Cost impact of prospective HLA-B*5701-screening prior to abacavir/lamivudine fixed dose combination use in Germany

Objective

Avoiding abacavir in HIV-infected patients tested positive for HLA-B*5701 reduces the risk of abacavir hypersensitivity reaction (ABC-HSR). Our aim was to assess the costs of clinically suspected HSR and to estimate potential cost savings of implementing prospective HLA-B*5701-screening for HIV-infected patients initiating abacavir/lamivudine fixed-dose combination (ABC/3TC FDC) compared to initiating respective treatment without screening.

Methods

Employing a decision tree model the expected HSR-related costs of screening vs. no screening were estimated from the societal and healthcare payer perspective (reference year 2007). A retrospective standardized assessment of all clinically suspected ABC-HSR cases without screening at 5 German HIV-centres was performed to measure resource consumption. In- and outpatient care, discarded ABC/3TC FDC and concomitant medication were considered. Direct resource utilization was valued using German fees (EBM, G-DRGs). Indirect costs were measured with the human capital approach. Estimates for the HLA-B*5701-prevalence, HSR-incidence, and hospitalization rate were based on clinical trials and cohorts and it was assumed that screening reduces the incidence of clinically suspected ABC-HSR from 10% to 0.5%.

Results

Thirty-two ABC-HSR cases were identified from 1998 to 2007. Mean direct and total costs per clinically suspected HSR case were € 1,362 and € 2,235, respectively. Hospital costs contributed 63.3% to direct costs. Potential cost savings when implementing genetic screening were estimated at € 44 and € 127 per screened patient, from a healthcare payer or societal perspective.

Conclusion

HLA-B*5701 screening prior to ABC/3TC FDC initiation prevents significant HSR-related costs per screened patient and is likely to lead to overall net savings.

Abdominal actinomycosis

A 59-year-old, healthy Croatian presented with a slowly growing tumor in the left lower abdomen, which was slightly painful on compression. He complained of neither dyspepsia nor fever. There were no pathologic findings in laboratory analysis, particularly no elevation of leukocytes or C-reactive protein. MRI of the abdomen (T1w, fat saturated, and iv-contrast) shows a diffuse contrast enhancing mass of the left abdominal wall (Figure 1a, arrow) with infiltration of the peritoneal cavity (Figure 1b, arrow). Because a malignant process was suspected the patient underwent abdominal surgery and excision of the tumor. Histopathological examination showed chronic-fibrosing and granulocytic, abscess-forming inflammation with Gram- and PAS-positive bacteria, corresponding to the diagnosis of chronic actinomycosis (Figure 1c). Following surgery, the patient was treated 1 month with iv and 6 more months with oral penicillin. The patient remained well 1 year after surgery. Actinomycosis is a rare, chronic granulomatous disease, which affects most commonly the cervicofacial and abdominal area. Actinomycetes are filamentous, gram-positive, anaerobic bacteria and commensal inhabitants of the oral cavity and intestinal tract; however, they acquire pathogenicity through invasion of the breached tissue. Because of its rarity and non-specific symptoms, abdominal actinomycosis is usually diagnosed postoperatively since most patients undergo exploratory laparotomy for a suspected neoplasm.

Treatment with CCR5 antagonists: which patient may have a benefit?

The concept of CCR5 antagonists introduces an additional molecular target. Maraviroc (MVR) is approved by the FDA for use in HIV-1 infected patients for combination antiretroviral treatment of adults infected with only CCR5-tropic HIV-1 who have evidence of viral replication and HIV-1 strains resistant to multiple antiretroviral agents. Tropism and treatment history should guide the use of MVR. Data from clinical trials show significant efficacy of MVR for patients with pre-treatment and multiple class failure. Additional clinical data show a CD4 reconstitution that is more pronounced than with comparator in treatment naive and in late stage patients even without CCR5-tropic virus indicating patients in earlier stages and even patients without CCR5 testing will benefit from MVR. MVR is not licensed for treatment naive patients but it has a high potential for further development in this patient group. It shows better immunological reconstitution than efavirenz. Pooled safety data from all available trials shows good short term tolerability. Caution is needed in hepatitis co-infection with pre-existing liver damage and in patients with heart failure. Isolates from different geographic regions differ in coreceptor usage. Summarizing knowledge on HIV-1 subtypes and CCR5 tropism shows that in principle all subtypes are susceptible to MVR. However, in subtypes A and D dualtropic and alternative coreceptor use were found. Clinical efficacy in patients from regions with A and D predominance should be studied in future trials. In conclusion, MVR will be of benefit for patients in various treatment situations and regions.

