Using Patient Preferences in Health Technology Assessment: Evaluating Quality-Adjusted Survival Equivalents (QASE) for the Quantification of Non-health Benefits.

Interest in using patient preference (PP) data alongside traditional economic models in health technology assessment (HTA) is growing, including using PP data to quantify non-health benefits. However, this is limited by a lack of standardised methods. In this article, we describe a method for using discrete choice experiment (DCE) data to estimate the value of non-health benefits in terms of quality-adjusted survival equivalence (QASE), which is consistent with the concept of value prevalent among HTA agencies. We describe how PP data can be used to estimate QASE, assess the ability to test the face-validity of QASE estimates of changes in mode of administration calculated from five published DCE oncology studies and review the methodological and normative considerations associated with using QASE to support HTA. We conclude that QASE may have some methodological advantages over alternative methods, but this requires DCEs to estimate second-order effects between length and quality of life. In addition, empirical work has yet to be undertaken to substantiate this advantage and demonstrate the validity of QASE. Further work is also required to align QASE with normative objectives of HTA agencies. Estimating QASE would also have implications for the conduct of DCEs, including standardising and defining more clear attribute definitions.

Development of WHO Recommendations for the Final Phase of Elimination and Prevention of Re-Establishment of Malaria.

The WHO recommends that all affected countries work toward the elimination of malaria, even those still experiencing a high burden of disease. However, malaria programs in the final phase of elimination or those working to prevent re-establishment of transmission after elimination could benefit from specific evidence-based recommendations for these settings as part of comprehensive and quality-controlled malaria guidelines. The WHO convened an external guideline development group to formulate recommendations for interventions to reduce or prevent malaria transmission in areas with very low- to low-transmission levels and those that have eliminated malaria. In addition, several interventions that could be deployed in higher burden areas to accelerate elimination, such as mass drug administration, were reviewed. Systematic reviews were conducted that synthesized and evaluated evidence for the benefits and harms of public health interventions and summarized critical contextual factors from a health systems perspective. A total of 12 recommendations were developed, with five related to mass interventions that could be deployed at higher transmission levels and seven that would be most appropriate for programs in areas close to elimination or those working to prevent re-establishment of transmission. Four chemoprevention, two active case detection, and one vector control interventions were positively recommended, whereas two chemoprevention and three active case detection interventions were not recommended by the WHO. None of the recommendations were classified as strong given the limited and low-quality evidence base. Approaches to conducting higher quality research in very low- to low-transmission settings to improve the strength of WHO recommendations are discussed.

How do study design features and participant characteristics influence willingness to participate in clinical trials? Results from a choice experiment.

BACKGROUND: Research about the decision to participate in a clinical study has tended to be limited to single indications and has focused on narrow sets of study and participant characteristics. This study applied stated preference methods to understand the clinical trial design attributes that most influence willingness to participate and how this varied with participant characteristics. METHODS: Adults residing in the US, China, or Poland with a self-reported diagnosis of cancer, heart disease, migraine, rheumatoid arthritis, or multiple sclerosis completed an online survey. Participants were asked whether they would participate in clinical studies defined by seventeen attributes within five categories (payment/support, administration/procedures, treatment-related, study location/time commitment, and data collection/feedback). Participants saw six different hypothetical clinical study profiles. Depending on their participation decision to an initial clinical study profile, the subsequent five questions had one design attribute (randomly selected per question) consecutively improved or deteriorated to elicit preferences. A logistic regression was used to determine which participant characteristics influenced participation decisions. A latent class logit model was used to identify how the influence of study design features varied between participants and whether groups of participants with similar preferences could be identified. RESULTS: The survey was completed by 487 participants (32% China, 35% Poland, 33% US; 8%-19% per indication). Willingness to participate was found to be a function of participant age, certain elements of quality of life, and previous treatment experience, in particular number of lines of treatment received and experience of adverse events. Willingness to participate was influenced by study design features such as payment, study duration, and time commitment - both the overall time and whether the time was at home or away from home, with the latter being particularly relevant to participants experiencing fatigue due to their disease. CONCLUSIONS: This study quantifies how study designs influence willingness to participate and how this varies with participant types. These findings suggest that it is how an indication influences quality of life and treatment experience, rather than the indication alone, that impacts participation rates, opening the way for insights that are transferrable across indications, which may be particularly useful when considering rare diseases.

