Heleen A. Visser-Wisselaar

Somatostatin analogs: Clinical application in relation to human somatostatin receptor subtypes

SRIFt was described originally by Krulich et al. [l] as a factor present in hypothalamic extracts capable of inhibiting GH release by cultured rat anteriorpituitarycells.Brazeauetal. [2]characterized this factor as a cyclic peptide (SS14) consisting of 14 amino acids. Several years later, a second bioactive form, an NHz-terminally extended somatostatin molecule, consisting of 28 amino acids (SS28), was isolated and characterized [3]. In mammals, both SS14 and SS28 originate from a 10.3 kDa prohormone called preprosomatostatin [4]. Somatostatin has an inhibitory action on a variety of physiological functions in different organ systems, including the hypothalamus, the anterior pituitary gland, the gastrointestinal tract, and the endocrine and exocrine pancreas [5]. In the brain, somatostatin may have a role in neurotransmission, both stimulatory and inhibitory [6,7]. On the basis of its widespread inhibitory actions, somatostatin may play a role in the treatment of human disease due to hyperfunction of the above organ systems. However, the clinical use of somatostatin was hampered because the native peptide had several disadvantages [S, 91. In particular, the need for continuous i.v. infusion due to its very short halflife in the circulation (< 3 min), its diversity of action (i.e. its potent inhibitory action on normal insulin secretion), and, finally, the rebound hypersecretion of hormones by normal tissues after 5514 infusion are major disadvantages [lo, 111. A logical step, therefore, was the development of structural analogs of somatostatin, not having the disadvantages of SS14 as described above. This research has led to

Melphalan, prednisone, and lenalidomide versus melphalan, prednisone, and thalidomide in untreated multiple myeloma.

The combination of melphalan, prednisone, and thalidomide (MPT) is considered standard therapy for newly diagnosed patients with multiple myeloma who are ineligible for stem cell transplantation. Long-term treatment with thalidomide is hampered by neurotoxicity. Melphalan, prednisone, and lenalidomide, followed by lenalidomide maintenance therapy, showed promising results without severe neuropathy emerging. We randomly assigned 668 patients between nine 4-week cycles of MPT followed by thalidomide maintenance until disease progression or unacceptable toxicity (MPT-T) and the same MP regimen with thalidomide being replaced by lenalidomide (MPR-R). This multicenter, open-label, randomized phase 3 trial was undertaken by Dutch-Belgium Cooperative Trial Group for Hematology Oncology and the Nordic Myeloma Study Group (the HOVON87/NMSG18 trial). The primary end point was progression-free survival (PFS). A total of 318 patients were randomly assigned to receive MPT-T, and 319 received MPR-R. After a median follow-up of 36 months, PFS with MPT-T was 20 months (95% confidence interval [CI], 18-23 months) vs 23 months (95% CI, 19-27 months) with MPR-R (hazard ratio, 0.87; 95% CI, 0.72-1.04; P = .12). Response rates were similar, with at least a very good partial response of 47% and 45%, respectively. Hematologic toxicity was more pronounced with MPR-R, especially grades 3 and 4 neutropenia: 64% vs 27%. Neuropathy of at least grade 3 was significantly higher in the MPT-T arm: 16% vs 2% in MPR-R, resulting in a significant shorter duration of maintenance therapy (5 vs 17 months in MPR-R), irrespective of age. MPR-R has no advantage over MPT-T concerning efficacy. The toxicity profile differed with clinically significant neuropathy during thalidomide maintenance vs myelosuppression with MPR.

Implementation of erythroid lineage analysis by flow cytometry in diagnostic models for myelodysplastic syndromes

Flow cytometric analysis is a recommended tool in the diagnosis of myelodysplastic syndromes. Current flow cytometric approaches evaluate the (im)mature myelo-/monocytic lineage with a median sensitivity and specificity of ~71% and ~93%, respectively. We hypothesized that the addition of erythroid lineage analysis could increase the sensitivity of flow cytometry. Hereto, we validated the analysis of erythroid lineage parameters recommended by the International/European LeukemiaNet Working Group for Flow Cytometry in Myelodysplastic Syndromes, and incorporated this evaluation in currently applied flow cytometric models. One hundred and sixty-seven bone marrow aspirates were analyzed; 106 patients with myelodysplastic syndromes, and 61 cytopenic controls. There was a strong correlation between presence of erythroid aberrancies assessed by flow cytometry and the diagnosis of myelodysplastic syndromes when validating the previously described erythroid evaluation. Furthermore, addition of erythroid aberrancies to two different flow cytometric models led to an increased sensitivity in detecting myelodysplastic syndromes: from 74% to 86% for the addition to the diagnostic score designed by Ogata and colleagues, and from 69% to 80% for the addition to the integrated flow cytometric score for myelodysplastic syndromes, designed by our group. In both models the specificity was unaffected. The high sensitivity and specificity of flow cytometry in the detection of myelodysplastic syndromes illustrates the important value of flow cytometry in a standardized diagnostic approach. The trial is registered at www.trialregister.nl as NTR1825; EudraCT n.: 2008-002195-10

Genomic array as compared to karyotyping in myelodysplastic syndromes in a prospective clinical trial

Karyotyping is considered as the gold standard in the genetic subclassification of myelodysplastic syndrome (MDS). Oligo/SNP‐based genomic array profiling is a high‐resolution tool that also enables genome wide analysis. We compared karyotyping with oligo/SNP‐based array profiling in 104 MDS patients from the HOVON‐89 study. Oligo/SNP‐array identified all cytogenetically defined genomic lesions, except for subclones in two cases and balanced translocations in three cases. Conversely, oligo/SNP‐based genomic array profiling had a higher success rate, showing 55 abnormal cases, while an abnormal karyotype was found in only 35 patients. In nine patients whose karyotyping was unsuccessful because of insufficient metaphases or failure, oligo/SNP‐based array analysis was successful. Based on cytogenetic visible abnormalities as identified by oligo/SNP‐based genomic array prognostic scores based on IPSS/‐R were assigned. These prognostic scores were identical to the IPSS/‐R scores as obtained with karyotyping in 95%‐96% of the patients. In addition to the detection of cytogenetically defined lesions, oligo/SNP‐based genomic profiling identified focal copy number abnormalities or regions of copy neutral loss of heterozygosity that were out of the scope of karyotyping and fluorescence in situ hybridization. Of interest, in 26 patients we demonstrated such cytogenetic invisible abnormalities. These abnormalities often involved regions that are recurrently affected in hematological malignancies, and may therefore be of clinical relevance. Our findings indicate that oligo/SNP‐based genomic array can be used to identify the vast majority of recurrent cytogenetic abnormalities in MDS. Furthermore, oligo/SNP‐based array profiling yields additional genetic abnormalities that may be of clinical importance.