schools.

METHODS

The match outcomes for all OCS graduates since the first graduating class in November 2012 were compared to the match outcomes in the NRMP database for graduates from other types of medical schools in the years 2013-2015. We also examined the number of OCS students electing residencies in primary care compared to the number of US medical school graduates overall during the same time period of 2013-2015.

RESULTS

The cumulative match rate from 2013-2015 for applicants from OCS was 91.8%. The OCS graduates' match rate was greater than the match rate for US citizen graduates of international medical schools during the same period (53.0% vs 91.8% [z=6.066, P<0.0002]), greater than the match rate for applicants from US osteopathic medical schools (77.3% vs 91.8% [z=25.233, P<0.0002]), and greater than the match rate for applicants from Canadian medical schools (62.7% vs 91.8% [z=3.815, P<0.0002]). The OCS match rate was not significantly different from that of US medical school graduates: 94.0% vs 91.8% (z=-0.728, P=0.4666). During the 2013-2015 time frame, 44.3% of OCS graduates chose residencies in primary care fields compared to 38.3% of US graduates (z=-0.9634, P=0.337).

CONCLUSION

Graduates of OCS are obtaining residency positions through The Match at rates comparable to those of US medical school graduates and at rates significantly greater than other groups, and we are seeing a trend in the number of graduates choosing careers in primary care.

Estimation of measurement uncertainty in pesticide residue analysis

Proficiency test results from 5 countries involving 61 separate interlaboratory proficiency tests for pesticide residues were examined in this study. A total of 24 different matrixes and 869 relative standard deviations of the mean (or median) pesticide residue concentration were statistically evaluated in relation to the Horwitz function. The aim was to determine whether or not the concentration-dependent relationship described by Horwitz would hold for the much narrower range of chemicals and concentrations covered in routine pesticide residue analysis. Although for fatty (animal-derived) matrixes the variability increased as the concentration decreased in line with the Horwitz equation, the between-laboratories relative standard deviations for nonfatty matrixes (fruit, vegetables, and grain) remained at 25% over the entire concentration range of 1 microg/kg to 10 mg/kg for the pesticides studied. Given these findings, the Horwitz equation remains valid for calculating uncertainties involving pesticide residues in fatty matrixes. However, for pesticide residue analyses involving nonfatty matrixes, a constant relative standard deviation of 25% is more appropriate for calculating uncertainties, particularly when a reported result is assessed against a regulatory limit.

Effect of alpha subunit on allosteric modulation of ion channel function in stably expressed human recombinant gamma-aminobutyric acid(A) receptors determined using (36)Cl ion flux

Inhibitory gamma-aminobutyric acid (GABA)(A) receptors are subject to modulation at a variety of allosteric sites, with pharmacology dependent on receptor subunit combination. The influence of different alpha subunits in combination with beta3gamma2s was examined in stably expressed human recombinant GABA(A) receptors by measuring (36)Cl influx through the ion channel pore. Muscimol and GABA exhibited similar maximal efficacy at each receptor subtype, although muscimol was more potent, with responses blocked by picrotoxin and bicuculline. Receptors containing the alpha3 subunit exhibited slightly lower potency. The comparative pharmacology of a range of benzodiazepine site ligands was examined, revealing a range of intrinsic efficacies at different receptor subtypes. Of the diazepam-sensitive GABA(A) receptors (alpha1, alpha2, alpha3, alpha5), alpha5 showed the most divergence, being discriminated by zolpidem in terms of very low affinity, and CL218,872 and CGS9895 with different efficacies. Benzodiazepine potentiation at alpha3beta3gamma2s with nonselective agonist chlordiazepoxide was greater than at alpha1, alpha2, or alpha5 (P < 0.001). The presence of an alpha4 subunit conferred a unique pharmacological profile. The partial agonist bretazenil was the most efficacious benzodiazepine, despite lower alpha4 affinity, and FG8205 displayed similar efficacy. Most striking were the lack of affinity/efficacy for classical benzodiazepines and the relatively high efficacy of Ro15-1788 (53 +/- 12%), CGS8216 (56 +/- 6%), CGS9895 (65 +/- 6%), and the weak partial inverse agonist Ro15-4513 (87 +/- 5%). Each receptor subtype was modulated by pentobarbital, loreclezole, and 5alpha-pregnan-3alpha-ol-20-one, but the type of alpha subunit influenced the level of potentiation. The maximal pentobarbital response was significantly greater at alpha4beta3gamma2s (226 +/- 10% increase in the EC(20) response to GABA) than any other modulator. The rank order of potentiation for pregnanolone was alpha5 > alpha2 > alpha3 = alpha4 > alpha1, for loreclezole alpha1 = alpha2 = alpha3 > alpha5 > alpha4, and for pentobarbital alpha4 = alpha5 = alpha2 > alpha1 = alpha3.

