Improved nonclinical safety profile of a novel, highly selective inhibitor of the immunoproteasome subunit LMP7 (M3258)

M3258 is the first selective inhibitor of the immunoproteasome subunit LMP7 (Large multifunctional protease 7) in early clinical development with the potential to improve therapeutic utility in patients of multiple myeloma (MM) or other hematological malignancies. Safety pharmacology studies with M3258 did not reveal any functional impairments of the cardiovascular system in several in vitro tests employing human cardiomyocytes and cardiac ion channels (including hERG), guinea pig heart refractory period and force contraction, and rat aortic contraction as well as in cardiovascular function tests in dogs. Following single dose M3258 administration to rats, no changes were observed on respiratory function by using whole body plethysmography, nor did it change (neuro)behavioral parameters in a battery of tests. Based on pivotal 4-week toxicity studies with daily oral dosing of M3258, the identified key target organs of toxicity were limited to the lympho-hematopoietic system in rats and dogs, and to the intestine with its local lymphoid tissues in dogs only. Importantly, the stomach, nervous system, heart, lungs, and kidneys, that may be part of clinically relevant toxicities as reported for pan-proteasome inhibitors, were spared with M3258. Therefore, it is anticipated that by targeting highly selective and potent inhibition of LMP7, the resulting favorable safety profile of M3258 together with the maintained potent anti-tumor activity as previously reported in mouse MM xenograft models, may translate into an improved benefit-risk profile in MM patients.

The interferon gene cluster: a candidate region for MS predisposition? Multiple Sclerosis Study Group

The clinical benefits of interferon (IFN) beta therapy in some multiple sclerosis (MS) patients are still unexplained, raising the question whether polymorphism within the IFNB gene itself would provide an explanation. Screening the IFNB gene by single strand conformation polymorphism (SSCP) analysis and sequencing, a single nucleotide polymorphism was identified. Both alleles were distributed with similar frequencies in MS patients and controls. Significant linkage disequilibrium (LD) between the IFN allele [153C] and allele [02] of the previously analyzed IFNA microsatellite (Epplen et al. Ann Neurol 1997; 41: 341-352) was observed in MS patients only, indicating a disease related haplotype. On the other hand an increased risk (RR = 12.41; Pc < 8 x 10(-5)) was observed for allele [07]. Hence the study was extended to neighbouring genes. Functionally relevant polymorphisms, i.e., premature stop codons in the IFNA10 [Cys20Stop] and IFNA17 [58Stop] genes and an aminoacid (aa) substitution [ile 184Arg] in the IFNA17 gene were analyzed. Patients carrying a non-functional IFNA17 allele bear an increased risk to develop MS (RR = 25.68; Pc < 0.06). In addition, LD analysis between IFNA10 [Cys20Stop], IFNA17 [58Stop] and the IFNA microsatellite alleles provides evidence for IFNA14, IFNA16 or IFNA5 as additional, most likely candidate genes. The present study excludes the IFNB gene as a candidate for MS predisposition but provides first evidence for predisposing IFNA genes.

Polymerase chain reaction-single strand conformation polymorphism or how to detect reliably and efficiently each sequence variation in many samples and many genes

A simple and fast method with high reliability is necessary for the identification of mutations, polymorphisms and sequence variants (MPSV) within many genes and many samples, e.g. to clarify the genetic background of individuals with multifactorial diseases. We evaluated polymerase chain reaction-single strand conformation polymorphism (PCR-SSCP) analysis to identify MPSV in several genes, which are thought to be involved in the pathogenesis of multifactorial autoimmune diseases like multiple sclerosis. The method is based on the property, that the electrophoretic mobility of single-stranded nucleic acids depends not only on its size but also on its sequence. The target sequence was amplified, digested into fragments ranging from 50-200 bp, heat-denatured and analyzed on native gels. The analysis of 55 PCR systems, including a total of 145 fragments demonstrates, that the detection rate of MPSV depends primarily on the fragment lengths. Appropriate dilutions of samples enhances the proportion of ssDNA compared to dsDNA. Changing the gel conditions, glycerol concentrations and/or the addition of urea may increase fragment resolution in some cases. In general, the detection of MPSV is neither influenced by their location within the fragment nor by the type of substitution, i.e. transitions or transversions. The standard PCR-SSCP system described here provides high reliability and detection rates and allows the efficient analysis of many samples and many genes.