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Oral BG-12 (dimethyl fumarate) for relapsing-remitting multiple sclerosis: a review of DEFINE and CONFIRM. Evaluation of: Gold R, Kappos L, Arnold D, et al. Placebo-controlled phase 3 study of oral BG-12 for relapsing multiple sclerosis. N Engl J Med 2012;367:1098-107; and Fox RJ, Miller DH, Phillips JT, et al. Placebo-controlled phase 3 study of oral BG-12 or glatiramer in multiple sclerosis. N Engl J Med 2012;367:1087-97.[Pubmed:23971970]

Expert Opin Pharmacother. 2013 Oct;14(15):2145-56.

INTRODUCTION: Multiple sclerosis (MS) is an autoimmune neurodegenerative disease of the central nervous system involving inflammation, chronic demyelination and axonal loss. MS affects more than 2 million people worldwide. AREAS COVERED: This article aims to summarize the findings from two pivotal 2-year, randomized, double-blind, placebo-controlled, Phase III studies of BG-12 (dimethyl fumarate) for relapsing-remitting MS (RRMS): DEFINE (Determination of the Efficacy and Safety of Oral Fumarate in RRMS) and CONFIRM (Comparator and an Oral Fumarate in RRMS). Results from both studies demonstrated that BG-12 provides clinical and radiological efficacy over 2 years across a range of outcomes. These results were apparent as early as 12 weeks and sustained over the course of both studies. BG-12 was found to have an acceptable safety profile, with a similar overall incidence of adverse events across all treatment groups. EXPERT OPINION: The combination of robust efficacy, ease of administration and established safety profile is unique to a new therapy in MS. Findings from the pivotal Phase III studies support BG-12 as a potential initial oral treatment for patients with RRMS or as an alternative to other currently available therapies.

Molecular and pharmacological evidence for MT1 melatonin receptor subtype in the tail artery of juvenile Wistar rats.[Pubmed:10433507]

Br J Pharmacol. 1999 Jun;127(4):987-95.

1. In this study reverse transcriptase-polymerase chain reaction (RT-PCR) has been used to identify mt1 and MT2 receptor mRNA expression in the rat tail artery. The contributions of both receptors to the functional response to melatonin were examined with the putative selective MT2 receptor antagonists, 4-phenyl-2-propionamidotetraline (4-P-PDOT) and 2-benzyl-N-pentanoyltryptamine. In addition, the action of melatonin on the second messenger cyclic AMP was investigated. 2. Using RT-PCR, mt1 receptor mRNA was detected in the tail artery from seven rats. In contrast MT2 receptor mRNA was not detected even after nested PCR. 3. At low concentrations of the MT2 selective ligands, neither 10 nM 4-P-PDOT (pEC50=8.70+/-0.31 (control) vs 8.73+/-0.16, n=6) nor 60 nM 2-benzyl-NV-pentanoyltryptamine (pEC50= 8.53+/-0.20 (control) vs 8.83+/-0.38, n = 6) significantly altered the potency of melatonin in the rat tail artery. 4. At concentrations non-selective for mt1 and MT2 receptors. 4-P-PDOT (3 microM) and 2-benzyl-N-pentanoyltryptamine (5 microM) caused a significant rightward displacement of the vasoconstrictor effect of melatonin. In the case of 4-P-PDOT, the estimated pKB (6.17+/-0.16, n=8) is similar to the binding affinity for mt1 receptor. 5. Pre-incubation with 1 microM melatonin did not affect the conversion of [3H]-adenine to [3H]-cyclic AMP under basal condition (0.95+/-0.19% conversion (control) vs 0.92+/-0.19%, n=4) or following exposure to 30 microM forskolin (5.20+/-1.30% conversion (control) vs 5.35+/-0.90%, n=4). 6. Based on the above findings, we conclude that melatonin receptor on the tail artery belongs to the MT1 receptor subtype, and that this receptor is probably independent of the adenylyl cyclase pathway.

Comparison of the structure-activity relationships of melatonin receptor agonists and antagonists: lengthening the N-acyl side-chain has differing effects on potency on Xenopus melanophores.[Pubmed:9840420]

Naunyn Schmiedebergs Arch Pharmacol. 1998 Nov;358(5):522-8.

The potency and affinity of two series of melatonin receptor ligands were examined using the pigment aggregation response in a clonal line of Xenopus laevis melanophores and radioligand binding assays on native receptors in chicken brain, recombinant human mt1 and MT2 and Xenopus laevis mel1c receptor subtypes. One series was based on melatonin and had a methoxy group at the 5-position of the indole ring, while the other was based on luzindole and lacked this substituent but did have a 2-benzyl moiety; the N-acyl group of each series of analogues was varied from one to five carbon atoms. All analogues in the melatonin series were full agonists in melanophores (pEC50 7.76-10.24), while all compounds in the luzindole series were competitive melatonin antagonists (pA2 5.47-6.60). With the agonist series, increasing the N-acyl side-chain from one to three carbon atoms was well tolerated in both the functional and binding assays, but further lengthening of the side-chain progressively and dramatically reduced potency and affinity. In contrast, for the antagonist series neither potency nor binding affinity changed substantially with the length of the N-acyl chain, except at the recombinant MT2 subtype where two of the analogues had a lower affinity. In binding assays, three of the five antagonists were MT2-selective; the most selective analogue (N-pentanoyl 2-benzyltryptamine, MT2 pKi 8.03) having 89- and 229-fold higher affinity than at mt1 or mel1c receptor subtypes. The different structure-activity relationships of these receptor agonists and antagonists is discussed with regard to the possible binding sites of agonists and antagonists within the receptor protein.