Identification and characterization of A-105972, an antineoplastic agent

A high-throughput screening assay was designed to select compounds that inhibit the growth of cultured mammalian cells. After screening more than 60,000 compounds, A-105972 was identified and selected for further testing. A-105972 is a small molecule that inhibits the growth of breast, central nervous system, colon, liver, lung, and prostate cancer cell lines, including multidrug-resistant cells. The cytotoxic IC50 values of A-105972 were between 20 and 200 nM, depending on the specific cell type. The potency of A-105972 is similar in cells expressing wild-type or mutant p53. A majority of cells treated with A-105972 were trapped in the G2-M phases, suggesting that A-105972 inhibits the progression of the cell cycle. Using [3H]A-105972, we found that A-105972 bound to purified tubulin. Unlabeled A-105972 competed with [3H]A-105972 binding with an IC50 value of 3.6 microL. Colchicine partially inhibited [3H]A-105972 binding with an IC50 value of approximately 90 microM, whereas paclitaxel and vinblastine had no significant effect. Tumor cells treated with A-105972 were observed to contain abnormal microtubule arrangement and apoptotic bodies. DNA ladder studies also indicated that A-105972 induced apoptosis. A-105972 caused a mobility shift of bcl-2 on SDS-PAGE, suggesting that A-105972 induced bcl-2 phosphorylation. A-105972 treatment increased the life span of mice inoculated with B16 melanoma, P388 leukemia, and Adriamycin-resistant P388. These results suggest that A-105972 is a small molecule that interacts with microtubules, arrests cells in G2-M phases, and induces apoptosis in both multidrug resistance-negative and multidrug resistance-positive cancer cells. A-105972 and its analogues may be useful for treating cell proliferative disorders such as cancer.

Gamma-aminobutyric acid type B receptors with specific heterodimer composition and postsynaptic actions in hippocampal neurons are targets of anticonvulsant gabapentin action

Gamma-aminobutyric acid (GABA) activates two qualitatively different inhibitory mechanisms through ionotropic GABA(A) multisubunit chloride channel receptors and metabotropic GABA(B) G protein-coupled receptors. Evidence suggests that pharmacologically distinct GABA(B) receptor subtypes mediate presynaptic inhibition of neurotransmitter release by reducing Ca2+ conductance, and postsynaptic inhibition of neuronal excitability by activating inwardly rectifying K+ (Kir) conductance. However, the cloning of GABA(B) gb1 and gb2 receptor genes and identification of the functional GABA(B) gb1-gb2 receptor heterodimer have so far failed to substantiate the existence of pharmacologically distinct receptor subtypes. The anticonvulsant, antihyperalgesic, and anxiolytic agent gabapentin (Neurontin) is a 3-alkylated GABA analog with an unknown mechanism of action. Here we report that gabapentin is an agonist at the GABA(B) gb1a-gb2 heterodimer coupled to Kir 3.1/3.2 inwardly rectifying K+ channels in Xenopus laevis oocytes. Gabapentin was practically inactive at the human gb1b-gb2 heterodimer, a novel human gb1c-gb2 heterodimer and did not block GABA agonism at these heterodimer subtypes. Gabapentin was not an agonist at recombinant GABA(A) receptors as well. In CA1 pyramidal neurons of rat hippocampal slices, gabapentin activated postsynaptic K+ currents, probably via the gb1a-gb2 heterodimer coupled to inward rectifiers, but did not presynaptically depress monosynaptic GABA(A) inhibitory postsynaptic currents. Gabapentin is the first GABA(B) receptor subtype-selective agonist identified providing proof of pharmacologically and physiologically distinct receptor subtypes. This selective agonism of postsynaptic GABA(B) receptor subtypes by gabapentin in hippocampal neurons may be its key therapeutic advantage as an anticonvulsant.

