Craniospinal Irradiation for CNS Leukemia: Rates of Response and Durability of CNS Control

PURPOSE/OBJECTIVE(S)

Craniospinal irradiation (CSI) is used in the management of leukemia patients with central-nervous-system (CNS) involvement, though the data on response and local control are limited. Given the radioresponsiveness of leukemia, we hypothesized that response to CSI would be high, but CNS control would be influenced by control of systemic disease.

MATERIALS/METHODS

This retrospective, single-institution analysis included consecutive pediatric and adult patients between 2009-2021 with leukemia that underwent CSI for CNS involvement, defined as presence of blasts (i.e., >0%) on CSF flow cytometry. Endpoints included CNS response rate (RR), CNS local recurrence (LR), progression-free survival (PFS), and overall survival (OS), which were estimated from start of CSI. The probability of CNS LR was summarized using a cumulative incidence estimate, where death without LR was considered a competing risk. The probabilities of OS and PFS were obtained using Kaplan-Meier estimates.

RESULTS

Among the 39 eligible patients (43% AML, 49% ALL, 8% blast-phase CML), most were male (59%). All had CSF confirmation of disease. Median age at CSI was 31 years (range 7-67). CSI (protons 54%, photons 46%) was utilized early within the CNS disease course (median 0 CNS relapses prior to CSI). Twenty-five patients (64%) received CSI immediately prior to a stem-cell transplant (SCT), of which 21 (84%) had TBI conditioning to a median dose of 12 Gy (range 2-13.2). Patients treated with CSI alone received a higher CSI dose (median 18 Gy; range 10.8-24) than those treated with SCT consolidation (median 12 Gy; range 10.8-24). Fifteen patients had CSF-positive disease immediately prior to CSI; all 14 of those assessed for response (RR 100%) had confirmed clearance of blasts at a median of 23 days (range 7-197) from CSI start. With a median follow-up of 48 months (range 0.4-123) for survivors, 2-year PFS and OS estimates were 32% and 43%, respectively. Only 5 CNS relapses were noted (2-year CNS LR of 14%). All CNS relapses either occurred after (n = 4) or concurrently (n = 1) with a systemic relapse. In Cox regression univariate models, age, sex, time to CNS disease, positive CSF immediately prior to CSI, and SCT did not show demonstrable evidence of association with CNS LR. However, systemic relapse after CSI (HR 5.9, 95% CI 2.5-13.8, P<0.0001) and systemic disease at the time of CSI (HR 3.9, 95% CI 1.6-9.5, P = 0.003) were associated with higher risk of CNS LR. No grade-3+ acute toxicity was seen during CSI.

CONCLUSION

CSI is a well-tolerated and effective treatment option for patients with CNS leukemia. Though CNS local recurrence was modest, there was a high risk of systemic relapse and/or death. Control of systemic disease, both before and after CSI, may be important for CNS local control, and raises consideration that CNS recurrence may reflect reseeding from the systemic space.

A prospective study of the impact of COVID-19-related restrictions on activities and mobility upon physical activity, travel behaviour and attitudes

Background and aims

Public health measures adopted to contain the spread of COVID-19 included restrictions on activities and mobility as people were asked to stay at home and schools moved to online learning. This may have increased risk of non-communicable disease by limiting recreational and transport-related physical activity. Building on an existing study, we assessed changes in self-reported and device-measured physical activity and travel behaviour before, during and after the peak of local COVID-19 outbreak and restrictions (March-July 2020). We examined beliefs in effectiveness of strategies to increase active and public transport after restrictions were reduced.

Methods

A longitudinal study of adult infrequent bus users (average ≤ 2 trips per week; n = 70; 67% women) in Hobart, Australia. One-week assessment periods at four separate timepoints (before, during, 0-3 months after, and 3-6 months after the peak restrictions period) involved wearing an accelerometer, daily transport diaries, online surveys and tracking bus smartcard boardings.

