Cardiovascular effects of sodium-glucose co-transporter-2 inhibitors and glucagon-like peptide-1 receptor agonists: The P value and beyond

Despite growing awareness of the dangers of a dichotomous interpretation of trial results based on the ‘statistical significance’ of a treatment effect, the uptake of new approaches has been slow in diabetes medicine. We showcase a number of ways to interpret the evidence for a treatment effect applied to the cardiovascular outcome trials of glucagon-like peptide-1 receptor agonists (GLP-1RAs) and sodium-glucose co-transporter-2 inhibitors (SGLT-2is): the P value function (or confidence curves), which depicts the treatment effect across the whole spectrum of confidence levels; the counternull value, which is the hazard ratio (i.e. treatment effect size) supported by the same amount of evidence as the null value (i.e. no treatment effect); and the S value, which quantifies the strength of the evidence against the null hypothesis in terms of the number of coin tosses yielding the same side. We show how this approach identifies potential treatment effects, highlights similarities among trials straddling the threshold of statistical significance, and quantifies differences in the strength of the evidence from trials reporting statistically significant results. For example, while REWIND, CANVAS and CREDENCE failed to reach statistical significance at the .05 level for all-cause mortality, their counternull values indicate that reduced death rates by 19%, 24% and 31%, respectively, are supported by the same amount of evidence as that indicating no treatment effect. Moreover, similarities among results emerge in trials of GLP-1RAs (REWIND, EXSCEL and LEADER) lying closely around the threshold of ‘statistical significance’. Lastly, several S values, such as for the primary outcome in HARMONY Outcomes (S value 10.9) and all-cause death in EMPAREG-OUTCOME (S value 15.0), stand out compared with values for other outcomes and other trials, suggesting much larger differences in the evidence between these studies and several others that cluster around the .05 significance threshold. P value functions, counternull values and S values should complement the standard reporting of the treatment effect to help interpret clinical trials and make decisions among competing glucose-lowering medications.     

Single lead ST-segment recovery: a simple, reliable measure of successful fibrinolysis after acute myocardial infarction

Background

Successful reperfusion after acute ST-elevation myocardial infarction improves prognosis. Among the different electrocardiographic markers of reperfusion, sum ST resolution is considered the hallmark of reperfusion, but is cumbersome to use.

Methods

To assess the usefulness of a single lead ST resolution at 90 minutes after fibrinolysis compared with the sum ST resolution in predicting Thrombolysis in Myocardial Infarction (TIMI) grade 3 flow, we used prospectively collected data from the Limitation of Myocardial Injury Following Thrombolysis in Acute Myocardial Infarction (LIMIT-AMI) study. All patients had electrocardiograms recorded at presentation and 90 minutes and a coronary angiogram 90 minutes after fibrinolysis.

Results

Infarction artery patency was assessed in 238 patients with 4 different ST resolution criteria: single lead ST resolution ≥50% and ≥70% and sum ST resolution ≥50% and ≥70%. The most sensitive criteria for TIMI grade 3 flow was single lead ST resolution ≥50% (sensitivity rate, 70%; specificity rate, 54%), whereas sum ST resolution ≥70% was most the specific criteria (sensitivity rate, 45%; specificity rate, 79%). The proportion of patients with TIMI grade 3 flow was similar in all 4 ST resolution groups (P = .84). Pre-discharge infarction size and ejection fraction were also similar. No single lead or sum lead measure of ST resolution was significantly associated with an increased risk of death, heart failure, or reinfarction.

Conclusion

We propose that single lead ST-resolution ≥50% as an optimal electrocardiographic indicator for successful reperfusion 90 minutes after fibrinolysis. This simple electrocardiographic measure should be combined with bedside clinical and hemodynamic assessment to optimize decision making after fibrinolysis.     

