Insa Gathmann

Six-year follow-up of patients receiving imatinib for the first-line treatment of chronic myeloid leukemia

Imatinib mesylate is considered standard of care for first-line treatment of chronic phase chronic myeloid leukemia (CML-CP). In the phase III, randomized, open-label International Randomized Study of Interferon vs STI571 (IRIS) trial, previously untreated CML-CP patients were randomized to imatinib (n=553) or interferon-α (IFN) plus cytarabine (n=553). This 6-year update focuses on patients randomized to receive imatinib as first-line therapy for newly diagnosed CML-CP. During the sixth year of study treatment, there were no reports of disease progression to accelerated phase (AP) or blast crisis (BC). The toxicity profile was unchanged. The cumulative best complete cytogenetic response (CCyR) rate was 82%; 63% of all patients randomized to receive imatinib and still on study treatment showed CCyR at last assessment. The estimated event-free survival at 6 years was 83%, and the estimated rate of freedom from progression to AP and BC was 93%. The estimated overall survival was 88%––or 95% when only CML-related deaths were considered. This 6-year update of IRIS underscores the efficacy and safety of imatinib as first-line therapy for patients with CML.

Imatinib pharmacokinetics and its correlation with response and safety in chronic-phase chronic myeloid leukemia : a subanalysis of the IRIS study

Imatinib at 400 mg daily is standard treatment for chronic myeloid leukemia in chronic phase. We here describe the correlation of imatinib trough plasma concentrations (C(mins)) with clinical responses, event-free survival (EFS), and adverse events (AEs). Trough level plasma samples were obtained on day 29 (steady state, n = 351). Plasma concentrations of imatinib and its metabolite CGP74588 were determined by liquid chromatography/mass spectrometry. The overall mean (+/- SD, CV%) steady-state C(min) for imatinib and CGP74588 were 979 ng/mL (+/- 530 ng/mL, 54.1%) and 242 ng/mL (+/- 106 ng/mL, 43.6%), respectively. Cumulative estimated complete cytogenetic response (CCyR) and major molecular response (MMR) rates differed among the quartiles of imatinib trough levels (P = .01 for CCyR, P = .02 for MMR). C(min) of imatinib was significantly higher in patients who achieved CCyR (1009 +/- 544 ng/mL vs 812 +/- 409 ng/mL, P = .01). Patients with high imatinib exposure had better rates of CCyR and MMR and EFS. An exploratory analysis demonstrated that imatinib trough levels were predictive of higher CCyR independently of Sokal risk group. AE rates were similar among the imatinib quartile categories except fluid retention, rash, myalgia, and anemia, which were more common at higher imatinib concentrations. These results suggest that an adequate plasma concentration of imatinib is important for a good clinical response. This study is registered at http://clinicaltrials.gov as NCT00333840.

Relative response of patients with myelodysplastic syndromes and other transfusion-dependent anaemias to deferasirox (ICL670): a 1-yr prospective study

Objectives/methods:  This 1‐yr prospective phase II trial evaluated the efficacy of deferasirox in regularly transfused patients aged 3–81 yrs with myelodysplastic syndromes (MDS; n = 47), Diamond–Blackfan anaemia (DBA; n = 30), other rare anaemias (n = 22) or β‐thalassaemia (n = 85). Dosage was determined by baseline liver iron concentration (LIC).

Artemether-lumefantrine for the treatment of multidrug-resistant falciparum malaria

The efficacy and safety of the 6-dose regimen of artemether-lumefantrine were assessed in an open randomized trial in children and adults presenting with acute, uncomplicated Plasmodium falciparum malaria in Thailand between November 1997 and March 1998. 200 patients were enrolled in 2 centres: 150 received artemether-lumefantrine (i.e., a median total dose of 9.6 mg/kg [interquartile range 8.7-10.7] and 57.9 mg/kg of lumefantrine [52.4-64.0]) and 50 the standard combination of artesunate (12 mg/kg over 3 d) and mefloquine (25 mg/kg). All patients had rapid initial clinical and parasitological responses. The 28 d cure rates were high: 97.7% (95% confidence interval [95% CI] 93.5-99.5%) for artemether-lumefantrine and 100% (95% CI 92.5-100%) for artesunate-mefloquine. The 6-dose regimen of artemether-lumefantrine was better tolerated than, and as effective as, artesunate-mefloquine, the current standard treatment in this area of multidrug-resistant P. falciparum malaria.

