The development of HTA collaboration at European level and the challenge of the EU regulation

Issue

The establishment of HTA has been an important topic in Europe for many years. The engagement of HTA agencies, scientists, politicians and many other stakeholders throughout more than 20 years lead to the EU-HTA regulation, which came into force beginning of 2022. Now it is time to prepare for a sustainable European Network for HTA.

Description

The implementation of HTA in Europe is of high importance of the EU-commission for more than 20 years. Started with the first projects in 1994 (EUR-ASSESS) it needed quite a bunch of different projects and, in the end, three joint actions for finally providing legal ground for HTA with the EU-HTA regulation. This journey seemed a long one. However, referring to the need of addressing the requirements of Health Care of 27 Member States combined with the demand of reliable high methodological quality and applicability, investing all the time and effort for a sustainable European Network of HTA was definitely worthwhile. Joint Scientific Consultation (JSC) and Joint Clinical Assessments (JCA) will play a central role for national HTA and decision making in health care. But for understanding role, content, national uptake and further development of means, products and results of a European Network for HTA it is quite important to get a perception of the development of HTA collaboration in Europe. Based on this the challenge of the EU-HTA regulation and its implementation will be tackled easier.

Effects

Through provision of the main pillars of the previous EU-HTA collaboration the appreciation and understanding of the differences and complexities behind the HTA processes in the EU-healthcare systems will made aware. Based on this understanding the challenges of the implementation of the EU-HTA regulation will be discussed.

Multi-locus stepwise regression: a haplotype-based algorithm for finding genetic associations applied to atopic dermatitis

Background

Genome-wide association studies (GWAS) provide an increasing number of single nucleotide polymorphisms (SNPs) associated with diseases. Our aim is to exploit those closely spaced SNPs in candidate regions for a deeper analysis of association beyond single SNP analysis, combining the classical stepwise regression approach with haplotype analysis to identify risk haplotypes for complex diseases.

Methods

Our proposed multi-locus stepwise regression starts with an evaluation of all pair-wise SNP combinations and then extends each SNP combination stepwise by one SNP from the region, carrying out haplotype regression in each step. The best associated haplotype patterns are kept for the next step and must be corrected for multiple testing at the end. These haplotypes should also be replicated in an independent data set. We applied the method to a region of 259 SNPs from the epidermal differentiation complex (EDC) on chromosome 1q21 of a German GWAS using a case control set (1,914 individuals) and to 268 families with at least two affected children as replication.

Results

A 4-SNP haplotype pattern with high statistical significance in the case control set (p = 4.13 × 10^-7 after Bonferroni correction) could be identified which remained significant in the family set after Bonferroni correction (p = 0.0398). Further analysis revealed that this pattern reflects mainly the effect of the well-known FLG gene; however, a FLG-independent haplotype in case control set (OR = 1.71, 95% CI: 1.32-2.23, p = 5.6 × 10^-5) and family set (OR = 1.68, 95% CI: 1.18-2.38, p = 2.19 × 10^-3) could be found in addition.

Conclusion

Our approach is a useful tool for finding allele combinations associated with diseases beyond single SNP analysis in chromosomal candidate regions.

Distinct barrier integrity phenotypes in filaggrin-related atopic eczema following sequential tape stripping and lipid profiling

BACKGROUND

Filaggrin gene (FLG) loss-of-function mutations have been shown to represent the strongest so far known genetic risk factor for atopic dermatitis (AD). Whereas the barrier characteristics in FLG mutation carriers under baseline conditions have been investigated, there are only limited data on the permeability barrier function in filaggrin-AD under compromised conditions.

AIM

We investigated: (i) stratum corneum (SC) integrity/cohesion; (ii) barrier recovery after controlled mechanical and irritant-induced barrier abrogation; and (iii) the lipid composition of the non-lesional and lesional skin of AD patients harbouring the European R501X, 2282del4, 3702delG, R2447X or S3247X FLG variants.

METHODS

Thirty-seven AD patients (14 FLG mutation carriers and 23 non-carriers) and 20 healthy controls participated in the study. Stratum corneum integrity/cohesion was assessed by measurement of transepidermal water loss (TEWL) and amount of removed protein following sequential tape stripping. Barrier recovery was monitored by repeated measurements of TEWL and erythema up to 96 h after barrier abrogation. Samples for lipid analysis were obtained from non-lesional and lesional skin using the cyanoacrylate method.

RESULTS

Tape stripping revealed distinct genotype-related impairment of the SC integrity/cohesion. No differences in the rate of barrier recovery among the groups were found. The SC lipid analysis revealed significant differences regarding the percentage amount of cholesterol, ceramide/cholesterol ratio and triglycerides in the uninvolved skin as well as the amounts of free fatty acids, CER[EOH] and triglycerides in the skin lesions of the AD FLG mutation carriers.