Catastrophic ATP loss underlies a metabolic combination therapy tailored for MYCN-amplified neuroblastoma

MYCN-amplified neuroblastoma is a lethal subset of pediatric cancer. MYCN drives numerous effects in the cell, including metabolic changes that are critical for oncogenesis. The understanding that both compensatory pathways and intrinsic redundancy in cell systems exists implies that the use of combination therapies for effective and durable responses is necessary. Additionally, the most effective targeted therapies exploit an “Achilles’ heel” and are tailored to the genetics of the cancer under study. We performed an unbiased screen on select metabolic targeted therapy combinations and correlated sensitivity with over 20 subsets of cancer. We found that MYCN-amplified neuroblastoma is hypersensitive to the combination of an inhibitor of the lactate transporter MCT1, AZD3965, and complex I of the mitochondrion, phenformin. Our data demonstrate that MCT4 is highly correlated with resistance to the combination in the screen and lowly expressed in MYCN-amplified neuroblastoma. Low MCT4 combines with high expression of the MCT2 and MCT1 chaperone CD147 in MYCN-amplified neuroblastoma, altogether conferring sensitivity to the AZD3965 and phenformin combination. The result is simultaneous disruption of glycolysis and oxidative phosphorylation, resulting in dramatic disruption of adenosine triphosphate (ATP) production, endoplasmic reticulum stress, and cell death. In mouse models of MYCN-amplified neuroblastoma, the combination was tolerable at concentrations where it shrank tumors and did not increase white-blood-cell toxicity compared to single drugs. Therefore, we demonstrate that a metabolic combination screen can identify vulnerabilities in subsets of cancer and put forth a metabolic combination therapy tailored for MYCN-amplified neuroblastoma that demonstrates efficacy and tolerability in vivo.

Despite their relative rarity compared to blood cancers, solid-tumor pediatric cancers are now the leading cause of pediatric cancer-related deaths. Among the most deadly is high-risk neuroblastoma (NB): amplification of MYCN confers high risk and is the clear driver of NB in these cancers (1). As such, MYCN remains the most important drug target in NB and one of the most important in pediatric cancer. Unfortunately, direct chemical targeting of MYCN has not yet been successful, and despite advancements in anti-GD2 immunotherapy (2), alternate ways of targeting MYCN-amplified NB may be needed to successfully treat this cancer.One approach is to find tumor-specific vulnerabilities, which are exploitable pharmacologically. Many efforts, including ours (3), have exhaustively looked for kinase inhibitors with particular efficacy in MYCN-amplified NBs. However, the emerging picture is a lack of kinase inhibitor efficacy in MYCN-amplified NB. Other vulnerabilities may be classified under the broad category of drugs targeting epigenetic modifiers. For example, using a CRISPR/Cas9 screen, Stegmaier and colleagues demonstrated that MYCN-amplified NB may be susceptible to targeting the H3K27me methylase EZH2 (4); in a different study, they demonstrated the susceptibility of MYCN-amplified NB to the combination of BRD4 inhibitors with CDK7 inhibitors (5). In addition, Thiele and colleagues (6) demonstrated high-risk NBs were susceptible to inhibition of the lysine methyltransferase SETD8. As promising as these data are, it remains unknown whether tolerability and/or clinical activity in MYCN-amplified NB will occur and SETD8, BRD4, and CDK7 inhibitors so far are not in the pediatric clinic. Cell death inducers constitute a third category. To this point, we recently uncovered a susceptibility of MYCN-amplified NB to the BCL-2 inhibitor venetoclax (3), confirmed by others (7). There, MYCN-driven NOXA expression sensitizes cells to venetoclax (3). Venetoclax is now in early phase trials in pediatric patients including those with NB ({"type":"clinical-trial","attrs":{"text":"NCT03236857","term_id":"NCT03236857"}}NCT03236857). It remains to be seen whether or not it will elicit responses in NB patients as a single agent.A fourth distinct category of therapeutic strategies to indirectly target oncogenes is through metabolism targeting, involving the growing coterie of drugs targeting the pathways fulfilling the high-energy demands of cancer cells. A major energy currency in cells is adenosine triphosphate (ATP). The Warburg effect describes the propensity of cancer cells (and highly proliferating normal cells) to produce ATP in the presence of oxygen with the less efficient, extramitochondrial glycolysis, as opposed to the more efficient mitochondria-based oxidative phosphorylation occurring in most noncancerous cells (8). The mechanistic explanation of the Warburg effect and how it might benefit cancer cells has been revised dramatically over the years. It was originally proposed that mitochondria from cancer cells were defective and lacked oxidative phosphorylation capabilities (9); on the contrary, emerging data show that many cancers rely on oxidative phosphorylation to facilitate the generation of ATP (8, 10). Interestingly, while amplified MYCN directly regulates the expression of many of the key glycolytic enzymes and as such contributes to the Warburg effect (11, 12), a study utilizing a Seahorse respirator demonstrated that a MYCN-amplified NB cell line favored oxidative phosphorylation over glycolysis for the metabolic needs, while the reverse was true for a MYCN wild-type NB cell line (13). In an independent study, MYCN was associated with higher glycolytic flux and oxidative phosphorylation and conferred sensitivity to fatty acid oxidation disruption (12). Overall, since c-MYC, which shares ∼40% binding homology to DNA-binding sites throughout the genome with MYCN, has been extensively characterized as a metabolic master regulator (14, 15), it is likely there are other MYCN-driven metabolic processes that may represent significant drug targets.Monocarboxylate transporters (MCTs) consist of four members (MCT1–4) in mammalian cells. Among their most critical substrates are lactate and pyruvate; MCT1 and MCT4 are responsible for lactate export across the plasma membrane to the extracellular space (16). AZD3965 (17) (AstraZeneca) is the first in-class–specific MCT1/2 dual inhibitor and is currently in early phase trials for diverse cancers; however, other inhibitors from different companies have recently been developed as well (18). Of note, AZD3965 has demonstrated good tolerability in diverse patients (clinical trial number {"type":"clinical-trial","attrs":{"text":"NCT01791595","term_id":"NCT01791595"}}NCT01791595). Although rare (65 cases/100,000 person-years), lactic acidosis led to the market retrieval of phenformin in America (19), yet phenformin remains in use as a type II antidiabetic drug in Europe, functioning centrally as a mitochondrial complex I electron transport chain (ETC) inhibitor. Phenformin reduces both glycolytic intermediates and pyruvate, increases shunting of glucose-derived carbon (increasing total lactate production), and markedly reduces tricarboxylic acid cycle intermediates (20). Indeed, there has been a recent resurgence in interest in the use of phenformin to treat cancer. For example, in BRAF mutant melanoma, phenformin sensitized cells to BRAF inhibitor through cooperative suppression of the metabolic sensor pathway mTORC1 (21). These preclinical data have led to a clinical trial of phenformin in combination with BRAF inhibitor in BRAF mutant melanoma ({"type":"clinical-trial","attrs":{"text":"NCT03026517","term_id":"NCT03026517"}}NCT03026517). Overall, while targeting individual metabolic pathways has demonstrated some preclinical success in different cancer models, it is limited with significant redundancy in pathways to generate ATP and regenerate NAD+ (22). We therefore assessed potential combination therapies involving metabolic targeting drugs to identify a strategy for MYCN-amplified NB.     

