Evaluation of Xpert® MTB/RIF assay as a diagnostic test for pulmonary tuberculosis in children in Myanmar

BACKGROUND

The Xpert® MTB/RIF assay has been recommended for the diagnosis of pulmonary tuberculosis (PTB). However, there are limited data from the South-East Asian region.

SETTING

This study was carried out at a tertiary-level children's hospital in Mandalay, Myanmar.

OBJECTIVE

To evaluate the performance of Xpert as a diagnostic test for PTB in children.

METHODS

A cross-sectional descriptive study of children with suspected PTB. Gastric lavage aspirate samples were tested using Xpert, solid culture and smear microscopy. The performance of Xpert, solid culture and smear microscopy were evaluated using the revised National Institute of Health classification for intrathoracic TB in children as the reference standard.

RESULTS

TB was bacteriologically confirmed in 38 (16.5%) of 231 children with suspected PTB. Of the 38 children with confirmed TB, 36 cases were identified using Xpert, 16 using solid culture and 12 using smear microscopy. With confirmed TB as the reference standard, the sensitivity of Xpert, solid culture and smear microscopy was respectively 94.7% (95%CI 80.9-99.1), 42.1% (95%CI 26.7-59.1) and 31.6% (95%CI 18.0-48.8).

CONCLUSION

Xpert has improved the bacteriological confirmation of PTB among hospitalised children in Myanmar.

Abstract P1-16-04: Risk of venous thromboembolism with abemaciclib based regimen versus other CDK 4/6 inhibitor containing regimens in patients with hormone receptor-positive HER2-negative metastatic breast cancer

Background: Approximately 70% of patients with metastatic breast cancer (MBC) are hormone receptor (HR) - positive and the cyclin dependent kinases (CDK) along with their D-type cyclin catalysts, have been shown to play a role in mediating the resistance to endocrine therapy. Several CDK-targeted agents have been recently approved by FDA. Nevertheless, the risk of venous thromboembolism (VTE) with the use of different CDK 4/6 inhibitors has never been reported. We undertook a systematic review and meta-analysis of randomized controlled trials (RCT) to determine the risk of VTE with abemaciclib based regimens versus other CDK 4/6 inhibitor containing regimens in patients with HR-positive HER2-negative MBC.

Methods: We systematically conducted a comprehensive literature search using MEDLINE, EMBASE databases and meeting abstracts through February 2018. The randomized controlled trials that mention deep vein thrombosis and pulmonary embolism as adverse effects of CDK 4/6 inhibitor therapy were incorporated in the analysis. The primary meta- analytic approach was a fixed effects model using the Mantel-Haenszel (MH) method. It was used to calculate the estimated pooled risk ratio (RR) and risk difference (RD) with 95% confidence interval (CI).

Results: Five phase 3 studies and one phase 2 study with a total of 3,159 patients with HR-positive HER2-negative MBC were eligible for analysis. The study arms used palbociclib-letrozole, palbociclib-fulvestrant, ribociclib-letrozole, abemaciclib-fulvestrant, and abemaciclib-nonsteroidal aromatase inhibitors (either letrozole or anastrozole) while the control arms utilized placebo in combination with letrozole or anastrozole or fulvestrant. The randomization ratio was 2 to 1 in PALOMA-2, PALOMA-3, MONARCH-2 and MONARCH-3 studies and 1 to 1 in PALOMA-1 and MONALEESA-2 trials. CDK 4/6 inhibitors were utilized as first line treatment in PALOMA-1, PALOMA-2, MONALEESA-2 and MONARCH-3. The I2 statistic for heterogeneity was 0, and the heterogeneity X2 (Cochran's Q) was 1 (P= 0.707), suggesting homogeneity among RCTs. The VTE incidence was 25 (3.255%) in the abemaciclib group vs 2 (0.520%) in the control group. The pooled relative risk for VTE was 6.222 (95% CI: 1.481 – 26.145, P = 0.013) and the absolute RD was 0.027 (95% CI: 0.013 – 0.042, P < 0.0001). In other CDK 4/6 inhibitor containing regimens, the VTE incidence was reported at 15 (1.243%) vs 2 (0.374%) in the control arm. The pooled RR for VTE was 2.312 (95% CI: 0.852 –6.272, P = 0.100) and the absolute RD was 0.008 (95% CI: - 0.000 – 0.017, P = 0.259).

