Timothy W. Synold

Phase I study of nelfinavir in liposarcoma

PurposeHIV protease inhibitors are associated with HIV protease inhibitor–related lipodystrophy syndrome. We hypothesized that liposarcomas would be similarly susceptible to the apoptotic effects of an HIV protease inhibitor, nelfinavir.MethodsWe conducted a phase I trial of nelfinavir for liposarcomas. There was no limit to prior chemotherapy. The starting dose was 1,250xa0mg twice daily (Level 1). Doses were escalated in cohorts of three to a maximally evaluated dose of 4,250xa0mg (Level 5). One cycle was 28xa0days. Steady-state pharmacokinetics (PKs) for nelfinavir and its primary active metabolite, M8, were determined at Levels 4 (3,000xa0mg) and 5.ResultsTwenty subjects (13 males) were enrolled. Median (range) age was 64xa0years (37–81). One subject at Level 1 experienced reversible, grade 3 pancreatitis after 1xa0week and was replaced. No other dose-limiting toxicities were observed. Median (range) number of cycles was 3 (0.6–13.5). Overall best responses observed were 1 partial response, 1 minor response, 4 stable disease, and 13 progressive disease. Mean peak plasma levels and AUCs for nelfinavir were higher at Level 4 (7.3xa0mg/L; 60.9xa0mg/Lxa0×xa0h) than 5 (6.3xa0mg/L; 37.7xa0mg/Lxa0×xa0h). The mean ratio of M8:nelfinavir AUCs for both levels was ~1:3.ConclusionsPKs demonstrate auto-induction of nelfinavir clearance at the doses studied, although the mechanism remains unclear. Peak plasma concentrations were within range where anticancer activity was demonstrated in vitro. M8 metabolite is present at ~1/3 the level of nelfinavir and may also contribute to the anticancer activity observed.

Single-dose pharmacokinetic and toxicity analysis of pyrrole-imidazole polyamides in mice.

PurposePyrrole–imidazole (Py-Im) polyamides are programmable, sequence-specific DNA minor groove–binding ligands. Previous work in cell culture has shown that various polyamides can be used to modulate the transcriptional programs of oncogenic transcription factors. In this study, two hairpin polyamides with demonstrated activity against androgen receptor signaling in cell culture were administered to mice to characterize their pharmacokinetic properties.MethodsPy-Im polyamides were administered intravenously by tail vein injection. Plasma, urine, and fecal samples were collected over a 24-h period. Liver, kidney, and lung samples were collected postmortem. Concentrations of the administered polyamide in the plasma, excretion, and tissue samples were measured using LC/MS/MS. The biodistribution data were analyzed by both non-compartmental and compartmental pharmacokinetic models. Animal toxicity experiments were also performed by monitoring weight loss after a single subcutaneous (SC) injection of either polyamide.ResultsThe biodistribution profiles of both compounds exhibited rapid localization to the liver, kidneys, and lungs upon injection. Plasma distribution of the two compounds showed distinct differences in the rate of clearance, the volume of distribution, and the AUCs. These two compounds also have markedly different toxicities after SC injection in mice.ConclusionsThe variations in pharmacokinetics and toxicity in vivo stem from a minor chemical modification that is also correlated with differing potency in cell culture. The results obtained in this study could provide a structural basis for further improvement of polyamide activity both in cell culture and in animal models.

A phase I trial of mushroom powder in patients with biochemically recurrent prostate cancer: Roles of cytokines and myeloid-derived suppressor cells for Agaricus bisporus-induced prostate-specific antigen responses.

Each year in the United States, nearly 50,000 prostate cancer patients exhibit a rise in prostate‐specific antigen (PSA) levels, which can indicate disease recurrence. For patients with biochemically recurrent prostate cancer, we evaluated the effects of white button mushroom (WBM) powder on serum PSA levels and determined the tolerability and biological activity of WBM.