Determination of Q1, an unknown organochlorine contaminant, in human milk, Antarctic air, and further environmental samples

Q1, an organochlorine component with the molecular formula C(9)H(3)Cl(7)N(2) and of unknown origin was recently identified in seal blubber samples from the Namibian coast (southwest of Africa) and the Antarctic. In these samples, Q1 was more abundant than PCBs and on the level of DDT residues. Furthermore, Q1 was more abundant in seals from the Antarctic than the Arctic. To prove this assumption, gas chromatography-electron-capture negative ion mass spectrometry (GC/ECNI-MS), which is sensitive and selective for Q1, allowed for screening of traces of Q1 even in samples with particularly high levels of other organochlorine contaminants. Q1 was isolated by high-performance liquid chromatography (HPLC) from a skua liver sample. A 1:1 mixture with trans-nonachlor in electron-capture detectors (ECDs) was used to determine the relative response factor with ECNI-MS. The ECNI-MS response of Q1 turned out to be 4.5 times higher than that of trans-nonachlor in an ECD. With GC/ECNI-MS in the selected ion-monitoring mode, four Antarctic and four Arctic air samples were investigated for the presence of Q1. In the Antarctic air samples, Q1 levels ranged from 0.7 to 0.9 fg/m(3). In Arctic air samples, however, Q1 was below the detection limit (<0.06 fg/m(3) or 60 ag/m(3)). We also report on high Q1 levels in selected human milk samples (12-230 microg/kg lipid) and, therefore, suggested that the unknown Q1 is an environmental compound whose origin and distribution should be investigated in detail. Our data confirm that Q1 is a bioaccumulative natural organochlorine product. Detection of a highly chlorinated natural organochlorine compound in air and human milk is novel.

Reasons for the decomposition of the fungicide thiram during preparation of fruit and vegetable samples and consequences for residue analysis

The concentration of thiram in aqueous solution decreases by 50-75% within 20 min in the presence of cut pieces of apple, cucumber or celeriac with a section surface area of 160 cm2 each. The decomposition rate is predominantly influenced by the section surface area of the cut fruit and vegetable samples. Denaturing reaction conditions (exchange of the solvent water by methanol; boiling of sample material) will significantly slow down the decomposition rate. It was concluded that the thiram decomposition had been caused by enzymes on the section surface of the fruit and vegetable samples. For a specific determination of thiram, a simple rinsing of the intact fruit and vegetable material was appropriate as extraction method. For the screening of thiram residues, the often used Keppel method, which determines CS2 from thiram or dithiocarbamates seems to be applicable even if samples had been coarsely cut, since decomposition of the CS2-forming intermediates is slower than the breakdown of thiram itself. Therefore, specific determination of thiram is necessary only, if maximum residue limits for dithiocarbamates are not adhered to.

Variation of toxaphene indicator compounds in fish from single fishing grounds: conclusions for sampling

The levels of three toxaphene indicator compounds were determined in individual lots of herring, redfish, Greenland halibut and farmed salmon. Concentration levels of the three marine fish species were characterised by a right-skewed frequency distribution whereas residue concentrations in farmed salmon were normally distributed. The toxaphene concentrations in the edible part of redfish, herring and Greenland halibut were found to be positively correlated to the sizes and thus to age. As results show, for representative sampling of a landed catch, not more than 10 individual fishes from typical size classes of a lot are necessary for a pooled sample.

Mass spectrometric characterization of Q1, a C(9)H(3)Cl(7)N(2) contaminant in environmental samples

Q1, a heptachloro component of unknown structure and origin, was recently identified as a major organochlorine contaminant in samples from Africa and the Antarctic. Gas chromatography in combination with low resolution mass spectrometry (LRMS) was applied to establish a molecular weight of m/z 384 including seven chlorine atoms. Three possible molecular formulae (C(11)H(7)Cl(7), C(10)H(3)Cl(7)O, and C(9)H(3)Cl(7)N(2)) were proposed which could not be distinguished by LRMS. In this presentation the molecular composition of Q1 was studied using gas chromatography in combination with high resolution electron impact ionization mass spectrometry. With the option of further heteroatoms (P, S, N, O, F, and Br), 17 molecular formulae were obtained for the molecular weight of 384 u. In the selected ion monitoring (SIM) mode, performed with a resolution of 16,000, highest response was found at 383.812 or C(9)H(3)Cl(7)N(2). 11 fragment ions detected in the low resolution full scan mass spectrum of Q1 were also investigated in the high resolution SIM mode. In every case, the nitrogen-variant showed highest abundance while the other 16 structural variants could be definitely excluded. These investigations revealed that the molecular formula of Q1 is C(9)H(3)Cl(7)N(2). No stable component with this molecular formula has ever been reported in the literature, to our knowledge. Copyright 1999 John Wiley & Sons, Ltd.

Fusacandins A and B; novel antifungal antibiotics of the papulacandin class from Fusarium sambucinum. II. Isolation and structural elucidation

Two novel antifungal compounds of the papulacandin class, named fusacandins A and B, have been isolated from Fusarium sambucinum. Each compound contains two units of galactose and one of glucose, the latter connected as a C-glycoside to an aromatic moiety. Fusacandin A is esterified at two sites with long-chain, unsaturated fatty acids and fusacandin B at only one site. The structures of the fusacandins were elucidated through analysis of mass spectral and 1-D and 2-D homonuclear and heteronuclear NMR data.