The prognosis for patients with chronic myeloid leukemia who have clonal cytogenetic abnormalities in Philadelphia chromosome-negative cells

Clonal cytogenetic abnormalities (CCA) were detected in Philadelphia chromosome (Ph)‐negative cells in some patients with chronic myeloid leukemia (CML) who attained a cytogenetic response to imatinib mesylate. In some patients, CCA/Ph‐negative status was associated with myelodysplasia or acute myeloid leukemia. The objective of the current study was to determine the prognostic impact of CCA/Ph‐negative cells.

Efficacy and safety of CGP 56697 (artemether and benflumetol) compared with chloroquine to treat acute falciparum malaria in Tanzanian children aged 1–5 years

A randomized, open trial involving 260 Tanzanian children, aged 1–5 years, with acute Plasmodium falciparum malaria was conducted to evaluate the efficacy of the combination antimalarial CGP 56697 (artemether and benflumetol), and to compare it with chloroquine, the standard drug used for malaria treatment in the Kilombero area. Children who had received rescue medication within the first 48 h or had a negative slide at the same time were excluded. Seven‐day parasitological cure rates were 94% (95% CI 88–97.5) for CGP 56697 and 35.4% (95% CI 25.9–45.8) for chloroquine. Using the same definition, the 14‐day parasitological cure rates were 86.4% (95% CI 78.5–92.2) for CGP 56697 and 10.3% (95% CI 5.1–18.1) for chloroquine. Gametocytes were more effectively suppressed by CGP 56697 than by chloroquine. There were no major adverse events with either drug. CGP 56697 is highly efficacious against P. falciparum in this area of Tanzania. The study contributes to the discussion on treatment strategies, particularly whether chloroquine may still fulfil its role as first‐line drug in an area of high malaria transmission and very high levels of chloroquine resistance.

Pharmacogenomic Analysis of Cytogenetic Response in Chronic Myeloid Leukemia Patients Treated with Imatinib

Purpose: To better understand the molecular basis of cytogenetic response in chronic myeloid leukemia patients treated with imatinib, we studied gene expression profiles from a total of 100 patients from a large, multinational Phase III clinical trial (International Randomized Study of IFN-α versus STI571). Experimental Design: Gene expression data for >12,000 genes were generated from whole blood samples collected at baseline (before imatinib treatment) using Affymetrix oligonucleotide microarrays. Cytogenetic response was determined based on the percentage of Ph+ cells from bone marrow following a median of 13 months of treatment. Results: A genomic profile of response was developed using a subset of individuals that exhibited the greatest divergence in cytogenetic response; those with complete response (0% Ph+ cells; n = 53) and those with minimal or no response (>65% Ph+ cells; n = 13). A total of 55 genes was identified that were differentially expressed between these two groups. Using a “leave-one-out” strategy, we identified the optimum 31 genes from this list to use as our genomic profile of response. Using this genomic profile, we were able to distinguish between individuals that achieved major cytogenetic response (0–35% Ph+ cells) and those that did not, with a sensitivity of 93.4% (71 of 76 patients), specificity of 58.3% (14 of 24 patients), positive predictive value of 87.7%, and negative predictive value of 73.7%. Conclusions: Interestingly, many of the genes identified appear to be strongly related to reported mechanisms of BCR-ABL transformation and warrant additional research as potential drug targets. The validity and clinical implications of these results should be explored in future studies.