Effect of platelet-rich-plasma on cranial distraction osteogenesis in sheep: preliminary clinical and radiographic results

The purpose of this study was to investigate the effect of platelet-rich-plasma (PRP) on cranial distraction osteogenesis. Standardized calvaria critical size defects (6 cm x 5 cm) were created in 16 adult female sheep. Bifocal cranial transport distraction osteogenesis with autogenous free calvaria bone grafts (2 cm x 4 cm) was performed at a rate of 1mm once daily to a total of 30 mm. The 16 sheep involved in the experiment were randomly divided into four groups, four animals in each: Group 1 (no PRP, latency 5 days); Group 2 (no PRP, latency 0 day), Group 3 (PRP, latency 5 days) and Group 4 (PRP, latency 0 day). After a consolidation phase of 6 weeks, the animals were sacrificed and specimens harvested for conventional radiological and 3D quantitative computer tomographic (3D-QCT) assessment. New bone was generated in the distraction zone in all groups. There were significantly (P < 0.05) higher densities in the proximal region of the distraction regenerate in Group 4 (PRP, latency 0 day) compared to Group 2. However, no significant differences in mean density of the total distraction regenerate were found, neither in volume of the bony regenerate between the experimental groups. This study showed that PRP only had an effect on bone regeneration if active distraction was started immediately after application of PRP in the distraction gap.

Untersuchung der Angiogenese im Tissue Engineering

INTRODUCTION

Tissue engineering (TE) applications include the isolation, culture, and seeding of cells into a suitable matrix or scaffold prior to in vivo transplantation. After transplantation, vascularization of the scaffold is a principal factor limiting cell viability for the first 6-8 days post transplantation. A model has been developed for systematic analysis of this process.

METHODS

Fertilized white Leghorn eggs were incubated and opened at day 3 of incubation. Preadipocyte-seeded fibrin constructs were implanted in a specially designed plastic cylinder and placed through the opening onto the surface of the chorioallantoic membrane (CAM) at day 8 of incubation. Vascularization of the constructs by chorioallantoic blood vessels was assessed for up to 8 days post transplantation.

RESULTS

The survival rate for embryos receiving constructs was about 90%. Histology confirmed transplant cell viability at day 4 post transplantation, and vascularization of the constructs by avian endothelial cells progressively increased thereafter.

CONCLUSION

A new in vivo model to study the effect of angiogenesis in TE constructs including assessments of viability, proliferation, and differentiation of transplanted cells and biomaterial properties is presented. Advantages include easy access to the CAM vascular network, lack of immunocompetence, low cost, and avoidance of animal experiments.

Highlights of a ten-year experience with the Ross procedure

BACKGROUND

A review of a 10-year experience with the Ross procedure as a root replacement by a single group of surgeons featuring specific highlights is presented. Highlights include our results from a subset of patients with endocarditis and their management and a comparison of outcomes in patients with aortic insufficiency based on technical changes made after 5 years' experience.

METHODS

The total patient group was 191, with 148 male and 43 female participants with an age range from 1 day to 69 years. Five of the patients in the 0-to-20 age group were newborns. Fifty-three of the adults were operated on for infectious endocarditis. In the total patient group 43% had aortic insufficiency, 28% had aortic stenosis, and 29% had mixed disease.

RESULTS

Operative mortality was 5.2% with a late mortality of 2.6%. The actuarial survival was 90.2% at 10 years. Freedom from autograft explantation was 93.2% and freedom from homograft replacement was 98.4%. The endocarditis patients had an operative mortality of 3.8% with 100% cure of the infection. Freedom from reinfection on the autograft was 98.1%, and freedom from infection of the pulmonary homograft was 98.1%. The actuarial survival was 86.3%.

CONCLUSIONS

A specific review of the patients with aortic insufficiency resulted in a failure of the autograft in 7 patients among a cohort of 41 during the first 5 years of the study. After a change in technique in which the aortic annulus is narrowed and fixed to a measured size to match the body surface area, we have had no failures in the autograft. Although these results are early, we believe that these data support the use of the autograft as an excellent choice for replacement of the aortic valve in infective endocarditis. Finally, the use of the autograft for aortic insufficiency is reasonable with fixation of the aortic annulus so that subsequent dilation does not occur.

The effects of insulin and growth hormone on the release of somatomedin by the isolated rat liver

Livers from hypophysectomized (hypox) rats were perfused with oxygenated Waymouth's medium in a system which permitted continuous recirculation for separate 30 minute periods after which fresh medium was supplied. In most experiments 6 changes of medium were carried out over a 3 hour period. The somatomedin activity of each perfusate was determined by measuring its ability to stimulate sulfate uptake in hypox rat cartilage in vitro. For comparison between experiments the results are expressed as the per cent stimulation of sulfate uptake by the perfusate compared with the unperfused buffer. Without hormonal additions there was a progressive fall in the release of somatomedin activity during the 6 periods of study. When compared with the results without hormone, the addition of 1000 muU/ml of insulin per ml of medium during the 2nd to 6th period led to a significant increase in perfusate somatomedin activity at all periods. The addition of 100 muU/ml of insulin was without significant effect. The possible inter-relationship between insulin and growth hormone in the regulation of somatomedin release was studied with a dose of bGH of 250 ng/ml which had previously been shown to be insufficient by itsel to stimulate somatomedin release. When added to a medium containing 1000 muU/ml of insulin, this dose of bGH did not significantly stimulate somatomedin release beyond that obtained with insulin alone. However, when 250 ng/ml was added to a medium containing 100 muU/ml insulin, a significant stimulation of somatomedin release was observed while the addition of each hormone separately was without significant effect. These results support the hypothesis that insulin shares with GH the regulation of somatomedin release by the liver. Differences in insulin concentration may explain some clinical situations in which somatomedin concentrations cannot be correlated with GH levels.