A Neuropharmacokinetic Assessment of Bafetinib, a Second Generation Dual BCR-Abl/Lyn Tyrosine Kinase Inhibitor, in Patients with Recurrent High-Grade Gliomas

PURPOSEnThe primary objective of this study was to use intracerebral microdialysis (ICMD) to determine the neuropharmacokinetics of bafetinib, a dual BCR-Abl/Lyn tyrosine kinase inhibitor that may have activity against gliomas.nnnMETHODSnA microdialysis catheter was placed into either peritumoural or enhancing brain tissue of seven patients at the time of tumour resection or biopsy. Twenty-four hours later, bafetinib was administered, 240 or 360 mg po, repeating the same dose 12 h later. Dialysate samples were continuously collected for 24h, with plasma samples obtained in parallel. One to two weeks after finishing ICMD, patients were allowed to resume taking bafetinib continuously while being observed for toxicity and tumour response.nnnRESULTSnTwenty-six dialysate samples per patient were collected (n=6) and analysed for bafetinib by tandem mass spectrometry. Bafetinib concentrations in the brain were below the lower limit of detection of the assay (0.1 ng/ml) in all samples except one from a single subject that was 0.52 ng/ml. The mean plasma bafetinib maximum concentrations after dose 1 and 2 were 143±99 and 247±73 ng/ml, respectively. Only one patient remained on treatment past two cycles, and no radiographic responses were seen.nnnCONCLUSIONSnBafetinib does not sufficiently cross intact or disrupted blood-brain barrier, and therefore, systemic administration of bafetinib is not recommended when investigating this drug as a treatment for brain tumours. ICMD can be a valuable research tool in early drug development. Lead-in ICMD studies can be performed relatively quickly, requiring only a small number of patients, and without significantly disrupting standard cancer care.

Bioimaging real-time PXR-dependent mdr1a gene regulation in mdr1a.fLUC reporter mice

The MDR1 gene encodes P-glycoprotein, a transmembrane drug efflux transporter that confers multidrug resistance in cancer cells and affects drug pharmacokinetics by virtue of its expression in the liver, kidney, and colon. Nuclear receptors human steroid and xenobiotic receptor (SXR) and constitutive androstane receptor (CAR) are possible master regulators of xenobiotic-inducible MDR1 expression in drug processing organs, but the mechanism of MDR1 regulation has yet to be directly demonstrated in vivo. Moreover, it has previously been impossible to determine the sustained or cumulative effect of repeated doses of xenobiotics on in vivo MDR1 expression. We previously reported a mouse model containing firefly luciferase (fLUC) knocked into the mdr1a genomic locus, allowing noninvasive bioimaging of intestinal mdr1a gene expression in live animals. In the current study, we crossed mdr1a.fLUC mice into the pxr knockout (pxr−/−) genetic background and injected mice with pregnenolone-16α-carbonitrile (PCN), a strong mouse pregnane X receptor (PXR) ligand, and two therapeutically relevant taxanes, paclitaxel and docetaxel. All three agents induced mdr1a.fLUC expression (bioluminescence), but only PCN and docetaxel appeared to act primarily via PXR. Luminescence returned to baseline by 24–48 hours after drug injection and was reinducible over two additional rounds of drug dosing in pxr+/+ mice. TCPOBOP, a CAR ligand, modestly induced mdr1a.fLUC in pxr+/+ and pxr−/− strains, consistent with CAR’s minor role in mdr1a regulation. Collectively, these results demonstrate that the mdr1a.fLUC bioimaging model can capture changes in mdr1 gene expression under conditions of repeated xenobiotic treatment in vivo and that it can be used to probe the mechanism of gene regulation in response to different xenobiotic agents.