Conclusion: VTE is a major cause of morbidity and mortality and is particularly common in patients with breast cancer. Our meta-analysis demonstrated that the addition of abemaciclib to endocrine therapy notably contributed to a higher incidence of VTE with a relative risk of 6.22. However, no significant increase in the risk of VTE was noted in other CDK 4/6 inhibitor-based regimen. More randomized trials are required to determine the actual relation and definitive incidence of VTE among different CDK-targeted agents when added to endocrine therapy.

Citation Format: Thein KZ, Ball S, Zaw MH, Quirch M, Hardwicke F, Awasthi S, Oo TH, Jones C. Risk of venous thromboembolism with abemaciclib based regimen versus other CDK 4/6 inhibitor containing regimens in patients with hormone receptor-positive HER2-negative metastatic breast cancer [abstract]. In: Proceedings of the 2018 San Antonio Breast Cancer Symposium; 2018 Dec 4-8; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2019;79(4 Suppl):Abstract nr P1-16-04.

Abstract P1-17-08: Efficacy of lapatinib and capecitabine combination therapy in brain metastases from HER-2 positive metastatic breast cancer: A systematic review and meta- analysis

Background:

Brain metastases contribute to significant morbidity and mortality in breast cancer. Approximately one fourth of breast tumors overexpress the human epidermal growth factor receptor 2 (HER2) protein and are twice as likely to develop brain metastases. There are currently no systemic therapies approved. We undertook a systematic review and pooled analysis of trials to determine the efficacy of lapatinib and capecitabine combination therapy in brain metastases from HER-2 positive metastatic breast cancer (MBC).

Methods:

We performed a comprehensive literature search using MEDLINE, EMBASE databases, and meeting abstracts through December 31, 2016. Trials that utilized lapatinib and capecitabine combination therapy in brain metastases from HER-2 positive MBC were incorporated in the analysis. The pooled estimated rates were calculated using random effects model. Heterogeneity was assessed using I2 statistic.

Results:

A total of 513 patients with brain metastases from HER-2 positive MBC from 6 trials and a subgroup of another 4 trials were included in our analysis. Lapatinib and capecitabine therapy was used as second-line treatment in 9 studies (n= 468) and as first-line treatment in the LANDSCAPE study (n= 45). Three studies were retrospective evaluations of randomized trials and the rest were phase 2 trials. CNS objective response rate (ORR) was 26% (95% CI: 19 – 33, I2: 65.9%). Complete response (CR) rate was 1% (95% CI: 0 - 2, I2: 0.0%) and partial response (PR) rate was noted at 24% (95% CI: 17- 31, I2: 66.1%). Stable disease (SD) occurred in 37% (95% CI: 29- 45, I2: 66.6%) and progressive disease (PD) in 19% (95% CI: 12- 25, I2: 66.5%). The first line LANDSCAPE study had the highest PR (49%) and ORR (53%) without a significant impact on CR rate; PD was 7%.

Conclusion:

Brain metastases in breast cancer is an area of urgent unmet need. Our meta-analysis showed that lapatinib/capecitabine therapy had some first line or second line activity in brain metastases from HER-2 positive MBC. Nevertheless, further randomized controlled trials are required in this patient population.

Citation Format: Thein KZ, Zaw MH, Yendala R, Igid HP, Chai-Adisaksopha C, Hardwicke F, Awasthi S, Radhi S. Efficacy of lapatinib and capecitabine combination therapy in brain metastases from HER-2 positive metastatic breast cancer: A systematic review and meta- analysis [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P1-17-08.

