Abstract CT139: Durability of responses to the combination of SD-101 and pembrolizumab in advanced metastatic melanoma: Results of a phase Ib, multicenter study

Background: This phase 1b trial evaluates the safety and antitumor efficacy of the combination of SD-101, a synthetic CpG-oligonucleotide that stimulates Toll-like receptor 9 (TLR9), and pembrolizumab in patients with recurrent Stage IIIC/IV malignant melanoma.

Methods: Dose escalation of SD-101 used a modified 3+3 design. SD-101 was injected in a single tumor lesion (weekly x 4 doses then every 3 weeks x 7 doses over 6 months) at 1, 2, 4, or 8 mg and pembrolizumab was administered intravenously at 200 mg every 3 weeks up to 2 years. Tumor responses were assessed per investigator using RECIST v1.1 taking into account both injected and non-injected lesions.

Results: Of the 22 patients, 9 were naïve to anti-PD-1/L1 therapy at baseline and 13 had progressive disease while receiving prior anti-PD-1/L1 therapy. Treatment was well tolerated with no Grade 3 or higher treatment-related AEs in longer term follow up. Among the 9 patients who were anti-PD-1/L1 naïve, best objective responses were CR: 2, PR: 5, PD: 1, not evaluated [NE]: 1. Median PFS, duration of response, and OS have not been reached. Estimated 12 month PFS was 88% and OS was 89%. After a median of 18 months of follow-up, 86% of responses were ongoing. One patient with a PR developed progressive disease after 20 months of treatment. Among patients who had received prior anti-PD-1/L1 therapy, best objective responses were PR: 2, SD: 5, PD: 5, NE: 1. One patient with stable disease and 1 patient with a PR continued on combination therapy without progression for at least 10.5 months. The other 10 patients developed progressive disease ranging from 1.5 to 8 months after enrollment. Percent change in tumor size from baseline in injected and non-injected lesions will also be presented.

Conclusion: These early results suggest that combining an intratumoral TLR9 innate immune stimulant with PD-1 blockade can potentially provide more clinical responses that are meaningfully durable than PD-1 blockade alone based on historical data.

Citation Format: Antoni Ribas, Theresa Medina, Shivaani Kummar, Asim Amin, Joseph J. Drabick, Minal Barve, Gregory Daniels, Deborah L. Wong, Emmett V. Schmidt, Abraham C. Leung, Robert Janssen. Durability of responses to the combination of SD-101 and pembrolizumab in advanced metastatic melanoma: Results of a phase Ib, multicenter study [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr CT139.

Abstract CT098: Phase Ib/II, open label, multicenter study of intratumoral SD-101 in combination with pembrolizumab in anti-PD-1 treatment naïve patients with recurrent or metastatic head and neck squamous cell carcinoma (HNSCC)

Background and Objectives: SD-101 is a synthetic CpG-ODN agonist of TLR9 that stimulates dendritic cells to release IFN-alpha and mature into antigen presenting cells to activate T cell anti-tumor responses. Pembrolizumab is a PD-1 inhibitor that has demonstrated activity in HNSCC with ORR of 14%. Study DV3-MEL-01 (NCT02521870) assesses the safety and preliminary efficacy of SD-101 in combination with pembrolizumab in patients with recurrent or metastatic HNSCC.

Methods: In phase 2 expansion cohort for anti-PD-1 treatment naïve HNSCC patients, SD-101 was injected in a single tumor lesion (weekly x 4 doses then every 3 weeks x 7 doses) at 8 mg and pembrolizumab was administered intravenously at 200 mg every 3 weeks. Responses are assessed per investigator using RECIST v1.1/irRECIST.

