Comparison of species, virulence genes and clones of Aeromonas isolates from clinical specimens and well water in Okinawa Prefecture, Japan

AIMS

To reveal the sources of Aeromonas infection in Okinawa Prefecture of Japan, the species, virulence genes and clones of strains isolated from clinical specimens and well water were compared.

METHODS AND RESULTS

The properties of both isolates were investigated by sequencing of rpoD, detection of 10 virulence genes using PCR and genotyping with pulsed-field gel electrophoresis. In all, 68 clinical and 146 well water strains of Aeromonas were isolated and the main species were A. caviae, A. dhakensis, A. hydrophila and A. veronii biovar sobria. Aeromonas dhakensis possessed various virulence genes; however, A. caviae possessed only fla. The same or similar clones were distributed in certain areas of Okinawa and one clone had survived several months in the biliary system of two patients, respectively.

CONCLUSION

Although the same Aeromonas clone was not isolated from clinical and well water samples, our study revealed the detected patterns of virulence genes in both isolates, the distribution of identical/similar clones in the Okinawan environment and long-time survival in patient's organs.

SIGNIFICANCE AND IMPACT OF THE STUDY

We investigated the association between Aeromonas patients and well water exposure. This study provides the properties of species, virulence genes and clones of Aeromonas isolated from samples of these origins.

Abstract P6-18-10: A phase 1b/2 study of ribociclib plus trastuzumab for the treatment of advanced, treatment-refractory HER2-positive breast cancer

Introduction:

Despite the success of anti-HER2 therapy, acquired resistance usually develops in the metastatic setting. CDK4/6 pathway activity has been identified as a mediator of this resistance, and in preclinical studies the combination of CDK4/6 and HER2 blockade can be more effective than either therapy alone. We conducted a single-arm phase 1b/2 study of the CDK4/6 inhibitor ribociclib given with trastuzumab or T-DM1 to subjects with advanced, treatment-refractory HER2-positive breast cancer. The results of the trastuzumab cohort are presented below. The primary objective was to determine the clinical benefit rate (CBR) at 24 weeks, and secondary endpoints included objective response rate (ORR), progression-free survival (PFS), and adverse events.

Methods: Individuals with locally advanced or metastatic, measurable HER2-positive breast cancer were eligible. All subjects must have previously received trastuzumab, pertuzumab, and T-DM1 as (neo)adjuvant or metastatic therapy. There was no limit on the number of prior lines of treatment. Patients with previous CDK4/6 inhibitor exposure, QTcF > 450msec on EKG, or without stable brain metastases were excluded. An initial safety run-in phase (with dose-limiting toxicity (DLT) monitoring) included six subjects who received trastuzumab (8mg/kg loading then 6mg/kg IV three-weekly) and ribociclib 400mg PO daily on a continuous schedule (cycle length 21 days). The study had a two-stage design. The first stage required 20 patients, at least 6 of whom must have demonstrated clinical benefit (CR+PR+ SD>24 weeks) in order to recruit 15 more patients to the second stage. All patients with accessible disease underwent metastatic tumor biopsies at baseline and C2D1.

Results: 13 patients were enrolled (6 in the safety run-in and 7 in the expansion cohort). One patient was found to have HER2-negative disease and did not receive treatment. Patient characteristics are shown in Table 1 No DLTs were observed during the safety run-in phase, and ribociclib was thus used at 400mg po daily for the expansion cohort. Grade 3/4 toxicities were observed in 5 patients (41.7%) and included neutropenia (n=2), and fatigue, pain, and muscle weakness (all n=1). No patient demonstrated QTc prolongation >480 msec, or grade 3/4 LFTs. 1/12 patients ((8.3%); 95% CI 0.2%-38.5%) achieved stable disease>24 weeks; no objective responses were observed, and median PFS was 41.5 days. The trastuzumab portion of study was closed early due to limited clinical activity observed (the T-DM1 with ribociclib cohort remains open).

Table 1Age (median, range)50.5 (42 - 71)Number of prior lines of systemic therapy for metastatic disease (median, range)5.5 (0-14)Number with Hormone receptor-positive disease (%)8 (67 %)Number of metastatic sites (median, range)2.5 (2 - 5)

Conclusions: The combination of trastuzumab and ribociclib (400mg daily continuous schedule) is safe, with no new safety signals observed. The limited activity seen in this heavily pretreated population suggests that future efforts to incorporate CDK4/6 inhibition should be limited to a less extensively treat population.

Citation Format: Goel S, Spring L, Rees R, Andrews C, Tahara RK, Mayer EL, Bardia A, Winer EP, Tolaney SM. A phase 1b/2 study of ribociclib plus trastuzumab for the treatment of advanced, treatment-refractory HER2-positive breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P6-18-10.