Abstract P3-14-02: Incidence of venous thromboembolism in patients with hormone receptor-positive HER2-negative metastatic breast cancer treated with CDK 4/6 inhibitors: A systematic review and meta- analysis of randomized controlled trials

Background:

The cyclin dependent kinases (CDK) along with their partners, the cyclins, have a crucial role in regulation of the cell cycle. Several CDK-targeted agents have been employed in hormone receptor positive metastatic breast cancer (MBC) with noteworthy safety concerns. Nevertheless, the impact of this agent on risk of venous thromboembolism (VTE) remains uncertain. We performed a systematic review and meta-analysis of randomized controlled trials (RCT) to determine the risk of VTE among patients with hormone receptor-positive HER2-negative MBC treated with CDK 4/6 inhibitors.

Methods:

We systematically conducted a comprehensive literature search using MEDLINE, EMBASE databases and meeting abstracts through June 2017. Trials that mention deep vein thrombosis and pulmonary embolism as adverse effects were incorporated in the analysis. The primary meta- analytic approach was a fixed effects model using the Mantel-Haenszel (MH) method. It was used to calculate the estimated pooled risk ratio (RR), and risk difference (RD) with 95% confidence interval (CI). Pooled VTE rates were estimated as follows: we multiplied the median follow-up duration by the sample size. Crude study-specific VTE rates were then calculated by dividing the number of incident VTE cases by the total number of person-months follow-up.

Results:

A total of 2671 patients with hormone receptor-positive HER2-negative MBC from four phase 3 studies and one phase 2 study were eligible for analysis. The study arm used palbociclib-letrozole, palbociclib-fulvestrant, ribociclib-letrozole and abemaciclib-fulvestrant while the control arm utilized placebo in combination with letrozole or fulvestrant. The I2 statistic for heterogeneity was 13.6, and the heterogeneity X2 (Cochran's Q) was 4.6 (P= 0.3), suggesting homogeneity of results among the randomized trials. The VTE incidence was 24 (1.46%) in CDK 4/6 group vs 4 (0.39%) in control group. The pooled RR for VTE was 2.736 (95% CI: 1.115 – 6.714, P = 0.028) and the absolute RD was 0.010 (95% CI: 0.002 – 0.018, P = 0.010) according to the fixed effects model. By the random effects model, the pooled RR was 2.411 (95% CI: 0.809 – 7.181, P = 0.114) and RD was 0.009 (95% CI: 0.0 – 0.019, P = 0.048). Over median follow up of 36 months, the RR for VTE was 3.792 (95% CI: 1.838 – 7.822, P < 0.0001) and RD was 0.024 (95% CI: 0.014 – 0.034, P < 0.0001) with the fixed effects model. By the random effects model, the pooled RR for VTE was 4.248 (95% CI: 0.952- 18.959, P = 0.058) and RD was 0.026 (95% CI: 0.004 – 0.021, P < 0.0001). The pooled rate of VTE among CDK 4/6 group was 2.99 per person years compared to 0.50 per person years among control arm.

Conclusion:

Approximately 1% of patients on letrozole or fulvestrant alone developed VTE in previous studies. Our meta-analysis demonstrated that the addition of CDK 4/6 inhibitors to letrozole or fulvestrant, contribute to higher incidence of VTE. More randomized trials are required to determine the actual relation and definitive incidence of VTE, a major cause of morbidity and mortality among these patients.

Citation Format: Thein KZ, Zaw MH, Tun AM, Jones C, Radhi S, Hardwicke F, Oo TH. Incidence of venous thromboembolism in patients with hormone receptor-positive HER2-negative metastatic breast cancer treated with CDK 4/6 inhibitors: A systematic review and meta- analysis of randomized controlled trials [abstract]. In: Proceedings of the 2017 San Antonio Breast Cancer Symposium; 2017 Dec 5-9; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2018;78(4 Suppl):Abstract nr P3-14-02.