Preliminary Data and Results: 16 anti-PD-1 treatment naïve HNSCC patients are enrolled to date: median age 65 y/o, male 94%, ECOG PS1 63%, median prior lines of therapy 1. SD-101 safety profile consists of flu-like symptoms and injection-site reactions. Grade≥3 treatment-related AEs observed to date included influenza-like symptoms, myalgia, headache, injection site pain and swelling, and fatigue with each of the toxicities occurring in 1 patient (6.7%). No increase in frequency of known pembrolizumab immune-related AEs has been observed to date. ORR in evaluable pts (n=10) was 40% (4 PRs; 1 SD, 5 PDs with 1 still on treatment). The duration of response will be characterized when follow-up data become more mature.

Conclusions: In anti-PD-1 treatment naïve HNSCC patients, SD-101 in combination with pembrolizumab showed a promising response rate and has been well tolerated. Full accrual of subjects in this cohort is ongoing.

Citation Format: Ezra Cohen, Sarwan Bishnoi, Douglas E. Laux, Deborah Wong, Asim Amin, Lisle Nabell, Emmett V. Schmidt, Biao Xing, Abraham C. Leung, Robert Janssen. Phase Ib/II, open label, multicenter study of intratumoral SD-101 in combination with pembrolizumab in anti-PD-1 treatment naïve patients with recurrent or metastatic head and neck squamous cell carcinoma (HNSCC) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2018; 2018 Apr 14-18; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2018;78(13 Suppl):Abstract nr CT098.

Abstract LB-239: Pharmacodynamic changes confirm the mechanism of action mediating SD-101 efficacy, in combination with pembrolizumab, in a phase 1b/2 study in metastatic melanoma (MEL-01)

Introduction: SD-101 is a synthetic CpG oligonucleotide agonist of Toll-like receptor 9. SD-101 stimulates dendritic cells to release interferon-alpha and mature into antigen presenting cells that effectively activate T cell responses. Pembrolizumab is a PD-1 inhibitor that has been approved for the treatment of multiple tumors including metastatic melanoma. In mouse tumor models, SD-101 synergizes with anti-PD-1 inducing substantial infiltration of tumor-reactive T cells and durable, complete responses in all treated animals. The MEL-01 trial assesses the safety and preliminary efficacy of SD-101 in combination with pembrolizumab in stage IIIC-IV melanoma. Previously presented clinical data suggest enhanced efficacy for this combination. Biomarker data from the MEL-01 trial support the mechanism of action of SD-101.

Methods: The dose escalation phase of this trial is a modified 3 + 3 design with 4 dose levels of SD-101 (1, 2, 4, and 8 mg) in combination with pembrolizumab. SD-101 is injected into a single tumor lesion qw X 4 followed by q3w X 7. Pembrolizumab is dosed at 200 mg IV q3w. Specimens for biomarker analyses included biopsies of the injected tumor and peripheral blood, and were taken before and after treatment (Days 29, 85 and 169). Biopsies were analyzed by multiplexed immunohistochemistry and Nanostring to evaluate the immunophenotype of the tumor environment. Peripheral blood collected immediately before and 24 hours after dosing was analyzed by qPCR with a panel of interferon (IFN) responsive genes to confirm target engagement. Tumor responses were assessed using RECIST v1.1.

Results: IFN signature profiling in blood indicated that SD-101 engages its target in a dose-dependent manner. In tumor biopsies taken after the fourth intratumoral injection, an elevated IFN signature was also observed, confirming persistent local immune activation. Nanostring assessments demonstrated increases in multiple immune cell types in tumors in a subset of patients. In particular, an increase in Th1 responses and a decrease in Th2 responses were found, a shift which is consistent the mechanism of action of SD-101. Immunophenotypic signatures generally correlated with tumor response and were greater in patients naïve to PD-1 treatment compared to patients who previously progressed on PD-1 treatment. Signals for immune suppression generally showed an inverse correlation with clinical response. An elevated CD8 profile was detected by Nanostring and confirmed by immunohistochemistry showing increased CD8+ T cell infiltration in tumors.

Conclusions: Biomarker assessments of the tumor microenvironment in melanoma patients receiving SD-101 and pembrolizumab demonstrate an immunophenotype with CD8 infiltration and a Th1 driven immune response consistent with the mechanism of action and anti-tumor activity of this combination.

