Adapting Health Technology Assessment agency standards for surrogate outcomes in early stage cancer trials: what needs to happen?

INTRODUCTION: An avalanche of early stage cancer clinical trials is coming. The majority of these solely use surrogate outcomes that have not been validated against a target outcome of interest (e.g. overall survival). Current HTA guidance on surrogate outcome validation are not methodologically or practically conducive to this scenario. AREAS COVERED: We provide a high-level overview of methods, approaches, and conceptual thinking for making better use of limited evidence within early stage cancer HTA submissions. We outline regulatory and HTA issues and emphasize how evidence transitions from one to another, what major gaps currently exist, and how these may be bridged. We summarize current methodologies and practices, their pros and cons. We outline how complementary measurements strengthen evaluations and address fallacies and biases of conventional statistical methods for surrogate outcomes validation. The value of real-world data to support some of the necessary validity components is discussed. Lastly, we address the importance of the patient voice for better understanding which surrogate outcomes may appropriately inform HTA. EXPERT OPINION: Conventional surrogate outcome validation represents a fraught and sub-optimal framework for HTA purposes, particularly for early stage cancer. Tools for optimizing use of limited evidence exist. Education of stakeholders is highly needed.

A Survey of Patient Experience in CML: American and Canadian Perspectives.

Purpose: With treatment, chronic myeloid leukemia (CML) has a favorable prognosis, however, individuals with CML experience impairment to their quality of life (QoL). The aim of this study was to examine the perspectives and experiences of individuals with CML and to understand their challenges communicating with their CML physician. Patients and Methods: An online survey in adults with CML (n=100) in the US and Canada assessed QoL, patient-provider relationships, treatment satisfaction, and understanding of CML and treatment goals via the MD Anderson Symptom Inventory, the Cancer Therapy Satisfaction Questionnaire and de novo survey questions. Participants were recruited via an external patient recruiter and CML Patient Groups. Results: Many participants reported hardships due to CML and its treatment. The main impacts were on the ability to work (21%), engage in personal activities (e.g., hobbies, 28%), and to enjoy sexual relations (median=2.00, IQR=8.50). A substantial proportion (21-39%) wished to discuss additional topics with their providers (e.g., management of CML and/or its impacts). While participants reported satisfaction with therapy overall (median=85.71, IQR=17.86), they indicated low to moderate treatment satisfaction with specific components, including concerns regarding side effects (median=43.75, IQR=43.75). Participants generally had a good understanding of CML (97%) and its treatment goals (92%). Conclusion: These findings advance our understanding of issues that need improvement to support QoL for individuals living with CML. Future work is needed to improve patient-provider relationships, address treatment-related side effects, and provide clinical information that is easier for patients to understand.

Genetic response of Salmonella enterica serotype Enteritidis to thioridazine rendering the organism resistant to the agent.

Thioridazine (TZ)-induced accumulation of the universal efflux pump substrate ethidium bromide and its subsequent efflux by Salmonella strains with various degrees of overexpressed efflux pumps takes place automatically at pH 7.4, is independent of a metabolic source, is not affected by a proton ionophore and is precluded by palmitic acid. Salmonella enterica serotype Enteritidis cultured in medium containing increasing concentrations of TZ does not grow during the first 6-8h, after which time its growth is similar to unexposed controls. At the end of a 16-h exposure period, the organism is resistant to >250mg/L TZ. Parallel assessment by real-time reverse transcription quantitative polymerase chain reaction (RT-qPCR) of the activity of genes that regulate and code for the AcrB transporter of the main efflux pump (AcrAB) of the organism at periodic intervals suggests a sequence of activation beginning with the stress gene soxS, followed by the global regulator ramA, then by the local regulator marA and then by the transporter acrB. These activations take place during the period of no growth. By the end of a 16-h culture period, only the acrB transporter gene is still highly overexpressed. Assessment of the activity of genes of the two-component regulon PmrA/B indicates that TZ also activates this regulon. Because activation of pmrA/B also activates acrB, development of high resistance to TZ during a 16-h culture period is in part due to activation of the two-component regulon.

Biological activity of twenty-three hydantoin derivatives on intrinsic efflux pump system of Salmonella enterica serovar Enteritidis NCTC 13349.

BACKGROUND: Hydantoin derivatives have important biochemical and pharmacological properties. In the present study, 23 hydantoin compounds were evaluated for their efflux-modulating effects in Salmonella enterica serovar Enteritidis NCTC 13349 using real-time fluorimetry based on the intracellular accumulation of ethidium bromide (EB), a universal substrate of efflux pumps. MATERIALS AND METHODS: Twenty-three hydantoin derivatives were tested for intrinsic efflux pump modulation in S. enterica Enteritidis NCTC 13349 by an automated real-time fluorimetric method that monitors the intracellular accumulation of ethidium bromide. RESULTS: None of the compounds were found to have antibacterial activities at concentrations as high as 200 mg/l. Among the hydantoin derivatives tested in our study, only compound SZ7 showed efflux modulating activity on S. enterica Enteritidis NCTC 13349 in the assays that contained or omitted glucose as the singular source of metabolic energy. CONCLUSION: SZ7 is shown to be non-toxic and it could be evaluated to cure an efflux mediated MDR Salmonella infection, furthermore a quantitative activity-structural relationship is also planned in order to determine the site of the SZ7 molecule responsible for its efflux pump inhibitory activity.