Speciation of iron and manganese in dam water particles using electron spectroscopy for chemical analysis (ESCA)

The speciation of iron and manganese compounds retained by membrane filtration of dam water samples was studied by use of electron spectroscopy for chemical analysis (ESCA). Samples were taken at various depths and times of year from North Pine Dam near Brisbane, Australia. Both surface and bulk properties of samples representative of the water column profile were investigated. ESCA results showed that iron(III) compounds were found to predominate in the whole water column in any season of the year while the significance of iron(II) species varied in the hypolimnion (the bottom layer). In summer, although various ratios of manganese(II), manganese(III) and manganese(IV) compounds were found to occur down the water column, manganese(IV) compounds were predominant in the epilimnion (the top layer), while both manganese(II) and (IV) compounds predominated in the metalimnion (the middle layer) and the hypolimnion. The majority of Mn(IV) compounds were found throughout the water column after heavy rain and winter season. The ratios of atomic concentrations of iron and manganese as determined by atomic absorption spectrophotometry and ESCA are also discussed.

Alternative method for (64)Cu radioisotope production

The method for (64)Cu production based on a (64)Ni target using an 18MeV proton energy beam was developed. The studies on the optimisation of targetry for the 18MeV proton bombardments were performed in terms of the cost-effective target utilisation and purity of the (64)Cu product. The thickness-specific (64)Cu yield (microCi/(microA x microm)) was introduced into the optimisation calculation with respect to cost-effective target utilisation. A maximum target utilisation efficacy factor (TUE) was found for the proton energy range of 2.5-13MeV with corresponding target thickness of 36.2microm. With the optimised target thickness and proton energy range, the (64)Ni target thickness saving of 45.6% was achieved, while the overall (64)Cu yield loss is only 23.9%, compared to the use of the whole effective proton energy range of 0-18MeV with target thickness of 66.6microm. This optimisation has the advantage of reducing the target amount to a reasonable level, and therefore the cost of the expensive (64)Ni target material. The (64)Ni target electroplated on the Au-Tl multi layer coated Cu-substrate was a new and competent design for an economic production of high quality (64)Cu radioisotope using an 18MeV proton energy cyclotron or a 30MeV cyclotron with proton beam adjustable to 18MeV. In this design, the Au coating layer plays a role of protection of "cold" Cu leakage from the Cu substrate and Tl serves to depress the proton beam energy (from 18MeV to the energy optimised value 13MeV). The ion exchange chromatographic technique with a gradient elution was applied to improve the (64)Cu separation with respect to reducing the processing time and control of (64)Cu product quality.

Private GPs contribute to TB control in Myanmar: evaluation of a PPM initiative in Mandalay Division

SETTING

Mandalay Division, Myanmar.

AIM

To assess the effect of an initiative to involve private general practitioners (GPs) in the National Tuberculosis Programme (NTP) and to identify lessons learnt for public-private mix scale-up.

METHODS

Source of referral/diagnosis and place of treatment were included in the routine recording and reporting systems to enable disaggregated analysis of the contribution of GPs to case notification and treatment outcomes. Case notification trends were compared between the intervention and control areas over a 4-year period.

RESULTS

Private GPs contributed 44% of new smear-positive cases registered during the study period (July 2002-December 2004). The notification of new sputum smear-positive TB in the study area increased by 85% between the year prior to the GP involvement and 2 years after (from 46 to 85/100,000). Case notification increased by 57% in the control townships and by 42% in all of Mandalay Division. The treatment success rate for new smear-positive cases treated by GPs was 90%.

CONCLUSIONS

The involvement of private GPs substantially increased TB case notification, while a high treatment success rate was maintained. Success factors include a well-developed local medical association branch, strong managerial support, training and supervision by the public sector and provision of drugs and consumables free of charge by the NTP.

Basing policy on evidence: low HIV, STIs, and risk behaviour in Dili, East Timor argue for more focused interventions

BACKGROUND

East Timor is a newly independent, poor nation with many internally displaced people and foreign peace keeping forces. Similarities with Cambodia, which now has Asia's worst HIV epidemic, caused donors to earmark money for HIV prevention in East Timor, but no data were available to plan appropriate programmes.

OBJECTIVES

To determine levels of infection with HIV and other sexually transmitted infections (STIs) and associated risk behaviours in Dili, East Timor, in order to guide resource allocation and appropriate prevention and care strategies.

METHODS

In mid-2003, a cross sectional survey of female sex workers, men who have sex with men (MSM), taxi drivers, and soldiers was conducted. Participants provided biological specimens and all answered structured questionnaires.