Citation Format: Albert Candia, Cristiana Guiducci, Robert L. Coffman, Graeme Currie, Abraham Leung, Robert Janssen, Shivaani Kummar, Sanjiv Agarwala, John Nemunaitis, Rene Gonzalez, Joseph Drabick, Antoni Ribas. Pharmacodynamic changes confirm the mechanism of action mediating SD-101 efficacy, in combination with pembrolizumab, in a phase 1b/2 study in metastatic melanoma (MEL-01) [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr LB-239. doi:10.1158/1538-7445.AM2017-LB-239

Phase 1b/2, open label, multicenter, study of intratumoral SD-101 in combination with pembrolizumab in anti-PD1 naïve & experienced metastatic melanoma patients

9550

Background: SD-101 is a synthetic CpG-ODN agonist of TLR 9 that stimulates dendritic cells to release IFN-alpha and mature into antigen presenting cells to activate T cell anti-tumor responses. Pembro is a PD-1 inhibitor approved for the treatment of metastatic melanoma. This study, MEL-01 (NCT02521870), assesses the safety and preliminary efficacy of SD-101 in combination with pembro in stage IIIC-IV melanoma. Methods: A modified 3+3 design was used for SD-101 dose escalation of 1, 2, 4, and 8 mg injected in a single tumor lesion Q1W x 4 then Q3W x 7 in combination with pembro (200 mg IV Q3W). Tumor responses were assessed per investigator using RECIST v1.1. Results: In phase Ib, 22 pts were enrolled: median age 64 y/o, male 68%, white 82%, Stage IV/IIIc 86%/14%, LDH > 1 ULN 27%, ≥ 3 prior lines therapy 36%, anti-PD-1 naïve (n = 9) and experienced (n = 13). There has been no dose limiting toxicity (DLT) to date. The most common (≥20%) treatment-related AEs (TRAEs) were transient low-grade fatigue, myalgia, headache, chills and injection site reactions. Grade ≥ 3 TRAEs were observed in 59.1% pts (most common: myalgia 13.6% and injection site pain 13.6%). Immune-related AEs occurred in 2 pts. One had a G2 pneumonitis on Day 23 resulting in drug withdrawal and the other G3 hypophysitis (85 days after last treatment). No deaths occurred. Responses were observed at all doses in PD-1 inhibitor naïve pts, both at the injected and non-injected lesions. A response was seen at the 8 mg dose in PD-1 inhibitor experienced pts. With median f/u of 97 days (max 382), the ORR was 66.7% in the PD-1 inhibitor naïve patients with best overall response of CR 22.2% (n = 2), PR 44.4% (n = 4), SD 11.1% (n = 1), PD 11.1% (n = 1), and NE 11.1% (n = 1). In the PD-1 inhibitor experienced pts: PR 7.7% (n = 1) and SD 38.5% (n = 5). Conclusions: The combination of SD-101 and pembro was well tolerated and demonstrates no worsening of the expected toxicities of each of the individual monotherapies. These interim data support enhanced activity of adding SD-101 to pembro in anti-PD-1 naive metastatic melanoma as well as potential activity in anti-PD-1 experienced pts. Additional follow up data through May 15, 2017 will be presented. Clinical trial information: NCT02521870.

Abstract CT047: SD-101, a novel intratumoral class C CpG-ODN, given with low-dose radiation in patients with untreated low-grade B-cell lymphoma: interim results of a phase I trial

Prior studies have shown preliminary clinical efficacy in combining CPG-ODN with radiation therapy (XRT) to patients with indolent B-cell lymphoma. We report Phase 1 data of combination XRT and SD-101, a synthetic class C CPG-ODN, selected for strong induction of type I interferon.