CONCLUSIONS

Our results provide evidence for discernible FLG-related barrier integrity phenotypes in atopic eczema.

Genetic association of DLG5 R30Q with familial and sporadic inflammatory bowel disease in men

BACKGROUND

The association of DLG5 R30Q with IBD has been replicated in several populations, but is not statistically significant in others. We studied the incidence of DLG5 alleles in a population of IBD patients from Pennsylvania.

METHODS

DLG5 R30Q (rs1248696) and G1066G (rs1248634) were analyzed with PCR-based RFLP methods in a total of 521 subjects, that included 105 individuals with IBD and 139 without IBD from a familial IBD registry, 107 with sporadic IBD, and 170 unrelated healthy controls. R30Q was further analyzed with SNPlex Genotyping System in 473 samples.

RESULTS

RFLP genotyping data showed that, DLG5 R30Q was significantly associated with IBD overall (p=0.006), and separately with CD (p=0.009) and UC (p=0.024). The association of R30Q with IBD was entirely due to a male-associated effect (male vs female p=0.015 vs 0.241 (IBD), p=0.024 vs 0.190 (CD), and p=0.019 vs 0.575 (UC)). The frequency of the A allele carriage was elevated in both affected and unaffected members in the familial IBD cohort compared to healthy controls (p=0.037). In the family pedigrees, we observed differences in the expression of IBD in individuals carrying the A allele between families.

CONCLUSIONS

In the studied population, DLG5 R30Q was associated with all forms of IBD. An elevated presence of the R30Q variant was observed in all members of a familial IBD registry. This association of the R30Q variant with IBD was male-specific.

Genetic association of nonsynonymous variants of the IL23R with familial and sporadic inflammatory bowel disease in women

PURPOSE

To replicate the association of IL23R R381Q (rs11209026) with inflammatory bowel disease (IBD), examine the effect of the two nonsynonymous variations, Q3H and L310P, on IBD, and to study gender distribution of these variants in IBD patients.

RESULTS

IL23R R381Q was associated with Crohn's disease (CD) (P = 0.010), but not with ulcerative colitis (UC); L310P was associated with UC (P = 0.004), but not with CD; no association was observed for Q3H with CD or UC. A female-specific association of R381Q with CD (P = 0.041), and of L310P with UC (P = 0.008) was observed.

CONCLUSION

We replicated the association of IL23R R381Q with CD but not UC, and we observed an association of L310P with UC, but not CD, in a central Pennsylvania population. Further analysis of the distribution of IL23R variants revealed that these effects were largely female-specific. The results suggest that IL23R R381Q confers protection against CD and that L310P confers protection against UC in females.

TBX21 gene variants increase childhood asthma risk in combination with HLX1 variants

BACKGROUND

The T cell-specific T-box transcription factor (TBX21) plays a crucial role in the regulation of the immune system because this factor induces the differentiation of T(H)1 and blocks T(H)2 commitment together with the homeobox transcription factor HLX1.

OBJECTIVE

The role of genetic variants in TBX21 alone and in combination with HLX1 polymorphisms was investigated in the development of T(H)2-associated atopy and asthma.

METHODS

The TBX21 gene was resequenced in 37 adult volunteers. Polymorphisms identified were genotyped in a cross-sectional (N = 3099) and nested asthma case-control population (N = 1872) using mainly matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. Effects of promoter polymorphisms on TBX21 gene expression were studied by reporter gene assays. Furthermore, the impact of combinations of TBX21 and HLX1 polymorphisms on the development of asthma was assessed by using a risk score model. Statistical analyses were performed by using SAS/Genetics.

RESULTS

Forty-three polymorphisms were identified in the TBX21 gene. Considering a minor allele frequency of at least 10%, single nucleotide polymorphisms were assigned to 7 linkage disequilibrium blocks. Three tagging single nucleotide polymorphisms increased childhood asthma risk significantly (odds ratio [OR], 2.60, 95% CI, 1.34-5.03, P = .003; OR, 1.39, 95% CI, 1.02-1.90, P = .039; and OR, 1.97, 95% CI, 1.18-3.30, P = .009). TBX21 promoter polymorphisms contained in 2 blocks significantly influenced TBX21 promoter activity. In a risk score model, the combination of TBX21 and HLX1 polymorphisms increased the asthma risk by more than 3-fold.

CONCLUSIONS

These data suggest that TBX21 polymorphisms contribute to the development of asthma, potentially by altering TBX21 promoter activity. A risk score model indicates that TBX21 and HLX1 polymorphisms may have synergistic effects on asthma risk.