Good practice in social care: the views of people with severe and complex needs and those who support them

This paper reports findings drawn from a study of good practice in English social care for adults with disability and older people with severe and complex needs. People with severe and complex needs are a relatively small proportion of adult social care service users, but they are growing in numbers and have resource‐intensive needs. The study involved qualitative research with adults with disability and older people with severe and complex needs, family carers and members of specialist organisations (n = 67), focusing on the features of social care services they considered to be good practice. Data were collected between August 2010 and June 2011. The approach to data collection was flexible, to accommodate participants' communication needs and preferences, including face‐to‐face and telephone interviews, Talking Mats^© sessions and a focus group. Data were managed using Framework and analysed thematically. Features of good practice were considered at three levels: (i) everyday support; (ii) service organisation; and (iii) commissioning. Findings relating to the first two of these are presented here. Participants emphasised the importance of person‐centred ways of working at all levels. Personalisation, as currently implemented in English social care, aims to shift power from professionals to service users through the allocation of personal budgets. This approach focuses very much on the role of the individual in directing his/her own support arrangements. However, participants in this study also stressed the importance of ongoing professional support, for example, from a specialist key worker or case manager to co‐ordinate diverse services and ensure good practice at an organisational level. The paper argues that, despite the recent move to shift power from professionals to service users, people with the most complex needs still value support from professionals and appropriate organisational support. Without these, they risk being excluded from the benefits that personalisation, properly supported, could yield.