Abstract P1-18-04: CTCs and SUV to predict the efficacy of the bone-specific radiopharmaceutical agent radium-223 dichloride combined with hormonal therapy for hormone receptor-positive bone-dominant breast cancer metastasis

Background: Radium-223 dichloride (Ra-223) is a targeted alpha particle-based radiotherapeutic that has a localized cytotoxic effect on bone metastases. We sought to determine whether the circulating tumor cell (CTC) count and the presence of CTCs in epithelial-mesenchymal transition (EMT-CTCs) along with the standardized uptake value (SUV) on positron emission tomography-computed tomography (PET/CT) scans predict the efficacy of combined Ra-223 and hormonal therapy in patients with hormone receptor (HR)-positive bone-dominant metastatic breast cancer.

Patients and Methods: In this single-center phase 2 study (NCT02366130), 36 patients received Ra-223 (55 kBq/kg intravenously) on day 1 and then every 4 weeks for six cycles. Patients also received a standard care endocrine monotherapy. One non-bone metastatic site was allowed. The number of prior endocrine therapies was not limited and one prior chemotherapy was allowed for metastasis. Response was evaluated using the PET Response Criteria in Solid Tumors (PERCIST) with PET/CT at baseline, 6 and 9 months (mo) later. The CTC count (CellSearch) and the presence of EMT-CTCs (AdnaTest) was determined at baseline, 6 and 9 mo later. Progression-free survival (PFS) time was calculated to evaluate efficacy.

Results: Seven patients (20%) had a non-bone metastatic site. The median number of prior therapies for metastasis was 1 (range, 0-4). Six patients (17%) received chemotherapy. The median CTC count at baseline was 4 (range, 0-306). Only four patients (11%) were positive for EMT-CTCs at baseline. The median follow-up time was 14.7 mo (95% confidence interval [CI], 13.2 mo-not reached [NR]). The disease control rate at 9 mo was 46% in 33 patients who reached 9 mo or progressed up to 9 mo. The tumor response rate at 6 mo was 52% (complete/partialresponse rate; 22/30 %) in 27 patients whose disease was evaluable using PERCIST. The SUV on PET/CT decreased significantly at 6 and 9 mo after baseline (average decreases of 1.5 (p=0.0004) and 2.5 (p=0.0054), respectively). The median PFS duration was 7.4 mo (95% CI, 4.8 mo-NR). The median bone PFS was 16 mo (95% CI, 7.3 mo-NR). Patients with bone-only metastasis (N=28, 80%) had a significantly longer median PFS duration than did patients with non-bone metastases at baseline (N=7, 20%) (13.8 mo versus 4.5 mo; p=0.017). Patients without prior treatment (N=12, 34%) tended to have longer median PFS durations than did those who underwent prior treatment (N=23, 66%) (16.8 mo versus 4.8 mo; p=0.1865). Also, patients with <5 CTCs at baseline (N=19, 54%) tended to have longer median PFS durations than did those with ≥5 CTCs (N=16, 46%) (13.8 mo versus 4.8 mo; p=0.1277). EMT-CTCs status did not predict efficacy.

Conclusions: Bone-only metastatic breast cancer and SUV suppression by Ra-223 are predictive of efficacy. Patients with baseline <5 CTC count tended to have better outcomes than did those with ≥5 CTCs. Combined treatment with Ra-223 and a hormonal agent is especially effective at controlling bone metastasis in patients with HR-positive breast cancer. Bone-only metastatic disease and CTC count should be factored in future clinical trial designs.

Citation Format: Ueno NT, Tahara RK, Reuben JM, Gao H, Saigal B, Fujii T, Lucci A, Ibrahim NK, Damodaran S, Shen Y, Liu DD, Hortobagyi GN, Tripathy D, Lim B, Chasen BA. CTCs and SUV to predict the efficacy of the bone-specific radiopharmaceutical agent radium-223 dichloride combined with hormonal therapy for hormone receptor-positive bone-dominant breast cancer metastasis [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-18-04.

Abstract P1-16-02: Phase II study of the feasibility and safety of radium-223 dichloride in combination with hormonal therapy and denosumab for the treatment of patients with hormone receptor-positive breast cancer with bone-dominant metastasis

Background

Radium-223 dichloride (Ra-223) is a therapeutic alpha particle-emitting radiopharmaceutical compound which have antitumor effect targeted on bone metastases. Alpha particles induces double strand DNA breaks and localized cytotoxic effect to cancer cells with limiting harm on normal tissues. We are conducting a phase II clinical trial of combination of Ra-223, hormonal therapy, and denosumab treatment in patients with hormone receptor (HR)-positive bone-dominant metastatic breast cancer (NCT02366130). In this preliminary analysis of the study, we aimed to evaluate the feasibility and safety of this combination therapy.