Patient preferences for frontline therapies for Philadelphia chromosome-positive acute lymphoblastic leukemia: a discrete choice experiment.

Aim: We examined the preferences of adults with Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL) for benefits and risks of tyrosine kinase inhibitors combined with chemotherapy for first-line treatment. Methods: In a discrete choice experiment, 201 patients chose between hypothetical treatment alternatives with varied levels of remission duration and overall survival (OS), and risks of major cardiovascular (CV) events and myelosuppression. Results: Although OS was the most important attribute to patients with Ph+ ALL, they were willing to tolerate a 2.9% increase in CV risk for 1 additional month of OS. Older patients (>59 years) and patients not in remission were less likely to tolerate increased CV risk. Conclusion: Preferences and risk tolerance varied between patients, highlighting the importance of shared decision making when selecting treatments for Ph+ ALL.

Treatments differ in their potential benefits and side effects they may come with. Patients should be involved in deciding which treatments they receive. This is because patients may have different views than physicians on how the benefits and side effects of treatment would affect their quality of life. Additionally, patients may have different risk tolerances. This study shows how patients with a form of leukemia valued survival benefits and side effects of treatments, and the trade-offs that they were willing to make between these. On average, longer survival had most value to patients. They were willing to accept a higher risk of a major cardiovascular side effect (e.g., having a stroke) if the treatment would allow them to live longer. However, not all patients had the same opinion, and some groups of patients were less willing to accept risks to receive longer survival. By involving patients in treatment decisions, we can help ensure they receive treatments that match their personal preferences.

Evaluating the Consistency of Patient Preference Estimates: Systematic Variation in Survival-Adverse Event Trade-Offs in Patients with Cancer or Cardiovascular Disease.

BACKGROUND: The increased use of patient preference data in healthcare decision making has raised concerns about the reliability and consistency of the estimates generated by patient preference studies. However, literature reviews to assess the consistency of preferences are confounded by heterogeneity in study designs. METHODS: This paper adopted a novel approach to evaluating preference consistency: comparing estimates of a single trade-off-the marginal rate of substitution (MRS) between survival improvements and risks of adverse events-across multiple patient groups and using meta-regression to assess whether MRS varied systematically between patients. A log-linear, random effects regression was run, weighted for the sample sizes of studies from which estimates were extracted. RESULTS: Using studies identified in published reviews of patient preference data, 42 estimates of MRS were generated from the 12 studies. On average, patients obtained the same utility from a 2.3% reduction in the risk of an adverse event as from a 1-month increase in survival, with a range of 0.002-13.5%. The regression model had an R2 of over 90% and suggests that MRS depended on patients' expected survival and the type of adverse event being traded. CONCLUSION: These results suggest that although preferences vary between patients, they may do so in systematic and predictable ways. Further, they do so in ways consistent with societal preferences and decision maker priorities toward end-of-life settings. Further work is required to replicate this result in other patient groups and to explore the consistency of preferences for other treatment attributes.

Systemic and cerebrospinal fluid immune and complement activation in Ugandan children and adolescents with long-standing nodding syndrome: A case-control study.

OBJECTIVE: Nodding syndrome is a poorly understood epileptic encephalopathy characterized by a unique seizure type-head nodding-and associated with Onchocerca volvulus infection. We hypothesized that altered immune activation in the cerebrospinal fluid (CSF) and plasma of children with nodding syndrome may yield insights into the pathophysiology and progression of this seizure disorder. METHOD: We conducted a case-control study of 154 children (8 years or older) with long-standing nodding syndrome and 154 healthy age-matched community controls in 3 districts of northern Uganda affected by nodding syndrome. Control CSF samples were obtained from Ugandan children in remission from hematological malignancy during routine follow-up. Markers of immune activation and inflammation (cytokines and chemokines) and complement activation (C5a) were measured in plasma and CSF using ELISA or Multiplex Luminex assays. O volvulus infection was assessed by serology for anti-OV-16 IgG levels. RESULTS: The mean (SD) age of the population was 15.1 (SD: 1.9) years, and the mean duration of nodding syndrome from diagnosis to enrollment was 8.3 (SD: 2.7) years. The majority with nodding syndrome had been exposed to O volvulus (147/154 (95.4%)) compared with community children (86/154 (55.8%)), with an OR of 17.04 (95% CI: 7.33, 45.58), P < .001. C5a was elevated in CSF of children with nodding syndrome compared to controls (P < .0001). The levels of other CSF markers tested were comparable between cases and controls after adjusting for multiple comparisons. Children with nodding syndrome had lower plasma levels of IL-10, APRIL, CCL5 (RANTES), CCL2, CXCL13, and MMP-9 compared with community controls (P < .05 for all; multiple comparisons). Plasma CRP was elevated in children with nodding syndrome compared to community children and correlated with disease severity. SIGNIFICANCE: Nodding syndrome is associated with exposure to O. volvulus. Compared to controls, children with long-standing symptoms of nodding syndrome show evidence of complement activation in CSF and altered immune activation in plasma.