Results

Physical activity (especially among older participants), bus use and private motor vehicle use declined significantly during or 0-3 months after the peak restrictions period and returned to pre-restrictions levels by 3-6 months after the peak restrictions period, except bus use which remained significantly lower. Retrospective surveys overstated declines in bus use and active transport and self-reports understated declines in physical activity. Social distancing and improving service efficiency and frequency were seen as effective strategies for increasing bus use after restrictions but belief in effectiveness of distancing decreased over time.

Conclusions

When restrictions on mobility are increased, supportive health promotion measures are needed to prevent declines in physical activity, particularly for older adults. Public transport systems need capacity to implement temporary distancing measures to prevent communicable disease transmission. Providing convenient, flexible, and efficient options for public transport may help to replenish public transport use after restrictions are reduced.

The Management and Supervision Tool (MaST): an electronic crisis risk prediction tool to support safe and effective mental healthcare

Introduction

The increasing global burden of mental disorders has led to rising demand for mental healthcare services. Effective resource management is essential to ensure safe and timely access to care. Electronic health records (EHRs) provide a real-time source of data on clinical presentation and prognostic factors that could be harnessed to provide clinicians with actionable insights to prioritise mental healthcare delivery. We describe the development and evaluation of MaST, an EHR data visualisation tool that provides information to clinicians on risk of mental health crisis defined as an admission to a psychiatric hospital or acceptance into a community crisis service.

Objectives

(i) To develop an EHR-data driven risk prediction tool for risk of crisis. (ii) To evaluate predictive performance in a real-world clinical setting.

Methods

The risk of crisis algorithm was developed and evaluated with EHR data from six UK NHS mental health providers using Ordered Predictor List propensity scores grouped into 5 quintiles. The predictor variables were clinical and sociodemographic factors including previous mental health service contacts.

Results

Data from 2,620 patients contributed to algorithm development which was subsequently tested on data from 107,879 patients. The risk of crisis algorithm performed well with an overall accuracy for predicting the greatest risk of crisis (top quintile) ranging from 64% to 80%.

Conclusions

The MaST algorithm accurately predicted risk of mental health crisis in UK community mental health services. EHR data visualisation tools can provide actionable insights to clinicians to prioritise mental healthcare delivery in real-world clinical practice.

Disclosure

This study was funded in full by Holmusk.

Is greater public transport use associated with higher levels of physical activity in a regional setting? Findings from a pilot study

BACKGROUND

Public transport users often accumulate more physical activity than motor vehicle users, but most studies have been conducted in large metropolitan areas with multiple public transport options with limited knowledge of the relationship in regional and rural areas. In a regional city, this pilot study aimed to (1) test the feasibility of preliminary hypotheses to inform future research, (2) test the utility of survey items, and (3) establish stakeholder engagement.

METHODS

Data were collected via a cross-sectional online survey of 743 Tasmanian adults. Physical activity outcomes were walking (min/week), total moderate- to vigorous-intensity physical activity (min/week) and attainment of physical activity guidelines (yes/no). Transport variables were frequency of public and private transport use per week. Truncated and log binomial regression examined associations between public/private transport use and physical activity.

RESULTS

Neither frequency of public nor private transport use was associated with minutes of walking (public transport: B - 24.4, 95% CI: - 110.7, 61.9; private transport: B - 1.1, 95% CI: - 72.4, 70.1), minutes of total physical activity (public transport: B - 90.8, 95% CI: - 310.0, 128.5; private transport: B 0.4, 95% CI: - 134.0, 134.9) or not meeting physical activity guidelines (public transport: RR 1.02, 95%CI: 0.95, 1.09; private transport: RR 1.02, 95%CI: 0.96, 1.08).

