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Patients with breast cancer brain metastases have extremely limited survival and no approved systemic therapeutics. Triple-negative breast cancer (TNBC) commonly metastasizes to the brain and predicts poor prognosis. TNBC frequently harbors BRCA mutations translating to platinum sensitivity potentially augmented by additional suppression of DNA repair mechanisms through PARP inhibition. We evaluated brain penetrance and efficacy of carboplatin ± the PARP inhibitor ABT888, and investigated gene-expression changes in murine intracranial TNBC models stratified by BRCA and molecular subtype status. Athymic mice were inoculated intracerebrally with BRCA-mutant: SUM149 (basal), MDA-MB-436 (claudin-low); or BRCA–wild-type (wt): MDA-MB-468 (basal), MDA-MB-231BR (claudin-low). TNBC cells were treated with PBS control [intraperitoneal (IP), weekly], carboplatin (50 mg/kg/wk, IP), ABT888 (25 mg/kg/d, oral gavage), or their combination. DNA damage (γ-H2AX), apoptosis (cleaved caspase-3, cC3), and gene expression were measured in intracranial tumors. Carboplatin ± ABT888 significantly improved survival in BRCA-mutant intracranial models compared with control, but did not improve survival in BRCA-wt intracranial models. Carboplatin + ABT888 revealed a modest survival advantage versus carboplatin in BRCA-mutant models. ABT888 yielded a marginal survival benefit in the MDA-MB-436, but not in the SUM149 model. BRCA-mutant SUM149 expression of γ-H2AX and cC3 proteins was elevated in all treatment groups compared with control, whereas BRCA-wt MDA-MB-468 cC3 expression did not increase with treatment. Carboplatin treatment induced common gene-expression changes in BRCA-mutant models. Carboplatin ± ABT888 penetrates the brain and improves survival in BRCA-mutant intracranial TNBC models with corresponding DNA damage and gene-expression changes. Combination therapy represents a potential promising treatment strategy for patients with TNBC brain metastases warranting further clinical investigation. Mol Cancer Ther; 14(4); 920–30. ©2015 AACR.

This file contains additional details on the microarray analysis and normalization.

This file contains the compiled Supplemental Figures S1-S9. Figure S1 is a flowchart describing the process of normalizing the microarray data for the SUM149 model for the different scanners used. Figure S2 depicts the scanner differences in the microarray data for the SUM149 model before and after normalization. Figure S3 is a flowchart depicting the analytical process used to analyze and compare the SUM149 and MDA-MB-436 models microarray results, and Figure S4 shows the difference in scale between models before and after the scaling process for visual comparison of the SUM149 and MDA-MB-436 models. Figure S5 demonstrates the lack of survival benefit of Carboplatin +/- ABT88 in the two BRCA-wt models, MDA-MB-468 and MDA-MB-231BR. Figure S6 contains representative images of IHC cC3 staining for the BRCA-wt model, MDA-MB-468. Figure S7 shows the unsupervised clustering of the BRCA-mut SUM149 and MDA-MB-436 models with treatment. Figure S8 contains the supervised clustering based on carboplatin treatment in these two models. Figure S9 demonstrates the expression levels of the 38 commonly regulated genes in both models with carboplatin treatment.

This file contains the differentially expressed genes and enriched pathways lists from the gene expression microarray analyses in Supplemental Table S1, with sample information in S1a. Lists are for the following comparisons: SUM149 Control vs. ABT888 (S1b), MDA-MB-436 Control vs. ABT888 (S1c), SUM149 Control vs. Carboplatin (S1d), MDA-MB-436 Control vs. Carboplatin (S1e), SUM149 Control vs Carboplatin+ABT888 (S1f), MDA-MB-436 Control vs Carboplatin+ABT888 (S1g), SUM149 Carboplatin vs Carboplatin+ABT888 (S1h), MDA-MB-436 Carboplatin vs Carboplatin+ABT888 (S1i). DAVID pathway enrichment analysis results are shown for the significantly up-regulated (S1j) and down-regulated (S1k) genes with Carboplatin treatment for both models.

This file contains the figure legends for Supplemental Figures S1-S9.