Ethidium bromide efflux by Salmonella: modulation by metabolic energy, pH, ions and phenothiazines.

The main efflux pump of Salmonella enterica serotype Enteritidis, which obtains its energy for the extrusion of noxious agents from the proton-motive force, was studied with the aid of an ethidium bromide (EtBr) semi-automated method under conditions that define the role of metabolic energy, ions and pH in the extrusion of the universal substrate EtBr. The results obtained in this study indicate that in minimal medium containing sodium at pH 5 efflux of EtBr is independent of glucose, whereas at pH 8 metabolic energy is an absolute requirement for the maintenance of efflux. In deionised water at pH 5.5, metabolic energy is required for the maintenance of efflux. The inhibitory effect of the ionophore carbonyl cyanide m-chlorophenylhydrazone (CCCP) on efflux is shown to be minimised by low pH, and at high pH by metabolic energy. Similarly, thioridazine, an inhibitor of metabolic enzymes, inhibits efflux of EtBr only at pH 8 and the degree of inhibition is lessened by the presence of metabolic energy.

Posthemorrhagic hydrocephalus in very low birth weight infants--a new gentle surgical technique for external ventricular drainage.

OBJECTIVE: The germinal matrix hemorrhage in premature infants is related to the immaturity of the subependymal vascular bed. Posthemorrhagic ventricular dilation (PVD) in extremely low birth weight infants (ELBI) is a medical challenge and is associated with a high risk of long-term disability. Our aim was to find a safe and gentle surgical technique for external ventricular drainage implantation for this patient population. PATIENTS AND METHODS: We implanted eight external ventricular drainages in ELBI with birth weights ranging from 479 to 884 g (24 to 27 weeks gestational age) and a grade III to IV hemorrhage, who developed a PVD soon after birth. A replacement of the drainage was required three times in one infant with a birth weight of 479 g. Due to the subcutaneous tunneling and drawing of the catheter through the sleeve, the skin contact remains slight, and thus, infections are avoided. RESULTS: There were no complications during the procedures which can also be carried out in the neonatal intensive care unit. Only in one case (479 g birth weight and severe concomitant diseases) was an infection observed, though the origin was most likely abdominal. In the same case, a temporary leakage was treated by suture. This patient died of non-neurological complications related to the patient's prematurity. Three of the five preterms were shunted over time. CONCLUSIONS: Although there is only a small number of extremely low birth weight infants with posthemorrhagic hydrocephalus who were treated with this technique, our findings suggest that this method is very safe and useful. It reduces the risk of infection and cerebrospinal fluid leaks and might be a better alternative to serial lumbar or transfontanel punctures in extremely low birth weight infants for bridging the first weeks of life.

Role of calcium in the efflux system of Escherichia coli.

Efflux of antibiotics by Escherichia coli AG100 is performed by a variety of efflux pumps, ensuring survival of the bacterium in widely diverse media. At pH 5, efflux is independent of metabolic energy during the period of time the assay is conducted; at pH 8 it is totally dependent upon metabolic energy. Because calcium ions (Ca(2+)) are important for membrane transport channels and the activity of ATPases that provide energy functions, the role of Ca(2+) in the extrusion of an efflux pump substrate under conditions that challenge the bacterium was investigated. Real-time accumulation and efflux of ethidium bromide (EtBr) by E. coli K-12 AG100 strain [argE3 thi-1 rpsL xyl mtl Δ(gal-uvrB) supE44] was determined by a semi-automated fluorometric method in the presence and absence of Ca(2+) and agents that are known to inhibit access of calcium to enzymes that provide energy. Chlorpromazine (CPZ), an inhibitor of calcium binding to proteins (calcium-dependent enzymes), and ethylene diamine tetra-acetic acid (EDTA), a chelator of Ca(2+), increased accumulation and efflux of EtBr at pH 8 but not at pH 5. Ca(2+) reverses these effects when the assay is conducted at pH 8. In conclusion, the activity of the efflux pump system of E. coli is dependent upon metabolic energy at pH 8. Because at pH 8 hydrolysis of ATP is favoured and contributes protons for activation of the AcrAB-TolC efflux pump, CPZ is suspected of having its effects on accumulation/efflux of EtBr by indirectly affecting ATPase activity that is dependent upon Ca(2+).