The widespread clinical use of the cytostatic doxorubicin together with the induction of chronic cardiomyopathy necessitates the conduct of further pharmacokinetic trials. Novel analytical ...technologies suitable for point-of-care applications can facilitate drug level analyses but might be prone to interferences from structurally similar compounds. Besides the alcohol metabolite doxorubicinol, aglycone metabolites of doxorubicin might affect its determination in plasma. To evaluate their analytical relevance, a validated HPLC method for the quantification of doxorubicin, doxorubicinol and four aglycones was used. The degradation pattern of doxorubicin in plasma under long-term storage was analysed with respect to the formation of aglycone products. In addition, overall 50 clinical samples obtained within the EPOC-MS-001-Doxo trial were analysed. Substantial degradation of doxorubicin in plasma occurred within a storage period of one year, but this did not lead to the formation of aglycones. In clinical samples, 7-deoxydoxorubicinolone was the major aglycone detectable in 35/50 samples and a concentration range of 1.0-12.7 µg L
. If at all, the other aglycones were only determined in very low concentrations. Therefore, analytical interferences from aglycones seem to be unlikely with the exception of 7-deoxydoxorubicinolone whose concentration accounted for up to 65% of the doxorubicin concentration in the clinical samples analysed.
Purpose
The benefits of asparaginase (ASNASE) in the treatment of ALL and NHL are indisputable and new ASNASE preparations are under clinical development to overcome limitations of the actual ASNASE ...therapy, especially immunogenicity. Apart from ALL and NHL further indications of ASNASE are preclinically and clinically evaluated.
Methods
We reviewed ASNASE literature and especially focused on the mechanism of action, on biomarker, which determine ASNASE sensitivity and resistance, and on ASNASE pharmacodynamics in vivo.
Results
More than 40 years after the clinical introduction of ASNASE its mechanism of action is yet not fully understood. Studies on asparagine synthetase (ASNS) as biomarker for ASNASE resistance are contradictory and complicated by methodological obstacles. The role of glutamine hydrolysis for ASNASE efficacy is still debated, other mechanisms are possibly not yet identified. In addition, individual pharmacokinetic/-dynamic relationships cannot be properly addressed because of methodological limitations.
Conclusion
More sophisticated preclinical models and suitable methods for monitoring of ASNASE pharmacodynamics are urgently needed (1) to understand the mechanism of action, (2) to establish valid biomarkers for ASNASE sensitivity and resistance, (3) to evaluate the pharmacokinetics/-dynamics of ASNASEs in individual patients, and (4) to compare the bioequivalence of clinically established, as well as new ASNASE preparations.
Acute lymphoid leukemia is a childhood cancer that in high-income countries has event-free survival rates of 80% and global survival rates of 90%. In Brazil these rates are under 70%. This difference ...may be due to the implementation of supportive care, including the assessment of asparaginase (ASNase) activity. ASNase may cause hypersensitivity reactions and silent drug inactivation. For this reason, ASNase activity monitoring is an essential tool to ensure an effective treatment. Our aim was to implement an ASNase activity measurement technique at a hospital setting. samples from children who were given Escherichia coli-derived ASNase were collected. The results of the analyses conducted in our laboratory Hospital de Clínicas de Porto Alegre were compared to those of two institutions: Centro Infantil Boldrini and University of Munster. 262 samples were assessed. The results of the first analyses were compared with those obtained at Centro Infantil Boldrini and showed an ICC of 0.954. Thirty samples were sent to the University of Munster and presented an ICC was 0.960. Our results, when compared to those of national and international centers, showed an excellent agreement. The study was able to implement an ASNase activity test to monitor the treatment.
A comparison of genotyping arrays Verlouw, Joost A M; Clemens, Eva; de Vries, Jard H ...
European journal of human genetics : EJHG,
11/2021, Letnik:
29, Številka:
11
Journal Article
Recenzirano
Odprti dostop
Array technology to genotype single-nucleotide variants (SNVs) is widely used in genome-wide association studies (GWAS), clinical diagnostics, and linkage studies. Arrays have undergone a tremendous ...growth in both number and content over recent years making a comprehensive comparison all the more important. We have compared 28 genotyping arrays on their overall content, genome-wide coverage, imputation quality, presence of known GWAS loci, mtDNA variants and clinically relevant genes (i.e., American College of Medical Genetics (ACMG) actionable genes, pharmacogenetic genes, human leukocyte antigen (HLA) genes and SNV density). Our comparison shows that genome-wide coverage is highly correlated with the number of SNVs on the array but does not correlate with imputation quality, which is the main determinant of GWAS usability. Average imputation quality for all tested arrays was similar for European and African populations, indicating that this is not a good criterion for choosing a genotyping array. Rather, the additional content on the array, such as pharmacogenetics or HLA variants, should be the deciding factor. As the research question of a study will in large part determine which class of genes are of interest, there is not just one perfect array for all different research questions. This study can thus help as a guideline to determine which array best suits a study's requirements.