RESULTS

HIV prevalence was 3% among female sex workers (3/100), 0.9% among MSM (1/110), and zero in the other groups. All the HIV infected sex workers reported sex with foreign clients. Partner turnover reported by all groups was among the lowest in Asia, so was condom use. Access to basic HIV prevention services, including condoms and STI services, was extremely low in all groups.

CONCLUSIONS

A few sex workers are infected with HIV in East Timor, but the virus is not circulating widely among their clients, and sexual networking is limited. The risk of a generalised HIV epidemic in East Timor is minimal. HIV can be contained by the provision of basic services to the small minority of the population at highest risk, preserving resources for other health and development needs.

Seasonal changes of redox potential and microbial activity in two agricultural soils of tropical Australia: some implications for soil-to-plant transfer of radionuclides

Very little is known of the factors controlling soil-to-plant transfer of radionuclides in tropical environments. As part of an IAEA/FAO coordinated research project (CRP) designed to elucidate some of those factors, near-surface samples of two agricultural red-earth soils (Blain and Tippera) were collected from a study site in the Northern Territory. The climate is tropical monsoonal with crops being grown over the wet season from December to March/April. It is important to understand soil variables that may be related to this dramatic seasonality. In this investigation, soil redox state and microbial populations were assessed before and after the growing season with a view to generating hypotheses for future evaluation. The X-ray absorption near edge structure (XANES) technique was used to determine overall changes in the solid-state redox speciation of Fe and Mn in soils across the growing period. Fe speciation did not change but approximately 10% of the total Mn was oxidised from Mn(II) to Mn(III) and Mn(IV) in both soils between October 1999 and April 2000. An apparent disconnect between Fe and Mn was not unexpected given the >10 times higher concentration of Fe in the soils compared with Mn. These results have implications for the bioavailability of redox sensitive radionuclides such as Tc and Pu. Similarly, microbial population estimates were derived before and after the growing period. Total bacterial populations did not vary from 10(6) to 10(7) colonies per gram. Fungal populations increased over the growing season from 3-6 x 10(5) to 1-4 x 10(6) colonies per gram of soil. Fungi have the potential to decrease soil pH and hence increase the bioavailability of radionuclides such as Cs. In addition, fungi act to facilitate plant nutrition. This could lead to enhanced accumulation of nutrient analogues (e.g. Sr and Ra for Ca; Tc for Mn), but this effect may be masked by improved biomass production.

Emergence of new forms of human immunodeficiency virus type 1 intersubtype recombinants in central Myanmar

We have previously shown that HIV-1 env subtypes B' (a Thai-B cluster within subtype B) and E (CRF01_AE) are distributed in Yangon, the capital city of Myanmar. However, HIV strains from the rest of country have not yet been genetically characterized. In the present study, we determined env (C2/V3) and gag (p17) subtypes of 25 specimens from central Myanmar (Mandalay). Phylogenetic analyses identified 5 subtype C (20%), in addition to 10 CRF01_AE (40%) and 4 subtype B' (16%). Interestingly, the remaining six specimens (24%) showed discordance between gag and env subtypes; three gag subtype B'/env subtype C, one gag subtype B'/env subtype E, one gag subtype C/env subtype B', and one gag subtype C/env subtype E. These discordant specimens were found frequently among injecting drug users (4 of 12, 33%) and female commercial sex workers (2 of 8, 25%) engaging in high-risk behaviors. The recombinant nature of these HIV-1 strains was verified in three specimens, indicating the presence of new forms of HIV-1 intersubtype C/B' and C/B'/E recombinants with different recombination breakpoints. The data suggest that multiple subtypes of B', C, and CRF01_AE are cocirculating in central Myanmar, leading to the evolution of new forms of intersubtype recombinants among the risk populations exhibiting one of the highest HIV infection rates in the region.

