Abstract P4-12-16: Safety profile and costs of related adverse events of trastuzumab emtansine compared to other regimens in the Canadian health care system

Background

Trastuzumab Emtansine (T-DM1) is an antibody–drug conjugate (ADC) comprised of the microtubule inhibitory cytotoxic agent DM1 and trastuzumab which, in addition to its antitumor properties, targets T-DM1 to HER2–overexpressing cells. The phase III EMILIA study compared the safety and efficacy of T-DM1 (n = 496) versus capecitabine plus lapatinib (CAP+LAP, n = 495) in patients with HER2-positive locally advanced or MBC previously treated with trastuzumab and a taxane. The phase II TDM4450g study compared the safety and efficacy of T-DM1 (n = 67) versus trastuzumab plus docetaxel (TRAZ+DOCE, n = 70) in patients with previously untreated MBC. These trials demonstrated statistically and clinically meaningful differences between T-DM1 and its comparators. In the EMILIA trial, the proportion of patients who developed grade ≥3 treatment-related AEs that were deemed related to treatment by the investigators was lower in the T-DM1 arm (30.6%) compared to the CAP+LAP arm (48.8%) and 5.9% of patients on T-DM1 discontinued treatment due to an AE, compared with 10.7% of patients on CAP+LAP.

In the TDM4450g study, the proportion of patients who developed grade ≥3 AEs that were deemed related to treatment by the investigators was lower in the T-DM1 arm (33.3%) versus the TRAZ+DOCE arm (81.82%) and 7.2% of patients on T-DM1 discontinued treatment due to an AE, compared with 34.8% of patients on TRAZ+DOCE.

The objective of this analysis was to estimate and compare the Canadian costs of managing the treatment-related AEs of T-DM1 as reported in the EMILIA and TDM4450g trials, from the perspective of Canadian public payers.

Methods

An Excel based spreadsheet model was utilized to estimate the costs of managing the treatment-related AEs. Clinical data (number and severity of AEs) were obtained from the two trials. Resource utilization and costing information were obtained from the literature, clinical experts, and Canadian standard costing sources (minimum and maximum costs were used). Costs were reported as 2012 CAD. The AEs that were considered for costing in this analysis were all treatment-related grade ≥3 AEs as well as grade 2 AEs that occurred in ≥5% of patients in both arms of either study.

Results

The management of treatment-related AEs by using T-DM1 resulted in cost savings ranging from $1,684 - $8,036 versus CAP+LAP as reported in the EMILIA trial and from $4,326 - $25,402 versus TRAZ+DOCE as per the TDM4450g trial (see Table 1).

Table 1: Range of Costs of Managing Treatment-Related AEs as Reported in the EMILIA and TDM4450g trials EMILIATDM4450g T-DM1CAP + LAPT-DM1TRAZ+DOCECost per patient$1,376 - $2,463$3,060 - $10,499$798 - $2,215$5,124 - $27,617Cost savings$1,684 - $8,036$4,326 - $25,402

Conclusions

This analysis demonstrated that utilizing T-DM1 for the management of HER2-positive MBC results in significant cost savings of related AEs management due to the improved safety profile compared to CAP+LAP and TRAZ+DOCE.

Citation Information: Cancer Res 2013;73(24 Suppl): Abstract nr P4-12-16.

Comparison of genomic and antimicrobial resistance features of latex agglutination test-positive and latex agglutination test-negative Staphylococcus aureus isolates causing bovine mastitis

The dairy industry suffers massive economic losses due to staphylococcal mastitis in cattle. The Staphaureux latex agglutination test (Oxoid, Basel, Switzerland) was reported to lead to negative results in 54% of bovine Staphylococcus aureus strains, and latex-negative strains are thought to be less virulent than Staphaurex latex-positive strains. However, comparative information on virulence and resistance profiles of these 2 groups of Staph. aureus is scarce. Our objective was to associate the latex agglutination phenotype of Staph. aureus strains isolated from bovine mastitis milk with data on clonal complexes, virulence genes, and antibiotic resistance to (1) determine the virulence profiles of the Staphaureux test positive and Staphaurex test negative groups, and (2) provide data needed to improve treatment of bovine mastitis and to identify potential vaccine targets. Seventy-eight Staph. aureus strains isolated from 78 cows on 57 Swiss farms were characterized. Latex agglutination was tested by Staphaureux kit, and resistance profiles were generated by disk diffusion. A DNA microarray was used to assign clonal complexes (CC) and to determine virulence and resistance gene profiles. By the Staphaureux test, 49% of the isolates were latex-positive and 51% were latex-negative. All latex-negative strains were assigned to CC151, whereas latex-positive strains were assigned to various clonal complexes, including CC97 (n=16), CC8 (n=10), CC479 (n=5), CC20 (n=4), CC7 (n=1), CC9 (n=1), and CC45 (n=1). Although the latex-negative isolates were susceptible to all antimicrobial agents tested, 24% of latex-positive isolates were classified as intermediate with regard to cefalexin-kanamycin and 13% were resistant to both ampicillin and penicillin. Microarray profiles of latex-negative isolates were highly similar, but differed largely from those of latex-positive isolates. Although the latex-negative group lacked several enterotoxin genes and sak, it exhibited significantly higher prevalence rates of genes encoding enterotoxin C, toxic shock syndrome toxin, and leukocidins (lukM/lukF-P83, lukD). Our findings suggest that latex-negative isolates represent a group of closely related strains with specific resistance and virulence gene patterns.