Methods: This dose-escalation Phase I trial (3+3 design) enrolled patients with untreated indolent B-cell lymphoma. The primary endpoints were safety and alpha-interferon-gene induction. Secondary endpoints included efficacy assessment using Cheson (1999) criteria and quantification of changes in tumor-infiltrating lymphocytes. Patients had a single lesion treated with XRT (2 Gy daily X 2 days) followed by weekly intratumoral SD-101 × 5 doses. Pharmacodynamic assessment included flow cytometry assessment of T-cell infiltrates in a FNA sample of the treated tumor and RT-PCR RNA assay of whole blood to assess induction of alpha-interferon genes. Efficacy assessment included imaging (CT at 3, 6, and every 6 months thereafter).

Results: As of 23 Dec 2015, 13 patients total were enrolled and treated with SD-101 doses of 1, 2, 4 or 8 mg/dose. There were no dose limiting toxicities. Twelve patients received all planned doses of XRT and SD-101. One patient (8 mg) withdrew consent for treatment after receiving 1 SD-101 dose due to Grade 2 confusion and flu-like symptoms. The most common adverse events (AEs) (decreasing frequency) were chills, malaise, myalgia, fatigue, headache, pyrexia, and nausea, typically resolving within 48 hours. One serious AE occurred (Grade 3 Pulmonary Embolism (4 mg)) which was incidental and asymptomatic. There were 2 dose delays due to an AE (Grade 3 neutropenia) in the same patient (8 mg) that resolved without treatment. The other AE was Grade 3 malaise reported in 2 patients (8 mg). At study Day 90, a reduction of the product of diameters in treated tumors occurred in 12 patients (median -45.3%; range [-87, +100]) and in non-treated tumors occurred in 11 patients (median -8.1%; range [-48, +45]). An induction of alpha-interferon genes occurred at all dose levels with similar level of induction. At the treated site, regulatory T-cells (T Regs) were reduced in 8 of 10 patients (average decrease 22.3 + 9.5%) at Day 8. There was an average reduction of 83.3 + 9.9% in follicular T helper cells (Tfh) at Day 8 (n = 9 with baseline Tfh).

Conclusions: SD-101 combined with radiation therapy showed preliminary abscopal anti-tumor activity and was well tolerated. A maximum tolerated dose has not yet been reached at the doses explored. Target engagement of the TLR-9 receptor (induction of interferon-alpha genes) was observed across all dose groups. A decrease in the proportion of T Regs and Tfh cells suggests modulation of their inhibitory effects and tumor growth promoting effects, respectively. The study is currently enrolling 2 expansion cohorts at 1 mg and 8 mg.

Citation Format: Ronald Levy, Nancy Bartlett, Jonathan Friedberg, Patrick Reagan, Leo Gordon, Craig Bergman, Robert Coffman, Robert Janssen, Albert Candia, Michael Khodadoust, Matthew Frank, Steven Long, Debra Czerwinski, Michael Chu, Holbrook Kohrt. SD-101, a novel intratumoral class C CpG-ODN, given with low-dose radiation in patients with untreated low-grade B-cell lymphoma: interim results of a phase I trial. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr CT047.

[Two sisters with lung emphysema]

BACKGROUND

α1-antitrypsin is an antiprotease that is mainly produced in the liver; it plays a crucial role in the protection of lung parenchyma against the destructive effects of proteases. Mutations in the α1-antitrypsin gene can cause α1-antitrypsin deficiency. Individuals homozygous for the Z-genotype have drastically lowered serum α1-antitrypsine concentrations and often develop lung emphysema at an early age.

CASE DESCRIPTION

A 38-year-old woman and her 43-year-old sister both developed lung emphysema at an early age; this could be attributed to severe α1-antitrypsin deficiency. The only treatment for this condition is α1-antitrypsin supplement therapy, but this therapy is not reimbursed by health insurance companies in the Netherlands.