Patient Preferences of Low-Dose Aspirin for Cardiovascular Disease and Colorectal Cancer Prevention in Italy: A Latent Class Analysis.

BACKGROUND: Patients taking low-dose aspirin to prevent cardiovascular disease (CVD) may also benefit from a reduced risk of colorectal cancer (CRC). OBJECTIVE: The aim was to examine the preferences of people eligible for preventive treatment with low-dose aspirin and the trade-offs they are willing to make between CVD prevention, CRC prevention, and treatment risks. METHODS: A cross-sectional study using a discrete choice experiment (DCE) survey was conducted in Italy in 2019 to elicit preferences for three benefit attributes (prevention of ischemic stroke, myocardial infarction, and CRC) and four risk attributes (intracranial and gastrointestinal bleeding, peptic ulcer, and severe allergic reaction) associated with use of low-dose aspirin. Latent class logit models were used to evaluate variation in treatment preferences. RESULTS: The DCE survey was completed by 1005 participants eligible for use of low-dose aspirin. A four-class model had the best fit for the primary CVD prevention group (n = 491), and a three-class model had the best fit for the secondary CVD prevention group (n = 514). For the primary CVD prevention group, where classes differed on age, education level, type 2 diabetes, exercise, and low-dose aspirin use, the most important attributes were intracranial bleeding (two classes), myocardial infarction (one class), and CRC (one class). For the secondary CVD prevention group, where classes differed on various comorbidities, self-reported health, exercise, and CVD medication use, the most important attributes were intracranial bleeding (two classes), myocardial infarction (one class), and gastrointestinal bleeding (one class). CONCLUSION: Patient preferences for the benefits and risks of low-dose aspirin differ significantly among people eligible for treatment as primary or secondary CVD prevention.

Benefit-Risk or Risk-Benefit Trade-Offs? Another Look at Attribute Ordering Effects in a Pilot Choice Experiment.

BACKGROUND: Studies recommend randomising the order of attributes in discrete choice experiments (DCEs) to avoid bias; however, in a benefit-risk setting, this may increase the cognitive burden of respondents who compare the benefits and risks of treatments, or may affect their decision-making process. Based on these concerns, this paper explored attribute ordering effects in a benefit-risk DCE. METHOD: Attribute ordering effects were explored in a large pilot DCE relating to the medical treatment of insomnia. Participants were randomised to one of three presentation orders: (1) benefits were presented before risks (BR); (2) risks were presented before benefits (RB); (3) all attributes were randomised (RN). For the RB and BR presentation orders, attributes were randomised within benefits and risks. Responses were assessed in three ways. First, variations in respondents' self-reported choice certainty were obtained. Second, variations in failure rates of stability and dominance tests were calculated. Third, a heteroscedastic error component model tested for differences in choice consistency across the three attribute orderings. RESULTS: The final analysis included 156 respondents (RN: 54; BR: 49; RB: 53). No differences were found between the presentation orders with respect to stated choice certainty, or the proportion of respondents failing either the dominance or stability test. However, deterministic attribute grouping was associated with higher choice consistency. CONCLUSION: To increase choice consistency, DCE attributes should be randomised within logical groups that may be further randomised to reduce the risk of ordering effects.

Plasmodium falciparum Merozoite Associated Armadillo Protein (PfMAAP) Is Apically Localized in Free Merozoites and Antibodies Are Associated With Reduced Risk of Malaria.