An evaluation of the genetic-matched pair study design using genome-wide SNP data from the European population

Genetic matching potentially provides a means to alleviate the effects of incomplete Mendelian randomization in population-based gene-disease association studies. We therefore evaluated the genetic-matched pair study design on the basis of genome-wide SNP data (309,790 markers; Affymetrix GeneChip Human Mapping 500K Array) from 2457 individuals, sampled at 23 different recruitment sites across Europe. Using pair-wise identity-by-state (IBS) as a matching criterion, we tried to derive a subset of markers that would allow identification of the best overall matching (BOM) partner for a given individual, based on the IBS status for the subset alone. However, our results suggest that, by following this approach, the prediction accuracy is only notably improved by the first 20 markers selected, and increases proportionally to the marker number thereafter. Furthermore, in a considerable proportion of cases (76.0%), the BOM of a given individual, based on the complete marker set, came from a different recruitment site than the individual itself. A second marker set, specifically selected for ancestry sensitivity using singular value decomposition, performed even more poorly and was no more capable of predicting the BOM than randomly chosen subsets. This leads us to conclude that, at least in Europe, the utility of the genetic-matched pair study design depends critically on the availability of comprehensive genotype information for both cases and controls.

Investigation of the colorectal cancer susceptibility region on chromosome 8q24.21 in a large German case-control sample

Human chromosome 8q24.21 has been implicated as a susceptibility region for colorectal cancer (CRC) as a result of genome-wide association and candidate gene studies. To assess the impact of molecular variants at 8q24.21 upon the CRC risk of German individuals and to refine the disease-associated region, a total of 2,713 patients with operated CRC (median age at diagnosis: 63 years) were compared with 2,718 sex-matched control individuals (median age at inclusion: 65 years). Information on microsatellite instability in tumors was available for 901 patients. Association analysis of SNPs rs10505477 and rs6983267 yielded allelic p-values of 1.42 x 10(-7) and 2.57 x 10(-7), respectively. For both polymorphisms, the odds ratio was estimated to be 1.50 (95% CI: 1.29-1.75) under a recessive disease model. The strongest candidate interval, outside of which significance dropped by more than 4 orders of magnitude, was delineated by SNPs rs10505477 and rs7014346 and comprised 17 kb. In a subgroup analysis, the disease association was found to be more pronounced in MSI-stable tumors (odds ratio: 1.71). Our study confirms the role of genetic variation at 8q24.21 as a risk factor for CRC and localizes the corresponding susceptibility gene to a 17 kb candidate region.

Polymorphisms of the IL12B and IL23R genes are associated with psoriasis

Psoriasis is a common inflammatory and hyperproliferative skin disease with a multifactorial genetic basis. A recent study reported that psoriasis was associated with the IL12B haplotype rs3212227 (3'-untranslated region)-rs6887695 (60 kb, 5') and the IL23R haplotype rs7530511 (L310P)-rs11209026 (Q381R). We examined these four single-nucleotide polymorphisms (SNPs) for association with psoriasis in two groups of North American and German Caucasians: (1) 1,810 cases and 2,522 controls; and (2) 509 pedigrees. Both IL12B markers showed highly significant association with psoriasis in the case-control (rs3212227, odds ratio (OR)=1.62, P=1.7 x 10(-15); rs6887695, OR=1.49, P=2.7 x 10(-15)) and in the family-based analysis (rs3212227, P=2.2 x 10(-3); rs6887695, P=1.7 x 10(-3)). The IL23R SNPs also showed significant association in the cases and controls (rs7530511, OR=1.22, P=3.9 x 10(-3); rs11209026, OR=1.40, P=3.8 x 10(-4)). For both genes, common risk haplotypes were identified whose statistical significance approached (IL23R) or exceeded (IL12B) genome-wide criteria. We found no statistical evidence for interactions of these haplotypes with HLA-Cw6. Our results confirm associations between IL12B and IL23R and psoriasis in Caucasians, and provide a genetic basis for the clinical association between psoriasis and Crohn's disease.

Genome-wide association study for Crohn's disease in the Quebec Founder Population identifies multiple validated disease loci

Genome-wide association (GWA) studies offer a powerful unbiased method for the identification of multiple susceptibility genes for complex diseases. Here we report the results of a GWA study for Crohn's disease (CD) using family trios from the Quebec Founder Population (QFP). Haplotype-based association analyses identified multiple regions associated with the disease that met the criteria for genome-wide significance, with many containing a gene whose function appears relevant to CD. A proportion of these were replicated in two independent German Caucasian samples, including the established CD loci NOD2 and IBD5. The recently described IL23R locus was also identified and replicated. For this region, multiple individuals with all major haplotypes in the QFP were sequenced and extensive fine mapping performed to identify risk and protective alleles. Several additional loci, including a region on 3p21 containing several plausible candidate genes, a region near JAKMIP1 on 4p16.1, and two larger regions on chromosome 17 were replicated. Together with previously published loci, the spectrum of CD genes identified to date involves biochemical networks that affect epithelial defense mechanisms, innate and adaptive immune response, and the repair or remodeling of tissue.