Atherogenic diets exacerbate colitis in mice deficient in glutathione peroxidase

Background: The proinflammatory effect of high‐fat diet has been observed beyond the cardiovascular system, but there is little evidence to support its role in triggering inflammatory bowel disease. GPx1/2‐double‐knockout (DKO) mice deficient in 2 intracellular glutathione peroxidases, GPx1 and GPx2, on a C57BL/6 (B6) background, have mild ileocolitis on a conventional chow. Methods: We fed B6 DKO mice 2 atherogenic diets to test the dietary effect on atherosclerosis and ileocolitis. Both atherogenic diets have high cholesterol—the Chol+/CA diet has cholic acid (CA), and the Chol+ diet has no CA. Results: The Chol+/CA diet induced severe colitis, but not ileitis, in the DKO mice compared with the Chol+ and the Chol− control diet. On the Chol+/CA diet, the wild‐type (WT) mice had levels of aortic lesions and hypercholesterolemia similar to those of DKO mice but had no intestinal pathology. The diet‐associated inflammatory responses in the DKO mice included increased colonic proinflammatory serum amyloid A3 expression, plasma lipopolysaccharide, and TNF‐&agr; levels. The Chol+/CA diet lowered the expression of the unfolded protein response genes ATF6, CHOP, unspliced XbpU, and Grp78/Bip, in WT and DKO mice compared with mice on the Chol− diet. Conclusions: We concluded that a cholesterol diet weakens the colon unfolded protein response, which can aggravate spontaneous colitis, leading to gut barrier breakdown. GPx has no impact on atherosclerosis without ultrahypercholesterolemia. Inflamm Bowel Dis 2010

HIV replication and latency in a humanized NSG mouse model during suppressive oral combinational ART

ABSTRACT Although current combinatorial antiretroviral therapy (cART) is therapeutically effective in the majority of HIV patients, interruption of therapy can cause a rapid rebound in viremia, demonstrating the existence of a stable reservoir of latently infected cells. HIV latency is therefore considered a primary barrier to HIV eradication. Identifying, quantifying, and purging the HIV reservoir is crucial to effectively curing patients and relieving them from the lifelong requirement for therapy. Latently infected transformed cell models have been used to investigate HIV latency; however, these models cannot accurately represent the quiescent cellular environment of primary latently infected cells in vivo. For this reason, in vivo humanized murine models have been developed for screening antiviral agents, identifying latently infected T cells, and establishing treatment approaches for HIV research. Such models include humanized bone marrow/liver/thymus mice and SCID-hu-thy/liv mice, which are repopulated with human immune cells and implanted human tissues through laborious surgical manipulation. However, no one has utilized the human hematopoietic stem cell-engrafted NOD/SCID/IL2rγnull (NSG) model (hu-NSG) for this purpose. Therefore, in the present study, we used the HIV-infected hu-NSG mouse to recapitulate the key aspects of HIV infection and pathogenesis in vivo. Moreover, we evaluated the ability of HIV-infected human cells isolated from HIV-infected hu-NSG mice on suppressive cART to act as a latent HIV reservoir. Our results demonstrate that the hu-NSG model is an effective surgery-free in vivo system in which to efficiently evaluate HIV replication, antiretroviral therapy, latency and persistence, and eradication interventions. IMPORTANCE HIV can establish a stably integrated, nonproductive state of infection at the level of individual cells, known as HIV latency, which is considered a primary barrier to curing HIV. A complete understanding of the establishment and role of HIV latency in vivo would greatly enhance attempts to develop novel HIV purging strategies. An ideal animal model for this purpose should be easy to work with, should have a shortened disease course so that efficacy testing can be completed in a reasonable time, and should have immune correlates that are easily translatable to humans. We therefore describe a novel application of the hematopoietic stem cell-transplanted humanized NSG model for dynamically testing antiretroviral treatment, supporting HIV infection, establishing HIV latency in vivo. The hu-NSG model could be a facile alternative to humanized bone marrow/liver/thymus or SCID-hu-thy/liv mice in which laborious surgical manipulation and time-consuming human cell reconstitution is required.

Association of Pre‐Chemotherapy Peripheral Blood Pro‐Inflammatory and Coagulation Factors with Physical Function in Women with Breast Cancer

Breast cancer is a disease associated with aging. Before initiation of chemotherapy, an assessment of functional reserve is needed; however, simple performance assessment scores may not reflect the diverse nature of physical function and risk of toxicity among older adults. The focus of this article is on understanding the association between pre‐chemotherapy biomarkers (IL‐6, CRP, and D‐dimer) and measures of physical function.