Objective:To assess association of pharmacist gender with acceptance of antibiotic stewardship recommendations.Design:A retrospective evaluation of the Reducing Overuse of Antibiotics at Discharge (ROAD) Home intervention.Setting:The study was conducted from May to October 2019 in a single academic medical center.Participants:The study included patients receiving antibiotics on a hospitalist service who were nearing discharge.Methods:During the intervention, clinical pharmacists (none who had specialist postgraduate infectious disease residency training) reviewed patients on antibiotics and led an antibiotic timeout (ie, structured conversation) prior to discharge to improve discharge antibiotic prescribing. We assessed the association of pharmacist gender with acceptance of timeout recommendations by hospitalists using logistic regression controlling for patient characteristics.Results:Over 6 months, pharmacists conducted 295 timeouts: 158 timeouts (53.6%) were conducted by 12 women, 137 (46.4%) were conducted by 8 men. Pharmacists recommended an antibiotic change in 82 timeouts (27.8%), of which 51 (62.2%) were accepted. Compared to male pharmacists, female pharmacists were less likely to recommend a discharge antibiotic change: 30 (19.0%) of 158 versus 52 (38.0%) of 137 (P < .001). Female pharmacists were also less likely to have a recommendation accepted: 10 (33.3%) of 30 versus 41 (8.8%) of 52 (P < .001). Thus, timeouts conducted by female versus male pharmacists were less likely to result in an antibiotic change: 10 (6.3%) of 158 versus 41 (29.9%) of 137 (P < .001). After adjustments, pharmacist gender remained significantly associated with whether recommended changes were accepted (adjusted odds ratio [aOR], 0.10; 95%confidence interval [CI], 0.03–0.36 for female versus male pharmacists).Conclusions:Antibiotic stewardship recommendations made by female clinical pharmacists were less likely to be accepted by hospitalists. Gender bias may play a role in the acceptance of clinical pharmacist recommendations, which could affect patient care and outcomes.

This retrospective study was conducted to determine whether the number of peripherally inserted central-catheter lumens affected the rate of central-line associated bloodstream infections (CLABSIs) in adult patients with acute leukemia. The results show that CLABSI rates were not significantly different between patients with triple-lumen or double-lumen PICCs (22.1% vs 23.4%; P = .827).

Background: TNBC frequently spreads to the central nervous system and is associated with poor outcome. Twenty percent of women with TNBC harbor a BRCA mutation(mut). BRCA dysfunction impairs repair of DNA double-strand breaks by homologous recombination(HR) and sensitizes tumor cells to DNA-damaging cytotoxic agents. Emerging evidence suggests that TNBC responds to platinums(Pt) and drugs potentiating efficiency of DNA damage, such as PARP inhibitors; combination therapy may enhance DNA damage and induce additional cytotoxicity. Recognizing that Pt and many PARP inhibitors penetrate the blood brain barrier(BBB), we evaluated the efficacy of carboplatin(Carbo) alone and with the PARP inhibitor, ABT888(ABT), in murine intracranial(IC) TNBC models characterized by BRCA status. Methods: Athymic (nu/nu) mice(10wks) were inoculated intracerebrally with 2×105 SUM149(BRCA1mut, pTEN-; basal) cells expressing luciferase. On day14, tumor-bearing mice began treatment with Control(PBS IP weekly), Carbo(50mg/kg IP weekly) and ABT(25mg/kg OG daily) as single agents, or in combination. Survival and IC tumor growth via bioluminescence were compared by treatment. Net PAR levels(PARpg/ml/100ug total protein) were measured in IC tumor tissue(ELISA pharmacodynamic assay) 14days post ABT. Presence of Pt DNA adducts was measured in IC tumor tissue following Carbo+/-ABT by ICP-MS. Survival and IC tumor growth via bioluminescence of the MDA-MB468(BRCAnon-mut, pTEN-; basal) IC model treated with the same regimens were assessed. Results: In the SUM149 TNBC IC model, Carbo+/-ABT resulted in improved survival compared to control (Table). Single agent ABT did not yield a survival benefit over control. Combination Carbo/ABT showed a modest advantage in survival compared to Carbo alone (p = 0.28). IC tumor mean net PAR levels ± SEM were significantly lower in ABT-treated animals compared to control (182.1 ± 91.3 vs 825.7 ± 174.7, p = 0.0043). Addition of ABT did not impair Carbo BBB penetration; Mean ± SEM Pt-DNA adducts were detected in IC tumor after administration of Carbo and Carbo/ABT (0.91±0.13 and 1.46±0.03 pgPt/ugDNA). In contrast to the SUM149 IC model, there was no survival improvement for the MDA-MB468 IC model treated with Carbo+/-ABT compared to control(p = 0.81). SUM149(BRCA1mut)MDA-MB468(BRCA1non-mut)TreatmentNMedian Survival (95%CI), dayspValueNMedian Survival (95%CI), daysControl1736(34-40)N/A535(29-57)ABT1039(30-46)p = 0.22544(33-57)Carbo1658(47-67)p Conclusions: This study shows Pt analogues, specifically Carbo, represent a promising treatment strategy for TNBC brain metastases with BRCA dysfunction. Improved survival relies on the ability of Pt analogues to penetrate the BBB and higher cytotoxicity may be due to compromised HR in TNBC as compared to models with functional BRCA. Although inhibitory activity of ABT was detected in IC tumors, we did not observe a significant additive effect of ABT to Carbo when used in combination. Confirmatory studies in additional IC TNBC models, including claudin-low subtype, as well as mechanistic studies evaluating DNA damage via γH2AX foci and differential gene expression in response to treatment are ongoing. Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P6-11-06.