An integrated assessment of the clinical safety of artemether-lumefantrine: a new oral fixed-dose combination antimalarial drug

Artemether-lumefantrine (A-L), a new fixed-dose oral antimalarial drug, combines the fast onset of action of artemether (an artemisinin derivative) in terms of parasite clearance with the high cure rate of lumefantrine in the treatment of acute uncomplicated Plasmodium falciparum malaria. The extensive clinical trial database of A-L has allowed a comprehensive evaluation of its tolerability and safety in a total of 1869 patients (including 243 children aged 5-12 years and 368 children aged < 5 years). The most commonly reported and possibly related adverse effects following A-L therapy involved the gastro-intestinal (abdominal pain, anorexia, nausea, vomiting, diarrhoea) and central nervous (headache, dizziness) systems. Pruritus and rash were reported by < 2% of patients. More than 90% of the reported adverse events, many of which overlapped considerably with the clinical symptomatology or evolution of acute malaria, were rated mild to moderate in intensity. Compared to A-L, significantly higher incidences of vomiting and pruritus were observed with chloroquine, dizziness, nausea and vomiting with mefloquine, somnolence with pyrimethamine + sulfadoxine, and vomiting and dizziness with quinine. There were no serious or persistent neurological side-effects related to A-L administration. A-L did not lead to any clinically relevant alterations of the laboratory parameters. Serial electrocardiographic data were available for 713 patients. The frequency of QT interval prolongations was similar to or lower than that observed with chloroquine, mefloquine, or artesunate + mefloquine; these changes were considerably less frequent than with quinine or halofantrine. All patients with QT prolongation remained asymptomatic and no adverse clinical cardiac events were reported. Artemether-lumefantrine can thus be expected to show, both in children and in adults, a favourable safety profile for the treatment of acute, uncomplicated, P. falciparum malaria; it could as well be a reserve treatment option for travellers to endemic countries.

Treatment of African Children with Uncomplicated Falciparum Malaria with a New Antimalarial Drug, CGP 56697

New antimalarial drugs are urgently needed. The use of short courses of the new antimalarial drug artemether as monotherapy has been limited by secondary malaria episodes following parasite clearance. Therefore, a new antimalarial drug, CGP 56697, has been developed, which combines artemether with a longer-acting antimalarial agent, benflumetol. A safety trial was undertaken in 60 Gambian children 1-6 years old with uncomplicated Plasmodium falciparum malaria. All children treated with CGP 56697 cleared their parasites 72 h after the start of treatment. No neurologic, cardiac, or other adverse reactions were observed. Second episodes of falciparum malaria were recorded in 16 (27%) of the children. Second infections were more frequent during the rainy season than during the dry season. Molecular epidemiologic studies suggested that 12 of the 14 second episodes of malaria in children treated with CGP 56697 were due to new infections. CGP 56697 proved to be a safe and effective antimalarial drug in African children.

The comparative efficacy and tolerability of CGP 56697 (artemether + lumefantrine) versus halofantrine in the treatment of uncomplicated falciparum malaria in travellers returning from the Tropics to The Netherlands and France.

CGP 56697 (Riamet) is a new oral anti-malarial drug composed of artemether and lumefantrine (benflumetol) which combines the fast, short-acting artemether for rapid parasite clearance with the prolonged action of lumefantrine for intended radical cure. In this double-blind, comparative trial, the efficacy and tolerability of CGP 56697, given as a course of 4 x 4 tablets over 48 h, was compared to halofantrine, given as 3 x 2 tablets over 12 h with a second course 1 week later. Patients (mostly non-immune) with acute, uncomplicated Plasmodium falciparum infection were randomly assigned to either CGP 56697 (n = 51) or halofantrine (n = 52). CGP 56697 proved superior with respect to parasite clearance time (median 32 vs. 48 h, P < 0.001) and parasite reduction at 24 h (median 99.7 vs. 89.6%, P < 0.001) with a non-significant difference in resolution of fever (median 24 vs. 32 h, P = 0.835). However, a 28-day cure rate of 82% was observed for CGP 56697 and 100% for halofantrine. Significant QTc prolongations (> 30 ms) were seen 6-12 h after halofantrine intake but not after CGP 56697 intake. CGP 56697 is an effective, well-tolerated treatment for uncomplicated falciparum malaria but for this dosing regimen the recrudescence rate is unacceptablyhigh (18%). For travellers contracting malaria abroad, we propose a six-dose regimen of CGP 56697 over 3 days.