Association of pre-chemotherapy peripheral blood pro-inflammatory and coagulation factors with reduced relative dose intensity in women with breast cancer

BackgroundChemotherapy decreases the risk of relapse and mortality in early-stage breast cancer (BC), but it comes with the risk of toxicity. Chemotherapy efficacy depends on relative dose intensity (RDI), and an RDIu2009<u200985% is associated with worse overall survival. The pro-inflammatory (interleukin (IL)-6, C-reactive protein (CRP)) and coagulation factors (D-dimer) serve as biomarkers of aging. The purpose of this study is to determine if these biomarkers are associated with reduced RDI in women with stage I–III BC.MethodsThis study enrolled women with stage I–III BC. Prior to adjuvant or neoadjuvant chemotherapy, peripheral blood was collected for biomarker measurement. Dose reductions and delays were captured and utilized to calculate the RDI delivered. Univariate and multivariate analyses were performed to describe the association between pre-chemotherapy IL-6, CRP, and D-dimer levels and an RDIu2009<u200985%, controlling for relevant tumor and patient factors (age, stage, receptor status, chemotherapy regimen, and pre-chemotherapy physical function and comorbidity).ResultsA total of 159 patients (mean age 58xa0years, range 30–81, SD 11.3) with stage I–III BC were enrolled. An RDIu2009<u200985% occurred in 22.6% (Nu2009=u200936) of patients and was associated with higher pre-chemotherapy IL-6 (OR 1.14, 95% CI 1.04–1.25; pu2009=u20090.006) and D-dimer (OR 2.32, 95% CI 1.27–4.24; pu2009=u20090.006) levels, increased age (pu2009=u20090.001), increased number of comorbidities (pu2009=u20090.01), and decreased physical function by the Medical Outcomes Survey Activities of Daily Living (ADL) Scale (pu2009=u20090.009) in univariate analysis. A multivariate model, including two biomarkers (IL-6 and D-dimer), age, ADL, BC stage, and chemotherapy regimen, demonstrated a significant association between the increased biomarkers and reduced RDIu2009<u200985% (OR 2.54; pu2009=u20090.04).ConclusionsIncreased pre-chemotherapy biomarkers of aging (IL-6 and D-dimer) are associated with reduced RDI (<85%). Future studies are underway to validate these findings.Trial registrationClinicalTrials.gov, NCT01030250. Registered on 3 November 2016.

634. Translation of a Neural Stem Cell-Mediated Enzyme/Prodrug Gene Therapy for Metastatic Neuroblastoma

Neuroblastoma (NB), a neuroendocrine tumor, is the most common extracranial solid tumor of childhood. Forty-five percent of these patients are diagnosed with metastatic high-risk tumors, for which treatment options are limited both in anti-tumor efficacy and patient tolerance. We have previously shown that neural stem cells (NSCs), engineered to secrete a modified rabbit carboxylesterase (CE), can home to metastatic NB tumor foci, and convert the prodrug CPT-11 (Irinotecan; IRN) to the 1000-fold more potent anti-cancer agent SN-38, resulting in significant therapeutic efficacy. The goal of our current biodistribution, efficacy and safety/toxicity IND-enabling studies is to identify the optimal dose and schedule of intravenously administered clinically relevant NSCs secreting a modified human CE (hCE1m6), followed by human equivalent doses of irinotecan. This would ideally provide a tumor selective, more effective and less toxic treatment for children with high-risk NB.In vitro cytotoxicity studies demonstrated IC50 values for four human NB tumors were significantly more sensitive to CPT-11 in the presence of hCE1m6 (similar to treatment with SN-38) compared to IRN alone. The sensitivity of NB tumor cells to CPT-11 was enhanced ≈6000-fold by hCE1m6 for KCNR tumor, while the sensitivity of SKNAS cells was enhanced ≈1200-fold for SKNAS, and approximately 150 to 600-fold decrease in IC50s of IRN for CHLA-136 and CHLA-255 NB cells. In vivo qPCR and MRI studies demonstrate NSC clearance through normal circulation and organs (lung, liver, brain) in naive non-tumor bearing Es1e/SCID mice is 24h following intravenous adminstration. In subcutaneous models of human NB we have quantified NSC tumor distribution and performed pharmacokinetics studies demonstrating a significant increase in tumor specific conversion of IRN to SN-38 with the CE-NSCs. Therapeutic efficacy studies are ongoing. If successful, we plan to be in Phase I studies in pediatric patients with refractory or relapsed high-risk neuroblastoma. This would be a first-in-human use of NSC-mediated enzyme/prodrug therapy in metastatic cancer patients.