Patients with breast cancer brain metastases have extremely limited survival and no approved systemic therapeutics. Triple-negative breast cancer (TNBC) commonly metastasizes to the brain and predicts poor prognosis. TNBC frequently harbors BRCA mutations translating to platinum sensitivity potentially augmented by additional suppression of DNA repair mechanisms through PARP inhibition. We evaluated brain penetrance and efficacy of carboplatin ± the PARP inhibitor ABT888, and investigated gene-expression changes in murine intracranial TNBC models stratified by BRCA and molecular subtype status. Athymic mice were inoculated intracerebrally with BRCA-mutant: SUM149 (basal), MDA-MB-436 (claudin-low); or BRCA–wild-type (wt): MDA-MB-468 (basal), MDA-MB-231BR (claudin-low). TNBC cells were treated with PBS control [intraperitoneal (IP), weekly], carboplatin (50 mg/kg/wk, IP), ABT888 (25 mg/kg/d, oral gavage), or their combination. DNA damage (γ-H2AX), apoptosis (cleaved caspase-3, cC3), and gene expression were measured in intracranial tumors. Carboplatin ± ABT888 significantly improved survival in BRCA-mutant intracranial models compared with control, but did not improve survival in BRCA-wt intracranial models. Carboplatin + ABT888 revealed a modest survival advantage versus carboplatin in BRCA-mutant models. ABT888 yielded a marginal survival benefit in the MDA-MB-436, but not in the SUM149 model. BRCA-mutant SUM149 expression of γ-H2AX and cC3 proteins was elevated in all treatment groups compared with control, whereas BRCA-wt MDA-MB-468 cC3 expression did not increase with treatment. Carboplatin treatment induced common gene-expression changes in BRCA-mutant models. Carboplatin ± ABT888 penetrates the brain and improves survival in BRCA-mutant intracranial TNBC models with corresponding DNA damage and gene-expression changes. Combination therapy represents a potential promising treatment strategy for patients with TNBC brain metastases warranting further clinical investigation. Mol Cancer Ther; 14(4); 920–30. ©2015 AACR.

The pharmacokinetics (PK) of carrier-mediated agents (CMA) is dependent upon the carrier system. As a result, CMA PK differs greatly from the PK of small molecule (SM) drugs. Advantages of CMAs over SMs include prolonged circulation time in plasma, increased delivery to tumors, increased antitumor response, and decreased toxicity. In theory, CMAs provide greater tumor drug delivery than SMs due to their prolonged plasma circulation time. We sought to create a novel PK metric to evaluate the efficiency of tumor and tissue delivery of CMAs and SMs. We conducted a study evaluating the plasma, tumor, liver, and spleen PK of CMAs and SMs in mice bearing subcutaneous flank tumors using standard PK parameters and a novel PK metric entitled relative distribution over time (RDI-OT), which measures efficiency of delivery. RDI-OT is defined as the ratio of tissue drug concentration to plasma drug concentration at each time point. The standard concentration versus time area under the curve values (AUC) of CMAs were higher in all tissues and plasma compared with SMs. However, 8 of 17 SMs had greater tumor RDI-OT AUC0–last values than their CMA comparators and all SMs had greater tumor RDI-OT AUC0–6 h values than their CMA comparators. Our results indicate that in mice bearing flank tumor xenografts, SMs distribute into tumor more efficiently than CMAs. Further research in additional tumor models that may more closely resemble tumors seen in patients is needed to determine if our results are consistent in different model systems.