CONCLUSIONS

The hypothesis that public transport users would be more physically active than private transport users was not supported in this pilot study. Stakeholders were engaged and involved in various phases of the research including development of research questions, participant recruitment, and interpretation of findings. Further studies using representative samples and refined measures are warranted to confirm or refute findings.

trips4health: Protocol of a single-blinded randomised controlled trial incentivising adults to use public transport for physical activity gain

Background

Public transport (PT) users typically accumulate more physical activity (PA) than private motor vehicle users yet redressing physical inactivity through transport-related PA (TRPA) interventions has received limited attention. Further, incentive-based strategies can increase leisure-time PA but their impact on TRPA, is unclear. This study's objective is to determine the impact of an incentive-based strategy on TRPA in a regional Australian setting.

Methods

trips4health is a single-blinded randomised controlled trial with a four-month intervention phase and subsequent six-month maintenance phase. Participants will be randomised to: an incentives-based intervention (bus trip credit for reaching bus trip targets, weekly text messages to support greater bus use, written PA guidelines); or an active control (written PA guidelines only). Three hundred and fifty adults (≥18 years) from southern Tasmania will be recruited through convenience methods, provide informed consent and baseline information, then be randomised. The primary outcome is change in accelerometer measured average daily step count at baseline and four- and ten-months later. Secondary outcomes are changes in: measured and self-reported travel behaviour (e.g. PT use), PA, sedentary behaviour; self-reported and measured (blood pressure, waist circumference, height, weight) health; travel behaviour perspectives (e.g. enablers/barriers); quality of life; and transport-related costs. Linear mixed model regression will determine group differences. Participant and PT provider level process evaluations will be conducted and intervention costs to the provider determined.

Discussion

trips4health will determine the effectiveness of an incentive-based strategy to increase TRPA by targeting PT use. The findings will enable evidence-informed decisions about the worthwhileness of such strategies.

Trial registration

ACTRN12619001136190.

Universal trial number

U1111-1233-8050.

Hydrogel-Based Engineering of Beige Adipose Tissue

Brown and beige adipose tissues have a significant capacity for energy expenditure that may be exploited as a treatment for obesity and metabolic disease. However, the limited volumes of these tissues in adults hinders realization of this potential. Engineering beige adipose tissue may provide an alternative source of this tissue. In this paper we describe the preparation of poly(ethylene glycol) (PEGDA) hydrogels with mechanical properties similar to native adipose tissue. Adipose derived stem cells (ASC) were cultured in hydrogels without adhesive sequences or degradable monomers. Cells were able to differentiate, independent of scaffold properties and were maintained as a viable and functioning adipose tissue mass. The cells expressed their own basement membrane proteins consistent with the composition of adipose tissue. The ASCs could be induced to express uncoupling protein-1 (UCP-1) and cIDEA, makers of beige adipocytes with expression level varying with hydrogel stiffness. This hydrogel-based culture system serves as a first step in engineering beige adipose tissue.

Low expression of D2R and Wntless correlates with high motivation for heroin

Drug overdose now exceeds car accidents as the leading cause of accidental death in the United States. Of those drug overdoses, a large percentage of the deaths are due to heroin and/or pharmaceutical overdose, specifically misuse of prescription opioid analgesics. It is imperative, then, that we understand the mechanisms that lead to opioid abuse and addiction. The rewarding actions of opioids are mediated largely by the mu-opioid receptor (MOR), and signaling by this receptor is modulated by various interacting proteins. The neurotransmitter dopamine also contributes to opioid reward, and opioid addiction has been linked to reduced expression of dopamine D2 receptors (D2R) in the brain. That said, it is not known if alterations in the expression of these proteins relate to drug exposure and/or to the "addiction-like" behavior exhibited for the drug. Here, we held total drug self-administration constant across acquisition and showed that reduced expression of the D2R and the MOR interacting protein, Wntless, in the medial prefrontal cortex was associated with greater addiction-like behavior for heroin in general and with a greater willingness to work for the drug in particular. In contrast, reduced expression of the D2R in the nucleus accumbens and hippocampus was correlated with greater seeking during signaled nonavailability of the drug. Taken together, these data link reduced expression of both the D2R and Wntless to the explicit motivation for the drug rather than to differences in total drug intake per se.