Interleukin-18 is increased only in a minority of patients with active Crohn's disease

BACKGROUND AND AIMS

It has been suggested that Crohn's Disease (CD) is associated with an elevated T helper 1 response as manifested by increased production of interleukin-18 (IL-18). Local concentrations of neutralizing IL-18 binding proteins (IL-18 bp) may counteract biological functions of mature IL-18 in mucosal inflammation. Therefore, we investigated the IL-18/IL-18 bp system in a large group of patients with active inflammatory bowel disease (IBD) to identify patients that could respond theoretically to IL-18 neutralizing treatment strategies.

PATIENT/METHODS

IL-18 and IL-18 bp messenger RNA (mRNA) expression in colonic mucosa from patients with active CD (n = 72), active ulcerative colitis (UC; n = 32), and non-IBD controls (infectious colitis or diverticulitis; n = 19) and normal, non-diseased controls (n = 20) were measured by reverse-transcribed real-time polymerase chain reaction. Mature IL-18 protein and IL-18 bp expression in inflamed mucosa were assessed by Western blotting.

RESULTS/FINDINGS

Although IL-18 mRNA was increased in some patients with CD, the increase was not statistically significant. Densitometric evaluation of IL-18/alpha-actin ratio in patients with active CD (n = 20) and patients with UC (n = 10) demonstrated an increased ratio of IL-18 protein in CD when compared to UC (1.04 vs 0.72 [median]). On closer inspections, only 7/20 CD patients had an increased IL-18 protein expression in inflamed areas compared to noninflamed mucosa.

INTERPRETATION/CONCLUSION

IL-18 expression in active CD is heterogeneous, only a minority of patients expresses elevated levels. Further treatment strategies targeting IL-18 expression in active CD should be concentrated on this subgroup of patients.

Systematic association mapping identifies NELL1 as a novel IBD disease gene

Crohn disease (CD), a sub-entity of inflammatory bowel disease (IBD), is a complex polygenic disorder. Although recent studies have successfully identified CD-associated genetic variants, these susceptibility loci explain only a fraction of the heritability of the disease. Here, we report on a multi-stage genome-wide scan of 393 German CD cases and 399 controls. Among the 116,161 single-nucleotide polymorphisms tested, an association with the known CD susceptibility gene NOD2, the 5q31 haplotype, and the recently reported CD locus at 5p13.1 was confirmed. In addition, SNP rs1793004 in the gene encoding nel-like 1 precursor (NELL1, chromosome 11p15.1) showed a consistent disease-association in independent German population- and family-based samples (942 cases, 1082 controls, 375 trios). Subsequent fine mapping and replication in an independent sample of 454 French/Canadian CD trios supported the authenticity of the NELL1 association. Further confirmation in a large German ulcerative colitis (UC) sample indicated that NELL1 is a ubiquitous IBD susceptibility locus (combined p<10⁻⁶; OR = 1.66, 95% CI: 1.30–2.11). The novel 5p13.1 locus was also replicated in the French/Canadian sample and in an independent UK CD patient panel (453 cases, 521 controls, combined p<10⁻⁶ for SNP rs1992660). Several associations were replicated in at least one independent sample, point to an involvement of ITGB6 (upstream), GRM8 (downstream), OR5V1 (downstream), PPP3R2 (downstream), NM_152575 (upstream) and HNF4G (intron).

Functional P2X7Receptor Polymorphisms (His155Tyr, Arg307Gln, Glu496Ala) in Patients with Crohn's Disease

Genetic factors contribute to inflammatory bowel diseases. Recently, the P2X(7) receptor was found to be a key player in caspase-1-mediated processing of the proinflammatory cytokines, interleukin-1beta and interleukin-18. We therefore aimed to determine whether the gain-of-function single nucleotide polymorphism (SNP) His155Tyr and the loss-of-function SNP Arg307Gln and Glu496Ala were associated with susceptibility to Crohn's disease (CD). For association analysis, 681 unrelated CD patients and 736 healthy controls were enrolled. Furthermore, 490 CD trios were included for segregation analysis. Genotyping was performed by the application of the TaqMan(R) MGB biallelic discrimination system. The Arg307Gln polymorphism revealed a borderline significant difference in genotype frequencies between CD patients and controls (P = 0.06) without implying any pathological significance because of low case numbers. Case-control statistics for the variants His155Tyr and Glu496Ala showed no association with CD phenotype (P = 0.19 and 0.99). Subsequent family-based transmission disequilibrium test did not prove an association of the investigated single-nucleotide polymorphisms with CD. In conclusion, the analysed intragenetic variants of the P2X(7) receptor may not be a susceptibility factor for CD.