Understanding the functional role of proteins expressed by Plasmodium falciparum is an important step toward unlocking potential targets for the development of therapeutic or diagnostic interventions. The armadillo (ARM) repeat protein superfamily is associated with varied functions across the eukaryotes. Therefore, it is important to understand the role of members of this protein family in Plasmodium biology. The Plasmodium falciparum armadillo repeats only (PfARO; Pf3D7_0414900) and P. falciparum merozoite organizing proteins (PfMOP; Pf3D7_0917000) are armadillo-repeat containing proteins previously characterized in P. falciparum. Here, we describe the characterization of another ARM repeat-containing protein in P. falciparum, which we have named the P. falciparum Merozoites-Associated Armadillo repeats protein (PfMAAP). Antibodies raised to three different synthetic peptides of PfMAAP show apical staining of free merozoites and those within the mature infected schizont. We also demonstrate that the antibodies raised to the PfMAAP peptides inhibited invasion of erythrocytes by merozoites from different parasite isolates. In addition, naturally acquired human antibodies to the N- and C- termini of PfMAAP are associated with a reduced risk of malaria in a prospective cohort analysis.

Cost Effectiveness of Naloxegol for Opioid-Induced Constipation in the UK.

BACKGROUND AND OBJECTIVES: Opioid-induced constipation (OIC) is the most common adverse effect reported in patients receiving opioids to manage pain. Initial treatment with laxatives provides inadequate response in some patients. Naloxegol is a peripherally acting µ-opioid receptor antagonist used to treat patients with inadequate response to laxative(s) (laxative inadequate responder [LIR]). A cost-effectiveness model was constructed from the UK payer perspective to compare oral naloxegol 25 mg with placebo in non-cancer LIR patients receiving opioids for chronic pain, and a scenario analysis of naloxegol 25 mg with rescue laxatives compared with placebo with rescue laxatives in the same patient population. METHODS: The model comprised a decision tree for the first 4 weeks of treatment, followed by a Markov model with a 4-week cycle length and the following states: 'OIC', 'non-OIC (on treatment)', 'non-OIC (untreated)' and 'death'. Two phase III trials with a follow-up period of 12 weeks provided data on treatment efficacy, transition probabilities, adverse event frequency and patient utility. Resource utilisation data were sourced from a UK-based burden of illness study and physician surveys. A UK National Health Service and Personal Social Service perspective was adopted; costs and health-related quality of life gains were discounted at a rate of 3.5 %. The model was run over a time horizon of 5 years, reflecting the average period of opioid use. RESULTS: Naloxegol has an incremental cost-effectiveness ratio of £10,849 per quality-adjusted life-year gained versus placebo, and £11,179 when rescue laxatives are made available in both arms (2014 values). Model outcomes were only sensitive to variations in utility inputs. However, the probabilistic sensitivity analyses indicate that naloxegol has a 91 % probability of being cost effective at a £20,000 threshold when compared with placebo. CONCLUSIONS: Naloxegol is likely a cost-effective treatment option for LIR patients with OIC. This assessment should be supported by further work on the utility of patients with OIC, including how utility varies with more granular measures of OIC.

Prime-boost vaccination with chimpanzee adenovirus and modified vaccinia Ankara encoding TRAP provides partial protection against Plasmodium falciparum infection in Kenyan adults.

Protective immunity to the liver stage of the malaria parasite can be conferred by vaccine-induced T cells, but no subunit vaccination approach based on cellular immunity has shown efficacy in field studies. We randomly allocated 121 healthy adult male volunteers in Kilifi, Kenya, to vaccination with the recombinant viral vectors chimpanzee adenovirus 63 (ChAd63) and modified vaccinia Ankara (MVA), both encoding the malaria peptide sequence ME-TRAP (the multiple epitope string and thrombospondin-related adhesion protein), or to vaccination with rabies vaccine as a control. We gave antimalarials to clear parasitemia and conducted PCR (polymerase chain reaction) analysis on blood samples three times a week to identify infection with the malaria parasite Plasmodium falciparum. On Cox regression, vaccination reduced the risk of infection by 67% [95% confidence interval (CI), 33 to 83%; P = 0.002] during 8 weeks of monitoring. T cell responses to TRAP peptides 21 to 30 were significantly associated with protection (hazard ratio, 0.24; 95% CI, 0.08 to 0.75; P = 0.016).