Occurrence of 9- and 13-keto-octadecadienoic acid in biological membranes oxygenated by the reticulocyte lipoxygenase

Membranes of intact rabbit reticulocytes and rat liver mitochondrial membranes oxygenated by the pure reticulocyte lipoxygenase contain 13-keto-9Z,11E-octadecadienoic acid and 9-keto-10E,12Z-octadecadienoic acid. In mitochondrial membranes not treated with lipoxygenase and in rabbit erythrocyte membranes these products were not detected. The chemical structure of the compounds has been identified by cochromatography with authentic standards on various types of HPLC columns, by uv and ir spectroscopy and GC/MS. In the membranes of rabbit reticulocytes up to 2% of the linoleate residues are present as its 9- and 13-keto derivatives. Most of the keto compounds (up to 90%) are esterified in the membrane ester lipids, only about 10% were found in the free fatty acid fraction. It is proposed that the keto dienoic fatty acids are formed via decomposition of hydroperoxy polyenoic fatty acids originating from the oxygenation of the membrane lipids by the reticulocyte lipoxygenase.

Occurrence of free and esterified lipoxygenase products in leaves of Glechoma hederacea L. and other Labiatae

Leaves of Glechoma hederacea L. and other Labiatae contain (9S,10E,12Z,15Z)-9-hydroxy-10,12,15-octadecatrienoic acid, (10E,12Z,15Z)-9-oxo-10,12,15-octadecatrienoic acid, (9S,10E,12Z)-9-hydroxy-10,12-octadecadienoic acid and (10E,12Z)-9-oxo-10,12-octadecadienoic acid in a ratio of 71/14/12/3 (by mass), predominantly esterified in the membrane ester lipids. The leaves contain the highest level of these products, whereas only small amounts were found in the stalk and the roots. The chemical structures of these compounds were established by ultraviolet and infrared spectroscopy, by co-chromatography with authentic standards on various types of HPLC columns including chiral-phase HPLC and gas chromatography/mass spectrometry. The stereochemical specificity indicates the enzymatic origin of the products, most probably via a lipoxygenase reaction. Freshly harvested specimens of G. hederacea L. contain only small amounts of hydroxy-polyenoic fatty acids. Air-drying causes a strong increase in the content of free and esterified (9S,10E,12Z,15Z)-9-hydroxy-10,12,15-octadecatrienoic acid. Up to 80% of the hydroxy fatty acids of the total lipid extracts were esterified in the cellular lipids. The data presented indicate that lipoxygenase products occur in the cellular ester lipids of G. hederacea L. and other Labiatae. The results are discussed in the light of a possible involvement of the lipoxygenase pathway in the natural senescence of leaves.

Lipoxygenase catalyzed oxygenation of hydroxy fatty acids to lipoxins

The pure lipoxygenases from rabbit reticulocytes and soybeans convert a variety of substrates (arachidonic acid, 15-HPETE, 15-HETE, 5-HETE, various DiHETE isomers) to trihydroxy eicosanoids containing a conjugated tetraene system (lipoxins). In general, the methyl esters are better substrates for lipoxin formation than are the free acids. Lipoxygenase inhibitors (5,8,11,14-eicosatetraynoic acid, nordihydroguaiaretic acid) strongly inhibit the lipoxin formation. The complete stereochemistry of the lipoxin B formed from 15S-HETE methyl ester has been established by co-chromatography with authentic standards on various types of HPLC columns, by GC/MS analysis, by gas liquid chromatography of the ozonolysis fragments of the menthoxy carbonyl derivatives and 1H-NMR studies. The molar absorption coefficient of the conjugated tetraenes was measured as epsilon 301 = 53,000. The lipoxins formed from 15-HETE and various DiHETE isomers are formed exclusively via the oxygenation pathway as shown by experiments under an 17O2 atmosphere and/or by anaerobic incubations. Our results indicate that lipoxins can be synthesized via lipoxygenase-catalyzed sequential oxygenation of polyenoic fatty acids and their hydro(pero)xy derivatives.

