41 research outputs found
Reducing malaria misdiagnosis: the importance of correctly interpreting Paracheck Pf® "faint test bands" in a low transmission area of Tanzania
Although malaria rapid diagnostic tests (RDTs) have been extensively evaluated since their introduction in the early 1990's, sensitivity and specificity vary widely limiting successful integration into clinical practice. This paper reviews specific issues surrounding RDT use in field settings and presents results of research investigating how to interpret "faint test bands" on ParaCheck Pf® in areas of low transmission in order to reduce malaria misdiagnosis.\ud
A multi-phase cross-sectional study was conducted at a remote hospital in the northern Tanzanian highlands. Capillary blood samples were taken from consenting participants (n = 319) for blood smear and ParaCheck Pf® testing. Primary outcome variables were sensitivity, specificity and proportion misdiagnosed by ParaCheck Pf® and local microscopy. ParaCheck Pf® "faint bands" were classified as both true positives or true negatives during evaluation to determine appropriate clinical interpretation. Multivariate logistic regression adjusted for age and gender was conducted to determine odds of misdiagnosis for local microscopy and ParaCheck Pf®. Overall, 23.71% of all ParaCheck Pf® tests resulted in a "faint band" and 94.20% corresponded with true negatives. When ParaCheck Pf® "faint bands" were classified as positive, specificity was 75.5% (95% CI = 70.3%-80.6%) as compared to 98.9% (95% CI = 97.0%-99.8%) when classified as negative. The odds of misdiagnosis by local microscopy for those > 5 years as compared to those ≤ 5 years are 0.370 (95% CI = 0.1733-0.7915, p = 0.010). In contrast, even when ParaCheck Pf® faint bands are considered positive, the odds of misdiagnosis by ParaCheck Pf® for those > 5 years as compared to those ≤ 5 years are 0.837 (95% CI = 0.459-1.547, p = 0.5383). We provide compelling evidence that in areas of low transmission, "faint bands" should be considered a negative test when used to inform clinical decision-making. Correct interpretation of RDT test bands in a clinical setting plays a central role in successful malaria surveillance, appropriate patient management and most importantly reducing misdiagnosis
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Phase I/II Study of Clofarabine Combined with Standard Dose Cytarabine as Remission Induction Therapy of De Novo AML in Elderly Patients ≥60 Years
Abstract
Despite significant advances in the treatment of acute myeloid leukemia (AML) in younger adults, there has been little progress in the treatment of older patients (age≥60 years), who comprise the majority of those with the disease. Clofarabine is a purine nucleoside analog with single agent activity in patients with relapsed AML. In addition, clofarabine potentiates Ara-C cytotoxicity in vitro through increased intracellular Ara-CTP accumulation, making this an attractive combination.
A phase I/II study has therefore been initiated combining clofarabine with standard dose cytarabine (100mg/m2/day x 7) in pts age ≥60 years with de novo AML. The starting dose of clofarabine was 30mg/m2/day x 5 beginning on day 2 (Dose level I). Patients were accrued in cohorts of 3–6 to establish dose limiting toxicity (DLT); cohort expansion at the maximum tolerated dose (MTD) is planned in phase II using a Simon 2-stage design. Detailed plasma and intracellular pharmacokinetics were performed during induction therapy with Ara-C alone (day 1), and following the addition of clofarabine (day 2) to determine the effect of clofarabine on intracellular Ara-CTP accumulation. Pts with residual AML on d14–21 restaging bone marrow (BM) biopsy were eligible to receive Re-Induction with 5 days of clofarabine & Ara-C. Those achieving complete remission were also eligible to receive 1–2 cycles of consolidation with Ara-C (d1–5) & clofarabine (total 3 cycles of planned therapy).
Dose limiting toxicity was encountered at dose level I (see Table 1). 2/4 pts achieved CR, in 1 case with residual cytogenetic abnormality, and there were 2 treatment-related deaths from infxn (culture neg sepsis, n=1; Candida tropicalis, n=1). In the latter case (pt 4), BM aplasia was achieved, but the pt died on d25 prior to hematologic recovery. In view of the DLT, the protocol has therefore been amended to allow 25% dose de-escalation of clofarabine to Dose Level -I (22.5mg/m2/day x 5), and to limit eligibilty to pts age 60–75 yrs inclusive. Routine use of aggressive pre-hydration and antibiotic and antifungal prophylaxis is now mandated.
Clofarabine & cytarabine is a highly active induction regimen in older adults age ≥60 yrs with de novo AML, but has significant myelosuppressive and infectious toxicity. The study is proceeding in phase I at Dose Level -I to establish the MTD.
Phase I, Dose Level I PT AGE, GENDER FAB CYTOGENETICS F/U BM TOXICITY (Gr.III/IV) OUTCOME MLD - multilineage dysplasia; F&N - fever & neutropenia; CR - complete remission 1 66M M2 Diploid D21: residual AML renal, infxn Death 2 61M M2 Complex D14: aplastic F&N CR 3 69M M2 with MLD Intermediate Risk D21: recovering F&N CR 4 77F M2 Diploid D14: aplastic renal, infxn, capillary leak Deat