Local evaluation of a rapid HIV assay for use in developing countries

We present a research scheme for evaluating inexpensive HIV rapid tests in a developing country setting and assess the field validity of the Sero Strip HIV 1/2 rapid test. The research design features the random allocation of 100 true HIV-positive and 100 true HIV-negative serum specimens to 4 groups, followed by blind testing for HIV status. After one short training session, laboratory technicians at 4 township hospitals (25-35 beds) located 20-50 km from Yangon, Myanmar were sent 800 sera labelled with only an identification number and divided into four groups of 200 specimens each, half being HIV-positive and half HIV-negative. Testing was done in the field with the Sero-Strip HIV 1/2. Determination of the test's validity was based on 399 true HIV positive and 401 true HIV negative sera. All true positives were correctly identified, as were all but two of the true negatives. The sensitivity (% of true positives that test positive) was 100%, and the specificity (% of true negatives that test negative) was 99.5%. The research was completed by in-country scientists who are best suited to evaluate the validity of HIV tests conducted in local environments.

Solvent and viscosity effects on the rate-limiting product release step of glucoamylase during maltose hydrolysis

Release of product from the active site is the rate-limiting step in a number of enzymatic reactions, including maltose hydrolysis by glucoamylase (GA). With GA, an enzymatic conformational change has been associated with the product release step. Solvent characteristics such as viscosity can strongly influence protein conformational changes. Here we show that the rate-limiting step of GA has a rather complex dependence on solvent characteristics. Seven different cosolvents were added to the GA/maltose reaction solution. Five of the cosolvents, all having an ethylene glycol base, resulted in an increase in activity at low concentration of cosolvent and variable decreases in activity at higher concentrations. The increase in enzyme activity was dependent on polymer length of the cosolvent; the longer the polymer, the lower the concentration needed. The maximum increase in catalytic activity at 45 degrees C (40-45%) was obtained with the three longest polymers (degree of polymerization from 200 to 8000). A further increase in activity to 60-65% was obtained at 60 degrees C. The linear relationship between ln(kcat) and (viscosity)2 obtained with all the cosolvents provides further evidence that product release is the rate-limiting step in the GA catalytic mechanism. A substantial increase in the turnover rate of GA by addition of relatively small amounts of a cosolvent has potential applications for the food industry where high-fructose corn syrup (HFCS) is one of the primary products produced with GA. Since maltodextrin hydrolysis by GA is by far the slowest step in the production of HFCS, increasing the catalytic rate of GA can substantially reduce the process time.

Lake destratification and speciation of iron and manganese

A long-term study of the effect of artificial aeration (destratification) of a water storage dam upon the speciation of iron and manganese in the dam waters has been undertaken. Separation of dam samples into soluble and insoluble forms by selective membrane filtration was undertaken before using the techniques of EPR spectroscopy, ion chromatography and gel filtration to assess the speciation of soluble species, and selective extraction and surface analysis (ESCA, SIMS and SEM) techniques to determine the speciation of particulate iron and manganese species. The percentages of soluble iron and manganese before (1983-85) and after (1986-88) artificial aeration are compared for the periods Jan-Dec, Jan-Mar, and Jun-Aug at three depths 6 m, 15 m and 0.5 m above the dam base, to assess the importance of seasonal changes in the various depths of the dam. Although aeration had an initial marked reduction in levels of soluble iron and manganese at all depths of the dam, the concentrations of these mtals showed a steady increase over succeeding years. Analysis of the figures over summer and winter periods shows that the reduction of soluble iron was maintained in summer, but not during winter. Upon aeration, the initial reduction of soluble manganese concentration was maintained in succeeding years in the epilimnic regions of the dam, but not in the hypolimnion. Statistical analysis of data has been undertaken to correlate the changes in relationship between the various forms of iron and manganese with the advent of aeration.

In vitro sensitivity of Plasmodium falciparum isolates from Burma to chloroquine quinine and mefloquine

The in vitro sensitivity of 26 isolates of Plasmodium falciparum from Rangoon and Tharrawaddy areas in Burma were studied on chloroquine, mefloquine and quinine. The results indicated that the parasites were highly resistant to chloroquine but sensitive to mefloquine and quinine. The existence of correlation of sensitivity to mefloquine and quinine was detected and discussed. No correlation between the parasite sensitivity to chloroquine and mefloquine and or chloroquine and quinine was detected.