Formation of lipoxin B by the pure reticulocyte lipoxygenase via sequential oxygenation of the substrate

The pure reticulocyte lipoxygenase converts 15LS-hydroxy-5,8,11,13(Z,Z,Z,E)-icosatetraenoic acid (15LS-HETE) methyl ester to a complex mixture of products containing 5DS,14LR,15LS-trihydro(pero)xy-6E,++ +8Z,10E,12E-icosatetraenoate methyl ester (lipoxin B methyl ester), 5DS,15LS-DiH(P)ETE methyl ester and four 8,15LS-DiH(P)ETE methyl ester isomers [DiH(P)ETE = dihydro(pero)xy-icosatetraenoic acid]. After a short incubation period (15 min) 5DS,15LS-DiH(P)ETE methyl ester was found to be the main product, whereas after a 3-h incubation lipoxin B methyl ester was the predominant product. The reaction shows a remarkable stereoselectivity since only small amounts of other trihydroxy tetraenes are formed. Anaerobiosis, heat inactivation of the enzyme, or incubation in the presence of lipoxygenase inhibitors (icosatetraynoic acid, nordihydroguaiaretic acid) completely abolished the reaction. The complete steric structure of the major tetraene product (lipoxin B methyl ester) was established by ultraviolet spectroscopy, HPLC on four different types of columns, gas chromatography/mass spectrometry, gas/liquid chromatography of the ozonolysis fragments of the menthoxycarbonyl derivatives, and by 400-MHz 1H-NMR. Atmospheric oxygen was incorporated at carbon-5 and carbon-14 into the major product. 5DS,15LS-DiH(P)ETE methyl ester was shown to be an intermediate in the synthesis. Lipoxin B was also formed during the oxygenation of arachidonic acid, 15LS-HETE and 5DS,15LS-DiHETE. The results presented here indicate that lipoxin B can be formed by pure lipoxygenases via a sequential oxygenation of arachidonic acid or its hydro(pero)xy derivatives.

Analysis of the stereochemistry of lipoxygenase-derived hydroxypolyenoic fatty acids by means of chiral phase high-pressure liquid chromatography

A chiral phase HPLC method was developed for the simultaneous determination of the positional and optical isomers of the lipoxygenase-derived hydroxypolyenoic fatty acids. With a Bakerbond chiral phase HPLC column (dinitrobenzoyl phenylglycine as chiral phase) the positional and optical isomers of the reduced dioxygenation products (by triphenylphosphine or borohydride) of linoleic acid and arachidonic acid were separated after methylation of the carboxylic groups. No cumbersome chemical derivatization such as conversion to a diastereomer was necessary. As compared with the methods used up till now chiral phase HPLC proved to be simpler and more sensitive. About 10 pmol of hydroxy fatty acids suffice for an analysis. The chiral phase HPLC can be used for the preparative separation of the optical antipodes of the lipoxygenase products. An optical purity of more than 90% can be reached in one preparative run. The method was applied to the determination of the stereochemistry of the dioxygenation products of polyenoic fatty acids formed by the lipoxygenases from soybeans, reticulocytes, pea seeds (isoenzyme I and II), tomato fruits, by the quasilipoxygenase activity of hemoglobin, and by the methylene blue-mediated photooxidation of arachidonic acid.

[Analysis and stability of propiverine hydrochloride (Mictonorm)]

In acid, neutral and alkaline solution the hydrolytic degradation of the spasmolytic agent Mictonorm (1) was determined. As degradation products ester- and/or ether fragments (2-5), benzophenone (6) and a compound X (7) were identified. In comparison N-Methylpiperidinyl(4)-benzilate (2) and benzilic acid (3) were also investigated in the isothermal quick-assay test. The test showed that the ether bound in 1 was hydrolyzed before the ester group. The compounds 5-7 are formed also direct from 3.

Formation of lipoxin B by the pure reticulocyte lipoxygenase

The pure reticulocyte lipoxygenase converts 5,15-DiHETE via a lipoxygenase reaction to 5,14,15-trihydroxy-6,8,10,12-eicosatetraenoic acid (a lipoxin B isomer) as shown by GC/MS analysis of its trimethylsilyl ether. With arachidonic acid, 15-HETE and 15-HETE methyl ester this lipoxin B isomer was also formed. The results presented here indicate that pure mammalian lipoxygenases are able to form lipoxins via sequential multiple oxygenation of arachidonic acid or its hydroxy derivatives.

Mass spectrometric monitoring of solid phase phosphate triester synthesis of DNA fragments

A new and convenient pyrolysis mass spectrometric approach for monitoring solid phase phosphate triester synthesis of oligodeoxyribonucleotides in 5'-3' direction has been developed. The base-typical fragment ions produced by pyrolysis at 280 degrees C of the polymer-bound oligonucleotide triesters in the mass spectrometer permit the analytical monitoring of DNA chain growth, using simple mathematical operations. The base composition can be determined directly from the polymer. In addition, minor nucleosides can easily be detected.