Consensus guidelines from The American Society of Peritoneal Surface Malignancies on standardizing the delivery of hyperthermic intraperitoneal chemotherapy (HIPEC) in colorectal cancer patients in the United States

BACKGROUND

The American Society of Peritoneal Surface Malignancies (ASPSM) is a consortium of cancer centers performing cytoreductive surgery with hyperthermic intraperitoneal chemotherapy (HIPEC). This is a position paper from the ASPSM on the standardization of the delivery of HIPEC.

METHODS

A survey was conducted of all cancer centers performing HIPEC in the United States. We attempted to obtain consensus by the modified method of Delphi on seven key HIPEC parameters: (1) method, (2) inflow temperature, (3) perfusate volume, (4) drug, (5) dosage, (6) timing of drug delivery, and (7) total perfusion time. Statistical analysis was performed using nonparametric tests.

RESULTS

Response rates for ASPSM members (n = 45) and non-ASPSM members (n = 24) were 89 and 33 %, respectively. Of the responders from ASPSM members, 95 % agreed with implementing the proposal. Majority of the surgical oncologists favored the closed method of delivery with a standardized dual dose of mitomycin for a 90-min chemoperfusion for patients undergoing cytoreductive surgery for peritoneal carcinomatosis of colorectal origin.

CONCLUSIONS

This recommendation on a standardized delivery of HIPEC in patients with colorectal cancer represents an important first step in enhancing research in this field. Studies directed at maximizing the efficacy of each of the seven key elements will need to follow.

Label-free integrative pharmacology on-target of opioid ligands at the opioid receptor family

Background

In vitro pharmacology of ligands is typically assessed using a variety of molecular assays based on predetermined molecular events in living cells. Many ligands including opioid ligands pose the ability to bind more than one receptor, and can also provide distinct operational bias to activate a specific receptor. Generating an integrative overview of the binding and functional selectivity of ligands for a receptor family is a critical but difficult step in drug discovery and development. Here we applied a newly developed label-free integrative pharmacology on-target (iPOT) approach to systematically survey the selectivity of a library of fifty-five opioid ligands against the opioid receptor family. All ligands were interrogated using dynamic mass redistribution (DMR) assays in both recombinant and native cell lines that express specific opioid receptor(s). The cells were modified with a set of probe molecules to manifest the binding and functional selectivity of ligands. DMR profiles were collected and translated to numerical coordinates that was subject to similarity analysis. A specific set of opioid ligands were then selected for quantitative pharmacology determination.

Results

Results showed that among fifty-five opioid ligands examined most ligands displayed agonist activity in at least one opioid receptor expressing cell line under different conditions. Further, many ligands exhibited pathway biased agonism.

Conclusion

We demonstrate that the iPOT effectively sorts the ligands into distinct clusters based on their binding and functional selectivity at the opioid receptor family.

Ligand-directed functional selectivity at the mu opioid receptor revealed by label-free integrative pharmacology on-target

Development of new opioid drugs that provide analgesia without producing dependence is important for pain treatment. Opioid agonist drugs exert their analgesia effects primarily by acting at the mu opioid receptor (MOR) sites. High-resolution differentiation of opioid ligands is crucial for the development of new lead drug candidates with better tolerance profiles. Here, we use a label-free integrative pharmacology on-target (iPOT) approach to characterize the functional selectivity of a library of known opioid ligands for the MOR. This approach is based on the ability to detect dynamic mass redistribution (DMR) arising from the activation of the MOR in living cells. DMR assays were performed in HEK-MOR cells with and without preconditioning with probe molecules using label-free resonant waveguide grating biosensors, wherein the probe molecules were used to modify the activity of specific signaling proteins downstream the MOR. DMR signals obtained were then translated into high resolution heat maps using similarity analysis based on a numerical matrix of DMR parameters. Our data indicate that the iPOT approach clearly differentiates functional selectivity for distinct MOR signaling pathways among different opioid ligands, thus opening new avenues to discover and quantify the functional selectivity of currently used and novel opioid receptor drugs.

