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Exact and asymptotic inference in clinical trials with small event rates under inverse sampling.

In this paper, we discuss statistical inference for a 2 × 2 table under inverse sampling, where the total number of cases is fixed by design. We demonstrate that the exact unconditional distributions of some relevant statistics differ from the distributions under conventional sampling, where the sample size is fixed by design. This permits us to define a simple unconditional alternative to Fisher’s exact test. We provide an asymptotic argument including simulations to demonstrate that there is little power loss associated with the alternative test when the expected event rates are very small. We then apply the method to design a clinical trial in cataract surgery, where a rare side effect occurs in one in 1000 patients. The objective of the trial is to demonstrate that adjuvant treatment with an antibiotic will reduce this risk to one in 2000. We use an inverse sampling design and demonstrate how to set this up in a sequential manner. Particularly simple stopping rules can be defined when using the unconditional alternative to Fisher’s exact test.
Copyright © 2015 John Wiley &amp; Sons, Ltd.

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Dual inhibition of Ang-2 and VEGF receptors normalizes tumor vasculature and prolongs survival in glioblastoma by altering macrophages.

Glioblastomas (GBMs) rapidly become refractory to anti-VEGF therapies. We previously demonstrated that ectopic overexpression of angiopoietin-2 (Ang-2) compromises the benefits of anti-VEGF receptor (VEGFR) treatment in murine GBM models and that circulating Ang-2 levels in GBM patients rebound after an initial decrease following cediranib (a pan-VEGFR tyrosine kinase inhibitor) administration. Here we tested whether dual inhibition of VEGFR/Ang-2 could improve survival in two orthotopic models of GBM, Gl261 and U87. Dual therapy using cediranib and MEDI3617 (an anti-Ang-2-neutralizing antibody) improved survival over each therapy alone by delaying Gl261 growth and increasing U87 necrosis, effectively reducing viable tumor burden. Consistent with their vascular-modulating function, the dual therapies enhanced morphological normalization of vessels. Dual therapy also led to changes in tumor-associated macrophages (TAMs). Inhibition of TAM recruitment using an anti-colony-stimulating factor-1 antibody compromised the survival benefit of dual therapy. Thus, dual inhibition of VEGFR/Ang-2 prolongs survival in preclinical GBM models by reducing tumor burden, improving normalization, and altering TAMs. This approach may represent a potential therapeutic strategy to overcome the limitations of anti-VEGFR monotherapy in GBM patients by integrating the complementary effects of anti-Ang2 treatment on vessels and immune cells.

Patient-Reported Symptom Experiences in Patients With Carcinoid Syndrome After Participation in a Study of Telotristat Etiprate: A Qualitative Interview Approach.

Telotristat etiprate, a tryptophan hydroxylase inhibitor, was previously evaluated in a Phase II randomized, placebo-controlled clinical trial in patients with carcinoid syndrome (CS) and diarrhea not adequately controlled by octreotide. The objective of the current study was to characterize the symptom experiences of patients participating in that trial.
Consenting patients participated in one-on-one, qualitative interviews focused on eliciting symptoms they had experienced in association with their CS diagnosis and recollection of symptom changes they experienced while participating in the Phase II trial.
Among the 23 patients who participated in the previous 4-week dose-escalation study, 16 were eligible for interviews and 11 participated in the present study. The median time from study completion to the interview was 31 months; 4 of 11 patients were receiving telotristat etiprate in a follow-up, open-label trial at the time of interview. All of the patients (100%) described diarrhea as a symptom of CS, with effects on the emotional, social, and physical aspects of their lives. Improvement in diarrhea during the study was described by 82% of participants, and was very impactful in several patients. Results led to the design and implementation of a larger interview program in Phase III and helped to establish a definition of clinically meaningful change for the clinical development program.
The diarrhea associated with CS can have a large impact on daily lives, and patient interviews can characterize and capture clinically meaningful improvements with treatment. ClinicalTrials.gov Identifier: NCT00853047.
Copyright © 2016 The Authors. Published by Elsevier Inc. All rights reserved.

Repression of GSK3 restores NK cell cytotoxicity in AML patients.

Natural killer cells from acute myeloid leukaemia patients (AML-NK) show a dramatic impairment in cytotoxic activity. The exact reasons for this dysfunction are not fully understood. Here we show that the glycogen synthase kinase beta (GSK3β) expression is elevated in AML-NK cells. Interestingly, GSK3 overexpression in normal NK cells impairs their ability to kill AML cells, while genetic or pharmacological GSK3 inactivation enhances their cytotoxic activity. Mechanistic studies reveal that the increased cytotoxic activity correlates with an increase in AML-NK cell conjugates. GSK3 inhibition promotes the conjugate formation by upregulating LFA expression on NK cells and by inducing ICAM-1 expression on AML cells. The latter is mediated by increased NF-κB activation in response to TNF-α production by NK cells. Finally, GSK3-inhibited NK cells show significant efficacy in human AML mouse models. Overall, our work provides mechanistic insights into the AML-NK dysfunction and a potential NK cell therapy strategy.

ER2, a novel human anti-EGFR monoclonal antibody inhibit tumor activity in non-small cell lung cancer models.

The epidermal growth factor receptor (EGFR) abnormalities including amplification, mutation, and overexpression are frequent in non-small cell lung cancer (NSCLC). We investigated in vitro and in vivo antitumor activity of ER2, a novel human anti-EGFR monoclonal antibody, in NSCLC.
A panel of NSCLC cell lines (A549, H460, H322, H358, H1299, HCC827, PC9, H1975, and PC9-GR) was used to evaluate in vitro antitumor activity of ER2 and cetuximab. The inhibitory effects of ER2 and cetuximab on downstream signaling were assessed by western blot. Secreted VEGF was measured by Human VEGF Quantikine ELISA kit. Antitumor effects of ER2 and cetuximab as single agents and in combination with cisplatin were evaluated in H322, HCC827 and A549 xenograft models.
ER2 efficiently inhibits EGFR and its downstream signaling molecules including Akt and Erk1/2 in NSCLC cell lines with wild-type or mutant EGFR. ER2 inhibited cell viability of H322, HCC827 and A549 cells in a dose-dependent manner by inducing cell cycle arrest and apoptosis. Also, ER2 suppressed EGF-stimulated VEGF production as efficiently as cetuximab in H322, HCC827 and A549 cells. Moreover, ER2 alone and in combination with cisplatin showed a significant anti-tumor efficacy in xenograft mouse models.
Taken together, ER2 has significant anti-tumor activity in in vitro and in vivo NSCLC models, suggesting a rationale for clinical development of ER2 in NSCLC.
Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.