CONCLUSION

α1-antitrypsin deficiency is a relatively rare cause of lung emphysema and can be seen as an orphan phenotype of chronic obstructive pulmonary disease (COPD). We appeal for reconsideration of coverage of α1-antitrypsine supplement therapy by basic health insurance in the Netherlands, on the basis of a recent randomised placebo-controlled study in which the protective effect of this therapy on progressive emphysema was demonstrated by CT lung densitometry.

Single nucleotide polymorphisms in immune response genes in acute Q fever cases with differences in self-reported symptoms

Genes involved in human immune response are well recognized to influence the clinical course of infection. The association of host genetics with susceptibility to and severity of clinical symptoms in acute Q fever was investigated. Single nucleotide polymorphisms (SNPs) in the IFNG (rs2430561/rs1861493), STAT1 (rs1914408), and VDR (rs2228570) genes were determined in 85 patients from the 2007 Dutch acute Q fever outbreak, and a symptom score was calculated. IFNG rs1861493 showed a significant association with the symptom score; IFNG rs2430561 showed a similar trend. These SNPs were then used to reproduce results in a 2009 outbreak population (n = 123). The median symptom score differed significantly in both populations: 2 versus 7. The significant association of IFNG rs1861493 with symptom score in the first population was not reproduced in the second population. We hypothesize that individuals in the second outbreak were exposed to a higher Coxiella burnetii dose compared to the first, which overruled the protection conferred by the A-allele of IFNG rs1861493 in the first population.

Vitamin D-binding protein haplotype is associated with hospitalization for RSV bronchiolitis

BACKGROUND

Between 75 000 and 125 000 U.S. infants are hospitalized for respiratory syncytial virus (RSV) bronchiolitis every year. Up to half will be diagnosed with asthma in later childhood. Vitamin D deficiency has been associated with susceptibility to asthma and respiratory infections. Measured vitamin D is largely bound to vitamin D-binding protein (VDBP); VDBP levels are influenced by its gene (GC) haplotype.

OBJECTIVE

We assessed the relationship between polymorphisms rs7041 and rs4588, which define haplotypes GC1s, GC1f, and GC2, and RSV bronchiolitis susceptibility and subsequent asthma.

METHODS

We retrospectively recruited 198 otherwise healthy children (93% White) hospitalized for severe RSV bronchiolitis in Boston and 333 parents into a follow-up study to assess asthma diagnosis. Data were analysed using family-based genetic association tests. We independently validated our results in 465 White children hospitalized with RSV bronchiolitis and 930 White population controls from the Netherlands.

RESULTS

The rs7041_C allele (denoting haplotype GC1s) was overtransmitted (P = 0.02, additive model) in the entire Boston cohort, in Whites (P = 0.03), and especially in children subsequently diagnosed with asthma (P = 0.006). The GC1f haplotype was undertransmitted in the asthma subgroups (all races and White, both P < 0.05). The rs7041_C allele was also more frequent in the RSV bronchiolitis group compared with controls (OR 1.12, 95% CI 1.02, 1.4, P = 0.03) in the Netherlands, especially in mechanically ventilated patients (P = 0.009).

CONCLUSION AND CLINICAL RELEVANCE

GC1s haplotype carriage may increase the risk of RSV bronchiolitis in infancy and subsequent asthma development. The GC1s haplotype is associated with higher VDBP levels, resulting in less freely available vitamin D.

KEY MESSAGES

Vitamin D-binding protein (VDBP) haplotypes influence free vitamin D levels. We report an association between a VDBP haplotype and hospitalization for RSV bronchiolitis in infancy in two independent cohorts.

Reaction-Diffusion Dissipative Systems—Detailed Stability Analysis-Pattern of Growth and Effect of Inhomogenity

A detailed stability analysis of the one dimensional steady state solutions for the Brusselator model under the conditions of diffusion of initial (non-autocatalytic) components has been performed both for zero flux as well as fixed boundary conditions. In addition to subcritical as well as supercritical bifurcations, situations have been observed where all solution branches at a bifurcation point are unstable. A case of degenerate steady state bifurcation (2 solutions emanating from the same bifurcation point) has also been noticed. A transient simulation of the system in growth reveals the importance of growth rate on the pattern selection process and suggests that the selection of branches at a bifurcation point may be influenced by perturbations/ fluctuations. It also indicates that a stability analysis of the bifurcation diagram alone cannot decide the state of the system in a transient process, and under certain situations complex behavior may be observed at limit points.