Phase I study of dasatinib in combination with capecitabine, oxaliplatin, and bevacizumab followed by an expanded cohort in previously untreated metastatic colorectal cancer

513

Background: SRC is a non-receptor tyrosine kinase involved in normal and tumor cell signaling functions including cell proliferation, angiogenesis and survival. Dasatinib (D) is a potent inhibitor of SRC kinase activity. Preclinical data suggests the addition of D to standard chemotherapy agents for colon cancer may increase anti-tumor activity. We evaluated D in combination with capecitabine (C), oxaliplatin (O) and bevacizumab (B) in a phase I dose escalation study followed by an expanded cohort in 1st line colorectal.

Methods: For dose escalation, eligible patients had advanced solid tumors with adequate organ and bone marrow function and no increased risk for class-related toxicities. B and O were given intravenously, and C and D were orally administered; cycle length was 21 days. C was dosed at 850 mg/m2 on days 1-14; O was dosed at 130 mg/m2 and B was dosed at 7.5 mg/kg on day one of each cycle. D was dosed at 50 mg twice daily in cohort one and 70 mg once daily in cohort -1. Dose limiting toxicity (DLT) was assessed in cycle 1.

Results: Dose escalation is complete with 10 subjects evaluable for toxicity and 11 subjects evaluable for efficacy. Two DLTs were observed out of 5 evaluable subjects in cohort one. Six evaluable subjects were enrolled in the -1 cohort with 1 DLT. Possible grade ≥ 3 treatment-related adverse events (AEs) included neutropenia, febrile neutropenia, anorexia, diarrhea, fatigue, anemia, hypophosphatemia, hyponatremia and grade 5 GI-perforation. One non-treatment related death was due to disease progression. D-related nausea and fatigue were responsive to low dose oral steroids; fluid retention was responsive to diuretics. Of 10 subjects evaluable for efficacy, 1 subject had a partial response (PR), 2 had a minor response (MR), and 4 had stable disease (SD). Four subjects had disease control (PR, MR, or SD) ≥ 6 months.

Conclusions: D in combination with C, O and B is well-tolerated with a toxicity profile similar to standard C, O and B.The recommended phase II dose is C at 850 mg/m2 on days 1-14, O at 130 mg/m2 and B at 7.5 mg/kg on day one of each cycle, and D at 70 mg once daily. Enrollment in the expanded cohort of 1st line colorectal is ongoing.

[Table: see text]

Development of an assay to predict oxaliplatin sensitivity from formalin-fixed, paraffin-embedded (FFPE) colorectal cancer tissues

429

Background: Genomic profiling has improved our understanding of the underlying biology of tumors, accuracy of diagnosing disease, predictions of the courses of disease, and ability to determine the therapeutic agents that will be most effective in the treatment of particular tumors. However, in order for assays involving microarray data to be useful in the clinical setting, the ability to generate reliable and consistent data from FFPE tissues is essential.

Methods: Cancer cell lines from the NCI-60 collection exhibiting greatest sensitivity or resistance to oxaliplatin were identified. These cells were grown in culture, fixed for 24 hours in formalin, and paraffin-embedded. RNA from the FFPE cells was isolated, amplified, and hybridized to Affymetrix arrays. A Bayesian binary regression analysis was used to generate a predictor of oxaliplatin sensitivity from the gene expression data. Metastatic derived xenografts (MDXs) from resected colorectal tumors were established and treated with oxaliplatin. Samples from tumors prior to treatment were paraffin-embedded and used for RNA extraction, amplification, and hybridization to Affymetrix arrays. The gene expression signature predicting sensitivity to oxaliplatin was then validated with response data from MDXs treated with oxaliplatin.

Results: A predictor consisting of 300 genes that could predict sensitivity to oxaliplatin was generated using FFPE samples. Significant correlation was observed between the predicted probability of oxaliplatin sensitivity and the tumor growth inhibition measurement for a given MDX (p=0.0012).