Model-based cost-effectiveness analyses for the treatment of chronic lymphocytic leukaemia: a review of methods to model disease outcomes and estimate utility.

Assessing the economic value of treatments for chronic lymphocytic leukaemia (CLL) is necessary to support healthcare decision makers; however, it poses a number of challenges. This paper reviews economic models of CLL treatment to learn the lessons from this experience and support ongoing model efforts. A search of databases and submissions to key health technology assessment agencies identified nine models. The modelling approaches adopted across these studies were fairly similar, with most models adopting a cohort Markov structure, though one example of a discrete event simulation was identified. While the cohort Markov approach has been acceptable to the National Institute for Health and Care Excellence, the review identifies a number of key uncertainties with these models, including the extrapolation of survival outcomes beyond the period observed by the trial, the effectiveness of second-line therapies, and estimates of health state utility. Further work is required to overcome these uncertainties, including comprehensive sensitivity analysis, systematic review of the evidence on the natural progression of CLL, and the collection of longer-term trial and registry data.

Model-based cost-effectiveness analyses for the treatment of chronic myeloid leukaemia: a review and summary of challenges.

Assessing the economic value of treatments for chronic myeloid leukaemia (CML) is important but poses a number of challenges. This paper reviews economic models of CML treatment to learn lessons from this experience and support ongoing efforts to model CML. A search of databases and submissions to key health technology assessment agencies identified 12 studies that reported 22 models. Common practice included the use of cohort Markov models-most models used health states organised around the key stages in CML: chronic phase, accelerated phase and blast phase-and the use of utility estimates in the literature that correspond with the National Institute for Health and Care Excellence reference case. Two key areas of uncertainty were the extrapolation of survival outcomes beyond the period observed by the trial; and the effectiveness of second-line therapies. Further work is required to overcome these uncertainties in existing models, such as longer-term trial data collection, including trials of second-line therapies; validation of health-related quality-of-life instruments; and the testing of alternative modelling approaches. In the meantime, it is important that the impact of uncertainties is tested through the use of sensitivity and scenario analysis.

Mind the gaps: what's missing from current economic evaluations of universal HPV vaccination?

BACKGROUND: Since the original licensing of human papilloma virus (HPV) vaccination for women, evidence is accumulating of its effectiveness in preventing HPV-related conditions in men, and universal vaccination (vaccinating men and women) is now recommended in some countries. Several models of the cost-effectiveness of universal HPV vaccination have been published, but results have been mixed. This article assesses the extent to which economic studies have captured the range of values associated with universal HPV vaccination, and how this influences estimates of its cost-effectiveness. METHODS: Eight published economic evaluations of universal HPV vaccination were reviewed to identify which of the values associated with universal HPV vaccination were included in each analysis. RESULTS: Studies of the cost-effectiveness of universal HPV vaccination capture only a fraction of the values generated. Most studies focused on impacts on health and health system cost, and only captured these partially. A range of values is excluded from most studies, including impacts on productivity, patient time and costs, carers and family costs, and broader social values such as the right to access treatment. Further, those studies that attempted to capture these values only did so partially. DISCUSSION: Decisions to invest in universal HPV vaccination need to be based on a complete assessment of the value that it generates. This is not provided by existing economic evaluations. Further work is required to understand this value. First, research is required to understand how HPV-related health outcomes impact on society including, for instance, their impact on productivity. Second, consideration should be given to alternative approaches to capture this broader set of values in a manner useful to decisions-makers, such as multi-criteria decision analysis.

The blood-stage malaria antigen PfRH5 is susceptible to vaccine-inducible cross-strain neutralizing antibody.

Current vaccine strategies against the asexual blood stage of Plasmodium falciparum are mostly focused on well-studied merozoite antigens that induce immune responses after natural exposure, but have yet to induce robust protection in any clinical trial. Here we compare human-compatible viral-vectored vaccines targeting ten different blood-stage antigens. We show that the full-length P. falciparum reticulocyte-binding protein homologue 5 (PfRH5) is highly susceptible to cross-strain neutralizing vaccine-induced antibodies, out-performing all other antigens delivered by the same vaccine platform. We find that, despite being susceptible to antibody, PfRH5 is unlikely to be under substantial immune selection pressure; there is minimal acquisition of anti-PfRH5 IgG antibodies in malaria-exposed Kenyans. These data challenge the widespread beliefs that any merozoite antigen that is highly susceptible to immune attack would be subject to significant levels of antigenic polymorphism, and that erythrocyte invasion by P. falciparum is a degenerate process involving a series of parallel redundant pathways.