Background. Rodent studies are a vital step in the development of novel anticancer therapeutics and are used in pharmacokinetic (PK), toxicology, and efficacy studies. Traditionally, anticancer drug development has relied on xenograft implantation of human cancer cell lines in immunocompromised mice for efficacy screening of a candidate compound. The usefulness of xenograft models for efficacy testing, however, has been questioned, whereas genetically engineered mouse models (GEMMs) and orthotopic syngeneic transplants (OSTs) may offer some advantages for efficacy assessment. A critical factor influencing the predictability of rodent tumor models is drug PKs, but a comprehensive comparison of plasma and tumor PK parameters among xenograft models, OSTs, GEMMs, and human patients has not been performed. Methods. In this work, we evaluated the plasma and tumor dispositions of an antimelanoma agent, carboplatin, in patients with cutaneous melanoma compared with four different murine melanoma models (one GEMM, one human cell line xenograft, and two OSTs). Results. Using microdialysis to sample carboplatin tumor disposition, we found that OSTs and xenografts were poor predictors of drug exposure in human tumors, whereas the GEMM model exhibited PK parameters similar to those seen in human tumors. Conclusions. The tumor PKs of carboplatin in a GEMM of melanoma more closely resembles the tumor disposition in patients with melanoma than transplanted tumor models. GEMMs show promise in becoming an improved prediction model for intratumoral PKs and response in patients with solid tumors.

Background: The PK of CMA are dependent upon the carrier system. As a result, CMA PK differ greatly from the PK of SM drugs. Advantages of CMA included prolonged circulation time in plasma, increased delivery to tumors which results in increased antitumor response and decreased toxicity. In theory, the prolonged circulation time of CMA in plasma is thought to result in greater tumor delivery compared with SM. We conducted a meta-analysis evaluating the plasma, tumor, liver, and spleen PK of CMA and SM using standard PK parameters and a novel PK metric RDI-OT which measures efficiency of delivery. Methods: A literature search identified PK studies of CMA (n=17) and comparative SM (n=15) in plasma, tumor, liver and spleen of mice bearing synergistic and xenograft subcutaneous tumors. The area under the concentration versus time curves (AUC) were calculated. This data was also used to calculate a novel PK metric, RDI-OT. RDI-OT is defined as [Drug]tissue/[Drug]plasma at each time point. RDI-OT versus time plots were generated and the area under the curve (RDI-OT AUC) was calculated from 0 h to 24 h and last time point. Results: The table below summarizes the mean + SD and range of standard PK parameters and RDI-OT for CMA and SM. Summary of pharmacokinetic properties by agent type Agent Type CMA SM Mean + SD Range Mean + SD Range AUCplasma (mcg/ml*h) 8,113.7 + 21,620.6 10.5–90,889.6 18.2 + 33.7 0.5–133.8 AUCtumor (mcg/ml*h) 3,605.2 + 8,790.1 13.2–35,400.5 83.8 + 94.4 0.8–243.0 AUCtumor/AUCplasma 1.0 + 1.3 0.04–4.8 8.2 + 11.0 0.3–38.6 SM AUCtumor: AUCplasma 40.6 + 112.3 473.1–0.7 CMA AUCtumor: AUCplasma RDI-OTtumor AUC0-Last 46,289.3 + 179,143.8 3.0–741,095.9 1565.0 + 3053.6 0.8–11057.7 SM RDI-OTtumor AUC 1.7 + 3.1 0.00009–13.4 CMA RDI-OTtumor AUC RDI-OTtumor AUC0-24h 15.4 + 37.1 0.1–121.8 43.4 + 96.8 0.01–361.8 SM RDI-OTtumor AUC0-24h 30.5 + 78.2 0.1–319.2 CMA RDI-OTtumor AUC0-24h Conclusions: RDI-OT is a novel metric for assessing the efficiency of drug distribution into tumors and tissues. Our results indicate that in mice bearing flank tumor xenografts SM distribute into tumor more efficiently than CMA. The lower efficiency of delivery seen in CMA compared with SM suggests there may be a limit to CMA entry into flank tumors in mice. Further research in additional tumor models that may more closely resemble tumors seen in patients is needed to determine if our results are consistent in different model systems. Citation Format: Andrew J. Madden, Sumit Rawal, Kevin Chu, Katie Sandison, Ryan Schell, Lan Feng, Ping Ma, Russell Mumper, Joseph DeSimone, William C. Zamboni. Evaluation of the efficiency of tumor and tissue delivery of carrier mediated agents (CMA) and small molecule (SM) agents in mice using a novel pharmacokinetic (PK) metric relative distribution index over time (RDI-OT). [abstract]. In: Proceedings of the 104th Annual Meeting of the American Association for Cancer Research; 2013 Apr 6-10; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2013;73(8 Suppl):Abstract nr 3355. doi:10.1158/1538-7445.AM2013-3355