Numerical calculations on coupled cells indicate that a heterogenity in the system can introduce multiple (two) time scales in the system. As the ratio of time scales increases, aperiodic or irregular oscillations are observed for the 'fast' variable. A combination of cells with one cell in a steady-state mode and the other in a periodic motion results in a combined motion of the entire system. For a distributed parameter system, a heterogenity can cause development of sharp local concentration gradients, alter the stability properties of steady state as well as periodic solutions and can cause partitioning of the system.

Imperfect Bifurcations and Spatial Structures in Dissipative Systems

One-dimensional reaction-diffusion equations associated with the trimolecular model of Prigogine and Lefever ("Brusselator") are analyzed. A physical description of possibilities of keeping con-centrations of initial components constant is discussed. It is shown that the problem considering diffusion of initial components gives rise to an imperfect bifurcation problem. The diffusion equa-tions have been solved numerically by a continuation procedure for the fixed and zero flux boundary conditions. The analysis indicates that the models including diffusion of all reacting components do not admit an occurence of trivial solutions. These models, as a result, also exclude the pos-sibility of primary bifurcations. The models which consider diffusion of the initial components suppress the number of possible solutions of governing equations. These models may also predict both symmetric and asymmetric states. Apparently this type of models is more suitable for predic-tion of patterns of spatial organization in growth. Since the number of possible profiles is strongly reduced this principle may lead to a more deterministic way of an evolution process. Symmetric profiles occuring on an isola cannot be reached by an evolution process unless a large perturbation is imposed on the system.

Technical strategies to improve tissue engineering of cartilage-carrier-constructs

Technical aspects play an important role in tissue engineering. Especially an improved design of bioreactors is crucial for cultivation of artificial three-dimensional tissues in vitro. Here formation of cartilage-carrier-constructs is used to demonstrate that the quality of the tissue can be significantly improved by using optimized culture conditions (oxygen concentration, growth factor combination) as well as special bioreactor techniques to induce fluid-dynamic, hydrostatic or mechanical load during generation of cartilage.

Interactive spatial tools for the design of regional adaptation strategies

Regional adaptation strategies are plans that consist of feasible measures to shift a region towards a system that is flexible and robust for future climate changes. They apply to regional impacts of climate change and are imbedded in broader planning. Multiple adaptation frameworks and guidelines exist that describe the development stages of regional adaptation strategies. Spatial information plays a key role in the design of adaptation measures as both the effects of climate change as well as many adaptation measures have spatial impacts. Interactive spatial support tools such as drawing, simulation and evaluation tools can assist the development process. This paper presents how to connect tasks derived from the actual development stages to spatial support tools in an interactive multi-stakeholder context. This link helps to decide what spatial tools are suited to support which stages in the development process of regional adaptation strategies. The practical implication of the link is illustrated for three case study workshops in the Netherlands. The regional planning workshops combine expertise from both scientists and stakeholders with an interactive mapping device. This approach triggered participants to share their expertise and stimulated integration of knowledge.

Psychometric evaluation of a Dutch version of the Mini PAS-ADD for assessing psychiatric disorders in adults with different levels of intellectual disability

BACKGROUND

People with intellectual disabilities (ID) have an increased vulnerability to develop psychiatric problems. Moreover, the early recognition and the accurate diagnosis of psychiatric disorders in the population of persons with ID are challenging.

METHOD

A Dutch version of the Mini PAS-ADD, which is a screening instrument for identification of mental health problems in people with ID, was evaluated in terms of internal consistency, interinformant reliability, item grouping and criterion validity based on a large-scale random sample (n = 377) and a clinical sample (n = 99) of adults with ID.