The use of the effective antineoplastic agent cisplatin is limited by its serious side effects, such as oto- and nephrotoxicity. Ototoxicity is a problem of special importance in children, because ...deafness hampers their language and psychosocial development. Recently, organic cation transporters (OCTs) were identified in vitro as cellular uptake mechanisms for cisplatin. In the present study, we investigated in an in vivo model the role of OCTs in the development of cisplatin oto- and nephrotoxicity. The functional effects of cisplatin treatment on kidney (24 hours excretion of glucose, water, and protein) and hearing (auditory brainstem response) were studied in wild-type and OCT1/2 double-knockout (KO) mice. No sign of ototoxicity and only mild nephrotoxicity were observed after cisplatin treatment of knockout mice. Comedication of wild-type mice with cisplatin and the organic cation cimetidine protected from ototoxicity and partly from nephrotoxicity. For the first time we showed that OCT2 is expressed in hair cells of the cochlea. Furthermore, cisplatin-sensitive cell lines from pediatric tumors showed no expression of mRNA for OCTs, indicating the feasibility of therapeutic approaches aimed to reduce cisplatin toxicities by competing OCT2-mediated cisplatin uptake in renal proximal tubular and cochlear hair cells. These findings are very important to establish chemotherapeutical protocols aimed to maximize the antineoplastic effect of cisplatin while reducing the risk of toxicities.
Antibodies against polyethylene glycol (PEG) in healthy subjects raise concerns about the efficacy of pegylated drugs. We evaluated the prevalence of antibodies against PEG among patients with acute ...lymphoblastic leukemia (ALL) prior to and/or immediately after their first dose of pegylated E.coli asparaginase (PEG-ASNase). Serum samples of 701 children, 673 with primary ALL, 28 with relapsed ALL, and 188 adults with primary ALL were analyzed for anti-PEG IgG and IgM. Measurements in 58 healthy infants served as reference to define cut-points for antibody-positive and -negative samples. Anti-PEG antibodies were detected in ALL patients prior the first PEG-ASNase with a prevalence of 13.9% (anti-PEG IgG) and 29.1% (anti-PEG IgM). After administration of PEG-ASNase the prevalence of anti-PEG antibodies decreased to 4.2% for anti-PEG IgG and to 4.5% for anti-PEG IgM. Pre-existing anti-PEG antibodies did not inhibit PEG-ASNase activity but significantly reduced PEGASNase activity levels in a concentration dependent manner. Although pre-existing anti-PEG antibodies did not boost, pre-existing anti-PEG IgG were significantly associated with firstexposure hypersensitivity reactions (CTCAE grade 2) (p.
The incidence of hypersensitivity reactions (HSRs) to PEG‐asparaginase (PEG‐ASNase) was evaluated in 6136 children with ALL enrolled in the AIEOP‐BFM ALL 2009 study. Patients with B‐cell ...precursor‐acute lymphoblastic leukemia (BCP‐ALL) were stratified as standard‐risk/medium‐risk (MR)/high‐risk (HR) and those with T‐ALL as non‐High/HR. PEG‐ASNase was administered intravenously at 2500 IU/sqm/dose. All patients received 2 PEG‐ASNase doses in induction; thereafter non‐HR versus HR patients received 1 versus 6 PEG‐ASNase doses, respectively. After the single regular dose of PEG‐ASNase at the beginning of delayed intensification, BCP‐ALL‐MR patients were randomized to receive 9 additional PEG‐ASNase doses every 2 weeks (experimental arm EA) versus none (standard arm SA); HR patients were randomized to receive, in consolidation, 4 weekly PEG‐ASNase doses (EA) versus none (SA). The HSR cumulative incidence (CI) was estimated adjusting for competing risks. An HSR occurred in 472 of 6136 (7.7%) patients. T‐non‐ HR/BCP‐Standard‐Risk, BCP‐MR‐SA, BCP‐MR‐EA, HR‐SA and HR‐EA patients had 1‐year‐CI‐HSR (±SE) rates of 5.2% (0.5), 5.2% (0.5), 4.0% (0.8), 20.2% (1.2), and 6.4% (1.3), respectively. The randomized intensification of PEG‐ASNase did not significantly impact on HSR incidence in BCP‐MR patients (1‐y‐CI‐HSR 3.8% 0.8 versus 3.2% 0.6 in MR‐EA versus MR‐SA; P = 0.55), while impacted significantly in HR patients (1‐y‐CI‐HSR 6.4% 1.3 versus 17.9% 1.8 in HR‐EA and HR‐SA, respectively; P < 0.001). The CI‐HSR was comparable among non‐HR groups and was not increased by a substantial intensification of PEG‐ASNase in the BCP‐MR‐EA group whilst it was markedly higher in HR‐SA than in HR‐EA patients, suggesting that, in such a chemotherapy context, a continuous exposure to PEG‐ASNase reduces the risk of developing an HSR.