Conclusions: Reliable and consistent predictions of oxaliplatin sensitivity can be obtained from gene expression data from FFPE tissues. This method has potential utility in the clinical setting. The ability to predict response to a therapeutic in a FFPE sample has the potential to guide the choice of therapeutics, resulting in an option that could be most effective in treating an individual with metastatic colorectal cancer.

No significant financial relationships to disclose.

Expression of GPR177 (Wntless/Evi/Sprinter), a highly conserved Wnt-transport protein, in rat tissues, zebrafish embryos, and cultured human cells

GPR177 is an evolutionarily conserved transmembrane protein necessary for Wnt protein secretion. Little is currently known, however, regarding expression of GPR177, especially in vertebrate species. We have developed an antiserum against GPR177, and used it to examine expression of GPR177 in human tissue culture cells, adult mouse, and rat tissues, as well as developing zebrafish embryos. In rodents, GPR177 is expressed in virtually all tissue types and brain regions examined. In zebrafish, GPR177 polypeptides are expressed throughout embryogenesis, and are detectable as early as 1 hr post-fertilization. In situ hybridization analysis reveals that gpr177 mRNA expression is prominent in embryonic zebrafish brain and ear. Structural studies suggest that GPR177 is modified by N-linked sugars, and that the protein contains an even number of transmembrane segments. The relatively ubiquitous expression of GPR177 suggests that this protein may serve to regulate Wnt secretion in a variety of embryonic and adult tissue types.

Review. Colon cancer vaccines: an update

Despite advances in research and treatment modalities, colorectal cancer still accounts for around half a million deaths yearly worldwide. Traditional and even newer pharmaceutical therapeutic regimens are limited in terms of tolerance, efficacy and cross-resistance. Additional non-cross resistant therapies with non-overlapping toxicities are needed to improve the outcome for patients with colorectal cancer. Cancer vaccines, designed to activate immune effectors (T-cells and antibodies) to prevent recurrence or treat advanced cancers, have now demonstrated clinical benefit in prostate cancer and lymphoma. Because immune effector infiltration into colon tumours is associated with improved clinical outcome, vaccines intended to activate immune responses against colon cancer have generated significant interest. This review discusses data supportive of the immune responsiveness of colorectal cancer, as well as the current status of colon cancer vaccines under development including those based on whole tumour cells or lysates, peptide or protein antigens, anti-idiotype antibodies, viral vectors, and dendritic cells. We also discuss challenges to colon cancer vaccine development, such as tumour associated mechanisms for immune evasion, and how future strategies may address these challenges.

Subordinate quadratic forms and their complementary forms

Theorem 1. For alpha, beta on the range 1,..., mu, let Q(z) = (*)aalphabetazalphazbeta be a real valued, nonsingular, symmetric quadratic form. For positive integers r and s such that mu = r + s set (z(1),..., z(mu)) = (u(1),..., u(r):S(1),..., S(n)), Q(z) = P(u, s) and [Formula: see text] Let B = (z((1)),..., z((r))) be a base "over R" for points z epsilon pi(r). For an arbitrary r-tuple omega(1),..., omega(r) set [Formula: see text] index H(B)(omega) = kappa and nullity H(B)(omega) = nu. Then [Formula: see text].

Phase I clinical results of an APC-targeted hCGβ vaccine (CDX-1307) with TLR agonists

