Transcriptional and phenotypic heterogeneity underpinning venetoclax resistance in AML

The venetoclax BCL2 inhibitor in combination with hypomethylating agents represents a cornerstone of induction therapy for older AML patients, unfit for intensive chemotherapy. Like other targeted therapies, venetoclax-based therapies suffer from innate and acquired resistance. While several mechanisms of resistance have been identified, the heterogeneity of resistance mechanism across patient populations is poorly understood. Here we utilized integrative analysis of transcriptomic and ex-vivo drug response data in AML patients to identify four transcriptionally distinct VEN resistant clusters (VR_C1-4), with distinct phenotypic, genetic and drug response patterns. VR_C1 was characterized by enrichment for differentiated monocytic- and cDC-like blasts, transcriptional activation of PI3K-AKT-mTOR signaling axis, and energy metabolism pathways. They showed sensitivity to mTOR and CDK inhibition. VR_C2 was enriched for NRAS mutations and associated with distinctive transcriptional suppression of HOX expression. VR_C3 was characterized by enrichment for TP53 mutations and higher infiltration by cytotoxic T cells. This cluster showed transcriptional expression of erythroid markers, suggesting tumor cells mimicking erythroid differentiation, activation of JAK-STAT signaling, and sensitivity to JAK inhibition, which in a subset of cases synergized with venetoclax. VR_C4 shared transcriptional similarities with venetoclax-sensitive patients, with modest over-expression of interferon signaling. They were also characterized by high rates of DNMT3A mutations. Finally, we projected venetoclax-resistance states onto single cells profiled from a patient who relapsed under venetoclax therapy capturing multiple resistance states in the tumor and shifts in their abundance under venetoclax selection, suggesting that single tumors may consist of cells mimicking multiple VR_Cs contributing to intra-tumor heterogeneity. Taken together, our results provide a strategy to evaluate inter- and intra-tumor heterogeneity of venetoclax resistance mechanisms and provide insights into approaches to navigate further management of patients who failed therapy with BCL2 inhibitors.

Timing of drotrecogin alfa (activated) initiation in treatment of severe sepsis: a database cohort study of hospital mortality, length of stay, and costs

INTRODUCTION

For patients with critical conditions including severe sepsis, minimizing the time from presentation to treatment is important to improving outcomes. Understanding the factors influencing high hospital mortality and resource utilization in severe sepsis continues to interest clinicians and researchers. This study examined the associations between timing of drotrecogin alfa (activated) (DrotAA) initiation and hospital mortality, length-of-stay, and costs.

METHODS

We conducted a cohort study of adult patients (N = 1179) with intensive care unit stays from November 2001 to June 2003 who received DrotAA in US hospitals with data in the Solucient ACTracker database. We defined evident severe sepsis (ESS) as concurrent antibiotic plus ventilator and/or vasopressor use. We characterized the interval between ESS and DrotAA initiation as Same-day, Next-day, or Day 2+. We compared group characteristics and created multivariate models of hospital mortality, length-of-stay, and costs.

RESULTS

Forty-three percent of patients received Same-day DrotAA, 30% Next-day, and 27% Day 2+. Same-day and Next-day patients had more organ dysfunctions at ICU admission than Day 2+ patients (1.1 +/- 0.9 and 1.2 +/- 0.8 vs. 1.0 +/- 0.8; p = 0.021 and p < 0.001, respectively), but from ESS to DrotAA initiation, organ dysfunctions for Day 2+ patients had increased more (+0.0 and +0.4 vs. +0.6, respectively; all p < 0.0001). Increased mortality was observed with administration later than Same-day, although only for the Day 2+ group did the association remain significant (p < 0.05) after adjusting for clinical and demographic factors. Only Next-day initiation was associated with significantly decreased costs (p = 0.0145).

CONCLUSIONS

Timing of DrotAA initiation is associated with clinical and economic outcomes in severe sepsis. The potential impact of this timing on hospital mortality, length-of-stay, and costs deserves further study.

Combined supercritical fluid extraction/solid-phase extraction with octadecylsilane cartridges as a sample preparation technique for the ultratrace analysis of a drug metabolite in plasma

Supercritical fluid extraction was coupled with solid-phase extraction using octadecylsilane cartridges for the selective isolation of ultratrace levels of a drug metabolite, mebeverine alcohol, from plasma. Plasma was directly applied to the extraction cartridge, the cartridge was washed to remove protein and then extracted under supercritical conditions using CO2/5% methanol. The effluent from the extraction cell was bubbled through a small volume of 2-propanol to trap the extracted mebeverine alcohol. The effects of extraction pressure and temperature on analyte recovery were examined. The absolute recovery, selectivity, precision, and accuracy of the combined supercritical fluid extraction/solid-phase extraction approach were compared to those of conventional solid-phase extraction using gas chromatography/mass spectrometry in the selected-ion monitoring mode. Mebeverine alcohol was used as a model compound, and dog plasma was employed as the biological matrix for these studies.

Pupil Response: A Psychophysiological Measure of Fear during Analogue Desensitization,

15 highly aroused snake phobics individually constructed fear hierarchies by selecting colored photographs of snakes. Subjects either imagined fear scenes based on their photographs or were exposed to duplicate projected slides during desensitization. Pupillary responses of the Slide Group were also recorded before, during, and after desensitization. Fear of snakes was significantly reduced for both groups within five or fewer desensitization sessions. Changes in pupil size of the Slide Group appear to reflect arousal of fear as well as reduction of fear after treatment. Current technology makes pupillary response a viable psychophysiological measure of fear.

Pupil response: a psychophysiological measure of fear during analogue desensitization

15 highly aroused snake phobics individually constructed fear hierarchies by selecting colored photographs of snakes. Subjects either imagined fear scenes based on their photographs or were exposed to duplicate projected slides during desensitization. Pupillary responses of the Slide Group were also recorded before, during, and after desensitization. Fear of snakes was significantly reduced for both groups within five or fewer desensitization sessions. Changes in pupil size of the Slide Group appear to reflect arousal of fear as well as reduction of fear after treatment. Current technology makes pupillary response a viable psychophysiological measure of fear.

Increase and decrease in light and noise stimuli as reinforcers for albino rats

The effect upon response latencies of random increases or decreases in stimulus intensity following a barrier-crossing response in a Mowrer-Miller shuttle box was studied. Stimulus change was contingent upon the response. 32 albino rats were randomly assigned to a control group which received no stimulation and to three experimental groups: Group L (subjected to changes in light), Group N (subjected to changes in noise), and Group LN (subjected to changes in light and noise). It was found that (a) in terms of mean latencies Group LN differed significantly from Group L and the control group. (b) Although the trial effect was significant, response latency did not consistently decrease over trials. (c) The mean number of spontaneous crossings was significantly larger for Group LN than for all other groups. (d) The mean number of spontaneous crossings increased over trials.

Effects of thiopental sedation on learning and memory

Subjects who were administered thiopental showed a loss of memory for events discussed while they were under sedation. We tested the subjects for recognition memory of pictures and recall of associated pairs of letters and words, and found that the subsequent memory loss was correlated with the concentration of thiopental in the venous blood at the time the material was learned. Retention did not appear to be state-dependent because the subject, while under sedation, could recall material learned prior to sedation, and because recall was not facilitated by reinstatement of the sedation.