Methods

This single-center phase II study seeks to determine the efficacy and safety of Ra-223 in combination with hormonal therapy and denosumab. Major eligibility criteria include HR-positive breast cancer with bone and/or marrow predominant metastases. Patients with two or more visceral metastases were not eligible. There was no limit in the number of prior hormonal therapies in the metastatic setting. Patients received Ra-223 injection (55 kBq/kg intravenously) on day 1 of the study and then every 4 weeks thereafter for 6 cycles. Patients were also administered a single hormonal agent (i.e., tamoxifen, aromatase inhibitor, or fulvestrant at standard doses) daily and denosumab (120 mg subcutaneously) every 4 weeks. For this analysis, adverse events (AEs) were summarized using descriptive statistics.

Results

A total of 25 patients were enrolled and 22 were evaluable between March 2015 and December 2016. Median age was 58.5 years (range 31-79), and 59% of patients were postmenopausal. ECOG performance status was 0 in 16 patients (73%), and 1 in six patients (27%). HER2/neu was positive in only one patient. Four patients (18%) were de novo metastasis, no patients had visceral metastasis, and multiple bone metastases in 20 patients (91%) vs. focal metastasis in 2 (9%). Median time from diagnosis of bone metastasis was 4.8 months (range 0.5-96.6). Prior therapy for metastatic disease consisted of hormonal therapy in 50% of the patients (eight patients with one line and three patients with two lines), chemotherapy (9%), palbociclib (14%), radiation to bone metastasis (50%), and bone-supportive therapy (27% with zoledronic acid, 27% with denosumab). The median number of cycles of Ra-223 administered was 6 (range 4-6).

The median follow-up time was 4 months (range 2-8). There were no grade 3 or 4 AEs. Major non-hematological grade 1 and 2 AEs were bone pain (77%), fatigue (45%), nausea (36%), diarrhea (32%), AST/ALT elevation (23%), hot flashes (23%), and headache (18%). The most common hematological AEs were grade 1 or 2 neutropenia (23%), anemia (14%), and thrombocytopenia (18%). There was no treatment delay or discontinuation due to AEs.

Conclusion

Our results suggest that the addition of Ra-223 to hormonal therapy and denosumab is a feasible and safe combination therapy in patients with HR-positive breast cancer with bone-dominant metastasis. We continue to enroll patients in the phase II trial to evaluate the efficacy of the treatment.

Citation Format: Tahara RK, Fujii T, Saigal B, Ibrahim NK, Damodaran S, Barcenas CH, Murray JL, Chasen BA, Shen Y, Liu DD, Hortobagyi GN, Tripathy D, Ueno NT. Phase II study of the feasibility and safety of radium-223 dichloride in combination with hormonal therapy and denosumab for the treatment of patients with hormone receptor-positive breast cancer with bone-dominant metastasis [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P1-16-02.

Difference in hydrophobicity between botulinum type B activated and non-activated neurotoxins under low pH conditions

We showed that botulinum type B activated neurotoxin with a di-chain structure became hydrophobic more quickly and extensively than did the non-activated toxin with a single-chain structure on low pH exposure. The activated toxin possessed 50-fold higher toxicity than did the non-activated type. The difference in the susceptibility to hydrophobic change may be one clue to answering the question of why the activated toxin possesses a higher toxicity than does the non-activated type.

[Gonadal dysfunction]

Function of hypothalamic-pituitary-ovarian axis is an essential factor for the maintenance of regular cycles in mature women. The disturbance of function of those organs causes gonadal dysfunction such as anovulation, amenorrhea and menstrual disorders. Therefore, the correct diagnosis for the assessment of CNS and ovarian function is clinically important to treat the patients those who have an menstrual disorders. In this review, the mechanism of normal gonadal cycles and the diagnostic method and the treatment of gonadal dysfunction are described.

[Stage IIIa endometrial carcinoma: MR findings]

[PURPOSE]: An attempt was made to evaluate the ability of magnetic resonance (MR) imaging to diagnose stage IIIa endometrial carcinoma. [MATERIALS AND METHODS]: Thirty-three patients with endometrial carcinoma underwent MR imaging and surgery. Surgical staging was classified as I in 21 patients, II in 3 patients and III in 9 patients. The MR images of each patient were retrospectively reviewed by three radiologists. Only the clinical diagnosis of endometrial carcinoma was previously notified. Segmental disruption of the full thickness of the myometrium was considered serosal invasion. Intraperitoneal metastasis was diagnosed according to three criteria (intraperitoneal solid mass of isointensity compared with endometrial lesion, cystic mass excluding benign ovarian cysts, ascites). These evaluations were compared with the surgical findings and analyzed by the kappa statistic. [RESULTS]: The rates of sensitivity and positive predictive value (PPV) for serosal invasion were 33% and 6%, respectively. False positive evaluation frequently occurred when thickness of the intact myometrium was less than 5mm. The rates of sensitivity and PPV for intraperitoneal metastasis were 86% and 72%, respectively. The reason for false negative evaluation was small foci of intraperitoneal metastasis. Overall, sensitivity and PPV for stage IIIa were 86% and 69%, respectively. [CONCLUSION]: MRI was useful in detecting intraperitoneal metastasis of endometrial carcinoma with the exception of diagnosing serosal invasion. It is difficult to detect small foci of peritoneal metastasis. It is necessary to differentiate adnexal metastasis from benign adnexal masses.