3006

Background: Effective immunization requires efficient antigen delivery to antigen presenting cells (APCs). Antigens attached to the human antibody B11, targeting mannose receptors on APCs, have been shown to be processed and presented efficiently, and generate robust immune responses when combined with toll-like receptor (TLR) agonists. The CDX-1307 vaccine is composed of B11 fused with hCGβ, a tumor antigen correlated with advanced stage of disease and poor prognosis in a number of common epithelial cancers, but reported at variable rates of expression. Methods: Two phase I studies investigate intradermal (id) vs. systemic (iv) administration of CDX-1307. Patients with advanced epithelial cancers known to frequently express hCGβ receive 4 biweekly vaccinations of CDX-1307, alone or in combination with immunostimulants including GM-CSF (GM), the TLR3 agonist Poly-ICLC, and the TLR7/8 agonist resiquimod. Results: Dose-escalation is complete. In the id study, 37 patients received CDX-1307 at doses of 0.3, 1.0, and 2.5 mg, then 2.5 mg + GM, 2.5 mg + GM + Poly-ICLC, and 2.5 mg + GM + resiquimod. 2.5 mg + GM + Poly-ICLC + resiquimod is planned. In the iv study, 24 patients were treated at 1, 3, 10, and 30 mg, as well as 10 mg + GM and 30 mg + GM. 30 mg + GM + Poly-ICLC is enrolling. Treatment-related toxicities were generally mild to moderate with no dose-limiting toxicities, most frequently injection site reactions and fatigue in the id study, and fatigue, myalgia, and flu-like illness in the iv study. Humoral responses to hCGβ were increased in 56% of the analyzed patients receiving adjuvants. Serum hCGβ was frequently elevated at study entry or during treatment (males = 88%, females = 53%, pancreatic = 89%, colorectal = 78%, breast = 47%). hCGβ decreases were seen in some patients with immune responses. To date, a significant mixed response was seen in one patient with pancreatic cancer (id), while stable disease has been seen in 4 patients (2 with breast cancer = 25, 27 weeks and 2 with colorectal cancer = 9+ weeks). Conclusions: CDX-1307 is well tolerated and results in immune responses that are enhanced by immunostimulants. Elevated hCGβ was detected at a higher than expected frequency in these tumors.

[Table: see text]

A phase I study of gemcitabine plus dasatinib (GD) or gemcitabine plus dasatinib plus cetuximab (GDC) in refractory solid tumors

e15506

Background: Dasatinib (D) is a small molecule tyrosine kinase inhibitor with activity against both bcr-abl and src. Cetuximab (C) is a monoclonal antibody that blocks EGFR. Preclinical models suggest D reverses resistance to G. In addition, src and EGFR pathways interact; synergism of dual blockade by D + C is possible. We evaluated two combination regimens, GD and GDC, in a Phase I dose escalation study. Methods: Patients (pts) with advanced solid tumors were enrolled in cohorts of 3–6 to either GD or GDC. G was dosed in mg/m2 weekly for 3 of 4 weeks, D was dosed in mg PO BID, and C was dosed at 250 mg/m2 weekly after loading dose of C=400; cycle length was 28 days. Dose levels were as follows: 1) G 1000 + D 50 ± C; 2) G 1,000 + D 70 ± C; 3) G 1,000 + D 100 ± C. Standard cycle 1 DLT definitions were used. Eligible pts had advanced solid tumors, adequate organ and marrow function, and no co-morbidities that would increase risk of toxicity. Serum, plasma, and skin biopsy biomarkers were obtained pre- and on treatment. Results: 25 pts have been enrolled, including 21 with pancreatic adenocarcinoma, 3 of whom had received prior G. 21 pts were evaluable for toxicity and 18 for efficacy. Four DLT were observed: Gr 3 ANC with infection (GDC1, n=1), Gr 3 ALT (GD2, n=2), and Gr 5 pneumonitis (GDC2, n=1). Possible treatment-related adverse events in later cycles included: Gr3–4 ANC (n=4), Gr4 colitis (n=1), Gr3 bilirubin (n=2), Gr3 Hgb (n=2), Gr3 Plt (n=2), Gr3 edema/fluid retention syndrome (n=1), and Gr3 vomiting (n=2). One previously untreated pt had a partial response. Eight of 18 pts, 3 of whom had received prior G, had stable disease as best response, median duration = 5 months (range 1–7). Biomarker results are pending. Conclusions: The MTD of the GD arm is G1000/D50BID. Stable disease in previous G-refractory pts was noted. Hematologic toxicities were dose-limiting; later toxicities including hematologic, LFT changes, pneumonitis, and fluid retention were seen. To address these toxicities, once daily dosing of D will be explored, followed by an expanded cohort of G + daily D vs G + bid D in pts with treatment-naïve pancreatic cancer.