The plasma concentration of the B cell activating factor is increased in children with acute malaria.

Malaria-specific antibody responses in children often appear to be short-lived but the mechanisms underlying this phenomenon are not well understood. In this study, we investigated the relationship between the B-cell activating factor (BAFF) and its receptors expressed on B cells with antibody responses during and after acute malaria in children. Our results demonstrate that BAFF plasma levels increased during acute malarial disease and reflected disease severity. The expression profiles for BAFF receptors on B cells agreed with rapid activation and differentiation of a proportion of B cells to plasma cells. However, BAFF receptor (BAFF-R) expression was reduced on all peripheral blood B cells during acute infection, but those children with the highest level of BAFF-R expression on B cells maintained schizont-specific immunoglobin G (IgG) over a period of 4 months, indicating that dysregulation of BAFF-R expression on B cells may contribute to short-lived antibody responses to malarial antigens in children. In summary, this study suggests a potential role for BAFF during malaria disease, both as a marker for disease severity and in shaping the differentiation pattern of antigen-specific B cells.

Plasmodium falciparum var gene expression is modified by host immunity.

Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) is a potentially important family of immune targets, which play a central role in the host-parasite interaction by binding to various host molecules. They are encoded by a diverse family of genes called var, of which there are approximately 60 copies in each parasite genome. In sub-Saharan Africa, although P. falciparum infection occurs throughout life, severe malarial disease tends to occur only in childhood. This could potentially be explained if (i) PfEMP1 variants differ in their capacity to support pathogenesis of severe malaria and (ii) this capacity is linked to the likelihood of each molecule being recognized and cleared by naturally acquired antibodies. Here, in a study of 217 Kenyan children with malaria, we show that expression of a group of var genes "cys2," containing a distinct pattern of cysteine residues, is associated with low host immunity. Expression of cys2 genes was associated with parasites from young children, those with severe malaria, and those with a poorly developed antibody response to parasite-infected erythrocyte surface antigens. Cys-2 var genes form a minor component of all genomic var repertoires analyzed to date. Therefore, the results are compatible with the hypothesis that the genomic var gene repertoire is organized such that PfEMP1 molecules that confer the most virulence to the parasite tend also to be those that are most susceptible to the development of host immunity. This may help the parasite to adapt effectively to the development of host antibodies through modification of the host-parasite relationship.

Tumor necrosis factor and lymphotoxin-alpha polymorphisms and severe malaria in African populations.

The tumor necrosis factor gene (TNF) and lymphotoxin-alpha gene (LTA) have long attracted attention as candidate genes for susceptibility traits for malaria, and several of their polymorphisms have been found to be associated with severe malaria (SM) phenotypes. In a large study involving >10,000 individuals and encompassing 3 African populations, we found evidence to support the reported associations between the TNF -238 polymorphism and SM in The Gambia. However, no TNF/LTA polymorphisms were found to be associated with SM in cohorts in Kenya and Malawi. It has been suggested that the causal polymorphisms regulating the TNF and LTA responses may be located some distance from the genes. Therefore, more-detailed mapping of variants across TNF/LTA genes and their flanking regions in the Gambian and allied populations may need to be undertaken to find any causal polymorphisms.

The cost of future problem drug use associated with young people's behaviors and circumstances.

The UK Drug Strategy includes the objective of preventing young people from becoming drug misusers. It is the use of heroin, crack and heavy use of cocaine that accounts for most of the costs associated with drug use. However, research on the efficiency of young people's interventions at reducing such problem drug use is limited by the expense associated with long-term evaluations. An alternative to undertaking expensive long-term research is to model the probable longer-term problem drug use associated with young people's behavior and circumstances. This paper estimates the economic cost of future problem drug use associated with young people's behavior and circumstances, such as their cannabis, cigarette and alcohol use, delinquency and the drug use of their parents and peers.