The multikinase inhibitor regorafenib (BAY 73-4506) exerts both anti-angiogenic and anti-tumorigenic activity in adult solid malignancies mainly advanced colorectal cancer and gastrointestinal ...stromal tumors. We intended to explore preclinically the potential of regorafenib against solid pediatric malignancies alone and in combination with anticancer agents to guide the pediatric development plan. In vitro effects on cell proliferation were screened against 33 solid tumor cell lines of the Innovative Therapies for Children with Cancer (ITCC) panel covering five pediatric solid malignancies. Regorafenib inhibited cell proliferation with a mean half maximal growth inhibition of 12.5 μmol/L (range 0.7 μmol/L to 28 μmol/L). In vivo, regorafenib was evaluated alone at 10 or 30 mg/kg/d or in combination with radiation, irinotecan or the mitogen-activated protein kinase kinase (MEK) inhibitor refametinib against various tumor types, including patient-derived brain tumor models with an amplified platelet-derived growth factor receptor A (PDGFRA) gene. Regorafenib alone significantly inhibited tumor growth in all xenografts derived from nervous system and connective tissue tumors. Enhanced effects were observed when regorafenib was combined with irradiation and irinotecan against PDGFRA amplified IGRG93 glioma and IGRM57 medulloblastoma respectively, resulting in 100% tumor regressions. Antitumor activity was associated with decreased tumor vascularization, inhibition of PDGFR signaling, and induction of apoptotic cell death. Our work demonstrates that regorafenib exhibits significant antitumor activity in a wide spectrum of preclinical pediatric models through inhibition of angiogenesis and induction of apoptosis. Furthermore, radio- and chemosensitizing effects were observed with DNA damaging agents in PDGFR amplified tumors.
Asparagine levels in cerebrospinal fluid and serum asparaginase activity were monitored in children with acute lymphoblastic leukemia treated with pegylated-asparaginase. The drug was given ...intravenously at a dose of 2,500 IU/m
on days 12 and 26. Serum and cerebrospinal fluid samples obtained on days 33 and 45 were analyzed centrally. Since physiological levels of asparagine in the cerebrospinal fluid of children and adolescents are 4-10 μmol/L, in this study asparagine depletion was considered complete when the concentration of asparagine was ≤0.2 μmol/L, i.e. below the lower limit of quantification of the assay used. Over 24 months 736 patients (AIEOP n=245, BFM n=491) and 903 cerebrospinal fluid samples (n=686 on day 33 and n=217 on day 45) were available for analysis. Data were analyzed separately for the AIEOP and BFM cohorts and yielded superimposable results. Independently of serum asparaginase activity levels, cerebrospinal fluid asparagine levels were significantly reduced during the investigated study phase but only 28% of analyzed samples showed complete asparagine depletion while relevant levels, ≥1 μmol/L, were still detectable in around 23% of them. Complete cerebrospinal fluid asparagine depletion was found in around 5-6% and 33-37% of samples at serum asparaginase activity levels <100 and ≥ 1,500 IU/L, respectively. In this study cerebrospinal fluid asparagine levels were reduced during pegylated-asparaginase treatment, but complete depletion was only observed in a minority of patients. No clear threshold of serum pegylated-asparaginase activity level resulting in complete cerebrospinal fluid asparagine depletion was identified. The consistency of the results found in the two independent data sets strengthen the observations of this study. Details of the treatment are available in the European Clinical Trials Database at
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