Effect of dehydroepiandrosterone sulphate, oestrogens and prostaglandins on collagen metabolism in human cervical tissue in relation to cervical ripening

To clarify the mechanism of cervical ripening at term, collagenase activity in human cervical tissue was studied. The effects of steroids and prostaglandins on collagenase activity were also examined. Collagenase activities in cervical tissues obtained from non-pregnant (n = 5) and pregnant women (early-pregnant, n = 3; late-pregnant, n = 14) were measured, with or without the addition of steroids and prostaglandins into the incubation medium prior to the measurement of enzyme activity. The enzyme activity was significantly (P < 0.01-0.05) higher in the cervical tissue obtained from late-pregnant women than that from non-pregnant and early-pregnant women. Collagenase activity was significantly (P < 0.05) elevated when steroid sulphates such as dehydroepiandrosterone sulphate and oestrone sulphate were added to the incubation medium, while the addition of free steroids, prostaglandin E2 and prostaglandin F2 alpha did not alter the activity. These data suggest that conjugated steroid produced in the foetoplacental unit during pregnancy may be involved in cervical ripening through the enhancement of collagenase activity.

Determination of a new calcium antagonist, sesamodil fumarate (SD-3211), and its metabolite in plasma by liquid chromatography with electrochemical detection

A sensitive and selective high-performance liquid chromatographic method is described for the determination of a novel calcium antagonist, (+)-(R)-3,4-dihydro-2-[5-methoxy-2-[3-[N-methyl-N-[2-[(3,4- methylenedioxy)phenoxy]ethyl]amino]propoxy]phenyl]-4-methyl-3-oxo-2H- 1,4-benzothiazine hydrogen fumarate (sesamodil fumarate; JAN, SD-3211, I), and its N-desmethylated metabolite (II) in plasma. Compounds I and II and an internal standard were isolated from plasma by solid-phase and liquid-liquid extraction. The extract was chromatographed on a reversed-phase C18 column, and the compounds of interest were detected by dual coulometric electrodes operated in an oxidative screen mode. The limit of determination for both I and II was at least 0.4 ng/ml in plasma. The utility of the assay was demonstrated by determining plasma levels of I and II in five dogs administered an oral dose of 60 mg of the drug.

Steroid concentrations in human cervical tissue in relation to cervical ripening

Steroid concentrations in human cervical tissue were measured in order to study the mechanism of cervical ripening at term. Thirty-four women at 37 to 41 weeks of gestation were selected for the study and divided into two groups. Group A consisted of 21 cases with ripened cervix, and Group B consisted of 13 cases with non-ripened cervix. The condition of the cervix was judged by the Bishop's Score. Free and conjugated estrone (E1), estradiol (E2), estriol (E3), and dehydroepiandrosterone (DHA) concentrations in cervical tissue were measured by radioimmunoassay (RIA). Significantly higher concentrations of free E1, conjugated E2, E3 and DHA were found in Group A than in Group B. Cervical tissue during labor showed a further increase in the concentrations of these steroids. Pronounced increases of the steroid concentrations were noted following DHA-Sulfate (DHA-S) administration. These results suggest an intimate relationship between cervical ripening and steroid concentrations in cervical tissue during pregnancy.

Enhancement of human amniotic phospholipase A2 activity by steroid-sulphate derived from the foeto-placental unit

To study the control of production of prostaglandins (PG) during pregnancy and parturition, amniotic membranes obtained from normal vaginal delivery were incubated with the substrate of phosphatidylcholine containing [14C]arachidonic acid in the Sn-2 position. Phospholipase A2 activity was calculated as the rate of release of [14C]arachidonic acid from the substrate. Various steroids were added to the incubation medium to elucidate the effect of steroids on the enzymatic activity. The addition of dehydroepiandrosterone-sulphate (DHA-sulphate) to the medium increased by 7-fold the rate of [14C]arachidonic acid release from phosphatidylcholine at a concentration of 1.67 mM. The enhanced rate of arachidonic acid release suggests that DHA-sulphate stimulates phospholipase A2 activity. The same amounts of pregnenolone-sulphate and oestrone-sulphate also enhanced the enzymatic activity, while cholesterol-sulphate, free steroids such as DHA, progesterone, cortisol and oestrogens revealed no effect. These results suggest that steroid sulphates may be involved in the regulatory mechanism for PG synthesis in amniotic membrane.