Scale-up on basis of structured mixing models: A new concept

A new scale-up concept based upon mixing models for bioreactors equipped with Rushton turbines using the tanks-in-series concept is presented. The physical mixing model includes four adjustable parameters, i.e., radial and axial circulation time, number of ideally mixed elements in one cascade, and the volume of the ideally mixed turbine region. The values of the model parameters were adjusted with the application of a modified Monte-Carlo optimization method, which fitted the simulated response function to the experimental curve. The number of cascade elements turned out to be constant (N = 4). The model parameter radial circulation time is in good agreement with the one obtained by the pumping capacity. In case of remaining parameters a first or second order formal equation was developed, including four operational parameters (stirring and aeration intensity, scale, viscosity). This concept can be extended to several other types of bioreactors as well, and it seems to be a suitable tool to compare the bioprocess performance of different types of bioreactors. (c) 1994 John Wiley & Sons, Inc.

Spontaneous tension pneumothorax and CO₂ narcosis in a near fatal episode of chronic obstructive pulmonary disease exacerbation

Exacerbation of chronic obstructive pulmonary disease (COPD) is a disease pattern frequently seen in emergency medical services and intensive care units. Usually, exacerbations of COPD are of infectious origin, and an acute vital threat may take several days to develop. Tension pneumothorax in patients with COPD is a rare and often unexpected cause of acute vital threat. To the best of our knowledge, this is a unique case of CO2 narcosis after spontaneous tension pneumothorax in a patient with COPD. We describe the rapid development of respiratory insufficiency and near fatal pulmonary failure in a 65-year-old female patient with COPD due to spontaneous tension pneumothorax. The patient was in respiratory failure and comatose upon arrival of the emergency service. Before mechanical ventilation, coma could be confirmed to be due to CO2 narcosis caused by exorbitant arterial hypercapnia (PCO2, 193 mm Hg). Pneumothorax was diagnosed in the hospital by chest x-ray and resolved after pleural drainage. The patient could be extubated early and discharged without sequelae. In conclusion, we want to report the occurrence of a tension pneumothorax as an important and potentially overseen condition in patients with COPD with acute respiratory failure.

A new genus and species of Euptychiina (Lepidoptera: Nymphalidae: Satyrinae) from southern Brazil

This paper describes a new genus and a new species of Euptychiina from open grassland habitats (campos de cima da serra) in southern Brazil. The systematic position of this new taxon is discussed based on morphological and molecular data, and it is considered sister to Taydebis Freitas. Since the campos vegetation is considered endangered due to anthropogenic activities, this butterfly species deserves attention and should be included in future conservation plans for this biome.

Students' and general practitioners' perceptions of a recently introduced clerkship in general practice. A survey from Austria

BACKGROUND

In autumn 2007, the Medical University of Graz (MUG) upgraded the status of general practice in medical training by integrating a compulsory five-week clerkship in general practice surgeries in the sixth and last year of the curriculum. In cooperation with the Styrian Academy of General Practice (STAFAM), more than 200 general practitioners (GPs) had been accredited to introduce medical students to the specific tasks, problems and decision-making process in general practice. Between October 2007 and June 2009, more than 300 students completed the clerkship.

OBJECTIVE

To explore the perceptions of students and GPs towards this new approach to undergraduate teaching in Austrian general practice.

METHODS

Between March and June 2009, we conducted a cross-sectional survey by using a self-administered questionnaire with 14 items for students as well as GPs. To limit recall bias, we gave the questionnaire to all students (n = 146) and GPs (n = 146) immediately after the clerkship. The response rates were 146/146 (100%) and 114/146 (78%) for students and GPs, respectively.

RESULTS

The study results show high satisfaction rates among students as well as GPs. Most of the students and GPs perceive the compulsory clerkship in general practice as an essential part of medical education. The organization of the clerkship had the least positive outcome.

CONCLUSION

Our survey shows that the clerkship is well accepted among Austrian medical students and GPs.

[Culture and susceptibility testing of mycobacteria with VersaTREK]

OBJECTIVES

Our laboratory of microbiology use the VersaTREK/ESP Culture System II for the isolation of mycobacteria. In this study, we evaluate this system for the analysis carried out between April 2009 and March 2010.

METHOD

The Myco bottles are supplemented with growth supplements and an antimicrobial agent solution prior to inoculation with the specimen. The technology of the VersaTREK/ESP Culture System II is based on the detection of headspace pressure changes within a sealed bottle. It monitors changes in either gas production or gas consumption due to microbial growth. A special algorithm has been developed for detection of very slow growing mycobacteria. The bottles are incubated during 42 days. Meanwhile a solid medium is inoculated too. All specimen types can be analysed with this system.

RESULTS

Compared to solid culture, the time needed for detection of positive cultures was significantly shorter for the VersaTREK with a good recovery rate. For isolates recovered in both systems, mean time of detection is respectively 19.1 and 35.6 days for liquid and solid cultures. Mycobacteria identification may be determined using nucleic acid probs directly in Myco VersaTREK or in the solid medium. The susceptibility test of Mycobacteria tuberculosis complex is obtained between six and 13 days for rifampin, isoniazid, ethambutol, streptomycin and pyrasinamide.

CONCLUSION

This system offers a faster diagnosis and is an alternative to other instruments using liquid culture.

Rhizomelic chondrodysplasia punctata type 1: report of mutations in 3 children from India

Rhizomelic chondrodysplasia punctata is a rare autosomal recessive disorder characterized by stippled epiphyses and rhizomelic shortening of the long bones. We report 3 subjects of rhizomelic chondrodysplasia punctata from India and the PEX7 mutations identified in them. The common PEX7-L292X allele, whose high frequency is due to a founder effect in the northern European Caucasian population, was not identified in these patients. Instead, 2 novel alleles are described, including 64_65delGC, which was present on a single PEX7 haplotype and could represent a common allele in the Indian population.