[Table: see text]

Radioiodinated metaiodobenzylguanidine in the diagnosis and therapy of carcinoid tumors

Carcinoid tumors account for less than 1% of all malignancies and the majority arises in the gastrointestinal system. These tumors are slow-growing compared with adenocarcinomas and they differ from the other neuroendocrine malignancies by their protean clinical presentation. Carcinoid tumors were previously considered indolent, but they can manifest malignant characteristics with metastatic spread which often results in a poor prognosis. Although there have been advances in diagnostic and treatment modalities, carcinoid tumors are still frequently diagnosed late, often when the tumor has metastasized and patients have developed carcinoid syndrome. Diagnosis, prognosis and treatment options are based on biochemical markers and imaging investigations. High concentration of urinary 5-HIAA, elevated plasma serotonin and chromogranin A levels help to establish the initial diagnosis of carcinoid tumors. In addition to the computed tomography and magnetic resonance imaging, molecular imaging modalities such as OctreoScan, metaiodobenzylguanidine (MIBG) imaging and more recently PET imaging are used in detecting the primary malignancy and metastatic involvement. Surgery is the mainstay of treatment of non-metastatic carcinoid tumors. Cytotoxic chemotherapy has limited role because of the chemoresistant nature of these tumors. Because carcinoid tumors express somatostatin receptors, somatostatin analogues, which inhibit release of serotonin and other neuroendocrine peptides, are often used, but their use is limited to symptom control. Treatment using high doses of radionuclides, such as radiolabeled somatostatin analogues and MIBG, is a more recent option, which offers a definite advantage in management. In this article, we review the current state of the art in the diagnosis and treatment of carcinoid tumors as well as the role of MIBG in their diagnosis and management.

Induced sputum improves the diagnosis of pulmonary tuberculosis in hospitalized patients in Gaborone, Botswana

SETTING

Low sensitivity of acid-fast bacilli (AFB) sputum smears and absence of productive cough are obstacles to the diagnosis of pulmonary tuberculosis (PTB) in hospitals that lack access to bronchoscopy.

OBJECTIVES

To evaluate induced sputum, gastric content, blood and urine specimens to improve PTB diagnosis in patients not diagnosed by expectorated sputum AFB smears.

DESIGN

Patients admitted to the medical wards of a large public hospital in Gaborone, Botswana, were prospectively enrolled if they had symptoms consistent with PTB, an abnormal chest radiograph, were treated empirically with anti-tuberculosis chemotherapy or had no improvement on antibiotics, and had a non-productive cough or AFB smear-negative sputum. Induced sputum was stained for AFB and Mycobacterium tuberculosis cultures were performed on induced sputum, gastric contents, urine and blood.

RESULTS

Of 140 patients meeting the enrollment criteria, 113 (81%) were human immunodeficiency virus (HIV) positive. Fifty-seven (41%) had PTB based on positive cultures from one or more sites, including 48 (84%) from induced sputum, 17 (30%) urine, 13 (23%) gastric contents and 7 (12%) blood. AFB smears were positive in only 18 (32%) culture-proven PTB cases.

CONCLUSION

Induced sputum cultures greatly enhanced M. tuberculosis detection in patients with a high prevalence of HIV/AIDS in a hospital without access to bronchoscopy.

Epitaxially-grown Ge/Si avalanche photodiodes for 1.3 microm light detection

We designed and fabricated Ge/Si avalanche photodiodes grown on silicon substrates. The mesa-type photodiodes exhibit a responsivity at 1310 nm of 0.54 A/W, a breakdown voltage thermal coefficient of 0.05%/ degrees C, a 3 dB-bandwidth of 10 GHz. The gain-bandwidth product was measured as 153 GHz. The effective k value extracted from the excess noise factor was 0.1.