RESULTS

The Dutch version of the Mini PAS-ADD showed moderate internal consistency, and moderate concordance among informants. Both aspects of the reliability were comparable for different levels of ID. A factor analysis largely confirmed the scale structure. Concurrent validity with the Reiss Screen for Maladaptive Behavior was high for the Depression, Psychosis and Autism scale. The outcome of the criterion-validity analysis indicated high specificity. The sensitivity for specific psychiatric disorders by the corresponding scales was moderate, but the general sensitivity for the presence of psychopathology on the basis of any of the scales was satisfying.

CONCLUSIONS

The present research reconfirmed the use of the Mini PAS-ADD as a primary screening device for the identification of mental health problems among people with ID.

Confirmation of an association between single nucleotide polymorphisms in the VDR gene with respiratory syncytial virus related disease in South African children

Respiratory syncytial virus is a leading cause of lower respiratory tract infection in infants. Disease severity has been linked to host immune responses and polymorphisms in genes associated with innate immunity. A large-scale genetics study of single nucleotide polymorphisms (SNPs) in children in the Netherlands identified SNPs in the vitamin D receptor (VDR) and JUN genes which have a strong association with an increased risk of developing bronchiolitis following the first respiratory syncytial virus (RSV) infection. The Toll-like receptor 4 (TLR4) gene has two SNPs which have been associated previously with RSV disease severity in various populations. The aim of this study was to determine if these SNPs may be associated with RSV disease in African children in South Africa. RSV patient (n = 296) and control (n = 113) groups were established (median ages: 3 and 3.5 months) and DNA extracted from the collected specimens. Real-time polymerase chain reaction using hydrolysis probes was used to screen for SNPs in the VDR (Thr1Meth; rs10735810), TLR4 (Asp299Gly; rs4986790 and Thr399Ile; rs4986791) and JUN (c.750G/A; rs11688) genes. Carriers of the VDR (Thr1Meth) SNP minor T allele were more prone to RSV disease than individuals in the control group. The TLR4 (Asp299Gly), TLR4 (Thr399Ile), and JUN (c.750G/A) SNPs showed no significant association with RSV disease. It is concluded that children carrying the minor T allele of the VDR (Thr1Meth) SNP may be predisposed to RSV disease, as this SNP was identified as a risk factor for severe RSV disease in South African children, confirming the findings in the Netherlands.

Volumetric analysis of osteoclastic bioresorption of calcium phosphate ceramics with different solubilities

Commonly, to determine osteoclastic resorption of biomaterials only the resorbed area is measured. The depth of the resorption pit, however, may also be important for the performance of a material. To generate such data we used two calcium phosphate ceramics (Ca(10) and Ca(2)). The solubility of the materials was determined according to DIN EN ISO 10993-14. They were scanned three-dimensionally using infinite focus microscopy and subsequently cultivated for 4 weeks in simulated body fluid without (control) or with human osteoclasts. After this cultivation period osteoclasts number was determined and surface changes were evaluated two- and three-dimensionally. Ca(10) and Ca(2) showed solubilities of 11.0+/-0.5 and 23.0+/-2.2 mgg(-1), respectively. Both materials induced a significant increase in osteoclast number. While Ca(10) did not show osteoclastic resorption, Ca(2) showed an increased pit area and pit volume due to osteoclastic action. This was caused by an increased average pit depth and an increased number of pits, while the average area of single pits did not change significantly. The deduced volumetric osteoclastic resorption rate (vORR) of Ca(2) (0.01-0.02 microm(3)microm(-2)day(-1)) was lower than the remodelling speed observed in vivo (0.08 microm(3)microm(-2)day(-1)), which is in line with the observation that implanted resorbable materials remain in the body longer than originally expected. Determination of volumetric indices of osteoclastic resorption might be valuable in obtaining additional information about cellular resorption of bone substitute materials. This may help facilitate the development of novel materials for bone substitution.